Upper Roaring Fork River Management Plan 2017 A Joint City of Aspen and Pitkin County Project i Cbuut4 THE ASPEN @npo ACKNOWLEDGEMENTS This planning effort was only made possible through participation of members of the public and periodic engagement of a technical adviosry group comprised of stakeholders concerned with water issues in the upper Roaring Fork watershed. Specifically, we would like to thank the following organizations for dedicating their time and providing thier assistance throughout the planning process: City of Aspen – Stormwater, Parks, Utilities Departments Pitkin County – Healthy Rivers and Streams; Open Space and Trails Roaring Fork Conservancy Salvation Ditch Company Ruedi Water & Power Authority Colorado River Water Conservation District Twin Lakes Reservoir and Canal Company US Forest Service Colorado Parks and Wildlife Trout Unlimited Aspen Center for Environmental Studies Colorado Water Trust Colorado Water Conservation Board PLANNING TEAM Lotic Hydrological CDR Associates Rozaklis & Associates Miller Ecological Consultants, Inc. Greg Espegren i TABLE OF CONTENTS EXECUTIVE SUMMARY iii 1. PROJECT OVERVIEW 1 2. FUNCTIONAL ASSESSMENT OF LOCAL STREAMS AND RIVERS 2.1 Reach Descriptions 2.2 Needs Assessment Summary 4 11 19 3. WATER USES AND TRADE-OFFS 3.1 Water Use Impacts 22 26 4. COMMUNITY PREFERENCES 4.1 Review of Potential Water Management Actions 29 36 5. DECISION SUPPORT TOOLS 5.2 Hydrological Simulation Model 5.3 Ecological Evaluation Framework 39 39 40 6. CONCLUSIONS 42 43 43 6.1 6.2 Challenges to the Planning Process Next Steps 45 7. ANNOTATED BIBLIOGRAPHY Appendix A: Stakeholder Outreach and Engagement Appendix B: Hydrological Decision Support System Appendix C: Process for Evaluating Ecosystem Conditions ii EXECUTIVE SUMMARY In the early 2000s, several studies were completed that showed riparian and instream habitat degradation in the stretch of the Roaring Fork that flows through Aspen. In 2012, the Colorado Water Quality Control Division placed that stretch on Colorado’s list of Impaired Waters. Several factors can impact the health of aquatic and riparian plants and animals such as water quality and near-stream land use activities. However, fluvial ecologists generally treat streamflow as the “master variable” exerting the largest influence on river ecosystem conditions. Therefore, the City of Aspen and Pitkin County began the process of an Upper Roaring Fork River Management Plan, focusing on identifying impacts caused by modified patterns of streamflow and developing goals and strategies for managing land and water to improve or protect river health in the upper Roaring Fork watershed. The City and the County worked with a team of consultants and local stakeholders to prioritize ecological considerations and develop tools to assist in predicting effectiveness of various management alternatives. Streamflows in the upper Roaring Fork watershed are heavily modified due to transmountain diversions and in-basin agricultural and municipal diversions. Transmountain diversions reduce the average annual water yield in the Roaring Fork River above Mill Street by approximately 40%. An additional 10% reduction in average annual yield is due to agricultural and municipal uses near the City of Aspen. Of this 10%, approximately one quarter is used by the City of Aspen for water amenities on the pedestrian mall, irrigation of public parks, and support of the stormwater treatment wetlands at John Denver Park. Reductions in streamflow during late summer and fall low-flow periods can negatively impact habitat quality and availability for fish and insects. Reductions in flow also reduce a streams ability to assimilate solar radiation and chemical compounds that find their way to the river, potentially, degrading water quality conditions. Alterations of peak flows limit a stream’s ability to replenish important spawning habitat for native and sport fish, to maintain the physical shape and dynamics of the stream channel, and to replenish riparian vegetation and alluvial aquifers with water. The importance of ecological streamflow protections was recognized during the development of the Fry-Ark project and flow targets were incorporated into that project’s Operating Principles. Additionally, minimum in-stream flows necessary to meet environmental needs on many streams reaches in the upper Roaring Fork watershed were quantified and the Colorado Water Conservation Board (CWCB), which obtained water rights to protect those needs in the 1970s. More recently, local conservation organizations commissioned special studies to investigate the flood iii magnitude and recurrence interval necessary to maintain spawning habitat for trout. These numeric targets provide a starting point for identifying the locations and times of year when river health might be most impacted by streamflow alteration. Management recommendations for peak flows are regularly met on the Roaring Fork River. Recommended low flow thresholds, however, are not met on some sections of river during average and dry-year conditions. Minimum flow shortages are particularly prevalent on Hunter Creek, the Roaring Fork River between Lost Man Creek and Lincoln Creek, and on the Roaring Fork River through Aspen. Some shortages are due to the lack of native/natural water supply, indicating that in some locations and at some times of the year, the existing recommendations for minimum streamflows may need refinement or are not necessarily ideal targets for management activities. The largest shortages occur in late summer months and on the mainstem Roaring Fork typically below Stillwater Lane, where water diversions that support agriculture, ponds, private landscaping, and parks deplete late-summer streamflows. In general, shortages are more acute during dry conditions than during average or wet conditions. Developing viable strategies for addressing shortages to environmental water needs requires an understanding of the full suite of water uses in the Upper Roaring Fork watershed. While some shortages are natural and unavoidable, most of the shortages result from surface water diversions. It is important to recognize that the uses of water that impact river health are often vital to the functioning of local economies and ways of life. Therefore, the viability of efforts to manage water for the protection and benefit of the environment depend on a broad understanding of how water moves through the upper Roaring Fork watershed, the values associated with various water use types, and the difficult trade-offs associated with any change in existing water management. Stakeholders and members of the public participated in an exploration of geographic priorities, community values regarding the various ecosystem attributes, and the types of water management actions that the City of Aspen and Pitkin County may employ to improve river health (e.g. water transactions, water storage, channel reconfiguration, infrastructure upgrades, etc.). Geographic priorities identified by the community aligned with environmental flow need shortages. Though the consulting team had anticipated that there would be a clear preference for managing to improve or protect ecological conditions on the section of the Roaring Fork that flows through Aspen (and there was), Hunter Creek and the upper iv Roaring Fork were also called out as important areas for consideration, as portions of each are frequently dried up by water diversions. In ranking exercises and small-group discussions, ecological integrity received the highest allocation of points as a priority water use – both because of its singular importance for community members, and because of its function in supporting recreation and other uses. Domestic water supply was a close second in priority water use. The high allocation of preference points to managing for ecological integrity and domestic water supply—and the significant potential that management of one attribute will come at the expense of the other—confirms the critical importance of understanding the impacts of domestic water supply development on the ecological health of streams and rivers. The inverse is equally true. Responses indicated the local community is resistant to managing for river health at the expense of domestic supply reliability. The potential for conflicting management goals is high, which speaks to the need for continued engagement with stakeholders and members of the local community when conducting these types of planning efforts. Communications with stakeholders elucidated important community preferences for general categories of water management actions. The management actions considered by stakeholders ranged from water system efficiency upgrades to reservoir construction (Table 3). These actions were primarily relevant to managing low flows, since modifications of this aspect of streamflow are widespread in the upper Roaring Fork watershed. Sensitivity around ongoing legal cases—one involving Pitkin County and administration of transmountain water rights, the other regarding water supply development planning by the City of Aspen—prevented evaluation of any single specific action in detail. Nonetheless, this project did include a high-level effort to vet previously proposed management actions with stakeholders and community members. In addition to clarifying community values and preferences for water use, stakeholders weighed the potential ecological benefits of several water management opportunities against the financial, legal, administrative, and political constraints (and other tradeoffs) each posed. This process helped identify a number of management activities that may be used to effect positive change in measures of river health on the Roaring Fork River. Management opportunities that warrant further investigation include: • • • • • • • • Optimization of the Twin Lakes Exchange Joint Operation of City of Aspen Municipal Supply and Salvation Ditch Dry-Year Municipal Raw Water Supply Reductions Maroon Creek Municipal Water Right, CWCB lease or dedication Dry-Year Water Leasing with the Salvation Ditch Company Hunter Creek Cutthroat Trout Management Hallam Lake Cutthroat Trout Introduction North Star Preserve Wetland Drain Removal Moving forward, the City and the County should capitalize on the trust and relationship-building that occurred during this project among diverse stakeholders. Water supplies in the upper Roaring Fork watershed are finite, support a diversity of v uses, and are fully allocated at certain times of year. Management actions that support or improve one use opportunity for one type of water need may reduce use opportunities for another. For example, improving late summer flows in the Roaring Fork River through Aspen might be achieved through a reallocation of City of Aspenowned water from public parks and fountains to the river. Alternatively, low flow conditions might be improved through leasing programs or contractual relationships that allow for temporary reallocation of water from irrigated agriculture to the river. Both of these actions would likely benefit aquatic plants and animals but may do so at the expense of aesthetic enjoyment of water features in the City of Aspen or at the expense of water amenities, green viewscapes, and agricultural production in McClain Flats. In order for either option to proceed beyond conceptual planning levels, there will need to be widespread buy-in from key water users and the local community. In the course of this study, the entities that participated had the opportunity to discuss their goals for the river, concerns about current conditions, and interests in future river management. In discussing principles for building trust and mutual understanding, stakeholders underscored the importance of open, interest-based discussions when exploring creative, nuanced ways for managing the river to meet a multiplicity of needs. Stakeholders also highlighted a preference for improved dialog between City of Aspen and Pitkin County regarding river health and water planning issues moving forward. vi 1. Project Overview The City of Aspen and Pitkin County are committed to developing strategies for integrated water supply planning and management in the upper Roaring Fork watershed. The Roaring Fork River is highly valued by Aspen residents and visitors, and the quality of life in the valley and success of the local economy relies largely on the Roaring Fork’s ability to support a variety of water uses—both consumptive in nature like agricultural and commercial uses and non-consumptive in nature like environmental and recreational uses. This plan and accompanying work products and modeling tools provide an assessment of existing conditions and a decision-making framework for improving or maintaining the ecological health of the upper Roaring Fork River and its tributaries while reflecting local values and priorities and the administrative and legal realities governing the use of water in Colorado. This effort was motivated by several studies completed in the early 2000s, each showing varying degrees of ecological degradation in the stretch of the Roaring Fork that flows through Aspen. In response to those findings and in an effort to develop goals and strategies for managing land and water more effectively in the upper Roaring Fork watershed, in 2016 the City and the County worked with a team of consultants and local stakeholders to understand and synthesize these ecological considerations. For elements of river health considered degraded, specific stressors were identified, with a special focus on degradation caused by modified patterns of streamflow. The assessment area included the Roaring Fork mainstem and major tributaries between Lost Man Creek on Independence Pass and the Brush Creek confluence near Woody Creek (Figure 1). 1 Figure 1: Stream reaches in the project area Lessons learned from the planning process should inform future water management decision-making in the upper watershed. In addition to elucidating community values and preferences for water use, stakeholders weighed the potential ecological benefits of several water management opportunities against the financial, legal, administrative, and political constraints (and other tradeoffs) each posed. Final planning outcomes and deliverables provide the City and County with valuable insight into community perspectives on river health. The generated tools and information can be used to: 1. Inform future water development planning and approval processes; 2. Develop or align local water and land use policies; 3. Improve management of existing water infrastructure; 4. Inform strategic exercise or acquisition of water rights; and 5. Engage with local and regional organizations or individuals involved in water management decision-making. 2 Working together to achieve one of Aspen City Council’s Top Ten Goals: “Develop a River Management Plan that seeks to restore and maintain the health of the Roaring Fork River as it flows through Aspen.” Targeted Analysis Project Timeline This effort utilized a rich set of historical data and Fall 20 16 - Reviewed existing research and information and developed new decision support tools to studies to identify flow-related environmental help future decision makers understand the relationships management goals and objectives for stream between the health of local waterways, water rights reaches throughout the planning area. administration, hydrologic variability, and the ability of local Winter 20 16 - Conducted interviews with a water supplies to meet local demands. Project deliverables include a pair of hydrological and water rights simulation diverse group of local stakeholders and land models and a framework for understanding the ecological management agencies to clarify goals and response of streams and rivers to changes in flow brought expectations for river health. about by changes in land and water use or climate change. Spring 20 17 - Worked with City and County Stakeholder Engagement staff, residents, conservation organizations, This project brought a group of diverse stakeholders to the water rights holders and water management table to discuss water use and management in the upper organizations to identify principles for successful Roaring Fork watershed. Broad stakeholder support is stakeholder engagement and prioritize critical to the success of any water planning effort as local management areas. water users, interest groups, and residents will be directly or indirectly affected by most management actions. Therefore, Summer 20 17 - Identified several potential future engagement with stakeholders throughout the alternative management actions and project identification and vetting process is instrumental projects that may be useful in meeting stated in developing win-win solutions for agricultural, municipal, management goals. Conducted high-level environmental, and recreational interests. feasibility and effectiveness assessments with local stakeholders. Informed Actions This plan endeavors to support confident water resources Fall 20 17 - Completed development of analytical decision-making. Outcomes from public meetings, tools and ecological assessment frameworks to stakeholder focus groups, and community surveys support future water resources decision-making. characterize community values and preferences when Developed planning recommendations for City confronted with difficult decisions regarding water of Aspen and Pitkin County. management trade-offs. Characterization of ecological conditions, attributes at risk of degradation, and community Winter 20 17 - Hosted community workshops to values regarding use and management of limited water present findings and solicit final input regarding supply helps City and County staff understand ecological community priorities. Presented findings and needs and anticipate community response to future recommendations to the Aspen City Council and proposed projects. the Pitkin County Commissioners. ROZAKLIS& ASSOCIATES hydrological 3 ESPEGREN Miller Ecological Consultants, Inc. 2. FUNCTIONAL ASSESSMENT OF LOCAL STREAMS AND RIVERS The overarching goal of this project was to outline and prioritize options for improving or maintaining the ecological health of the upper Roaring Fork River and its tributaries in a way that reflects local values and priorities, as well as administrative and legal realities governing the use of water in Colorado. A critical first step in reaching this goal is developing a shared understanding of local riverine conditions and the factors that limit river health. The complex interplay between the human, physical, chemical, and biological components of the Roaring Fork River and its tributaries complicates the task of identifying appropriate management strategies that respond to local concerns about one or more environmental attributes of interest (e.g. native trout habitat). Channel dynamics, riparian health, and aquatic habitat quality are governed by complicated interactions between climatological and landscape characteristics that include stream flow, weather conditions, the presence of human infrastructure, invasive species, water diversions, particular seasons, and other factors. Each of these components must be considered in order to develop an overall management plan that responds to the greatest needs at the correct time and appropriate location in the watershed. A wealth of investigations and reports focused on channel geomorphology, riparian ecology, fisheries, and hydrology were completed in the study area over the last 20 years (Table 1). Most of these assessments evaluated current conditions and characterized the degree of departure from natural conditions using mathematical models or forensic, weight-of-evidence based approaches. The large variety of assessment methodologies—some rapid and coarse, some focused and intensive—employed by these studies produced evidence that reflects ecosystem processes across a range of spatial scales with varying degrees of objectivity. They also provide a basis for understanding the impacts of land and water management on river health conditions. 4 Table 1. Studies considering the ecological condition of streams and rivers in the upper Roaring Fork watershed. Ecosystem Indicator Example Metrics Assessments & Studies Flow Regime Peak Flow Roaring Fork Watershed Streamflow Survey Report (Clarke, 2006) Base Flow Review of City of Aspen’s Castle Creek Hydroelectric Project Aquatic Resource Documents (Espegren, 2011) Annual Yield Snapshot Assessment of the Roaring Fork Watershed (Mason, 2012) Preliminary Hydrologic and Biological Characterization of the North Star Nature Preserve (Hickey et al. 2000) Sediment Dynamics Water Quality Land Erosion Geomorphic Assessment of the Stability of the Roaring Fork River through the City of Aspen (Ayres Associates, 2011) Channel Erosion Preliminary Hydrologic and Biological Characterization of the North Star Nature Preserve (Hickey et al. 2000) Hydraulic Transport Geomorphic Assessment, North Star Nature Preserve (Goulder Associates, 2014) Physical Parameters Integrated Water Quality Monitoring and Assessment Report (CDPHE, 2014) Nutrients Roaring Fork Watershed Water Quality Report (Roaring Fork Conservancy, 2006) Metals Organic Compounds Floodplain Connectivity Extent Geomorphic Assessment of the Stability of the Roaring Fork River through the City of Aspen (Ayres Associates, 2011) Saturation Duration Preliminary Hydrologic and Biological Characterization of the North Star Nature Preserve (Hickey et al. 2000) Fragmentation Riparian Vegetation Debris Supply Extent Preliminary Hydrologic and Biological Characterization of the North Star Nature Preserve (Hickey et al. 2000) Structure and Complexity Castle Creek Hydroelectric Plant Environmental Report (Miller and Swaim, 2010) Fragmentation Geomorphic Assessment of the Roaring Fork River and Impacts of Groundwater Changes on Wetlands, North Star Nature Preserve (MEC and Ayres Associates, 2011) Large Wood Geomorphic Assessment, North Star Nature Preserve (Goulder Associates, 2014) Organic Matter Channel Morphology Planform Geomorphic Assessment of the Stability of the Roaring Fork River through the City of Aspen (Ayres Associates, 2011) Dimension Preliminary Hydrologic and Biological Characterization of the North Star Nature Preserve (Hickey et al. 2000) Profile Geomorphic Assessment, North Star Nature Preserve (Goulder Associates, 2014) Rate of Change Aquatic Habitat Complexity Review of City of Aspen’s Castle Creek Hydroelectric Project Aquatic Resource Documents (Espegren, 2011) Connectivity Castle and Maroon Creeks 2012 Aquatic Monitoring Reports (Miller and Swaim, 2011-2013) Quality Castle Creek Hydroelectric Plant Environmental Report (Miller and Swaim, 2010) Final Report Evaluation of River Health: Roaring Fork River near Aspen, Colorado (Miller, 2011) Aquatic Biota Macroinvertebrates Upper Roaring Fork River Aquatic Life Use Assessment (Mason, 2012) Trout Preliminary Hydrologic and Biological Characterization of the North Star Nature Preserve (Hickey et al. 2000) Amphibians Algae 5 A team of hydrologists, ecologists, and water resource engineers reviewed the references listed above to arrive at consensus regarding the values at risk on the upper Roaring Fork River and its tributaries. This assessment effort did not collect significant quantities of new data or perform new analyses. Rather, existing data and studies were synthesized and organized by stream reach using a functional assessment framework. The effort organized information about stream function in a way that simultaneously recognized the existence of complex interactions between the physical and biological components of river ecosystems and disaggregated the system into a collection of more easily understood attributes and behaviors. Those attributes and behaviors included: flow regime, sediment dynamics, water quality, floodplain connectivity, riparian vegetation, debris supply, channel morphology, aquatic habitat, and aquatic biota. Together, they describe fundamental ecosystem processes and provide a relatively straightforward basis for characterizing conditions on individual stream reaches. Results facilitate a comparative assessment across streams and rivers in the upper Roaring Fork watershed. Flow Regime to natural patterns of flow variability, including Broad patterns of precipitation and topography the frequency and timing of floods, may impact largely determine a river’s flow regime. In turn, fish, aquatic insects and other biota whose life fluvial ecologists generally treat flow regime cycles are tied to predictable rates of occurrence as the “master variable” exerting the largest or change. Changed hydrological regimes may influence on riverine ecosystem form and function. also impact patterns of water quality and rates of Activities that deplete or augment streamflow geomorphological change along a river’s course. have the potential to impact important regime characteristics, including: total annual volume, Sediment Regime magnitude and duration of peak and low flows, The production and transport of sediment within and variability in timing and rate of change. a stream system is a crucial determinant of Changes to total annual volume and peak stream form, habitat quality and general long- flows may impact channel stability, riparian term stability. A functional analysis considers vegetation, and floodplain functions. Water the amount and timing of sediment production quality may be impacted as flows decrease due to from the contributing watershed via surface reduced dilution capacity or increases in stream and channel erosion, and sediment transport to temperature that alter rates of transformation and through the stream channel. Watershed- of metals and nutrients in the water column. scale disruptions, such as deforestation, wildfire, The quality and availability of stream habitat avalanche, mudslides, large scale development may also change as flows decrease. Fish and or road construction can alter the sediment other aquatic species prefer specific habitat regime by elevating sediment loads to transport- types defined by water depth, velocity, cover limited channels. These changes may lead to type, temperature ranges, and substrate type. channel aggradation and elevated rates of bank Reduced flows frequently alter velocity and depth erosion and lateral channel movement. Sediment distributions and may result in increased average transport at local or regional scales may also be and maximum daily temperatures. Alterations impacted by physical infrastructure like dams 6 and weirs. These structures may trap sediment in or localized geomorphic impacts resulting supply-limited reaches, resulting in down-cutting from construction of artificial levees, ditches, of the river channel. channelization, or channel enlargement. Water Quality Riparian Vegetation Natural geological weathering and human Riparian vegetation performs several important activities occurring at the scale of the contributing functional roles for stream ecosystems. Root watershed largely dictate the physical and systems increase bank stabilization and the chemical characteristics of the water column. vegetative overstory provides a food source and Streamside development of commercial, shading for aquatic species. Riparian forests residential, and industrial land uses often supply the channel with woody debris, an contribute non-point source loads of various important determinant in local physical structure. chemical constituents (e.g. solvents, pesticides, The functional condition of riparian vegetation fertilizers). Wastewater treatment plants discharge considers species diversity and the structure point source loads that may exhibit nutrient of both the woody and herbaceous vegetation concentrations and temperatures that are elevated communities. Impacts to riparian vegetation can above instream concentrations. Biogeochemical result from deforestation, floodplain development processing (e.g. nutrient uptake) by stream or hydrological disconnections between the river organisms may alter local water quality conditions and the floodplain caused by altered streamflows, to some degree depending on carbon availability, channelization, or creation of physical barriers to temperature, and resulting rates of gross primary lateral water movement. productivity. Physical water quality conditions (e.g. water temperature), while somewhat influenced Debris Supply by local patterns of channel form and streamside Debris supply encompasses the amount, timing, vegetation, remain fundamentally controlled by and type of large woody debris and small organic watershed scale variables like latitude, elevation, detritus reaching a stream channel from nearby and drainage aspect. areas. Large woody debris performs an important function as a component of structural diversity Floodplain Connectivity on the streambed, altering channel hydraulics, The frequency, lateral extent, and duration of patterns of sediment transport, and habitat quality. interactions between the channel and 5-year Detritus represents a critical source of carbon and floodplain (i.e., through flooding) create a pattern energy for aquatic food webs. An impaired supply of floodplain connectivity that determines the of debris typically results from degradation of extent to which the river accesses and hydrates riparian forests, in response to active removal of overbank areas. The overbank flows that elevate vegetation, hydrological modification or floodplain the water table in the alluvial aquifer and produce dissection. favorable conditions for riparian vegetation in the upper Roaring Fork watershed are driven Channel Morphology by snowmelt runoff, with peak flows typically A stream’s morphological patterns reflect the occurring in late May to mid-June. Impairments interplay between hydrology, channel hydraulics, to typical floodplain connectivity result from sediment supply, debris supply, beaver activity, watershed‐scale impacts to the flow regime and streamside vegetation. Assessments of stream 7 morphology consider the patterns of channel evolution, Aquatic Biota longitudinal and cross-sectional dimensions, and Assessments of biotic structure frequently consider the channel profile. Impacts to stream morphology may total biomass, community composition, and species arise from construction of roads and levees, extirpation interactions of and between microbes, macrophytes, of beavers, reduction of the active floodplain width, macroinvertebrates, fish and amphibians, and other and disruption of sediment supplies. Evidence of animals. Measures of productivity and the degree to impairment on streams can include elevated channel which a stream can support complex trophic structures, instability or a reduction in physical complexity of the when assessed against reference conditions, provide streambed. a prime indicator of overall ecosystem health. The living components of the stream system are the most Physical Structure recognizable indicators of river health and are, generally, Physical heterogeneity in the streambed and water the parts of the ecosystem that human communities column results from the complex interplay between the derive the most value from. The biotic makeup of patterns of erosion, scour, and deposition that shape a stream is impacted by all other ecosystem state the streambed.24 As is the case for stream morphology, variables. As a result, any activity that impairs other biological drivers such as riparian vegetation, wood, processes at the watershed, reach, or channel scale may and beavers, may also exert significant control over similarly affect biotic structure. For example, disruptions channel structure. Assessments of physical structure in the hydrological regime impact the structural consider hydraulics (water depth and velocity complexity of the streambed and water column. This distributions), bed and bank features, and substrate complexity is an important control on habitat quality for material. Heterogeneity is a critical determinant of fish and macroinvertebrates and, where it is reduced, habitat quality for many aquatic organisms including a corresponding impairment of biotic structure may macroinvertebrates and fish. Activities that physically result. alter the structure of the streambed, disrupt the sediment regime, or reduce large woody debris supplies to a reach frequently impact the physical structure and degree of heterogeneity present in the stream channel. 2.1 REACH DESCRIPTIONS In this study, functional assessments were conducted on a reach-by-reach basis using readily available data, results from scientific studies, and conclusions reached in engineering investigations. Results were aggregated into narrative summaries for each stream reach in the study area. Results were further condensed into a set of easily interpretable graphics. Reach descriptions and accompanying infographics are not intended as exhaustive investigations of river health conditions. Rather, these summary products are designed to assist the City, the County, and members of the public to arrive at a common understanding regarding the prioritization of issues—both in type and location—that represent the greatest constraints on the healthy functioning of the stream ecosystem and constitute the greatest risk to delivery of important ecosystem goods and services on the Roaring Fork River and its tributaries near Aspen. For example, surface water diversions exist on most reaches considered by the assessment. However, discussion of those diversions in reach descriptions only occurs where the consultant team determined they were a significant driver of river health. For additional information regarding each reach, the reader is directed to the citations that appear in each reach description. 8 VALUES AT RISK POTENTIAL THREATS The values that local communities derive from healthy Protecting or restoring the values derived from aquatic ecosystems are tightly bound to the chemical, aquatic ecosystems begins with a thorough biological and physical characteristics of those understanding of the potential threats to healthy systems. Healthy rivers and streams often deliver the functioning of those ecosystems. A variety of threats greatest ecosystem goods and services. are documented in the Roaring Fork watershed. Aesthetic and Recreational Use Water from local streams and rivers supports the high quality of life enjoyed by local residents by providing aesthetically pleasing landscapes and diverse recreational use opportunities like swimming, boating and fishing. Flow Modification Storage and use of water to support municipal, agricultural, and industrial needs frequently modifies cycles of flooding, reduces connectivity between adjacent reaches of stream, and alters flows during late season low flow periods. Altered timing, magnitude, and frequency of high and low streamflows can adversely impact aquatic and riparian plants and animals by limiting habitat availability, connectivity, or quality. Clean Water Rainfall and snowmelt in the upper Roaring Fork watershed provide clean water for human consumption, safe recreational uses like swimming, and support of healthy aquatic life in local streams and rivers. Water Pollution Urban runoff, wastewater treatment plant effluent, historic mining areas and industrial discharges into rivers change the chemical makeup of the water column. Chronic or acute changes in water chemistry downstream of these discharges may alter community composition, productivity and mortality rates for aquatic biota. Riparian Health Riparian vegetation plays an important role in stabilizing stream banks, providing a food source for aquatic insects, and maintaining high quality habitat for numerous fish and bird species. Riparian zones are also important buffers against water quality degradation from adjacent land use activities. Development and Land Use Urbanization, development of transportation corridors, and recreational use facilities adjacent to waterways impact riparian area quality and extent, alter stream channel geometry, and frequently decrease connectivity between rivers and floodplains. Flood Control The ability of streams to overtop and spill onto floodplains during periods of high flow is a critical control on the severity and extent of flood impacts. Reduced connectivity between streams and floodplains can increase flooding risks to human safety and local infrastructure. Habitat Fragmentation Infrastructure and patterns of water use may create physical, thermal, or hydraulic barriers to the upstream-downstream movement of aquatic organisms. Culverts, dams, weirs, and flow depleted river segments may also restrict access to important habitat refuges. Aquatic Flora and Fauna Communities of plants, aquatic invertebrates, and fish constitute important components of freshwater food webs. The total number of organisms present, and interactions between different species, maintain and promote system biodiversity. Sport and native fisheries also provide recreational angling opportunities for visitors and residents. Invasive Species Introduction of non-native aquatic and riparian species often disrupts and degrades food webs. Invasive species may outcompete native species, limit rates of production, or decrease overall biodiversity. 9 Follow changing conditions on the Roaring Fork River from its headwaters to a point below the confluence with Maroon Creek. The river is divided into numbered stream segments and the the values and corresponding threats to each are color coded and symbolized. Value Status Fair Poor Not Assessed Good Low Moderate High Not Assessed Risk For Impact 1. Roaring Fork River above Difficult Creek Flow magnitude, duration, and inter-annual variation are altered by transmountain diversions. Significant streamflow reduction occurs in summer and spring months.3,4 The reach immediately below the transmountain diversions frequently runs dry. Small reaches, generally clustered near the confluences of Difficult and Lincoln Creeks, exhibit moderately or severely degraded aquatic and riparian habitat due to the presence of campgrounds, trails, parking lots and recreational uses adjacent to the river.4 1 2 2. Lincoln Creek Flow magnitude, duration, and variability are altered by transmountain diversions. Year-round flows reduced, with the most significant reductions occurring in spring and summer months.3,4 Instream Flow (ISF) water rights—recommended flows for aquatic life protection—often not met because of their junior status to Twin Lakes Diversion. Some potential for water quality degradation from historical mining activities. Geomorphology, water quality, and riparian health have not been assessed. 3. Roaring Fork River above the City of Aspen Transmountain diversions alter flows in a similar way to upstream segments. Channel geometry 3 and floodplain connectivity through North Star Nature Preserve altered as a result of reduced spring and summer flows and historical channel straightening activities. Aquatic habitat through the North Star Preserve is altered from historical channel modification, in-channel structures and flow depletion. Riparian communities above and through North Star Preserve moderately to severely degraded due to changes in flow regime, land use, recreational use, and invasive species. 4,9,10,14,20 5. Roaring Fork River through the City of Aspen 8. Roaring Fork River below Maroon Creek Significant riparian woodland communities exist in the Airport Ranch Open Space. Riparian habitat is heavily degraded near Brush Creek and downstream of Maroon Creek. The proximity of Highway 82, development on adjacent lands, invasive weed introduction from recreational river access trails, and changes in hydrology may contribute to degraded riparian conditions. Aquatic habitat is moderately degraded from similar threats,4 though a robust brown trout population remains. An historic railroad grade (now the Rio Grande Trail) through the gorge area contributes to streambank erosion.4 4. Hunter Creek 4 5 Transmountain and in-basin water diversions significantly reduce summer flows.3,4 Recommended flows for protecting aquatic life frequently not met. Riparian vegetation, water quality, and geomorphology have not been assessed. Hydrological regime altered by transmountain diversions and in-basin diversions in Aspen. Recommended minimum flows for aquatic life health often not met in late summer. The section between the North Star Preserve and Castle Creek are particularly vulnerable to dewatering.3,4,11 Urban development on floodplains impacts riparian area health.5,12 In-channel structures contribute to altered channel gradient, channel widening, bank erosion and localized aggradation, and impede fish passage during low flows.13 Infrequent elevated water temperatures could be detrimental to native and sport fish populations. 8 6. Castle Creek 7. Maroon Creek 7 Diversions for irrigation and hydropower production significantly reduce flows near Willow Creek. Snow-making activities impact flows in winter months in the lower creek.4 Both riparian and aquatic habitat are slightly modified where development is concentrated, mostly near the Roaring Fork River confluence. Moderate aquatic habitat degradation is caused by flow alteration, development pressure, and invasive species in the riparian zone.4, 15, 16, 17, 18 6 Diversions for municipal water supply, golf course irrigation, and snow-making alter hydrological regime. Riparian and aquatic habitat is primarily threatened by flow alteration, trails, roads, and general development pressures. Approximately 25% of the riparian zone in the lower creek is moderately modified.4 Aquatic habitat conditions degrade progressively going downstream with 33% of the habitat identified as moderately modified and 5% as heavily modified.4 Roaring Fork River: Lost Man Creek to confluence with Difficult Creek The upper Roaring Fork River between Lost Man Creek and Difficult Creek is characterized by narrow riparian areas, steep gradients and bedrock channels. Channel gradients decrease near Tagert Lake, but the river remains a single threaded cascade throughout most of this segment. The Colorado Natural Heritage Program (CNHP) delineates riparian areas throughout this reach as a Potential Conservation Area (PCA) due to their high biodiversity and the presence of rare and/ or significant plant communities. Most of this segment flows immediately adjacent to Highway 82 and sees significant recreational use near Tagert Lake, the confluence with Lincoln Creek, and at the Grottos. Riparian forests are somewhat impacted by concentrated recreational uses in these areas. Flow magnitude, duration, and inter-annual variation are altered by trans-basin diversions (TMDs). These diversions collect flows from the Roaring Fork River and Lost Man Creek near Lost Man Reservoir and convey up to 322 cubic feet per second (cfs) of water through the Twin Lakes Tunnel #2 to Grizzly Reservoir. Grizzly Reservoir, in turn, acts as a forebay for diversions through the Twin Lakes Tunnel #1, which carries water under the divide to Twin Lakes in the Arkansas basin.6 TMDs decrease year-round flows at least 10% on average, with a significant reduction in spring and summer flows.3,4 These flow reductions reduce aquatic habitat quality and availability, while the diversion structures themselves create barriers to upstream-downstream movement by aquatic organisms. Minimum streamflows identified by the Colorado Water Conservation Board (CWCB) and US Fish and Wildlife Service for the protection of aquatic life on the Roaring Fork downstream of Lost Man Creek (10-15 cfs) are often not met during summer due to flow diversions3. These impacts are likely moderated by the steep character of the river channel that somewhat limits aquatic organism migration to and through this segment naturally. Short reaches, generally clustered near the confluences of Difficult and Lincoln Creeks, exhibit moderately or severely degraded aquatic and riparian habitat due to the presence of campgrounds, trails, parking lots and recreational uses adjacent to the river.2,4 The Grottos Lincoln Creek Confluence Brent Gardener-Smith / Aspen Journalism Brent Gardener-Smith / Aspen Journalism 11 Lincoln Creek: Grizzly Reservoir to confluence with Roaring Fork River Lincoln Creek alternates between meandering alluvial channel forms near Grizzly Reservoir and steep bedrock canyons through Lincoln Gulch. Water from the upper portions of Grizzly Creek, Lincoln Creek, Tabor Creek, and New York Creek are captured by a collection system that diverts flows through series of canals to Grizzly Reservoir. From Grizzly Reservoir, up to 625 cfs of water is diverted through the Twin Lakes Tunnel #1 under the divide to Twin Lakes in the Arkansas basin. These transmountain diversions alter flow magnitude, duration, and inter-annual variation. TMDs reduce flows year-round, with a significant reduction in summer and spring flows.3,4 Minimum streamflows identified by the CWCB for the protection of aquatic life on lower Lincoln Creek (8 cfs) are often not met. Riparian health has not been assessed on this reach. Above Grizzly Reservoir, Lincoln Creek and its tributaries drain an area impacted by historical hardrock mining activities. Episodic discharges of metals-laden sediment from Grizzly Reservoir may produce short-duration water quality impairments on downstream segments of Lincoln Creek and the Roaring Fork River. While the impoundment of metals-laden sediment within Grizzly Reservoir may represent a net water quality benefit to downstream waters, the disruption of the natural sediment regime is likely to produce some impacts on channel form and dynamics in alluvial sections of Lincoln Creek. Above Roaring Fork Confluence Lincoln Gulch Brent Gardener-Smith / Aspen Journalism Brent Gardener-Smith / Aspen Journalism 12 Roaring Fork River: Confluence with Difficult Creek to Salvation Ditch Below Difficult Creek, the Roaring Fork River enters an alluvial valley where gradients decrease, riparian area widths expand, and rates of channel migration increase. The river flows through national forest, private land, and county open space in this segment. Upstream TMDs alter flows in a similar manner to upstream segments. CNHP delineates riparian forests along this segment as a PCA due to high biodiversity and/or the presence of rare or significant plant communities. Critically, previous studies characterize riparian communities as moderately to severely degraded due to changes in flow regime, development pressure, and invasive species.4,9,10,14,20 . This degradation seems concentrated in the area immediately above Aspen and does not extend through a majority of this reach. The North Star Preserve above Aspen sees heavy recreational use,.10 Channel geometry and floodplain connectivity through North Star Preserve are altered by reduced spring and summer flows and historical channel straightening activities9. Aquatic habitat quality and availability upstream of Aspen are moderately to severely altered from historical channel modifications and flow depletion. Limited macroinvertebrate monitoring does not indicate impairment to community structure. However, limited riffle habitat likely reduces overall abundance of aquatic insects and fish present in this reach.12 Northstar Preserve Paul Anderson / Aspen Journalism James H. Smith Paul Anderson / Aspen Journalism 13 Roaring Fork River: Salvation Ditch to confluence with Castle Creek The Roaring Fork River through the City of Aspen is bordered by a variety of land uses and infrastructure. In many areas, commercial and residential developments and transportation infrastructure (i.e. roads and bridges) bisect or eliminate historical floodplains and riparian zones. Several large water diversion structures convey water out of the river below Stillwater Lane to support irrigated agriculture on McClain Flats, ponds, water features, private landscaping, public parks in City of Aspen, and stormwater water quality treatment facilities. The river is paralleled by numerous footpaths and bordered by several parks that provide access points for residents and visitors. The City of Aspen’s primary stormwater discharge points meet the river in this reach. The hydrological regime is jointly altered by TMDs and surface water diversions for in-basin water uses. The minimum streamflow identified by CWCB for maintaining aquatic life health (32cfs) is often not met in the late summer as a result of upstream water uses.3,4 The section between the Aspen Club and Castle Creek is particularly vulnerable to dewatering.11 Urban development is significantly encroaching on riparian areas and floodplains. Grade control structures near John Denver Park and Jenny Adair Park contribute to a reduction in channel gradient, channel widening, bank erosion and localized aggradation1,13. Several of these structures may impede fish passage during low flows1. Drainage from impervious areas (e.g. roofs, roads, and parking lots) impacts sediment transport characteristics, habitat, and water quality by increasing the loading of fine sediment and other pollutants to the stream channel.19 Urban drainage also plays a large role in the degradation of aquatic insect populations in this segment—a circumstance that led the State of Colorado to list the Roaring Fork River through the City of Aspen as an impaired waterway.5, 12 Previous studies also attribute some of the degradation of aquatic insect communities to chronic flow modification.13 Reduced late summer streamflows may also produce episodic elevated water temperatures detrimental to the health of native and sport fish.11 Near Herron Park John Denver Park Aspen Center for Environmental Studies Brent Gardener-Smith / Aspen Journalism 14 Roaring Fork River: Confluence with Castle Creek to confluence with Brush Creek Below Castle and Maroon Creek, the Roaring Fork River enters a steep gorge and gains significant amounts of streamflow. The topography in this area restricts development activity. The Rio Grande trail parallels the river through this section providing access to recreational users. This section of river is heavily used by whitewater boaters during the early summer months when flows on the river are high. This reach also supports a fishery that attracts numerous local anglers and helps support an angling-based guiding economy. The Roaring Fork Gorge between Castle Creek and Brush Creek is designated as a PCA by CNHP. Residential development and landscaping negatively impact riparian vegetation in several areas near the Castle and Maroon Creek confluences.4 A few sizable stretches of significant riparian woodland communities exist in the Airport Ranch Open Space. Previous studies indicate that riparian habitat is heavily degraded near Brush Creek and below Maroon Creek.4 The proximity of Highway 82, development on adjacent lands, invasive weed introduction from recreational river access trails, and changes in hydrology likely contribute to degraded riparian conditions. Aquatic habitat is moderately degraded from similar threats, though Colorado Parks and Wildlife biologists indicate that a robust brown trout population remains in this reach. The historic railroad grade through the gorge area contributes to streambank erosion but the impacts on channel form and dynamics are not evident.4 Water quality data indicates improving conditions downstream from the City of Aspen.5 However, low-level nutrient enrichment and other water quality impacts may be caused by wastewater treatment plant discharges, runoff from agricultural lands, and urban drainage from the airport and adjacent business park. Slaughterhouse Falls Aspen Times Brent Gardener-Smith / Aspen Journalism 15 Hunter Creek: Fry-Ark diversions to confluence with Roaring Fork River Hunter Creek drains alpine and subalpine areas on the east side of the Roaring Fork River. Below its confluence with No Name Creek, Hunter Creek transitions from a step-pool and cascade morphology to a single-threaded meandering channel form where it traverses several high-valley meadows. Hunter Creek between No Name Creek and Red Mountain Ditch is designated by CNHP as a PCA. CPW considers the Hunter Creek watershed as a critical management zone for native cutthroat trout populations. The Fryingpan-Arkansas project diverts up to 270 cfs from upper Hunter Creek, Midway Creek, and No Name Creek through a system of surface water diversions, canals, and tunnels. Water is conveyed to the Hunter Tunnel and, eventually, through the Bousted Tunnel, to Turquoise Lake in the Arkansas basin. TMDs significantly reduce May-July flows on Hunter Creek 3,4 Minimum streamflow bypass requirements on the Hunter Creek collection system (4 cfs on No Name Creek, 5 cfs on Midway Creek, and 12 cfs on Hunter Creek) are intended to protect aquatic life health on downstream reaches. However, water collection structures (e.g. ditches, canals, and diversion dams) represent significant barriers to upstream-downstream migration of fish and other aquatic organisms. Surface water diversion at the Red Mountain Ditch conveys water to McClain Flats to supply irrigated agriculture and water amenities. This diversion can significantly reduce flows or dry up the creek during the late summer season, particularly in dry years.3 The health of riparian vegetation and aquatic biota have not been recently assessed on Hunter Creek or its tributaries. Brent Gardener-Smith / Aspen Journalism Paul Anderson / Aspen Journalism 16 Castle Creek: Conundrum Creek to confluence with Roaring Fork River Castle Creek drains a steep tributary subwatershed to the Roaring Fork River. Low density residential land uses and roadways border a majority of the creek between Conundrum Creek and the Roaring Fork River. The channel alternates between meandering, braided, and confined but mostly flows through low-gradient and relatively wide valley bottoms. Agricultural water diversion above the confluence with Conundrum Creek in addition to surface water diversions for drinking water, snow-making, and landscaping reduce summer and winter streamflows.3,4 Summertime water diversions above Keno Gulch support the City of Aspen municipal drinking water supply. The City maintains a streamflow bypass at this diversion point of at least 13 cfs to meet minimum streamflows identified as important for aquatic life health. Surface water diversions closer to Aspen supply water to ponds, private lands, and the municipal golf course located between Castle Creek and Maroon Creek. Riparian areas along Castle Creek below Keno Gulch are delineated by CHNP as a PCA. Riparian and aquatic habitat on this segment is primarily impacted by flow alteration, and secondarily from trails, roads, and general development pressures.4,15,16,17,18 Previous studies identify approximately 25% of the riparian zone near the confluence with the Roaring Fork River as moderately modified.4 Aquatic habitat conditions degrade progressively going downstream. Brent Gardener-Smith / Aspen Journalism Brent Gardener-Smith / Aspen Journalism 17 Maroon Creek: West Maroon Creek to confluence with Roaring Fork River Maroon Creek drains a steep, rugged subwatershed that is mostly National Forest and includes significant portions of federally designated Wilderness Area. While the upper watershed sees significant recreational visitation, most other sections along Maroon Creek are difficult to access. A road parallels a majority of the stream between the West Maroon Creek confluence and the Roaring Fork River. The lower reaches of the stream are bordered by residential developments and a private golf course. Several surface water diversions below West Maroon Creek and on Willow Creek supply water to the golf course, private landowners and other fields near Buttermilk Ski area. The City of Aspen operates a hydropower facility on Maroon Creek that diverts approximately 52 cfs above Willow Creek and returns it to Maroon Creek about one mile downstream. The City of Aspen bypasses at least 14 cfs at the hydropower diversion point to maintain minimum streamflows for aquatic life health. Surface water diversions reduce summer baseflows in lower Maroon Creek. Hydropower diversions deplete streamflows year-round on a 1-mile section of creek beginning near Willow Creek.3,4 The segment of Maroon Creek below Willow Creek is identified by CHNP as a PCA. Both riparian and aquatic habitat are slightly modified where development is concentrated along streambanks near the Roaring Fork confluence.4,15,16,17,18 This degradation led CNHP to delineate the Maroon Creek confluence as a Conservation Area of Concern. Brent Gardener-Smith / Aspen Journalism Brent Gardener-Smith / Aspen Journalism 18 2.2 NEEDS ASSESSMENT SUMMARY The review of historical data and assessment activities provided the basis for a functional assessment of ecological conditions. A modified version of the Functional Assessment of Colorado Streams (FACStream) framework provided a useful template for communicating assessment findings. The framework follows an academic grading scale for straightforward communication of results (Table 2). These results are intended to facilitate discussion about high-priority management locations and issues. Results may be modified in the future following more focused or intensive investigations on a given segment or in consideration of a particular ecosystem attribute. Table 2. Functional Assessment Scoring Criteria Grade Condition Description A Reference Standard Condition of the variable is self-sustaining and supports functional characteristics appropriate to sustain river health. Limited management to sustain and protect this level. B Highly Functioning The condition of the variable maintains essential qualities that support a high level of ecological function, yet there is some influence of stressors at a detectable, yet minor, level. The variable retains its essential qualities and supports a high level of ecological function but requires some limited management. C Functioning The condition of the variable has been altered and/or degraded by stressors that substantially influence the variable’s functionality. The variable still supports basic, natural, stream/riparian functioning. Management is likely required to support maintenance of the characteristic functional role of the variable. D Functionally Impaired The condition of the variable is severely altered by stressors that constrain the variable’s ability to support characteristic functioning and the overall health of the river. Extensive active management is required F Non-Functioning The condition of the variable is under the influence of significant deleterious alterations/stressors. The level of alterations/stressors. The level of alteration generally results in an inability of the functioning variable to support characteristic functioning or it otherwise makes the area biologically unsuitable. The anticipated effectiveness of any action should be carefully evaluated. The functional assessment scoring matrix (Figure 2) created for this project indicates widespread alteration of the flow regime in the upper Roaring Fork River watershed. These effects are most pronounced on tributary streams and the Roaring Fork River mainstem below transmountain diversions and points of in-basin surface water use. Alteration of the low streamflows affects aquatic habitat quality and availability during low-flow periods and may be partially responsible for the observed impairments of aquatic macroinvertebrate communities through the City of Aspen. Land development activities, transportation corridors, and alterations of peak flow magnitude and duration are generally responsible for observed reductions in floodplain connectivity and degradation of riparian vegetation. Critically, these results also highlight important gaps in data and information on several stream segments (e.g. the health of aquatic biota on Hunter Creek). Assessment results generally support the City and County’s focus on the section of the Roaring Fork River that flows through the City of Aspen, as this reach exhibits the greatest degree of functional alteration. 19 Figure 2. Functional assessment results for streams in the Upper Roaring Fork watershed The low grades for flow regime on river segments in the upper Roaring Fork watershed are significant for several reasons. Fluvial ecologists generally treat patterns of streamflow as the “master variable” exerting the largest influence on the ability of streams and rivers to provide important ecosystem goods and services. Water use activities that deplete or augment streamflow can impact important streamflow behaviors and metrics, including: total annual volume, magnitude and duration of peak and low flows, and variability in timing and rate of change. Changes to total annual volume and peak flows may impact channel stability, riparian vegetation, and floodplain functions. Water quality may be impacted as flows decrease due to reduced dilution capacity or increases in stream temperature that alter rates of transformation of metals and nutrients in the water column. The quality and availability of stream habitat may also change as flows decrease. Fish and other aquatic species prefer specific habitat types defined by water depth, velocity, cover type, temperature ranges, and substrate type. Reduced late-season flows alter water velocity and depth and may result in increased average and maximum daily temperatures. Alterations to natural patterns of flow variability, including the frequency and timing of floods, may impact fish, aquatic insects and other biota whose life cycles are tied to predictable rates of occurrence or change. Complex connections exist between patterns of streamflow and many aspects of river health (Figure 3). These connections make recognizing ecological needs an important component of water supply management or planning. 20 Figure 3. Measures of streamflow alteration at key locations in the upper Roaring Fork watershed. Results indicate the percent change in various measures of streamflow behavior when moving from natural streamflows to existing streamflows under moderate drought (i.e. 1-in-4 year) conditions. These patterns are relatively consistent across year types (i.e. wet, average, dry). More information regarding the Indicators of Hydrological Alteration (IHA) method and the parameters assessed here can be found in Appendix B. 21 3. WATER USES AND TRADE-OFFS Mountain snowpack provides almost all of the annual water yield from the upper Roaring Fork watershed. Warming spring temperatures coincide with peak flows on the river in May through July of each year. These peak flows are responsible for a bulk of the sediment transport in the Roaring Fork River and provide important functions for maintaining channel form, riparian forest health, and floodplain structure in and around Aspen. As the snowpack melts, springs and regional groundwater supplies sustain significantly lower flows through the fall and winter months. Most of the remaining water passes through the system as snowmelt in the late spring or early summer. Annual water yields in the Roaring Fork River above Mill Street are reduced by approximately 40% due to transmountain diversions and by approximately 10% due to in-basin agricultural and municipal uses. Flows and water yields increase substantially downstream of the Roaring Fork River’s confluences with Castle Creek and Maroon Creek (Figure 4). Diversion structures or systems that, historically, had the greatest effects on streamflows in the upper Roaring Fork include: the Independence Pass Transmountain Diversion System, the Salvation Ditch, the Wheeler Ditch, the Red Mountain Ditch, the Hunter Creek portion of the Fryingpan-Arkansas (Fry-Ark) Project collection system, the diversions operated by the City of Aspen on Castle Creek, the Maroon Creek Hydropower facility, the Willow Ditch, and the Herrick Ditch in the Maroon Creek drainage. The Wheeler Ditch has occasionally reduced flows in the Roaring Fork downstream from its headgate near the center of Aspen, but recently entered into a non-diversion agreement that bypasses flows in effort to maintain the minimum in-stream flow downstream. The Red Mountain Extension Ditch has reduced flows in the lower portion of Hunter Creek and in the Roaring Fork downstream of the Hunter Creek confluence. Numerous small diversions on the Roaring Fork River, upper Maroon Creek, and upper and lower Castle Creek also contribute to flow alteration across the study area. The City of Aspen’s municipal diversions from Castle Creek have reduced flows in Castle Creek and the Upper Roaring Fork downstream of the Castle Creek confluence. Together they represent the dominant water uses in the upper watershed: transmountain diversions, agricultural and raw water supply, treated municipal water, and hydropower production. 22 Figure 4. Patterns of surface water inflows and diversion in the upper Roaring Fork watershed. Line width corresponds to flow rate estimated by hydrological simulations (Appendix B) for moderately dry August conditions. Only major streams and active water diversion structures (greater than approx. 3 cfs) are included. All units are cubic feet per second. Flows move from top to bottom. 23 Transmountain Diversions The Independence Pass transmountain diversion system can move up to 625 cfs of water from the upper Roaring Fork watershed through two tunnels to Twin Lakes Reservoir. The Hunter Creek collection system can move up to 270 cfs of water, in the same manner, out of the Hunter Creek watershed to Turquoise Lake near Leadville. Diverted water is stored in reservoirs in the Arkansas River basin before making its way through a system of conveyance, and storage systems to water users (mainly municipalities) on Colorado’s eastern slope. Both systems divert large quantities of water during peak runoff, and smaller amounts at other times of the year. In May and June of each year, they may collectively divert approximately 50% of the flows from Hunter Creek, 40% of the flows from the upper Roaring Fork River, and 50% of the flows from Lincoln Creek. Administration of Colorado’s water rights priority system produces times in many years—generally late summer or early fall—when downstream users “call out” these diversions, requiring a reduction or cessation in delivery of water to the Arkansas basin. When these diversions are “called out”, flow is improved along the entire length of the Roaring Fork. Agricultural and Raw Water Supply Agricultural water sourced from the Roaring Fork watershed near Aspen comes, primarily, through surface water diversions on the Roaring Fork River, Hunter Creek, Castle Creek and Maroon Creek. Surface water diversions on the Roaring Fork River and Hunter Creek irrigate properties on McClain Flats. That water is used for amenities (e.g. ponds) and to support production of alfalfa and pasture grass for livestock. Some water from agricultural application McClain Flats is expected to make its way back to the river through groundwater and surface return flows between the City of Aspen and Brush Creek. Several ditches on upper Maroon Creek, upper Castle Creek, and lower Castle Creek provide water for landscaping, ponds, private golf courses and other amenities on private properties. Water diversions through ditches on lower Castle Creek supply water to the municipal golf course and private properties located between Castle and Maroon creeks. The City also uses water diverted from the Roaring Fork River near the Aspen Club by the Riverside Ditch and Wheeler Ditch to support the fountain on the pedestrian mall, irrigation for public parks and green spaces, and the stormwater treatment facility at John Denver Park. During dryer than average years, the City participates in a non-diversion agreement with the Colorado Water Trust and the Colorado River Water Conservation District to bypass Wheeler Ditch flows in effort to maintain the minimum in-stream flow downstream of the diversion structure. Many of the ditches listed above use less than their decreed surface water diversion rights. Treated Municipal Water Municipal water supplies for the City of Aspen come primarily from Castle Creek with some options for supplementation from surface water diversion on Maroon Creek and groundwater extraction near the Roaring Fork River. These supplies provide treated drinking water and outdoor irrigation supply to approximately 4,000 homes. The municipal water system also provides some snowmaking supply for ski areas. The City estimates that 36% of the total treated municipal supply is used for outdoor irrigation, 49% for indoor use, and 15% for snowmaking and unmetered or bulk sales of water.21 The City operates its water rights and water diversion infrastructure on Castle Creek in a manner that helps protect decreed minimum streamflows for aquatic life health. The City also continues to evaluate options for infrastructure modification and development of additional water supplies to meet future demands in the Aspen area and impart management flexibility in the entire system. Most water diverted for municipal use and used indoors is returned to the Roaring Fork River through the wastewater treatment plant downstream of the confluence with Maroon Creek. 24 The average annual water yield from the Roaring Fork watershed is primarily derived from melting of the winter snowpack. Most of the total volume of water passes downstream in the period between May and July. Estimates of annual supply and average water use presented here for the purpose of relative comparison. 106,700 69,800 acre feet Annual yield from the Roaring Fork River above Aspen. acre feet Annual yield from Hunter Creek. 23,000 acre feet Average annual raw water supply supporting lawns, viewscapes, golf courses, grazing, and limited local food production.b 106,000 acre feet Annual yield from Castle Creek. 156,800 acre feet Annual yield from Maroon Creek. 52,600 acre feet Average annual transmountain diversions in the upper Roaring Fork and Hunter Creek watershedsd that support municipal uses on the Front Range. Approximately 78% is sourced from the Roaring Fork River Average and Lincoln annual supply Creek. from Castle Creek providing drinking water, snowmaking supply, and outdoor irrigation for lawns and gardens at approximately 4000 homes.a 20,500 acre feet Average annual supply for City of Aspen hydropower production on Maroon Creek.c 4,700 acre feet Average annual diversions reported to CDWR for the Midland Flume on Castle Creek. Combined average annual diversions reported to CDWR for the Wheeler, Salvation, Nellie Bird, Riverside, Holden, Marolt, Herrick, Willow Creek, and Red Mountain Extension ditches. c Estimated from annual diversion records reported to CDWR for Maroon Ditch between 2012 and 2017. d Estimated from annual diversion records reported to CDWR for Fry-Ark diversion points in Hunter Creek and Twin Lakes Tunnel #1. a b 3.1 WATER USE IMPACTS The project relied on historical streamflow and water diversion data, as well as a pair of water rights and hydrological simulation models to understand the impacts of current patterns of water use on stream segments throughout the planning area. The lack of long-term streamflow observation data that captures the full range of natural and existing hydrological conditions and all points throughout the upper Roaring Fork watershed made it necessary to create a streamflow simulation tool. The simulation tools developed for this project compared natural hydrology to existing hydrology but should also be useful to the City and County in future efforts to understand the impacts of climate change, forest succession, changing land use, and changing water use needs on streamflows. For a full description of the hydrological simulation tools described above, see Appendix B. An initial review of streamflow modeling results indicates that the diversion and use of surface water has altered the natural flow regime in significant ways. These effects are most pronounced on Hunter Creek, Lincoln Creek, and the Roaring Fork River below Lost Man Creek and through the City of Aspen. Alteration of the hydrologic regime below transmountain diversions and points of in-basin water use affects aquatic habitat quality and availability during low-flow periods. Such alteration may be partially responsible for observed macroinvertebrate community impairments near the City of Aspen. Altered hydrology may also exacerbate the impacts of development activities and transportation corridors on floodplain connectivity and riparian vegetation. 5,700 acre feet of additional water is needed to meet daily flow targets recommended by the CWCB to protect aquatic ecosystems in the Roaring Fork River through the City of Aspen in dry years. Total volume calculated by comparing 25th percentile simulated daily streamflows below the Wheeler Ditch to the decreed CWCB ISF right for the reach. 25% deficit occurs November-May 75% deficit occurs July-October The ecological impacts of flow modification can be investigated with several different methods. Weight of evidence approaches, literature reviews, and rapid field assessments help investigators develop conceptual models of ecosystem behavior. Comparison of statistical measures of natural and existing streamflow response to “acceptable” levels of hydrological alteration established in scientific literature helps investigators predict the types and severity of impacts on various stream segments without specific data characterizing local ecology. Collection of long-term and detailed datasets tracking riparian condition and the health of aquatic species enables development of statistical or physically based models relating changes in flow to the condition of important ecosystem attributes or indicator species. Where the resolution or type of data is insufficient to establish direct relationships between changes in flow and river ecology, methods exist for relating physical measures of system behavior to theoretically based models of ecosystem response. The latter approach sees widespread use in Colorado, particularly in water rights or water supply planning efforts. For a more robust discussion of streamflow needs identification in the upper Roaring Fork watershed and warnings about relying solely on minimum flow thresholds to describe requirements for healthy river ecology, see Appendix C. While more nuanced methods exist for characterizing ecosystem need and biological and physical responses to flow alteration, minimum and maximum flow thresholds provide a useful means for describing ecosystem needs in the project area. Minimum flow thresholds are a coarse approach to describing habitat needs for fish during periods of low streamflow—typically the late summer and fall. Maximum streamflow thresholds can be similarly defined to indicate periods of streambed sediment mobilization, critical for maintenance of aquatic macroinvertebrate and fish spawning habitat. Use of threshold flows enables description of ecosystem needs as 26 water supply shortages in the same vocabulary that agricultural producers, water managers, and water supply planners for municipalities are accustomed to using. Minimum threshold streamflows for maintaining viable habitat for fish on segments of the Roaring Fork River and its tributaries are variously presented by CWCB instream flow water rights, the Operating Principals for the Twin Lakes an Fryingpan-Arkansas transbasin diversion systems, and by special studies commissioned by the City of Aspen and Pitkin County 13, 15, 16, 17, 18. Peak-flow environmental water use needs for mobilizing sediment and maintaining riparian areas are presented by special studies and local conservation organizations13. 4,000 acre feet of additional water, as estimated by hydrological simlulation models, is needed to meet monthly flow targets recommended by the Fryingpan-Arkansas Project Operating Principles to protect aquatic ecosystems in the Roaring Fork River upstream of Difficult Creek. Approximately 15% of this deficit is due to native water supply limitations. The rest of the deficit results from transmountain diversions. 85% deficit due to water diversions 15% deficit due to native supply Recommended peak flow thresholds are regularly met on the Roaring Fork River. Recommended low flows, however, are regularly unmet on some sections of river during drought conditions. An initial investigation into the timing and magnitude of low flow shortages under natural conditions (i.e., no exercise of water rights and no water use) and existing conditions provided a baseline for understanding the effects of current patterns of water administration, use, and management under drought or flood conditions. Environmental water use shortages are particularly prevalent on the Roaring Fork River below Lost Man Creek, Hunter Creek, and on the Roaring Fork River through Aspen. The largest shortages on the mainstem Roaring Fork typically occur below Stillwater Lane, where water diversions that support agriculture, ponds, private landscaping, and parks deplete late-summer streamflows. In general, shortages are more acute during dry conditions than during average or wet conditions. Interestingly, administration of water rights under the prior appropriation doctrine means that the transmountain diversions on Independence Pass and Hunter Creek are “called-out” by downstream senior water rights more often during dry years than during average or wet years. As a result, environmental low-flow shortages on the upper Roaring Fork River, Lincoln Creek, and Hunter Creek may, occasionally, be more acute during average years. This outcome may have important implications for the identification of alternative projects and processes to improve or protect river health. Furthermore, the occurrence of shortages on some streams under natural conditions indicates that in some locations and at some times of the year, the existing recommendations for minimum streamflows may either need refinement or need to be appropriately contextualized before they are used as the motivating basis for water management decision-making. Developing viable strategies for addressing shortages to environmental water needs requires an understanding of the full suite of water uses in the Upper Roaring Fork watershed. While not all shortages are caused by humans, most of the shortages result from the depletive effects of surface water diversions. It is important to recognize that the uses of water that impact river health are often vital to the functioning of local economies and ways of life. Therefore, the viability of efforts to manage water for the protection and benefit of the environment depend on a broad understanding of how water moves through the upper Roaring Fork watershed and the values associated with various water use types. Understanding the interplay between human water needs and ecological needs is essential for productive conversations regarding strategies for integrated management of a limited resource—conversations that must consider the difficult trade-offs associated with any change in existing water management. 27 27 RECOGNIZING TRADE OFFS Patterns of water use are dictated by water rights administration, local policy, patterns of development, and community values, needs, and preferences. Agriculture & Viewscapes Snowmelt and rainfall in the mountains above Aspen provide water for human uses and in support of river health. In fact, mountain snowpacks provide almost all of the annual water yield from the upper Roaring Fork watershed. Warming spring temperatures coincide with peak flows on the river in May and July of each year. As the snowpack melts out, springs and regional groundwater supplies sustain much lower flows through the fall and winter months. As streamflows decrease, less water is available to support all the human and environmental uses that exist on local streams and rivers. Water flowing through many local streams and rivers is allocated in such a way that makes it difficult to provide the entire supply needed to meet all uses, particularly during times of drought. Use of water to meet one need, often results in less water available to meet other needs. A review of hydrological information for the upper Roaring Fork watershed indicates that surface water diversion and use produces widespread alteration of the flow regime. These affects are most pronounced on tributary streams and the Roaring Fork River mainstem below trans-mountain diversions and points of in-basin water use. Fluvial ecologists generally treat flow regime as the “master variable” exerting the largest influence on riverine ecosystem form and function and their ability to provide important ecosystem goods and services. Water use activities that deplete or augment streamflow may adversely impact channel stability, riparian vegetation, and floodplain functions. Parks, Landscaping & Water Features Pitkin County is home to numerous active farms and ranches. Many of these ranches are cow-calf operations that hold water rights used to support production of hay and alfalfa. A few local farms grow produce, including leafy greens and potatoes. Pitkin County holds conservation leases on several agricultural parcels with water rights and owns numerous parcels and water rights, outright. This land is often leased back to agricultural producers and kept in production. Many private residences utilize irrigation water to provide pasture grass for horses or maintain open Drinking Water green spaces. The City of Aspen diverts surface water that supports a wide range of uses not immediately recognizable to many local residents. These uses include drinking water supply, snowmaking for augmentation of winter snowpacks on local ski resorts, water features, irrigation of local parks and green spaces, and treatment of polluted stormwater runoff in engineered wetlands at John Denver Sanctuary. Several HOAs, clubs and private residences also utilize water from the river to support landscaping and golf courses. 28 Ecological Integrity 4. COMMUNITY PREFERENCES In late 2016 and 2017, local management preferences and values systems were investigated through a facilitated stakeholder process that engaged river-oriented stakeholders and members of the community several times (Appendix A). In the fall/winter of 2016, informal interviews were conducted with roughly 20 stakeholders representing environmental, recreational, agricultural and community interests, as well as local, state and federal agencies, and knowledgeable river experts in the community. These interviews helped identify potential opportunities and challenges to the planning effort, as well as considerations for improving the health of the upper Roaring Fork watershed while meeting the needs of multiple water users and interests. The input received from all participants helped frame community perspectives regarding water use and river health. Specifically, these interactions framed important community preferences for the planning process itself. Themes identified for successful water management planning: • Water management planning is a priority: Overall water management planning for the upper Roaring Fork River seems appropriate, given the degraded quality of river health in many stream segments. • Don’t reinvent the wheel: Draw on wealth of existing ecological and hydrological studies rather than performing new detailed investigations. • Improve coordination and collaboration between the City and County: Plan strategically for improved working relationships and processes surrounding water management decision-making. • Build trust and communication among key water interests: Getting the key water users in the same room to talk about their needs, concerns, and priorities is a significant step toward exploring creative, mutually acceptable solutions to complex water problems. • Solicit community values and priorities: In light of the potential tradeoffs for different management alternatives, ensure adequate participation by a broad stakeholder group. • Don’t lose sight of the future: Work to resolve existing poor conditions while anticipating potential future climate, water or land use conditions that could further degrade the environmental health of the river. 29 Stakeholders and members of the public also participated in an exploration of geographic priorities, community values regarding the various ecosystem attributes, and the types of water management actions that the City of Aspen and Pitkin County may employ to improve river health (e.g. water transactions, water storage, channel reconfiguration, infrastructure upgrades, etc.). Several interviewees and other community members served on an advisory committee referred to as the Technical Advisory Group (TAG). This committee met over the summer of 2017 to provide more in-depth, substantive input on planning objectives and recommendations. In this way, the Technical Advisory Group helped guide the planning process by refining objectives and prioritizing recommended actions. The TAG was composed of representatives from the following organizations: City of Aspen – Stormwater, Parks, Utilities Departments Pitkin County – Healthy Rivers and Streams; Open Space and Trails Roaring Fork Conservancy Salvation Ditch Company Ruedi Water & Power Authority Colorado River Water Conservation District Twin Lakes Reservoir and Canal Company US Forest Service Colorado Parks and Wildlife Trout Unlimited Aspen Center for Environmental Studies Colorado Water Trust Colorado Water Conservation Board In working with the project team, City and County staff, the TAG, and the public, it was apparent that water issues are sensitive and tied to long histories. Therefore, a productive process to study and recommend river management actions needed to foster trust and openness among stakeholders while maintaining a commitment to satisfying the core needs of water users. In the course of this study, the entities listed above had the opportunity to begin to discuss their goals for the river, concerns about current conditions, and interests in future river management. In discussing principles for building trust and mutual understanding going forward, stakeholders underscored the importance of open, interest-based discussions when exploring creative, nuanced ways for managing the river to meet a multiplicity of needs. 30 Principles identified to guide meaningful discussion on water use issues:: • Include a diversity of views: The more groups that buy in to river health and feel their interests are recognized in the process, the more traction projects will get and action will follow. • Strive for open dialogue: Aim for transparency and mutual understanding while acknowledging areas of sensitivity and/or need for sidebars. • Focus on building relationships: Foster long-term creative problem-solving and coordinated action among all water users in the upper Roaring Fork watershed. • Recognize that all water uses are valid: Valuing a user’s priorities is different from trying to change his/her behavior. Remember words matter in whether people feel their priorities are valued. • Engage and educate: Stakeholders and community members should be briefed on the issues and data before being asked for nuanced feedback or evaluation of management alternatives and associated trade-offs. This input received from the TAG and other members of the community was essential to understanding the types of activities capable of satisfying broadly held interests and priorities for water in the upper Roaring Fork watershed. Understanding stakeholders’ needs and priorities helped avoid identification of “solutions” that run contrary to those interests, while helping the City and County find pathways to meet their environmental stewardship obligations, and the City’s obligation to provide a legal, reliable water supply to its citizens and customers. One of the consistent themes from stakeholder interviews and discussions was a desire to see more structured, regular, and open communication and coordination on management of the Upper Roaring Fork between the City of Aspen and Pitkin County. This planning effort was certainly seen by many stakeholders as a step forward in that regard. In addition to facilitated discussions by the TAG, the planning effort sought input and guidance from the general public. A project open house and a series of public meetings provided a venue for community members to reflect on their values and perspectives related to the various uses of water (e.g. agricultural, recreational, aesthetic, etc.) from the Roaring Fork River and its tributaries near Aspen. While these meetings tended to attract residents that care deeply about water use issues, they provided valuable information about the community’s relative priorities for water use, water management, and allocation of scarce resources to restoration or rehabilitation efforts. As discussed in the previous section, actions that alleviate environmental impairments in one part of the watershed may exacerbate shortages in other locations or for other water uses. Any streamflow management planning effort will require stakeholders in the upper Roaring Fork watershed to understand, consider, and weigh the interrelated impacts and tradeoffs of any management action. An identification of community members’ priority needs and 31 values surrounding water use can assist greatly in this assessment of tradeoffs. Through guided discussions and small-group exercises, residents and stakeholders identified high-priority stream reaches, outlined key considerations for water management trade-offs, and indicated preferences for general types of management actions. Three public meetings and a web survey provided venues for members of the community to reflect on their values surrounding water use and river health. Input received at public meetings indicated general community recognition of the intertwined nature of the local economy, the quality of life and experience enjoyed by residents and visitors alike, and the ecological integrity on local waterways. In total, 35 people participated in the project open house and subsequent public meetings and 62 people participated in the online survey. It is highly likely that the individuals that participated in these activities represent the portion of the community most invested or interested in river health issues. Therefore, extrapolation of the outcomes presented below to represent the entire breadth of community values or preferences should be approached with some caution. Figure 5. Public meeting responses allocating preference points to various water uses In ranking exercises and small-group discussions, ecological integrity received the highest allocation of points as a priority water use – both because of its singular importance for community members, and because of its function in supporting recreation and other uses (Figure 5). The high allocation of preference points to managing for ecological integrity and domestic water supply— and the significant potential that management of one attribute will come at the expense of the other—confirms the critical importance of understanding the impacts of domestic water supply development on the ecological health of streams and rivers. The inverse is equally true. Responses indicate the local community is resistant to managing for river health at the expense of domestic supply reliability. The potential for conflicting management goals is high, which speaks to the need for continued engagement with stakeholders and members of the local community when conducting these types of planning efforts. Participants noted their responses were less favorable to ‘Drinking Water Supply’ when it was articulated to include outdoor water use. Likewise, they were more favorable to ‘Local Food Production’ when it was articulated to mean broad agricultural uses that support open spaces and seasonally green viewscapes. Responses also changed depending on whether the focus was on ‘local food’ or ‘food production’ in general. The need to articulate the nature of trade-offs to the local community when managing water for one use or another is substantial. Importantly, participant responses in public meetings closely mirrored those collected from the web survey (Figure 6). 32 Figure 6. Web survey responses indicating community preferences for various water uses. Each line represents the combined preferences of a single respondent. Domestic water supply and snowmaking were combined as a use to reflect their interconnected nature in the City of Aspen municipal supply system. Ecological health and domestic supply received the highest density (total number of lines) and weighting (distance of lines from center) of preference points, indicating a common view among participants that these are the high-priority water management issues in the upper Roaring Fork watershed. Stakeholders’ prioritization of environmental management needs by geographic reach confirmed the appropriateness of the planning effort’s focus on the Roaring Fork between Difficult Creek and Brush Creek. Stream reach prioritizations were primarily provided by the TAG but were additionally informed by public meetings and interviews. Articulation of preferences by each TAG member was informed by 1) personal or professional interactions with local waterways, 2) mission statements or motivations of the represented organizations, and 3) through consideration of the functional assessment rankings outlined previously and the studies and information that underlie those rankings. Results were captured using an Analytical Hierarchy Process ‘pairwise comparison’ exercise of all the reaches in the planning area. Participants identified preferences, and the relative strength of those preferences, for allocating management funding and resources to one river segment over another (e.g., Hunter Creek vs. Maroon Creek). The aggregated results clarified areas of agreement and disparity between the geographic priorities held by the City, County, and other stakeholders (Figure 7). 33 Figure 7. TAG preferences for river segment protection/improvement. The City, County and consultant team had anticipated the exercise would reveal a clear preference for managing to improve or protect ecological conditions on the section of the Roaring Fork that flows through Aspen. While this segment received the most preference points, participants expressed a greater diversity of preferences than expected. Hunter Creek and the upper Roaring Fork were called out as important areas for consideration, as portions of each are frequently dried up by water diversions. The most favored segment received 20% of the allocated preference points, while the least favored segment received 8% . The divergent priorities among advisory group members limited overall consensus regarding management priorities. This outcome illustrates some areas common understanding, as well as some divergence in perspectives and priorities among the City, County, and local stakeholders. This outcome indicates the City and County may need to begin any project or process to improve ecological conditions in a particular geographic area with some targeted outreach that helps stakeholders and community members understand the basis for selection of one river segment over another. Figure 8. Public Preferences for Ecosystem Management. Members of the community present at the public meetings were also asked to indicate preferences for allocation of funding toward protection of different aspects of the river ecosystem. Results of simple ranking exercises and discussion indicated positive community response to efforts that aim to improve or protect riparian and wetland health (Figure 8). The community found efforts to improve or protect the health of native fish and aquatic macroinvertebrates 34 favorable as well. Participants clarified that their preference for riparian health management grew from a general understanding of the critical role that riparian areas play in creating terrestrial habitat for avian species and amphibians, and in providing high quality habitat and energy inputs for aquatic food webs. Aquatic macroinvertebrates received a high number of preference points due to awareness of the Clean Water Act Impaired Waterbody listing on the Roaring Fork River through the City of Aspen. A general affinity for cutthroat trout as an iconic local species elevated the preference rankings for native fish. Illustration of overlapping geographic priority areas and preferred ecosystem attributes helped clarify which river health projects are likely to enjoy the greatest public support (Figure 9). While cross referencing preferences in this way can be useful for showing alignment between locations and issues of concern, this study does not recommend using such results as the basis for managing to the exclusion of ecosystem attributes or locations that rank low in the comparison matrix. Instead, results should be instructive to the City or County regarding the needs for messaging around contemplated or proposed river health management projects. For example, a project intended to improve the health and resiliency of amphibian communities in the North Star Preserve may benefit either from 1) an enhanced public outreach campaign to educate residents on the importance of amphibians as indicator species, or 2) a reframing of the project to focus primarily on the riparian health improvements that have secondary benefits for amphibian communities. Figure 9. Combined priority rankings for allocation of funding and other resources to specific geographic locations and ecosystem attributes. Combined management preferences align most strongly for riparian and wetland vegetation, native fish, and aquatic macroinvertebrate focused projects on Hunter Creek and the Roaring Fork River between Difficult Creek and Castle Creek. 35 4.1 REVIEW OF POTENTIAL WATER MANAGEMENT ACTIONS Stakeholder engagement efforts also yielded important community and stakeholder preferences for general categories of water management actions. The management actions considered by stakeholders ranged from water system efficiency upgrades to reservoir construction (Table 3). These actions were primarily relevant to managing low flows, since modifications of this aspect of streamflow are widespread in the upper Roaring Fork watershed. Sensitivity around ongoing legal cases involving administration of transmountain water rights and water supply development by the City of the Aspen prevented evaluation of any single specific action in detail. Nonetheless, this project did include a high-level effort to vet previously proposed management actions with stakeholders and community members. Generally, the evaluation of potential management actions weighed the anticipated ecological benefits (the “effectiveness”) of any type of action against the presence of political, financial, administrative and legal constraints, and any displaced or secondary social costs (the “feasibility”). It is generally understood that the most effective management actions are unlikely to be the most feasible and vice versa. Rather, the best options will exhibit the most favorable ratio (in the eyes of stakeholders and the broader community) of ecological health benefits to trade-offs. The management actions that enjoyed the greatest overlap between effectiveness and feasibility are discussed below.. Table 3. Management actions contemplated with TAG for the protection or improvement of ecological conditions on stream segments throughout the upper Roaring Fork watershed. 36 Optimization of the Twin Lakes Exchange take must stay in the Roaring Fork anyway. Significant Opportunity may exist to reallocate, firm up and benefit may be achieved by allowing the Grizzly Reservoir otherwise optimize the Twin Lakes 3,000 AF exchange. to be filled with a portion of the bypasses made under This exchange was provided for in the enabling the Twin Lake Exchange, so the water can be released legislation for the Fryingpan-Arkansas project, and in when needed most, even during periods when the the Operating Principles. In general, it provides that Cameo call is on. The overall effectiveness of this strategy when the Fry-Ark project diverts from the Hunter Creek is ultimately limited by the relatively small size of Grizzly drainage, the first 3,000 acre-feet it diverts will be made Reservoir and the associated storage accounts. Strategies available to the Twin Lakes Company on the eastern for optimizing the Twin Lakes Exchange should be slope. In return, Twin Lakes will bypass an equivalent developed in partnership with the Colorado River District, amount (up to 3,000 acre-feet) that it could otherwise the City of Aspen, Pitkin County, Colorado Parks and divert from the Roaring Fork through its Independence Wildlife, Twin Lakes, and other interested parties. Pass Transmountain Diversion System (IPTDS). Fry Ark project typically diverts water during the runoff, when Joint Operation of Salvation Ditch and City of Aspen streamflows are high. However, the water bypassed by Water Supply System Twin Lakes is most valuable to the Roaring Fork when River health management goals may be advanced flows are decreasing as runoff tails off. through joint operation of Salvation Ditch and City of In addition to the Twin Lakes exchange, other Aspen’s potential water storage reservoir near Woody agreements with Twin Lakes are intended to benefit the Creek. It may be possible to build a pump delivery Roaring Fork. Under the terms of Twin Lake’s water court system from the potential storage site to the Salvation decree in Case No. 95CW321 and related stipulations, Ditch. Pumped water from the storage site into the water can be stored in Grizzly Reservoir for the benefit Salvation Ditch during low flow periods could satisfy of the western slope under the Grizzly Reservoir River a portion of the Salvation Ditch demands in dry years, District Account and a Mitigation Accounts. These and thereby reduce diversions at the Salvation Ditch accounts have a combined capacity of 240 AF, and headgate. This could benefit streamflows in the Roaring releases of up to 190 AF per year can be made from those Fork River through Aspen. Pumping, exchanges of water, accounts. However, at this time, the water stored in those or alternate points of diversion could also be considered accounts is water decreed to Twin Lakes under its 1994 between the City of Aspen and Salvation Ditch diversion priority water right, which is unreliable due to its junior and storage points as a potential approach to reducing status. the amount of pipeline required to supply water The utility of the Twin Lakes Exchange and the reliability from the Woody Creek reservoir site to the municipal of the Grizzly Reservoir Accounts may be increased by treatment and distribution system. Either approach allowing bypass flows under the Twin Lakes Exchange to would require an agreement between the City of Aspen be stored in the Grizzly Reservoir Accounts, rather than and the Salvation Ditch Company and, possibly, water being immediately delivered downstream. This would court proceedings. allow releases from storage at times most beneficial to The Salvation Ditch is a senior water right to the IPTDS the Roaring Fork. Currently, the bypasses made under and several stakeholders expressed concern that moving the Twin Lakes exchange (which are more reliable than it’s point of diversion or implementing water exchanges the water rights that can be stored in Grizzly, because could result a reduced number of administrative they come from Twin Lakes’ relatively senior 1936 priority calls and an increase in the amount of water diverted water right) may not be available at the most critical by the IPTDS. A review of the historical water rights times of the year. Such is the case when a call is placed administration call record for the upper Roaring Fork by senior water rights in the Grand Valley (i.e. the “Cameo indicates that, under historical and current climate call”) which precludes operation of the IPTDS in late conditions, reduced diversions by the Salvation Ditch summer. Bypasses cannot occur when Twin Lakes is at its headgate would not result in increased diversion called out; all of the water the IPTDS would otherwise rates through the Independence Pass Transmountain 37 Diversion System. Therefore, amounts not diverted at the best approach for bypass agreements would not the Salvation Ditch headgate would represent a net be through a CWCB leasing program, as the Salvation benefit to ecological conditions on the Roaring Fork Ditch Company has indicated disinterest in a water through Aspen. Future assessments of this option court process. Some newer statutory options might should consider the impacts that changing climate be considered. As noted previously, a review of the may have on water supply and administration of historical water rights administration call record for the senior Salvation Ditch water rights relative to the upper Roaring Fork indicates that reduced diversions Independence Pass Transmountain Diversion System. by the Salvation Ditch would not result in increased Any such assessment should be completed in close diversion rates through the Independence Pass collaboration between Salvation Ditch, City of Aspen, Transmountain Diversion System. Therefore, bypassed and other key stakeholders respecting parties’ needs, flows would represent a net benefit to ecological existing rights, and other interests. conditions on the Roaring Fork through Aspen. However, future assessments should verify that this Reduced City of Aspen Raw Water Supply condition will persist under an altered future climate During periods of low flow, particularly in drought and changed patterns in water rights administration. years, the City of Aspen can reduce diversions at Again, any such arrangement should be carefully the Riverside Ditch and Wheeler Ditch through considered by Salvation Ditch, City of Aspen, and other agreements similar the City’s current Non-Diversion key stakeholders in light of parties’ needs, existing Agreement with the Colorado Water Trust. Reductions rights, and other interests. in water diversions at these locations can reduce supply for the pedestrian mall fountain and for Secure Bypass Flows at Maroon Ditch irrigation supply to some public parks. Further study The City of Aspen currently operates a bypass at the may be needed to understand the impacts of reduced Maroon Ditch headgate in an amount no less than the supply on the stormwater treatment functions of decreed instream flow (14 cfs) to ensure adequate flows the artificial wetlands complex at John Denver Park. for protection of aquatic life during low-flow periods. A review of streamflow data and the historical call This bypass is not a protected water right and can be record indicates that groundwater inflows to the river diverted from the river by upstream junior water rights. between Salvation Ditch and the Wheeler Ditch likely The Utilities Department could evaluate a leasing make up a significant portion of the water diverted by agreement or permanent dedication of a portion of the Wheeler Ditch. This scenario makes it unlikely that the Maroon Ditch water right to the CWCB Instream bypassed water at the Wheeler Ditch would be used by Flow program so the bypass can be operated in priority the upstream junior rights. Any diversion reduction at for the benefit of river health. The latter option will the Riverside Ditch may require a separate agreement require lengthy water court proceedings and will likely between the City of Aspen and the eight other water be challenged by upstream junior water rights holders. rights holders on that ditch. . Several management opportunities that do not Water Leasing from Salvation Ditch involve water supply planning or management were Another option would require a public-private identified by Roaring Fork watershed stakeholders. partnership to reduce conveyance losses in the While identification and ranking of alternatives not Salvation Ditch, which would result either in reduced tied to water management were not the original focus total Salvation Ditch irrigation water requirements of this planning effort, several of the identified actions or in reductions in consumptive use shortages on align well with the management priorities indicated the lands irrigated by the Salvation Ditch. Efficiency by stakeholders and community members (Figure 7). improvements, funded in part by the City or County, In particular, Colorado Parks and Wildlife personnel could be coupled with a dry year bypass agreement for identified options for improving the local native fishery. the Salvation Ditch headgate. If this option in pursued, Pitkin County Open Space and Trails is also considering 38 management actions in the North Star Preserve and County could partner with the Aspen Center for that can benefit riparian health. Significantly, these Environmental Studies to improve the degrading dike opportunities involve property owned by Pitkin County, between the lake and river, then encourage CPW to a local non-profit, or managed by the U.S. Forest remove non-native fish species and stock cutthroat Service and could largely sidestep the contentious trout in their place. A native cutthroat trout population nature of water rights and water supply management in the center of Aspen could provide a unique asset for discussions. The three most promising opportunities engaging and educating the public about river health are discussed in greater detail below: issues. Hunter Creek Cutthroat Trout Management North Star Preserve Wetland Drain Removal The upper portion of Hunter Creek provides ideal Several historic ditches in the North Star Preserve drain habitat for expansion of native cutthroat trout range. a large wetland area and lower the water table in Diversion structures limit aquatic organism passage the alluvial aquifer. Filling, damming, or permanently and help to isolate at-risk populations. The City, County closing headgates on these ditches would help and private landowners could work to install fish impound more hillslope runoff in the wetland and screens on the Red Mountain Ditch and encourage increase water storage in the floodplain aquifer. This Colorado Parks and Wildlife to remove non-native project may yield small benefits to the Roaring Fork species and stock native trout in Hunter Creek above River by contributing a small amount of cool water that location. to late summer flows above and through the City of Aspen. The largest benefits are expected to accrue to Hallam Lake Cutthroat Trout Introduction the riparian vegetation within the North Star Preserve. Consistent cool temperatures from spring flows and Elevated water tables will likely help support existing no passable hydrological connections between Hallam vegetation and promote growth of new vegetation Lake and the Roaring Fork River make it a potential across a larger portion of the floodplain. location for rearing native cutthroat trout. The City 5. DECISION SUPPORT TOOLS A full understanding of trade-offs involved in any potential water management action will require application of a robust set of tools and methodologies that help planning process participants understand the likely outcomes of any given action. In anticipation of a second phase of work where one or more of the above management actions is further assessed for its validity and ability to deliver value to the City of Aspen, Pitkin County and other local stakeholders, this planning effort included development of: 1) A hydrology and water rights simulation tool (Appendix B), and 2) an evaluation framework for considering ecological needs and impacts on a given stream reach (Appendix C). A brief discussion of each is provided here. Detailed information can be found in the appendices to this document. 5.1 HYDROLOGICAL SIMULATION MODEL The daily, seasonal, and inter-annual variations in a stream’s flows make up its hydrologic regime. Hydrologic characteristics of interest for streams in the upper Roaring Fork watershed include the duration, frequency, and magnitude of different flow types on the mainstem and tributaries. Surface diversions and reservoir operations strongly alter the longitudinal (upstream-downstream) and temporal (day-to-day or seasonal) patterns of flow in many streams throughout the basin. Additionally, long term hydrological conditions like drought or wet periods can impart both obvious and subtle changes. Understanding interactions between human and natural systems is, therefore, critical for effective resource management. 39 The balance of water flowing into streams from snowmelt and rainfall, getting diverted for human uses, being consumed or evaporating, and returning to the river via surface or groundwater, creates the components of a water budget. The responses of physical and legal water demands to hydrological conditions determine the allocation of water among the various uses present in the system. Characterizing patterns of daily streamflow across a range of hydrological conditions and under different management regimes in the upper Roaring Fork watershed is possible at several locations where United States Geological Survey (USGS) gauges exist and maintain long data records. On the mainstem and on some tributaries, good streamflow records are relatively sparse both in geographic coverage and length of observations. In aggregate, historic and current data are inadequate to describe typical daily flow conditions at a sufficient spatial resolution to inform water management decisions at all locations where they may be considered. To provide these estimates at additional points intermediate to or above locations where historical data is available, this project utilized hydrological simulation tools. Simulation models and spreadsheet models were developed that utilized observed streamflow and diversion records, statistical data filling approaches, and algorithms approximating the administration of Colorado Water Law in order to produce daily timestep simulations of water availability, water demand, patterns of local use, and discrepancies between use needs and water supply. These simulation models allow City and County staff and their consultants to test “what-if” water use and management scenarios in the upper watershed in a consistent and data-driven manner. In addition to their use to further assess and refine the management opportunities listed previously, simulation tools and the ecological evaluation framework may be used to inform other parallel efforts. The daily hydrological simulation models may be useful to the City’s ongoing efforts to understand impacts of climate change on its water supplies and its future ability to simultaneously meet municipal demands, contract obligations, and the needs of the environment. Any effort to build climate change scenarios into the hydrological simulation models would also benefit future discussions about water management for river health but must be proceeded by an agreement among City departments regarding the types of and theoretical basis for selected climate change scenarios. 5.2 ECOLOGICAL EVALUATION FRAMEWORK An ancillary effort to the planning process developed of a general approach and articulation of data requirements for evaluating environmental impacts from future water development projects or environmental benefits from future water leasing/conservation/improved water efficiency projects within the upper Roaring Fork River basin. The resultant framework provides the City, County and future participants of water management planning processes with considerations about the suite of information available (or unavailable) for reaches throughout the upper watershed. Basic conceptual models developed for individual stream segments based on existing data/information and expert judgement should help decision makers understand the largest threats to river health on each reach and the limitations of existing data for informing alternative management actions. The framework also makes recommendations for iterative or ‘adaptive’ approaches to water management decision making. The step-wise process developed previously for Pitkin County8 is identified as an effective planning approach (Figure 10). 40 Figure 10. A process for assessing impacts or benefits of water management actions in the upper Roaring Fork watershed.8 The framework highlights the importance of a concise statement of project goals and objectives for any management effort. Specific goals and objectives provide context for the type of analysis needed to inform on the beneficial or detrimental impacts of a management action. Where the project fits on the scale from simple to complex and non-controversial to controversial can also aid in determining the range of study or data needed for the assessment. Consideration of hydrological simulation results (Appendix B) will place hydrological changes in the appropriate ecological context and help users predict the degree to which any management action will impact river health. Critically, application of the framework by county staff or municipal decisionmakers can and should be assisted by professionals in the specific disciplines potentially affected by the project. The initial result for framework application should be a listing of potential data needs, studies and timeline for analysis to better understand potential impacts of a management action. 41 6. CONCLUSIONS This effort was motivated by a body of reports and studies indicating degraded river health on several stream segments near Aspen. In 2012, the Colorado Water Quality Control Division placed the stretch of the Roaring Fork that flows through Aspen on Colorado’s list of Impaired Waters. In response, this effort sought to identify and categorize specific stressors to the health of aquatic and riparian plants and animals. Special emphasis was placed on identifying degradation caused by modified patterns of streamflow and, subsequently, utilizing a stakeholder process to develop effective and feasible water management responses. Functional assessment results produced for the Roaring Fork mainstem and major tributaries between Lost Man Creek on Independence Pass and the Brush Creek confluence near Woody Creek indicated widespread alteration of streamflows. Transmountain diversions and in-basin water uses reduce peak flows and deplete late summer baseflows. The latter limits habitat availability and quality for aquatic species. These impacts are most acute in the upper sections of the Roaring Fork River, Lincoln Creek, and Hunter Creek, but persist downstream to the confluence of the Roaring Fork River and Castle Creek, especially during drought years. Engagement with community members, water rights holders, and representatives from conservation organizations, state agencies, federal agencies, and special districts helped identify the competing values, perspectives, and needs around water. This input received from the TAG and other members of the community was essential to understanding the types of activities capable of satisfying broadly held interests and priorities for water management in the Upper Roaring Fork watershed. Understanding stakeholders’ needs and priorities, in turn, helped avoid identification of “solutions” that run contrary to those interests. Beneficial outcomes of the community engagement process included prioritizations of stream management reaches and ecological health issues. Prioritizations indicated a community preference for management of river health conditions on the Roaring Fork River between Difficult Creek and Castle Creek. The community seemed most inclined to support activities focused on riparian/wetland vegetation health, aquatic macroinvertebrates, and native fisheries. In addition to elucidating community values and preferences for water use, stakeholders weighed the potential ecological benefits of several water management opportunities against the financial, legal, administrative, and political constraints (and other tradeoffs) each posed. This process helped identify a number of management activities that may be used to effect positive change in measures of river health on the Roaring Fork River. Management opportunities that warrant further investigation include: Optimization of the Twin Lakes Exchange Joint Operation of City of Aspen Municipal Supply and Salvation Ditch Dry-Year Municipal Raw Water Supply Reductions Maroon Creek Municipal Water Right CWCB Dedication Dry-Year Water Leasing with the Salvation Ditch Company Hunter Creek Cutthroat Trout Management Hallam Lake Cutthroat Trout Introduction North Star Preserve Wetland Drain Removal 42 6.1 CHALLENGES TO THE PLANNING PROCESS Originally, the effort was designed to develop and evaluate, with extensive input from stakeholders, management approaches to address these identified stressors. Several consequential issues emerged early in the planning process, indicating it was premature to develop and vet any such alternatives in depth. First, the nature of legal proceedings concerning Roaring Fork water issues and participation of key several stakeholders in those proceedings made it increasingly clear that this planning effort could not result in concrete recommendations for river management actions. The project team anticipated and hoped these issues would resolve in time for useful integration into the planning process. However, given the unresolved, confidential nature of the legal proceedings, the potential for a changed administrative and water management landscape as a result of those proceedings, and overlap between the legal issues and potential management actions, City and County staff opted to change the scope to focus on building constructive stakeholder dialogue on river conditions, risks and priorities, in addition to delivering visuals, decision-support frameworks, and simulation tools useful for educating the public or characterizing costs and benefits of a variety of water management actions contemplated in the future. Fortunately, there was significant interest expressed among stakeholders for increased focus on the collaborative decision-making process itself. This interest focused on the dynamic at play between the City of Aspen and Pitkin County, but also among other users who rarely have the opportunity to communicate openly about water issues in a structured and facilitated setting. 6.2 NEXT STEPS While City and County interests have at times diverged due to discrete issues on the Roaring Fork, there is significant community interest in seeing more alignment of shared priorities and planning objectives between the two entities. To address this priority, a primary recommendation of this study is to jointly plan and convene a facilitated workshop for City and County water managers, planners, and relevant land managers to 1) discuss their interests and needs with respect to the Roaring Fork, 2) highlight points of shared interest as well as potential conflict, and work to develop approaches to each; and 3) identify strategies going forward to share information, coordinate river management efforts, and undertake joint planning and communications where useful. The intended net benefit of this workshop is reducing barriers to the joint advancement of the City of Aspen’s and Pitkin County’s water management goals and environmental stewardship obligations. A sample scope of work and budget for the workshop is included in Appendix A. Moving forward, the City and the County should capitalize on the trust and relationshipbuilding that occurred during this project among diverse stakeholders. Water supplies in the upper Roaring Fork watershed are finite, support a diversity of uses, and are fully allocated at certain times of year. Management actions that support or improve one use opportunity for one type of water need may reduce use opportunities for another. For example, improving late summer flows in the Roaring Fork River through Aspen might be achieved through a reallocation of City of Aspen-owned water from public parks and fountains to the river. Alternatively, low flow conditions might be improved through leasing programs or contractual relationships that allow for temporary reallocation of water from irrigated agriculture to the river. Both of these actions would likely benefit aquatic plants and animals but may do so at the 43 expense of aesthetic enjoyment of water features in the City of Aspen or at the expense of water amenities, green viewscapes, and agricultural production in McClain Flats. In order for either option to proceed beyond conceptual planning levels, there will need to be widespread buy-in from key water users and the local community. Optimizing management of local water resources to align with the City of Aspen’s obligations as a water provider and its river health goals, and Pitkin County’s management objectives for Open Space and Trails properties, therefore, relies on thoughtful, strategic collaboration among diverse stakeholders. Participants in such collaborative discussions should include water rights holders, City and County staff, resource management agency personnel, elected officials, and other organizations and individuals with an interest in Upper Roaring Fork watershed resource management. The participants list for the Technical Advisory Group should be a reference for potential contacts and willing participants in future water management related conversations. Effective and informed discussions about water issues in future community and/or stakeholder groups settings must be supported by reliable data and communication tools that speak to a diverse audience. Furthermore, any discussion that contemplates a change to water use or management should be supported by conceptual models, data products and simulation tools that help participants understand the likely outcomes of any given action. To this end, the project team developed a pair of hydrological and water rights simulation tools (Appendix B). These simulation models will allow City and County staff and their consultants to test “what-if” water use and management scenarios in the upper watershed. Consideration of simulation results using an ecological evaluation framework (Appendix C), also developed for this effort by the project team, will place hydrological changes in the appropriate ecological context and help users predict the degree to which any management action will impact river health. In addition to their use to further assess and refine the management opportunities listed previously, simulation tools and the ecological evaluation framework may be used to inform other parallel efforts. The daily hydrological simulation models may be useful to the City’s ongoing efforts to understand how climate change is likely to impact the Utility Department’s obligation to deliver contract water and treated municipal water. Any effort to build climate change scenarios into the hydrological simulation models would also benefit future discussions about water management for river health. Characterizing the range of hydrological variability expected in the future may help identify certain river health conditions that cannot be feasibly managed for given existing tools and strategies. For example, future reductions in snowfall and increases in temperature may make late season streamflows so low and water temperatures so warm that it becomes unreasonable to manage water in support of a cold-water trout fishery. This plan and accompanying work products and modeling tools provide an assessment of existing conditions and a decision-making framework for improving or maintaining the ecological health of the upper Roaring Fork River and its tributaries while reflecting local values and priorities and the administrative and legal realities governing the use of water in Colorado. Final planning outcomes and deliverables provide the City and County with valuable insight into community perspectives on river health and should support ongoing efforts to: 1) inform future water development planning and approval processes; 2) develop or align local water and land use policies; 3) improve management of existing water infrastructure; 4) inform strategic exercise, dedication, or acquisition of water rights; and 5) engage with local and regional organizations or individuals involved in water management decision-making. 44 7. ANNOTATED BIBLIOGRAPHY 1. Ayres Associates. 2011. Geomorphic Assessment of the Stability of the Roaring Fork River through the City of Aspen, Pitkin County, Colorado. Feb 11, 2011. This report evaluated existing geomorphic conditions in the Roaring Fork River from the Salvation Ditch downstream to Castle Creek. The report contains maps of channel geomorphology and structure locations, identifies instream structures, and provides recommendations for geomorphic conditions. Recommendations from the report include modifying or removing man-made structures constructed in the channel. Several of these structures impede fish passage during low flows, decrease the channel gradient, induce localized aggradation, and increase channel width via bank erosion. 2. Clarke, S., M. Fuller, and R.A. Sullivan. 2012. Roaring Fork Watershed Plan. Prepared for Reudi Water and Power Authority. This plan is the result of findings from the State of the Roaring Fork Watershed Report (2008), and collaborative discussion from subsequent public and technical meetings. The resulting goals, objectives and actions are organized under broad topics: Regional Water Management, Surface Water, Groundwater, Water Quality, and Riparian and Instream Habitat. No specific projects or flow-related recommendations for the upper Roaring Fork watershed were included in the report, but it did contain several recommendations for future efforts. 3. Clarke, S. 2006a. Roaring Fork Watershed Streamflow Survey Report. Prepared for Roaring Fork Conservancy. The project was designed to provide the technical foundation of the Roaring Fork Conservancy’s broader goal of pursuing sustainable flows in the watershed, motivated by recognition that stream health is important both economically and environmentally to local communities. The investigation concluded that most cases of significant hydrologic alteration are seasonal and due to agricultural irrigation and snowmaking activities. It also found that transbasin diversions contribute to year-round alterations, particularly during peak flows, in the upper Roaring Fork and that CWCB instream rights are often not met as a result—particularly in Lincoln Creek and at Lost Man. No specific projects or flow-related recommendations for the upper Roaring Fork watershed were included in the report, but it did contain several recommendations for future efforts. 4. Clarke, S. 2006b. State of the Roaring Fork Watershed. Prepared for Roaring Fork Conservancy. Phase I of the Roaring Fork Watershed Plan effort characterized the condition of the Roaring Fork watershed’s resources in terms of water quality, water quantity and overall ecosystem health. 5. Colorado Department of Health and Environment. 2014. Integrated Water Quality Monitoring and Assessment Report. The Roaring Fork River is provisionally listed on the 303(d) list for Aquatic Life use impairment between Hunter Creek and Brush Creek. 6. Driscoll, M. 2011. Front Range Water Supply Planning Update: Increased Storage, Increased Demands, Increased Transmountain Diversions. Submitted to Roaring Fork Conservancy. 7. Espegren, G. 2011. Review of City of Aspen’s Castle Creek Hydroelectric Project Aquatic Resource Documents. January 14, 2011. This report reviewed the City of Aspen’s Castle Creek Hydroelectric Project documents pertaining to the stream health and aquatic resources of Maroon and Castle Creeks. The objective was to determine whether Aspen had adequately addressed potential biologic impacts that could occur on these creeks as a result of proposed hydroelectric operations. Findings indicated that while Aspen was willing to ensure that the Colorado Water Conservation Board’s (CWCB) decreed instream flow (ISF) rights on both Castle and Maroon Creeks were maintained, the use of R2Cross to evaluate environmental impacts to these creeks had significant limitations. Aspen’s diversions during peak flow seasons would not likely have significant impacts on peak flows, however, hydropower diversion impacts on the ascending and descending limbs of the hydrograph, as well as during late summer and winter baseflows, could potentially impact riparian and aquatic health. Several recommendations were made for improving Aspen’s environmental impact analysis and its proposed monitoring and adaptive management plan. 8. Espegren, G. and L. Rozaklis. 2012. A Scientific/Social Framework for Managing Impacts of Water Diversions to Protect Stream Health in Pitkin County, Colorado. Prepared for Pitkin County Healthy Rivers and Streams. May, 2012. Prepared in response to Pitkin County Healthy Rivers and Streams interest in developing a framework to analyze, evaluate and manage potential impacts of water diversions to protect aquatic health in Pitkin County streams. This report outlines a scientific/social decision-making framework utilizing Ecologically Sustainable Water Management (ESWM) principles and the Ecological Limits of Hydrologic Alteration (ELOHA) framework. The report illustrates how this decision-making process might be applied to the City of Aspen’s Castle Creek Hydropower Plant project. Conclusions indicate that the “iterative process of monitoring and adaptively managing stream diversions provides an opportunity to maximize the benefits to human uses while ensuring that aquatic health is maintained at a level that is acceptable to the local community.” 9. Golder Associates. 2014. Geomorphic Assessment, North Star Nature Preserve. Prepared for Pitkin County Open Space and Trails. Provided and evaluation of channel form and channel dynamics in the North Star Nature Preserve. Indicated man-made activities that may affect stream function and channel evolution, including hydrological modification of the upper Roaring Fork River, and historical agricultural practices at the site. 10. Hickey, A., J.C. Emerick, and K.E. Kolm. 2000. Preliminary Hydrologic and Biological Characterization of the North Star Nature Preserve, Pitkin County, Colorado. Division of Environmental Science and Engineering, Colorado School of Mines, Golden, CO. Details the hydrologic and biological characteristics of the North Star Nature Preserve and makes recommendations for restoring the enclosed wetlands. The document includes groundwater data, vegetation identification, and information pertaining to small mammals and birds in the Preserve. In-channel aquatic data were neither collected nor presented. 45 11. Mason, S.K. 2012. Snapshot Assessment of the Roaring Fork Watershed. Prepared for Roaring Fork Conservancy. November 9, 2012. The assessment characterized low flow conditions on the Crystal and Roaring Fork Rivers in the autumn of 2012. The study employed a “synoptic sampling approach” to characterize upstream-downstream variability in streamflow as affected by tributary inputs and diversion outflows on the Roaring Fork River through the City of Aspen and along the Crystal River from Avalanche Creek to the confluence with the Roaring Fork River. Conclusions indicate that the upper Roaring Fork River was most vulnerable to low flows between the Aspen Club and the confluence with Castle Creek. Within this segment, diversions were found to deplete incoming streamflow by as much as 80% during the month of July. The study also concluded that extreme low-flow conditions on the Roaring Fork might produce water temperatures known to be detrimental to high quality trout populations. 12. Mason, S.K. 2013. 2012 Upper Roaring Fork River Aquatic Life Use Assessment. Prepared for Roaring Fork Conservancy. December 12, 2013. The assessment increased existing macroinvertebrate sampling datasets at several long-term data collection sites and provided baseline conditions for additional locations. The analysis utilized Colorado’s Multi-Metric Index (MMI), along with other statistical indices, to support a water quality assessment on the Roaring Fork River. Results indicated that five of the seven study sites attained Colorado Water Quality Control Division standards for aquatic life. Two sites near the City of Aspen were rated as impaired. These results were consistent with sampling conducted in 2011 and continued to support the State’s 2012 Provisional 303(d) listing of the Roaring Fork River below Hunter Creek. While the MMI assessment does not identify specific causes of impairment, it does indicate a general stress to macroinvertebrate communities from one or more sources. Potential sources of impairment were noted as (1) regularly occurring summer low flows attributable to transbasin and local diversions; (2) impacts from urbanization, such as alteration or destruction of riparian habitat, physical channel alteration and stormwater runoff; and/or (3) legacy effects of past land use practices or pollution. 13. Miller, W.J. 2011. Final Report Evaluation of River Health: Roaring Fork River near Aspen, Colorado. Submitted to Pitkin County Attorney. Miller Ecological Consultants, Inc., Fort Collins, CO. December 21, 2011. The objective of this study was to determine current baseline river health conditions in the Roaring Fork River from the Salvation Ditch diversion downstream to the confluence with Castle Creek, a distance of approximately 3.2 miles. Within this reach, the city of Aspen’s urban environment surrounds the majority of the river. This study included both physical and biological evaluations. The physical components included year-round hydrology, stream channel characteristics (including the near stream riparian zone), stream stability and instream habitat. The biological components included an assessment of benthic macroinvertebrates and fish populations. The study approach was a multi-phased analysis that included the following: 1) hydrologic analysis of existing and natural stream flows; 2) stream channel characteristics, including cross-sectional and longitudinal profiles; 3) geomorphic assessment of stream stability; 4) instream habitat evaluation using two-dimensional modeling methods; 5) benthic macroinvertebrate sampling; and 6) fish population sampling. The report noted several recommendations and conclusions for habitat improvement and made recommendations for flushing flows. 14. Miller Ecological Consultants, Inc. and Ayres Associates. 2011. Final Letter Report-Geomorphic Assessment of the Roaring Fork River and Impacts of Groundwater Changes on Wetlands, North Star Nature Preserve, Pitkin County, Colorado. Prepared for Pitkin County, Colorado. Miller Ecological Consultants, Inc., December 14, 2011. The objective of this report was to conduct a geomorphic assessment of the impacts of groundwater changes on the wetlands and grasslands along the valley floor and evaluate the current characteristics of the Roaring Fork River within the North Star Nature Preserve upstream of the City of Aspen. The assessment used existing literature, aerial photographs, topographic mapping and a field evaluation to complete the analysis. The study area on the North Star Nature Preserve extended from the Smith Open Space downstream to near Highway 82 and Stillwater Road. The report summarized existing reports, reviewed historical USGS mapping and made several recommendations for improving geomorphic conditions. 15. Miller, W.J. and K.M Swaim. 2010. Castle Creek Hydroelectric Plant Environmental Report. Prepared for the City of Aspen, Water Utilities, Aspen, Colorado. Miller Ecological Consultants, Inc., Fort Collins, CO. October 8, 2010. This report provided a general description of existing conditions in the Castle and Maroon Creek’s watersheds as well as specific descriptions of areas potentially affected by the proposed Castle Creek hydroelectric plant. This report summarized the “State of the Roaring Fork Watershed Report” (Clarke et al. 2008). Site-specific information on instream flows, fish populations, winter fish habitat, riparian and wetlands was collected by Miller Ecological Consultants, Inc. The new studies included R2Cross analysis in Castle Creek, fish population data on Castle and Maroon Creeks, winter habitat data for Castle Creek and boreal toad surveys. 16. Miller, W.J. and K.M. Swaim. 2011. Castle and Maroon Creeks 2010 Aquatic Monitoring Report. Prepared for the City of Aspen, Water Utilities. Aspen, Colorado. Miller Ecological Consultants, Inc., Fort Collins, CO. June 6, 2011. 17. Miller, W.J. and K.M. Swaim. 2012. Castle and Maroon Creeks 2011 Aquatic Monitoring Report. Prepared for the City of Aspen, Water Utilities. Aspen, Colorado. Miller Ecological Consultants, Inc., Fort Collins, CO. May 21, 2012. 18. Miller, W.J. and K.M. Swaim. 2013. Castle and Maroon Creeks 2012 Aquatic Monitoring Report. Prepared for the City of Aspen, Water Utilities. Aspen, Colorado. Miller Ecological Consultants, Inc., Fort Collins, CO. September 11, 2013. This series of reports presented the results of the 2010-2012 monitoring in Castle Creek and Maroon Creek. The monitoring was conducted as part of the monitoring plan developed by Colorado Division of Wildlife to address possible impacts to fisheries and stream habitat related to the proposed increased water diversions associated with the City of Aspen’s Castle Creek Hydroelectric Plant. Data were collected in fall 2010 at three sites on Castle Creek and three sites on Maroon Creek. Quantitative data were collected for fish populations, benthic macroinvertebrates, and aquatic habitat at each site. The 2012 report included combined results from all three years of monitoring. 46 19. Roaring Fork Conservancy. 2006. Roaring Fork Watershed Water Quality Report. Discusses water quality conditions in streams and rivers around the Roaring Fork Watershed and identifies reaches of concern based on exceedances of State of Colorado water quality standards. 20. Sanderson, J., B. Bledsoe, N.L. Poff, T. Wilding, W. Miller, and N. Fey. 2012. Colorado Basin Roundtable Watershed Flow Evaluation Tool Study. Prepared for Northwest Colorado Council of Governments. March, 2012. The Watershed Flow Evaluation Tool (WFET) is an approach for assessing non-consumptive water use needs status at a coarse resolution across a large watershed. WFET assumes that the flow regime is the primary driver of aquatic and riparian structure and function. The approach entails developing relationships between streamflow and ecological characteristics in order to map ecological risks throughout a watershed related to changes in streamflow. Flow-ecology relationships were developed for trout, warm-water fish, macroinvertebrates, and riparian vegetation. 21. City of Aspen Municipal Water Efficiency Plan. October, 2015. Element Water Consulting. Prepared for the City of Aspen in October, 2015. This planning document contemplates the impacts of future demand growth for treated and raw water use in the City of Aspen. 47 Appendix A STAKEHOLDER OUTREACH AND ENGAGEMENT MEMO To: From: Date: Re: April Long, City of Aspen Ryan Golten, Consensus Building Institute January 15, 2018 Roaring Fork Management Plan Attached are several documents summarizing the stakeholder engagement process conducted over 2016-17. To develop buy-in and support for the Roaring Fork Management Plan, this planning process included engagement of river managers, water users, and local river ‘experts’, as well as members of the public who will ultimately need to support any viable management actions for the upper Roaring Fork River and/or its tributaries. The City and County convened nearly two dozen key stakeholders in an ad hoc Technical Advisory Group (TAG) that met during the summer of 2017 to provide input and guidance to the project team in its planning efforts. An Open House held in May was designed to inform the public about the project, and interactive public meetings held in November sought community input on values and priorities for the river and its management. Attached to this Memo are the following documents related to these efforts: • RFMP Stakeholder Engagement Plan • February, 2017 Memo to project team with summary of stakeholder interviews • Summaries from the following meetings: o TAG meeting – May 23, 2017 o TAG meeting – August 30, 2017 o Community meetings – November 8 and 9, 2017 A couple of important themes emerged in the planning process. First, the nature of key legal proceedings concerning Roaring Fork issues and stakeholders made it increasingly clear this planning effort not be able to recommend concrete river management alternatives at this time, given the confidential nature of the proceedings and the potentially changing landscape. While it was continually hoped these issues would resolve in time to be integrated into the planning process, that did not happen. As a result, the consultant team was required to delay and then work around those issues, rather than being able to complete that part of the anticipated project scope. Secondly, there was significant expressed interest among Roaring Fork stakeholders in increased collaboration on river management – not only between the City of Aspen and Pitkin County (stated by many as a very strong interest), but also among other users, who rarely have the opportunity to communicate openly about water issues in a structured and facilitated setting. In interviewing stakeholders and then working with a 25-member Technical Advisory Group, we heard from stakeholders about the importance of open communication regarding river management, particularly when exploring creative, nuanced ways for water users to share water. These issues are sensitive and tied to long histories. Participants highlighted the opportunity this process presented to begin to build trust and mutual understanding, and to establish principles for dialogue going forward. This convening of key stakeholders certainly helps lay the groundwork for important and challenging discussions. We believe that, in the near future, there will be an opportunity to integrate many of the outcomes from existing proceedings into a collaborative management framework, and to explore creative river management alternatives to achieve a more healthy river based on the hydrological information, methodology, and tools presented by this planning effort. We believe that a critical first step is to improve alignment between City and County planning objectives, values, and perspectives around water issues. A proposed scope for a workshop that may be useful for improving alignment and improving understanding between the two entities is included here. Proposed Scope of Work for City of Aspen & Pitkin County Water Coordination (or ‘Alignment’) Workshop Background: The City of Aspen and Pitkin County are contemplating holding a workshop to improve communication, collaboration, and overall alignment between with City and County on water planning efforts in the Upper Roaring Fork Valley. Overlapping project goals, as well as plans, policies and principles that can sometimes be in conflict, make this a discussion well suited to using outside facilitators who are currently working with the City and County on other water initiatives. Scope of Work: This proposed scope of work includes four main elements: 1. Prepare for the workshop: This will involve the facilitators working closely with City and County staff to understand the context and impetus for holding this meeting, and to develop an approach, agenda and goals for the meeting. It is expected the facilitators will bring suggestions and ideas forward in working with the City and County to develop an approach and agenda for the meeting. 2. Interview participants: Facilitators will conduct approximately 10 interviews, which will be scheduled by City and County staff, to allow the facilitators a confidential opportunity to hear perspectives from participants prior to the meeting, and to help identify key issues in order to inform the meeting agenda and approach. 3. Facilitate one-day meeting: Trained facilitator will coordinate and guide a one-day workshop. The goal will be to engage participation from all invitees and cover the following objectives: a. Allow participants to acknowledge common goals as well as differing mandates, competing priorities, and/or other issues and the tension or conflicts they may cause. b. Building and relying on the above, discuss ways to better communicate, coordinate, and/or collaborate with respect to different City and County water projects. This will likely include developing a set of principles regarding future coordination between the two entities with respect to water issues. It should also include a discussion of how these principles can be put into practice. Examples may include: how to deal with conflict when it arises; how to preempt unnecessary conflict, how to acknowledge and work through common and differing interests in a way that is pragmatic, structural and systematic, rather than politicized (or personalized). The final part of the meeting should also include a discussion of how ideas from the day can be applied to key related projects anticipated in 2017-18. 4. Document the meeting in a concise report for the City and County. The report will include any necessary next steps for developing written agreements and/or plans based on the meeting discussion, particularly with respect to ‘operationalizing’ any agreements in principle. Deliverables: 1. Meeting agenda as informed by the interviews and preparatory meetings 2. Workshop facilitation 3. A summary of the meeting highlighting action items and next steps Proposed Budget A sample budget is include below to assist in estimation of order-of-magnitude costs for the scope outlined above. PROJECT LABOR DESCRIPTION Hours Background and Preparation - identify interviewees/interview questions with Project Team, map approach Up to 8 interviews with key City/County personnel - on phone, unless can combine with other trip to do in person Refine/prep workshop - ID/draft key issues & themes, outline meeting approach, communicate w/ core Facilitate workshop Draft meeting summary/memo, debrief and follow-up Travel time (assume 1 trip) Staffing Senior Level Facilitator PROJECT LABOR Hours 65.00 65.00 Rate $175.00 OTHER DIRECT COSTS (ODC) Mileage - 1 RT Hotel Per diem - travel days Units 480 2 4 Rate $0.54 $200.00 $36 8.00 16.00 18.00 14.00 6.00 4.00 $ $ Dollars 11,375.00 11,375.00 Amount $ 256.80 $ 400.00 $ 144.00 ODC ESTIMATE $ 800.80 TOTAL PROPOSED BUDGET $ 12,175.80 Stakeholder Engagement Plan Upper Roaring Fork Integrated Management Plan Purpose and Outcomes The goal of this process is to develop a broadly supported set of management recommendations for streams and rivers in the Upper Roaring Fork watershed that meet community expectations for river health. This stakeholder engagement plan outlines the anticipated approach for sharing information about the planning process, including proposed approaches for gathering public input at key points and using this input to inform the deliberations of a stakeholder group charged with recommending and vetting alternative management approaches or projects. How Public Input will be Used The City of Aspen and Pitkin County are committed to ensuring public involvement in planning efforts by providing the community with engaging, accessible information about current conditions in the watershed, together with meaningful opportunities to provide targeted input at relevant points in the process. Because an effective plan relies on broad support and buy-in from the community, the public needs to understand the current conditions of the upper watershed (including the river health concerns driving the study process), the management options available for improving the health of the river, and the trade-offs inherent in each of the options. The Consultant Team will initially seek input from community members regarding values on and priorities for river use, to inform them of the upcoming planning process and indicate the City and County’s desire to have them and their members engaged. These groups included local recreational interests, local conservation groups, regional water entities, environmental advocacy groups, and relevant local, state and federal agencies. Technical Advisory Group This input will be considered by a Technical Advisory Group (TAG) comprised of water rights holders, water managers, city and county staff, resource management agency personnel, and other technically oriented stakeholders with a stake in the Upper Roaring Fork watershed. The focus of this TAG will be to help flesh out project needs and identify and later vet potential management options. This group will include individuals/entities with data and a nuanced understanding of the hydrology and water rights administration in the Upper Roaring Fork watershed. It would not be a decision-making body. Rather, its function would be as an advisory group to help the City, County and project team 1) understand and frame the issues and possible River management options, and 2) develop and help vet potential options, in light of community input and other considerations. We may ask group members to be present at public workshops to convey information, answer specific questions, or simply to hear public input, as they are able and willing. A non-exclusive list of organizations recommended for inclusion on the TAG includes: • City of Aspen – Stormwater, Parks, Utilities, Climate Action Departments • Pitkin County – Healthy Rivers and Streams Board; Open Space and Trails Board; Community Development • • • • • • • • • • • Roaring Fork Conservancy Salvation Ditch Company Ruedi Water & Power Authority Colorado River Water Conservation District Twin Lakes Reservoir and Canal Company US Forest Service Colorado Parks and Wildlife Trout Unlimited Colorado & Ferdinand Hayden chapter Aspen Center for Environmental Studies Colorado Water Trust Colorado Water Conservation Board (CWCB) Stream and Lake Protection Section Public Outreach and Input The project team will engage with the broader community at strategic points during the process, starting with a public ‘launch’ in late March or early April 2017. A user-friendly website will be the primary communication forum for project information and activities, with outreach helping drive community members to the website. Throughout the spring and summer, outreach activities will include some or all of the following: email blasts, website posts, updates via traditional and social media, small group meetings (to present information and receive input or feedback), and broader public workshops. It could also include other activities such as surveys or open houses. The public outreach process will help us understand community input on questions such as: Ø What does river health mean to you? Ø Are there sections of the river you think of as being healthy? Why? Ø Are there sections of the river you think of as being unhealthy? Why? Ø What do you think the highest priorities for river water management should be? Ø In what ways is water in the Roaring Fork River and its tributaries being managed well? Ø In what ways is water not being managed well? Ø What conflicts do you perceive in meeting diverse water management needs? Public outreach activities will include the following: • Open House. The purpose will be to provide background information about the project; inform the community about project schedules and milestones; and ask participants to share their sense of relative priorities, needs, and concerns for water management and river health. We will alert community members to the different means for sharing information, e.g., project website, web surveys/questionnaires, and future public meetings. The open house visual tools such as large wall maps and/or table maps. • Public Workshop. The purpose will be to share public feedback gathered thus far (from the Open House, web surveys, and in-person interviews), explain how it has been incorporated to develop potential management alternatives for meeting diverse water use needs and enhancing or preserving river health, and gather stakeholder views regarding the different alternatives being explored. The workshop will include a presentation of river health data and an explanation of the different management alternatives, including which values and priorities each alternative helps achieve and 2 relative trade-offs of each (e.g. Options S through X could be done to improve river health, for Y reasons, and with Z trade-offs). Regarding the management alternatives, questions for the public will likely include: Ø What are your questions? Concerns? Thoughts? Ø Would you support any of the alternatives, and to what extent? Ø What might you need in order to support those you do not? Ø What do you see as better alternatives for improving river health? Why? Ø Use small groups to discuss, vet, and better understand relative priorities and tradeoffs in different management options. Planning Milestones The study and planning process will anchor outreach around meetings of the Technical Advisory Group and public meetings. These forums will serve as planning milestones, with the goal of finalizing the Plan by November, 2017. A preliminary schedule of activities is detailed below. 1. Open House – Project Overview; Gather Input on River Values & Priorities (Week of 2. 3. 4. 5. 6. April 24, 2017) Technical Advisory Group Meeting #1 - Develop Specific Planning Goals, Objectives, and How to Measure Success; Begin to Identify Opportunities to Achieve Planning Goals in Light of Community Values; Identify Data or Planning Needs (Late May, 2017). Technical Advisory Group Meeting #2 – Refine Potential Opportunities for Achieving Project Goals and Community Priorities, Identifying Feasibility Issues and Trade-Offs; Conduct Early Vetting and Prioritization (early July, 2017). Public Workshop – Report on Progress to Date; Discuss Community Input Used to Develop Values Criteria; Gather Input on Viable Management Options Based on Identified Trade-Offs (Late July, 2017) Technical Advisory Group Meeting #3 – Vetting and Prioritization of Alternatives Using Community Input (Early September, 2017) Final Public Presentation (Possibly Town Council and/or BOCC Meeting) – Present Final Planning Recommendations; Highlight Stakeholder Input & Community Process (Late October, 2017) Communication Tools • Email Lists for Periodic ‘Email Blasts’. These will be used to drive stakeholders to the project website when key updates are posted. The consultant team may help with text for emails. Emails will be distributed to community members by City staff. • Project Website. The website will be the primary communication platform for planning process. It will include background information, meeting materials (including agendas and summaries), and a schedule of stakeholder group & community meeting dates, along with regular updates about the planning process such as community input received and how it has been used. It will include interactive materials to seek input from the community regarding aspects of the planning process. The consultant team will provide City staff with relevant material for the website, including a list of questions that will be posted to the website for eliciting responses from community members relevant to the planning process. The City will 3 be responsible for maintaining the website and providing the TAG with community input relevant to the project collected from the website and other digital media. • Organizational Briefings & Updates. As requested and as budget allows, outreach will include updates to and discussions with relevant organizations at their prescheduled meetings. Depending on project timing, these meetings could also include targeted input and/or feedback on management options. Apart from City and County entities, these groups may include: o Aspen Center for Environmental Studies o Ruedi Water & Power Authority o Salvation Ditch Company o Twin Lakes Reservoir & Canal Company o Pueblo Board of Water Works o Southeastern CO Water Conservancy District o Colorado River Basin Roundtable • All public meetings may also be publicized by the City and County (with support from the consultant team) via: o Press releases o Flyers - distributed broadly to share with members, post on agency and organizational websites, share with existing listservs, etc. o Periodic outreach to project partners and relevant community groups o Social media posts o Radio interviews 4 MEMORANDUM TO: April Long, P.E., Stormwater Manager, City of Aspen FROM: Seth Mason, Lotic Hydrological DATE: February 23, 2017 SUBJECT: 2017 Workplan Based on recent conversations, the Consultant Team is pleased to provide you with an updated workplan for 2017 that articulates a framework schedule for engaging water rights holders and the general public around the Roaring Fork Integrated Management Plan. 1. Review of Project Goals and Objectives Geographic scope: Roaring Fork River and major tributaries above the confluence with Brush Creek. Primary Objectives: Identify, vet and obtain community support for viable, implementable management options for improving river health that reflect community values and priorities. From the City of Aspen’s perspective, this project should: • Focus on improving river health through City of Aspen reach (above Brush Creek). • Focus specifically on options to improve flows at certain times/conditions downstream of North Star. • Not repeat past mistakes (e.g. Energy Center) by committing to stakeholder education and buy-in. • Where relevant, reference the City of Aspen’s Collaborative Long-Range Water Study starting Summer 2017, which will examine the City’s future water needs and water supply options for meeting those needs. From the County’s perspective, this project should: • Provide an understanding, from an informed public, of the community’s expectations for a “healthy stream”, recognizing the competing interests and trade-offs in different River management options. • Specifically explore stakeholder review, vetting and prioritization of previously identified improvement projects for the North Star Preserve. Strategic Goals: • Replicability (with roadmap, lessons learned, etc.) • Strong public support • Development of public understanding of risks, priorities, and trade-offs regarding River • management options • Optimize collaboration between City/County as land and River management partners • Optimize collaboration and integration with relevant River-related efforts • Support of public-private partnerships 2. Stakeholder Engagement To meet the goals and objective identified above, this project should work to create an informed public. We will use one-on-one interactions, small and large group meetings and workshops, publically disseminated reports, and innovative, interactive website tools to educate the community about existing river conditions and the suite of potential river management options, including the impacts and trade-offs of each – in terms of river health, recreation, agriculture, economic development, and other relevant arenas. These approaches will attempt to solicit meaningful input and direction from the community in order to identify and prioritize implementable projects with broad local support. In early November, we agreed to spend the next 2-3 months reaching out to roughly 15 community stakeholders to get an initial sense of stakeholder interests and solicit input on the overall plan for community engagement. These stakeholders represented environmental, recreational, and landowner groups, in addition to relevant state, local and federal agencies and knowledgeable water and river experts in the community. Topics of discussion included overall community values with respect to potential River management options; local perspectives regarding water resource use; input for RFMP stakeholder engagement; and informal discussion and vetting of potential River management options. Those stakeholders and themes from these interviews are discussed below: Stakeholders interviewed so far: • John Currier, CRWCD • Jim Kravitz, ACES • Andre Wille, Healthy Rivers and Streams Board • Matt Rice, American Rivers • Nathan Fey, American Whitewater • Charlie MacArthur, Aspen Kayak and Stand Up Paddle-boarding (SUP) Academy • Mark Fuller, Ruedi Water & Power Authority (former director, Independence Pass Foundation) • Phil Overeynder, City Utilities • Karen Teague, Independence Pass Foundation • Rick Lafaro, Roaring Fork Conservancy • Chris Lemons, Aspen Flyfishing • Richard Gytenbeek, Trout Unlimited (by email) • Colorado Parks and Wildlife (Kendall Bakich; Dave Graff) (by email) • US Forest Service (Steve Hunter) (by email) Interviews scheduled for March-April: • Tom Moore and Mark Hamilton, Salvation Ditch • Kevin Lusk, Twin Lakes Reservoir & Canal Company and Colorado Springs Utilities • Lisa Tasker, Pitkin County Healthy Rivers and Streams Board • Linda Bassi and Brian Epstein, Colorado Water Conservation Board • Karen Wogsland, Colorado Water Trust Themes and ideas from the discussions thus far are listed below, without attribution to particular individuals or groups. This summary does not include discussions from the City and County kick-off meeting or follow-up scoping meeting. Several substantive comments (scope/goals/options) have come out of these discussions: • There are somewhat divergent opinions about North Star o County’s management role and priorities; community expectations for recreation • People are wary of reinventing the wheel but seem interested in reexamining creative management ideas, including for engaging Twin Lakes and Salvation Ditch in particular about river management options, to explore win-win options (without creating legal risks). Same possibly for Red Mountain Ditch and ditches off Hunter Creek. • Potential management opportunities in 3000 acre foot exchange, supplemental junior rights and small number of rights in Grizzly. Not much to play with. But potential of advocating for more creative, open-ended in modeling about how 3,000 AF exchange could be used – when, where, how much. • Potential usefulness of modeling climate change scenarios in light of the Cameo call/Twin Lakes/Salvation Ditch water rights scheme. • Other creative management options to get more water in river include ‘farther out’ ideas like developing front range yield to use for west slope; developing west slope storage to trade back in dry years (e.g., FR enlargements for more wet water, in order to take less dry-year water; pay wet water back). • One result of this Study should be better communication and coordination between the City, County and out-of-basin diverters (e.g., when/under what conditions Twin Lakes diverts) o Consider asking how City/County can communicate and coordinate more effectively in the future on river-related matters. Possibly create a structured way for regular communication on river issues. o There have been informal ideas floated about engaging with Front Range diverters in a LBD-style effort for the upper Roaring Fork. There may be an opportunity to do this in the context of the SMP or beyond. • Great opportunity to explore value of market-based water sharing, infrastructure improvements and other strategies to help flows and downstream users. • Examine Healthy River and Streams’ response to County's proposed management plan for North Star Preserve. They were supportive of many things; critical of a few. • American Whitewater has recreational user-preference data for upper Roaring Fork River. Consider how this fits with the project. Stakeholder interviews and discussions yielded several procedural comments (i.e. thoughts about engaging stakeholders to increase buy-in, likelihood of broad support, and better outcome): • ‘Storytelling’ aspect is important to helping community understand the reasons for project and why they should care (current conditions, long-term projections and risks) early in the process, and possible options and trade-offs later in process. Should happen throughout life of project. o ACES could be a partner with messaging, visual story-telling, social media, panels (Winter Lecture Series) – to show why there’s a need to improve river health, what this looks like, why flows are important. Comparison photos are great way to show this. • Generating interest among local stakeholders can help bring entities like Fry-Ark to table. • Ruedi Water and Power can play role in bridge-building and anticipating/addressing possible points of conflict between jurisdictions. Stakeholder interviews and discussions also yielded lists of other stakeholders to keep in mind and notify of meetings; many are being engaged in parallel projects as well. These included, e.g.: • Front Range stakeholders (American Rivers has offered to be supportive) • Castle Creek, Maroon Creek landowners, through their attorneys • Landowners above North Star • Landowners between Aspen and Woody Creek • North star permittees • Permitted river outfitters – e.g., Aspen Whitewater, Elk Mountain Guides, Blazing Adventures • Alan Martellaro, DWR (same as above) – contacted and will stay in the loop 3. Proposed 2017 Workplan The near-term project focus will be on 1) launching the project publically, primarily through the City’s website; and 2) assembling a panel of local experts and water rights holders as an Advisory Group to help identify and begin to vet potential management options. This group will include individuals/entities with data and a nuanced understanding of the hydrology and water rights administration in the Upper Roaring Fork watershed. This group would need to have a clear sense of its role and purpose, and how its function relates to the broader community outreach process. It would not be a decision-making body. Its general function would be as an advisory group to help the project team understand and frame the issues and possible River management options for the broader community. We may ask group members to be present at public workshops to convey information, answer specific questions, or simply to hear public input, as they are able and willing. For the remainder of the spring and summer we will continue to engage with the broader community at strategic points. This engagement could include: email blasts, website info/comments, surveys, open houses, outreach via traditional and social media, focus and neighborhood group meetings, open public meetings, and other activities. This outreach will help us understand community responses to questions such as: • In light of the information presented, what do you consider to be the most significant health needs of the River, above Brush Creek? We could include a bunch of sub-questions here, depending on what we/City/County want to know. • ‘If options S through X could be done to improve river health, for Y reasons and with Z tradeoffs: o What are your questions? Concerns? Thoughts? o Would you support this, and to what extent? o What might you need in order to support it? o What do you see as better alternatives for improving river health? Why? Gary and Lindsey at Pitkin County have significant experience and expertise with public outreach and will be closely involved with these efforts. Upper Roaring Fork River Management Plan Technical Advisory Group Kick-Off Meeting Notes Tuesday, May 23, 2017 11am-3pm City of Aspen Fire House Conference Room Welcome & Introductions April Long welcomed everyone on behalf of the City of Aspen and Pitkin County, the co-sponsors of the Roaring Fork River Management Plan (RFMP). Facilitator Ryan Golten led a round of introductions. A list of meeting attendees is at the end of this summary. Project & Technical Advisory Group (TAG) Overview Seth Mason from Lotic Hydrological provided a project overview. The goal of the project is to improve the health of the river from North Star Preserve to just above Brush Creek, a high priority as identified by numerous recent studies and a water quality impairment regulatory listing with the State of Colorado Department of Health and Environment. The project will explore alternatives for doing so that are feasible, data-driven, cognizant of existing water rights ownership and administration and other stakeholder interests in the Upper Roaring Fork watershed, and that promote broadly shared values and priorities for the river. It will culminate by the end of 2017 with a set of management recommendations provided to the City and County. This information is also provided on the City’s and County’s websites: http://www.pitkinostprojects.com/upper-roaring-fork-river-management-plan.html http://www.aspencommunityvoice.com/upper-roaring-fork-river-management-plan Seth Mason reported on work to date, including: 1) a technical summary of relevant studies to illustrate baseline conditions and ecological needs (shared with TAG members and posted on the project website); 2) a series of preliminary stakeholder discussions last fall and winter to share information about the project and help inform the planning and outreach process, including members of this TAG and representatives of river-oriented community groups and recreational users; and 3) preliminary public outreach conducted via the City and County websites, a public open house, targeted presentations at relevant preexisting meetings, media stories, a public survey (available on website), and emails sent to partner organizations to disseminate to their members and constituents. Facilitator Ryan Golten walked through the proposed purpose and role of the TAG, expectations of members, meeting guidelines, and other draft elements of the TAG Charter. The TAG’s proposed role is to provide input and guidance to the project team (including City and County), including identifying common interests or concerns, potential opportunities, and existing constraints. The TAG will provide guidance on planning goals and priorities and help identify and prioritize management alternatives. The TAG will not be asked to make decisions or reach consensus as a group. However, management options will be prioritized to the extent they satisfy multiple interests and are broadly supported by TAG members and other stakeholders. Themes from Stakeholder Discussions Seth shared the following themes from early discussions with TAG members and other stakeholders: • General buy-in for project’s focus on river health of reach from North Star Preserve to Brush Creek, based on demonstrated and expressed local needs in recent decades • Desire to work toward solving problematic conditions while leaving space for future planning and maintaining good existing conditions • Interest in not reinventing the wheel, drawing on wealth of studies to identify existing issues • Interest in looking forward, being creative and collaborative to solve the issues • Hope that this process will meet substantive goals while also improving coordination and dialogue within the stakeholders here for collaborating on river issues • Emphasis on soliciting community values and priorities in light of the anticipated tradeoffs for different management alternatives • Desire to resolve existing conditions and problematic issues, as well as to anticipate potential future conditions that could alter or degrade the river Goals, Areas of Focus, and Opportunities for the Project TAG members discussed the following goals, key interests, and sense of opportunities for the process. 1. Stakeholders’ expressed goals for the process: • Listen to others’ interests and concerns, represent our own, look for common ground • Understand community values/priorities as we evaluate potential projects to improve river health • Plan long-term – not just for future we know today, but future that we don’t • Apply learning from this process to larger scale (Colorado River basin) • Better understand appropriate community balance between recreation and ecosystem health over the long-term; look for ways to tell the story connecting snowpack, river, habitat, and wildlife • Look at river as a whole, not piece by piece; integrated management, focusing on big impacts • Get community input on where City and County’s funds should go to implement the plan • See the plan completed and project(s) implemented • Interest in river health education: river access points are often points of degradation, need for more awareness of individual impacts on river • Hope to explore ways to develop storage while improving river health • Interest in mitigating City's impacts on the river through large-scale projects • Use City's water rights to improve and maintain stream health • Help restore stream flows through creative, win-win means • Feel heard and understood as water right holders; opportunity to learn and hear others’ interests; build trust and relationships; be creative, push boundaries, engage in positive, open dialogue • This process advances long-term state goal; would love to see this occur in other communities 2. Needs/interests identified by some TAG members to share with others going into the process: • • • • • • • Recognition of local agricultural benefits: replenish aquifers, keep area green, increase land values, contribute to late season flows; history of local agricultural users sharing shortages during extreme drought years and helping where they can Interest in transparency to communicate and explore these issues in the community Interest in protecting existing water use and investments on the eastern slope Awareness of hydrological connection to other basins; need to evaluate ramifications elsewhere Interest in thinking ahead to implementation – will require resources, coordination, clear roles Interest in bringing regional resources/experience to help with creative methods to improve flows Awareness of the term ‘impacts;’ can appear pejorative and appear to target certain groups 3. Stakeholder-identified potential opportunities associated with this process: • Engaging private landowners in potential win-win projects • Because water originates on forest service land, possibilities for USFS to form partnerships to inform management decisions, potential to dovetail in planning issues • Great opportunity for integrated river planning; if we can’t do this in our community, who can? • Opportunity to build on prior planning efforts, work towards a broader management plan, and coordinated implementation • Huge expertise and resources (science, legal, policy, community) in Advisory Group • Opportunities to help develop east slope awareness of RF issues and concerns, discuss innovative approaches, encourage collaborative and creative thinking (including potentially how the 3,000 af exchange is tracked and implemented) • Collaboration that goes far beyond this process, connection hydrologically to other basins, could have ramifications elsewhere (positive or negative) • Lot of expertise and experience in TAG for maintaining and improving instream flows • Potential for funding projects if able to work together, rather than individually Principles for an Effective Process, Based on the Above Discussion From the above discussion, the following principles were identified as foundational for helping promote a productive planning process. These are not exhaustive and will be built upon in coming months: • Strive for open dialogue, acknowledging areas of sensitivity and/or need for sidebars • Focus on building relationships to foster long-term creative problem-solving, coordinated action • Recognize all water uses are valid; valuing a user’s priorities is different from trying to change her behavior (and words matter in whether people feel their priorities are valued) • Important to engage/educate the public before asking for evaluation of alternatives and trade-offs • The more groups buy in to river health and feel their interests are recognized in the process, the more traction projects will get and action will occur Project Planning Discussion Seth Mason discussed the project team’s interest in getting the TAG’s overall buy-in on the project focus and to hear from members about specific concerns regarding these geographic areas. Following this meeting, the technical team will begin working with TAG members to identify and explore alternatives for improving river health in the focus reach. Using substantive concerns identified by TAG members and other community stakeholders, the technical team will create a preliminary list of criteria for prioritizing the various alternatives to review with the TAG at the July meeting. A refined list of criteria will ultimately be used to help prioritize alternatives deemed likely to be effective and feasible. The technical team will use existing conditions to evaluate the relative effectiveness of each option. It would be useful to hear from the TAG, for example: • Thoughts on how certain actions might impact surrounding tributaries? • What river health issues are we trying to resolve (riparian health, macroinvertebrate populations, instream flows, etc)? Depending on what problem we want to solve, there are many options; flow isn’t the only variable. • How to balance alternatives with downstream impacts, e.g., flow regimes, with others such as riparian restoration that may only impact a small area? • In light of those types of considerations, to what extent should we be considering things other than flow regime (e.g., recreational impacts, access impacts, riparian impacts), since flows can only be improved so much in light of water rights regime? Geographic Focus and Other Watershed Priorities Following a brief presentation by Bill Miller of the Riverine Needs Assessment (posted on project website), there was a discussion about the geographic focus of the project and other areas of concern in the upper watershed. Because the river is a holistic system, projects to improve river health in the focus reach could address other priority issues as well. TAG members highlighted yearly low flows below the Lost Man diversion and low flows in lower Hunter Creek, below the red mountain diversion, as areas of ecological concern. There was discussion about the geographic and substantive focus of the project, the upcoming work of the technical team, the types and level of input sought and how this is relevant to refining alternatives, and the need to clearly articulate this for the public. (See next steps below.) In response to questions about ‘what future do we want to see for the river,’ it was clarified this project will rely on existing studies for numbers to quantify specific desired conditions such as inflow rates. However, that still allows us to think about options to meet these conditions – i.e., volume of water, physical system, biological aspects. How do we make all three work together to find appropriate solutions? It was suggested that the project have ‘goals’ as well as ‘stretch goals,’ in terms of the ability of different alternatives to achieve certain conditions as defined in the assessment report. There was also some discussion about the role of public outreach, as outlined in the Stakeholder Engagement Plan, and the interest in understanding the extent to which public perceptions may be consistent with the assessment. Does the public share these concerns about river health? It was recognized that asking the questions also helps to create awareness and start to build engagement. TAG members were asked to review and edit the Stakeholder Engagement Plan to help ensure it’s designed to effectively elicit and use public input in meaningful, targeted ways throughout the process. Next Steps Given the wide-ranging Project Planning discussion, the project team committed to describe more clearly the goal of the River Management Plan and how stakeholder concerns and priorities for the River will inform and guide planning efforts. The team will share the description with the TAG and seek follow-up input. This will also be posted on the project websites and used for messaging and outreach. In addition, TAG members should expect to receive, after this meeting and before the July meeting: • Draft meeting summary • TAG Charter & Stakeholder Engagement Plan for final review • Requests to engage your members or constituents, as relevant • List of criteria or objectives for prioritizing management options • High-level list of potential alternatives with pros/cons & anticipated trade-offs for each • Agenda for next meeting (discuss possible alternatives, pros/cons, criteria, public input) Many of you will be engaged to help explore potential management alternatives. Please let the project team know if you would like to discuss this, or if you have suggestions or questions about to clarify project messaging, with a focus on ensuring it’s clear to the public how input will be used in the process. Meeting Attendees - 5/23/17 Name April Long Austin Weiss Margaret Medellin Phil Overeynder Ashley Perl Lisa Tasker Gary Tennenbaum Laura Makar Cindy Houben Rick Lofaro Tom Moore Mark Hamilton Mark Fuller John Currier Kevin Lusk Steve Hunter Richard Gytenbeek Ken Neubacher Jim Kravitz Karen Wogsland Brian Epstein Kurtis Tesch Organization City of Aspen – Stormwater City of Aspen – Parks City of Aspen - Utilities City of Aspen - Utilities City of Aspen - Climate Action Pitkin County HRSB; Open Space& Trails Pitkin County – Open Space and Trails Pitkin County Attorney's Office Pitkin County Community Development Roaring Fork Conservancy Salvation Ditch Company Salvation Ditch Company Ruedi Water & Power Authority Colorado River Water Conservation District Twin Lakes Reservoir & Canal Company; CO Spring Utilities US Forest Service Trout Unlimited Trout Unlimited, Ferdinand Hayden chapter Aspen Center for Environmental Studies Colorado Water Trust CWCB Stream and Lake Protection Section Colorado Parks and Wildlife Technical team: Seth Mason Lee Rozaklis Bill Miller Greg Espegren Ryan Golten Lotic Hydrological Facilitator, Consensus Building Institute/CDR Upper Roaring Fork River Management Plan Technical Advisory Group Meeting Notes Wednesday, August 30, 2017 10:30am-2:30pm Aspen Historical Society Welcome & Introductions April Long and Gary Tennenbaum provided a project update. April explained the timing reasons for the July-August meeting delay and evolution of the project scope, in light of current negotiations on relevant Roaring Fork issues. Rather than risk evaluating management options that later become moot, or complicating existing discussions, the remainder of the project is going to focus on developing tools and methodology for evaluating river management alternatives and examining pre-identified alternatives at a high level. Those tools and discussions will be used by decision makers when management alternatives are ready to be explored. Given the uniqueness of this group of stakeholders, it’s possible water managers may also seek to reconvene the TAG when the timing is appropriate. Ryan Golten facilitated a round of introductions and reviewed today’s agenda. A list of meeting attendees is at the end of this summary. Reach Prioritization/Ranking Exercise At the May TAG meeting, participants provided input on the project team’s preliminary prioritization of reaches, based on the river health ‘report card’ presented to the TAG, as well as the City’s planning goals. The input from the group at that meeting suggested the team needed to further consider certain reaches that are regularly dry (lower Hunter and Lost Man). This small-group exercise was a chance for TAG members to drill down a bit, doing a pairwise comparison of reaches to assign relative priorities in terms of river health needs and desires. The quantitative results of this exercise will provide an additional source of input, albeit subjective, to decision-makers regarding TAG members’ relative reach priorities for addressing river health (including to allocate resources to one reach over another). In project planning, they can also help convey priorities in considering secondary or broader project impacts. The input would provide a starting point for discussions and refinement, rather than providing a final conclusion or end point. The group discussed additional caveats to the exercise, including the fact that ranking reaches against each other can seem arbitrary and depends on what lens you’re using and the exact nature of the question. The results can also highlight certain consistencies and inconsistencies in prioritized reaches. This is helped by allowing people to note the degree of intensity they feel about certain comparisons. The group discussed the application of this exercise to broader community stakeholders in a public meeting or focus groups, particularly in light of the caveats above. TAG members generally believe the results would be more meaningful if 1) conducted in-person rather than through on-line surveys, 2) it includes clear instructions on what ‘lens’ folks should use, particularly if they wear multiple ‘stakeholder’ hats, and 3) the exercise is combined with qualitative discussions regarding reach priorities and needs. Small groups met for 30 minutes to complete the exercise. TAG members were asked to submit their Matrix forms following the meeting if they did not finish – by scanning/emailing them to Ryan or Seth, or by mailing or hand-submitting to anyone on the project team. Discussion of Hydrological Modeling Tool – for Use in Future Decision-Making Regarding Flow Management Alternatives Seth Mason and Lee Rozaklis introduced a modeling tool to help local Roaring Fork decision makers understand system-wide impacts of any given alternative for managing flows by looking at historical, existing and anticipated future conditions. This model uses historical streamflow gauging and surface water diversion records. Some data records were filled in; the result is an approximation of upper Roaring Fork streamflows across a 35-year period that includes droughts, floods, and typical conditions. Ideally the tool would be used not only by the City and County, but other Roaring Fork water users and managers trying to make water management decisions using this type of input. Because most Roaring Fork flow-management discussions would involve various TAG members, it’s important to understand from this group 1) if the overall hydrological network has been captured correctly and makes sense structurally, and 2) what inputs may be missing. Are there other operational components that need to be included to make this tool useful to others beyond the immediate timeline horizon of this project? As discussed at the meeting, Seth and Lee will follow up with certain TAG members to help sync this tool with the data and inputs being used by others. The goal is to ensure it is as useful as possible to other Roaring Fork users and river managers, as well as to ensure it is both accurate and comprehensive. Update on Ecological Response Framework – for Future Evaluation of Flow Management Alternatives In light of the different minimum flow and flood flow numbers for the different reaches – which can be confusing to river managers and decision makers – the project team was asked to suggest a coherent, consistent rationale for evaluating the relative costs and benefits of water management alternatives in the future, in light of the existing suite of flow targets, hydrological data, hydraulic data, and biological data. This draft framework outlines a general process and data requirements for evaluating environmental impacts from future water development projects or environmental benefits from future water leasing, conservation, or improved water efficiency projects within the upper Roaring Fork River basin. Like the hydrological modeling tool discussed above, this guidance will be used in future water management decision-making processes. River Management Alternatives – High-Level Brainstorm This brainstorming exercise was intended to add creative ideas to previously identified management alternatives for improving river health. The intent was not to evaluate the merits or feasibility of any alternatives. Ideally, this list will be used as a reference for future groups considering specific management objectives on a specific reach in the upper watershed. Lee walked the group through a list of pre-identified management alternatives. Ryan organized participants in small groups with instructions to brainstorm, without evaluation, other creative management ideas that should be added to the list; and to identify or share, without detailed discussion: 1) particular alternatives that excite group members or where folks see current opportunity (and briefly why), and 2) particular alternatives that give folks heartburn or where may be non-self-evident challenges or constraints (and briefly why). This discussion and refined list will then form the basis for the evaluation of management alternatives in the upcoming future by the City and/or County. TAG members were asked to consider what everyone knows from experience living and working in the upper Roaring Fork, including river health studies and data as relevant. They were asked to think creatively about what other opportunities might exist to affect river health conditions in project area, acknowledge that hydrological needs vary by reach, season, and specific objectives. TAG members were also reminded of the initial discussion principles – i.e., to be sensitive, that words matter, that all water uses are valid, that no one is here to target or challenge certain water uses. Small groups met for 30 minutes, followed by a large-group debrief. Take-away points from the small groups, to be incorporated into the final report, included the following: • There are a lot of opportunities with storage – including the possibility of front range storage in new locations and increasing sizes of existing locations. Larrge capacities and small capacities should be considered. The concern with storage is no new water and it is expensive, but it is exciting because it provides flexibility in use and can benefit more than one entity or goal. • Development of East slope storage options is limited by Colorado-Kansas lawsuit. • Investigate exchange opportunities. There is excitement around collaboration and cooperation and perhaps that increases opportunity and appetite for exchanges. • There was interest in considering local opportunities for tighter coupling of land/water development. Transferrable development rights within Pitkin County could include transfers of water rights and subsequent use of those rights by the County to augment streamflows in times of need. • There was some discussion of municipal demand management as a pathway for reducing impact on local streams • Some consideration was given to the use of beavers as a management tool for storing water in alluvial aquifers • There was continued discussion about the value of alternate sources of water for the largest in-basin demands (e.g. a pipeline and siphon from Castle Creek to Salvation Ditch) • Forced quantification at diversion points (either under an application for alternate point of diversion or through an ISF leasing program with CWCB) may unnecessarily expose water rights. • The impacts of return flows from existing uses in timing and location should be contemplated. Wrap Up & Next Steps By Friday, September 22, please provide to the project team: • • Edits to this meeting summary The reach ranking matrix, if you did not submit it at the 8/30 TAG meeting. A blank copy is attached to the draft meeting notes. As promised, in the next few weeks we will circulate the hydrological model and ecological response framework notes for your review and comment. In addition, in the upcoming months the project team will schedule a public meeting and focus group conversations with key stakeholders to rank geographic and substantive priorities in light of high-level management tradeoffs. TAG members may be asked to circulate meeting information and encourage their colleagues, friends, and constituents to attend. Following that community input, TAG members should expect to see a draft Report for review and their comment. In the meantime, the project team may meet with some of you for additional input into the hydrological modeling tool and/or other technical tools presented at today’s meeting. Following the issuing of the draft Report, April Long underscored that this unique group of stakeholders may be asked by the City and/or County to reconvene for input and/or participation in future evaluation of river management alternatives. The project team conveyed gratitude to TAG members for their time and dedication in participating the past two meetings, particularly in light of the many current dynamics constraining the planning process. This is an invaluable group and one that is likely to be called upon in the future. Meeting Attendees – 8/30/17 Name April Long Margaret Medellin Phil Overeynder Ashley Perl Lisa Tasker Gary Tennenbaum Laura Makar Cindy Houben Rick Lofaro and Heather Lewin Tom Moore Mark Hamilton Mark Fuller John Currier Kevin Lusk Richard Gytenbeek Ken Neubacher Jim Kravitz Karen Wogsland Brian Epstein Kurtis Tesch Kendall Bakich (by phone) Organization City of Aspen – Stormwater City of Aspen - Utilities City of Aspen - Utilities City of Aspen - Climate Action Pitkin County HRSB; Open Space& Trails Pitkin County – Open Space and Trails Pitkin County Attorney's Office Pitkin County Community Development Roaring Fork Conservancy Salvation Ditch Company Salvation Ditch Company Ruedi Water & Power Authority Colorado River Water Conservation District Twin Lakes Reservoir & Canal Company; CO Spring Utilities Trout Unlimited Trout Unlimited, Ferdinand Hayden chapter Aspen Center for Environmental Studies Colorado Water Trust CWCB Stream and Lake Protection Section Colorado Parks and Wildlife Colorado Parks and Wildlife Technical team: Seth Mason Lee Rozaklis Bill Miller Greg Espegren Ryan Golten Lotic Hydrological Facilitator, Consensus Building Institute/CDR Upper Roaring Integrated Management Plan Community Meeting Summary – November 8 & 9, 2017 Meeting purpose The City of Aspen and Pitkin County hosted community meetings on the evenings of November 8 and 9 at Aspen City Hall. The purpose was to provide an overview of the Upper Roaring Fork Integrated Management Plan conducted over the course of the past year; share tools and information that have been developed regarding watershed conditions and hydrological system mapping and modeling; and reflect the input that has been received to date from stakeholders and how it has been incorporated into planning efforts. Most importantly, in small groups community members were asked to share priorities and considerations for making trade-offs regarding different river management goals and approaches. This input will be incorporated into the final Report, which will be presented to the City and County in January 2018. Participants were encouraged to take the online Management Plan survey and share the link with colleagues: http://www.aspencommunityvoice.com/upper-roaring-fork-rivermanagement-plan. Meeting Overview Nearly 30 people participated in the two community meetings: 13 attended the November 8 meeting, and 15 attended the November 9 meeting. To kick off both meetings, April Long welcomed participants on behalf of the City and County, the co-sponsors of the Roaring Fork Integrated Management Plan. As reflected in the meeting presentation, April explained the purpose and goals of the project, the process to date, and input received. Ryan Golten, project facilitator from the Consensus Building Institute, described the composition and input of the project’s Technical Advisory Group in advising the project team regarding current conditions, issues and areas of concern, and possible approaches on behalf of river managers, regulators, water rights owners, and local experts on the river system. Seth Mason, consultant lead from Lotic Hydrological, provided an overview of current river conditions, the hydrological system, and the relevance of different management strategies to the hydrological regime of the Upper Roaring Fork. Because the November 8 meeting was a smaller, recreation-focused group, participants were asked to share their goals and future hopes for the Upper Roaring Fork, along with their interest in this study. Strong interests from participants included increased river flows and a ‘healthy river’ (including in Castle and Maroon creek), downstream impacts from current and future river management approaches, and interest in seeing how a facilitated stakeholder process could incorporate recreational interests with river health planning. The focus and majority of time at each meeting was dedicated to interactive small-group exercise focused on 2 questions: 1) What considerations are most important to you in making trade-offs between different water uses?; and 2) What specific values and activities are most important to you in terms of the health of the upper Roaring Fork? The results from those discussions are below. 1) Water Use Trade-Offs At both meetings, participants were asked to assign relative points to each water use depending on how they prioritized that particular use or function of the river. General observations. One of the key take-aways from both meetings was that many of the key (including recreational) priorities rely on the river’s ecological integrity. This category received the highest points as a priority water use – both because of its singular importance for community members, and because of its function in supporting recreational and other uses as well. In addition, participants noted their responses were less favorable when ‘Drinking Water Supply’ was articulated to include all domestic uses (e.g., irrigation). Likewise, they were more favorable when ‘Local Food Production’ was articulated to mean broad agricultural uses that support open spaces and seasonally green viewscape – and that responses changed depending on whether the focus was on ‘local food’ or ‘food production’ in general. Specific responses are reflected in the tables below. November 8 – recreational users Ecological integrity (34 Drinking/domestic water supply (33 points) points) -Covers a lot of other values’ -Critical nonconsumptive use -Personal value -Economic value for visitors -Community value -Basic need, not optional -Economic driver/development Snowmaking (13 points) -Major economic driver -Important investment; community value -Already get enough snow on the mountain -Use of water could be better used elsewhere -Not wasted since doubles as spring melt -If we didn’t make snow for a whole season, what impact would that have?” Fishing/ boating (31 Public parks & fountains (5 points) points) -Covered by ensuring ecological integrity -Significant economic driver -Important for community -Personal value -Not as crucial -Little economic value -Lessen water use by xeriscaping or lowering water requirements -Value of green spaces -Can do without, not a necessity Local food production/ viewscapes (12 points) Aesthetics/legacy -Not as much value -‘Viewscape’ important -Economic driver -Local food is priority -Would be better if we had food for humans instead of low quality food for cattle -Important for keeping water rights in Valley. -Some ditches filling ponds or for landscaping; low value use of water -Need more local food production -Supports wildlife corridors November 9 – general public Ecological Integrity (63) -Critical to other values being addressed -Cultural identity and community benefit Environmental responsibility, future generations Drinking/ domestic water supply (45) -Necessity, pragmatic -Lack of understanding about the consequences if adequate allocation isn’t provided -In favor of cutting back in a drought year for irrigation Snowmaking (9) Fishing and boating (22) Public parks & fountains (7) -Economic viability/drive -Water storage option, adds to spring runoff -Shouldn’t be used in drought years -Artificial, shouldn’t use natural resources -Fish can be an indicator species -Economic driver, human recreation -Hand in hand with ecological integrity -Could be enjoyed other places if the water were needed elsewhere Local food production/ viewscapes (32) -Should use -Visual integrity, alternative beauty, social, water source aesthetics, for parks and scenic fountains -Ag is seen more -Parks great, on the Crystal fountains than RF wasteful -Water rights -Fountains are should be fun conserved more -High density –Value of locally living, enjoy produced food having green for human parks to play in consumption, with kids less fossil fuel consumption -Fosters future resilience/model 2) River Health Priorities Participants at both meetings were also asked: What values, activities, and/or locations are most important to you in terms of the health of the upper Roaring Fork? Responses are reflected below. November 8 – recreational users Native Fish (Cutthroat trout) (26) -Economic driver for fishing -Native fish can be important indicator of ecological integrity Sport Fish (rainbow/brown trout) (13) -Economic driver for fishing -Can sport fish elsewhere, Aspen should focus on native and not sport species Avian species (9) Riparian and Wetland Vegetation (35) Amphibians (13) -Dipper is best indicator of ecological health, need some funding here -Get benefit indirectly, not priority use of funding -Supports full system -Significant ecological value/impact -Filtering/water quality, health of the river -Not priority use of funding; get the benefit only indirectly Aquatic Macroinvertebrates (Bugs) (24) -Supports good fish communities and good water quality -Prereq for native fish -Underlying indicator of health November 9 – general public Native Fish (Cutthroat trout) (32) -In appropriate stretches of the river, better higher in the watershed -Interconnected habitat for fish supports other species -‘Native’ species have strong PR appeal, community can support this -Fish should be native, not introduced Sport Fish Avian species (rainbow/brown (27) trout) (11) -Species should be sustainable, avoid competition between native and non-native -Shouldn’t spend significant funding on this but it is an economic driver, should get some funding -Indicator species, should invest here -Should work to bring native species back in certain reaches -Should work from the “bottom” up to get to birds, not top down -Requires more land for habitat improvement, unsure of what a project for avian species would look like Riparian and Wetland Vegetation (54) Amphibians (16) -Invest here and health of other aspects will follow, as baseline need -Build from the bottom up -Supports vertical and horizontal diversity -Good indicator species -Important to food chain -iIportant but difficult to sell to public Aquatic Macroinvertebrates (Bugs) (42) -Foundational to river health -Base of food chain -Hard to do projects specific to them, hard to sell to public and expensive Wrap Up & Next Steps As discussed at both community meetings, the results of the input from these discussions will be incorporated into the final Report. The Report will highlight for the City and County where there may be strong support for certain types of management efforts, where other efforts might run into resistance, and where there might be particular need for education and outreach regarding existing needs, areas of risk, and potential management approaches. The Report will be presented to City Council and the County Commissioners and likely finalized in January. It will be made available to community members on the project website. Appendix HYDROLOGICAL DECISION SUPPORT SYSTEM Upper Roaring Fork Hydrological Decision Support System A product of the Roaring Fork River Management Plan City of Aspen Pitkin County Hydrological Decision Support Tools November, 2017 2 Prepared For: April Long Stormwater Manager City of Aspen 130 South Galena Street Aspen, CO 81611 Prepared By: Lotic Hydrological PO Box 1524 Carbondale, CO 81623 And Rozaklis and Associates 520 Concord Ave Boulder, Colorado 80304 Hydrological Decision Support Tools 3 Table of Contents 1. Introduction........................................................................................................................ 5 2. Water Budget for the Upper Roaring Fork ......................................................................... 5 2.1 Overview of Water Rights Considerations .................................................................................... 9 2.1.1 Independence Pass Transmountain Diversion System ..................................................................... 10 2.1.2 Grizzly Reservoir............................................................................................................................. 15 2.1.3 Salvation Ditch ............................................................................................................................... 15 2.1.4 Hunter Creek Collection System – Frying Pan Arkansas Project ....................................................... 16 2.1.5 Wheeler Ditch ................................................................................................................................ 17 2.1.6 Red Mountain Extension Ditch ....................................................................................................... 18 2.1.7 City of Aspen Water Supply System ................................................................................................ 19 3. Decision Support Tool Development ................................................................................ 21 3.1 Point Flow Model Development ................................................................................................. 22 3.2 Water Rights Simulation Model Development ........................................................................... 24 3.2.1 Inflow Hydrology ............................................................................................................................ 26 3.2.2 Water Demands ............................................................................................................................. 31 3.2.3 Water Rights Administration .......................................................................................................... 32 3.2.4 Simulation Model Performance ...................................................................................................... 33 3.2.5 Scenario Development ................................................................................................................... 35 4. Hydrological Regime Behavior ......................................................................................... 35 4.1 Hydrological Alteration............................................................................................................... 36 5. Conclusions ....................................................................................................................... 41 Hydrological Decision Support Tools 4 1. Introduction The structural form and functional integrity of a riverine system is described by a suite of hydrological, physiochemical, biological, geomorphological, and hydraulic processes. Complex bi-directional interactions occur between each, complicating evaluation of any one component of the system in isolation from the others. However, the overall form and function of a river is significantly influenced by its climate, geology, and hydrology. The Natural Flow Paradigm postulates that hydrology represents the key driver of riverine structure and function and fluvial ecologists often treat steamflow as the “master variable” exerting the largest influence on riverine ecosystem form and function (Poff et al., 1997). The daily, seasonal, and interannual variations in flows make up its hydrologic regime. Changes in the timing and magnitude of various elements of the hydrological regime can produce cascading effects—or positive feedback loops—between structural and biological components of the ecosystem. River systems subject to hydrological alteration due to changing climate or human management actions are vulnerable to degradation in measures of river health. Activities that deplete or augment streamflow have the potential to impact important regime characteristics, including: total annual volume, magnitude and duration of peak and low flows, and variability in timing and rate of change. Changes to total annual volume and peak flows may impact channel stability, riparian vegetation, and floodplain functions. Impacts to base flows frequently alter water quality and the quality and availability of aquatic habitat. Alterations to natural patterns of flow variability (e.g. the frequency and timing of floods) impact fish, aquatic insects and other biota with life history strategies tied to predictable rates of occurrence or change (Johnson et al., 2016). 2. Water Budget for the Upper Roaring Fork The balance of water flowing into streams from snowmelt and rainfall, getting diverted for human uses, being consumed or evaporating, and returning to the river via surface or groundwater (Figure 1), creates the components of a water budget. The responses of physical Hydrological Decision Support Tools 5 and legal water demands to hydrological conditions determine the allocation of water among the various uses present in the system. The diversity of, and competition among, these water uses in the Roaring Fork watershed produces gaps between existing supply—both in time and in place—and the supply needed to satisfy both consumptive and environmental and recreational use needs. Figure 1: Conceptual model indicating the various pathways water travels along between a stream or river and a typical point of agricultural use on Colorado streams and rivers. Hydrologic characteristics of interest for streams in the Roaring Fork watershed include the duration, frequency, and magnitude of different flows states on the mainstem Roaring Fork River and its major tributaries. Surface water diversions and reservoir operations strongly alter the longitudinal (upstream-downstream) and temporal (day-to-day or seasonal) patterns of flow in many stream segments throughout the watershed. Additionally, long-term hydrological conditions like drought or wet periods can impart both obvious and subtle changes in regime behavior. Stakeholders in the Roaring Fork watershed recognize that understanding human and natural controls on hydrology is a critical first step for effective resource management. To this end, the Roaring Fork River Management Plan sought to produce data and modeling tools capable of characterizing the hydrological regime at numerous locations throughout the watershed under a range of climatic or human management conditions. Hydrological Decision Support Tools 6 Directly characterizing patterns of daily streamflow across a range of hydrological conditions and under different management regimes in the upper Roaring Fork watershed is possible at several locations where United States Geological Survey (USGS) gauges exist and maintain long data records (Table 1, Figure 2). On the mainstem and on some tributaries, satisfactory streamflow records are somewhat sparse both in geographic coverage and length of observations. Without some amount of data processing or analysis, observed streamflow records are, thus, inadequate to describe daily flow conditions at a sufficient spatial resolution to inform water management decisions at all locations where stakeholders desire. Even in cases were streamflow records can be extended using statistical data filling techniques, water abstractions and tributary inflows upstream and downstream from gauge locations makes reliance on fixed measurement locations implausible for the types of questions germane to this planning effort. Table 1. Historical and current streamflow gauging stations in the upper Roaring Fork watershed considered in this assessment. Provider Site ID Drainage Area (sq mi) Site Name USGS 09072550 9.03 ROARING FORK RIVER ABV LOST MAN CR NEAR ASPEN, CO USGS 09073005 15.1 LINCOLN CREEK BELOW GRIZZLY RESERVOIR NR ASPEN, CO USGS 09073300 75.8 ROARING FORK RIVER AB DIFFICULT C NR ASPEN, CO USGS 09073400 106.0 ROARING FORK RIVER NEAR ASPEN, CO USGS 09074500 43.1 HUNTER CREEK AT ASPEN, CO USGS 09074000 41.7 HUNTER CREEK NEAR ASPEN, CO USGS 09074800 32.3 CASTLE CREEK ABOVE ASPEN, CO USGS 09075700 35.4 MAROON CREEK ABOVE ASPEN, CO CDWR ROABMCCO 289.0 ROARING FORK RIVER BELOW MAROON CREEK NEAR ASPEN, CO Hydrological Decision Support Tools 7 Figure 2. Locations of historical and current streamflow gauging locations in the upper Roaring Fork watershed. The presence of human management activities in the upper Roaring Fork watershed means that any useful hydrological decision support tool must explicitly account for the operation and administration of transmountain diversions; reservoirs; surface water diversions (and associated return flows) supporting agriculture, landscaping, municipal use, snowmaking; and hydropower diversions (Table 2). The most significant water diversion structures and projects in the upper watershed are discussed briefly below. Hydrological Decision Support Tools 8 Table 2. Surface water diversion structures and locations considered by this assessment. WDID Water Source Structure Name Total Decreed Rate (cfs) 3804617 Lincoln Creek Twin Lakes Tunnel #1 625 3801763 Roaring Fork River Twin Lakes Tunnel #2 486.16 3800981 Roaring Fork River Salvation Ditch 59 3801091 Roaring Fork River Wheeler Ditch 10 3800963 Roaring Fork River Riverside Ditch 3 3800904 Roaring Fork River Nellie Bird Ditch 4.94 3801594 Hunter Creek Fry-Ark PR Hunter Tunnel 270 3801790 Hunter Creek Red Mountain Ditch 27.34 3801026 Maroon Creek Stapleton Brothers Ditch 16.01 3800749 Maroon Creek Herrick Ditch 64.86 3800854 Maroon Creek Maroon Ditch 68.4 3801101 Willow Creek Willow Creek Ditch 40 3800869 Castle Creek Midland Flume Ditch 160 3800755 Castle Creek Holden Ditch 30 3800853 Castle Creek Marolt Ditch 18.6 3800992 Castle Creek SI Johnson Ditch 5.5 2.1 Overview of Water Rights Considerations There are three diversion structures or systems that have historically had the greatest effects on stream flows in the Upper Roaring Fork upstream and through the City of Aspen: the Independence Pass Transmountain Diversion System, the Salvation Ditch and the Hunter Creek portion of the Frying Pan/Arkansas Project collection system. Several other diversions significantly affect stream flows in other portions of the Upper Roaring Fork and its tributaries above Brush Creek. The Wheeler Ditch has occasionally reduced flows in the Roaring Fork downstream from its headgate near the center of Aspen. The Red Mountain Extension Ditch has reduced flows in the lower portion of Hunter Creek and in the Roaring Fork downstream of the Hunter Creek confluence. The City of Aspen’s municipal diversions from Castle Creek have Hydrological Decision Support Tools 9 reduced flows in Castle Creek and the Upper Roaring Fork downstream of the Castle Creek confluence. 2.1.1 Independence Pass Transmountain Diversion System The Independence Pass Transmountain Diversion System (IPTDS) is owned and operated by the Twin Lakes Reservoir and Canal Company (Twin Lakes). The IPTDS diverts from several Roaring Fork headwater tributaries. Diverted water is collected by pipelines and flows by gravity through Twin Lakes Tunnel #1 to the Arkansas basin, where it is used for municipal and irrigation (M&I) purposes by Twin Lakes shareholders. Grizzly Reservoir, with a 400 AF storage capacity, acts as a point of diversion, central collection point, and forebay for Tunnel #1. Diversions by the IPTDS have historically occurred year-round and have ranged from as low as 9,000 AF per year to as high as 66,000 AF per year, averaging approximately 43,000 AF per year 700 over the most recent 20 years (Figure 3). 0 100 200 Discharge ( cfs ) 300 400 500 600 Maximum 0.95 Quantile Mean Median 0.25 Quantile Minimum Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 3. Historical diversion patterns reported for Twin Lakes Tunnel #1. Hydrological Decision Support Tools 10 During the peak runoff season (typically late May through June) of wet years, the physical supplies at the IPTDS points of diversion typically exceed the system’s diversion and collection capacities and spills occur at those locations. At other times, the IPTDS generally diverts the entire physical supply whenever the IPTDS rights are in priority, subject to the terms of the IPTDS decrees and the Twin Lakes Exchange. The IPTDS operates under its original 1936 priority water rights and its supplemental 1994 priority rights. The 1936 priority rights were decreed in Civil Action No. 3082 for irrigation use and were subsequently changed to include municipal & industrial (M&I) uses in Case No. W1901. Those decrees imposed several limits on Twin Lakes’ diversions under the 1936 priority rights, including: (1) no more than 68,000 AF of diversions in any year, (2) no more than 570,000 AF of diversions in any ten-year period, and (3) no diversions at times when Twin Lakes Reservoir has stored its decreed capacity of 54,452 AF for the year and there is 726.28 cfs available in priority to the Colorado Canal June 9, 1890 irrigation right. In the 95CW321 decree, Twin Lakes obtained its supplemental 1994 priority rights, which allow Twin Lakes to divert at times when the 1994 rights are in priority and limit #3 above would otherwise curtail Twin Lakes’ diversions under its 1936 priority rights. The 1995 priority rights are decreed for direct flow and storage for irrigation and M&I uses. Twin Lakes’ combined diversions under the 1936 and 1994 priority rights are constrained by the same 68,000 AF annual and 570,000 AF ten-year volumetric limits. Diversions under the 1994 priority rights alone are limited to no more than 30,000 AF in any year and no more than 46,500 AF in any ten-year period. The Twin Lakes Exchange was initially described in the Operating Principles for the Frying Pan/Arkansas (FryArk) Project and is the subject of several subsequent agreements. Under the Twin Lakes Exchange, up to 3,000 AF per year of water is diverted from FryArk points of diversion in the Hunter Creek basin and is delivered to Twin Lakes via FryArk project facilities in exchange for an equivalent amount of bypass of water at the IPTDS points of diversion that would otherwise be divertible under the IPTDS 1936 priority rights. The 95CW321 decree and stipulations to that decree impose several conditions on Twin Lakes’ diversions under the 1994 Hydrological Decision Support Tools 11 priority rights. The conditions that provide additional water for the Roaring Fork can be generally summarized as follows1. Ø The first 40 AF of water available each year to the 1994 priority right is stored in a 40 AF Grizzly Reservoir Mitigation Account, for release during the current year to help meet instream flows on the Roaring Fork. Any leftover water in this account reverts to Twin Lakes. Ø One third of the next 2,360 AF available each year to the 1994 priority right each year (up to 787 AF) is allocated to the Colorado River Water Conservation District for the benefit of West Slope water users. Ø Up to 200 AF of the River District’s annual allocation is stored in a 200 AF River District Grizzly Reservoir account. Water can be released from the River District Grizzly Reservoir account for several purposes including satisfying deficits to the CWCB’s instream flow right upstream of Maroon Creek. Releases from the River District Grizzly Reservoir account are limited to 150 AF in any one year. Any water left over in the River District Grizzly Reservoir account is carried over to the next year. Ø Under a separate agreement, Pitkin County has the right to use up to 20 AF per year from the River District Grizzly Reservoir account for replacement and other purposes. The County’s use of this water for replacement generally results in the released water supporting instream flows on the Roaring Fork. Ø The balance of the River District’s 787 AF annual allocation is stored in available space in Arkansas River basin reservoirs and is generally used to meet the repayment obligations of certain West Slope water users to Aurora and Colorado Springs or can be substituted 1 It should be noted that this is just a summary. The 95CW321 decree and its stipulations should be read for more detailed descriptions. Also, allocations of water from the 1994 priority water rights for West Slope uses, including releases to support instream flows in the Roaring Fork, continue to be the subject of ongoing negotiations between the several parties. Hydrological Decision Support Tools 12 for additional bypasses of water at the IPTDS diversions in the Roaring Fork (beyond the bypasses comprising the 3,000 AF FryArk Exchange). Ø Releases from the River District Grizzly Reservoir account, along with any additional IPTDS bypasses, are generally used for satisfying deficits to the CWCB’s instream flow rights on the Roaring Fork upstream of Maroon Creek, with successive use of the released water downstream of Maroon Creek. The combined benefit of the 95CW321 conditions to instream flows in the Roaring Fork are potentially significant: up to 210 AF of Grizzly Reservoir releases and up to 787 AF of additional bypasses at IPTDS points of diversion in a given year. However, these potential benefits are dependent upon the yield of Twin Lakes’ 1994 priority IPTDS water rights, which are not reliable because the 1994 priority water rights are not available or needed for diversion in all years. In some below average years, the conditions imposed on the 1936 priority rights may not come into play and all IPTDS diversions would occur under the 1936 priority rights. In some wet years, Twin Lakes may not need to divert under the 1994 priority rights because of lack of demand in the Arkansas basin. From a basin-wide administration perspective, the IPTDS 1936 priority water rights are senior to the ISF rights on the Roaring Fork but are junior to most of the in-basin Roaring Fork ditch rights, including those of the Salvation and Wheeler ditches. The IPTDS 1936 priority water rights are also junior to the Cameo rights (a group irrigation rights associated with the Grand Valley Canal and the Grand Valley Project) and must be curtailed when there is a call from the senior Cameo rights. While the IPTDS 1936 priority water rights are junior to most of the inbasin Roaring Fork ditch rights, diversions by the IPTDS have not normally been called out by inbasin Roaring Fork ditch rights because intervening flows from Roaring Fork tributaries downstream of the IPTDS points of diversion have historically been sufficient to satisfy downstream senior Roaring Fork rights. This is evidenced by the lack of recorded historical calls by Roaring Fork ditch rights and was confirmed by discussions with the District 38 Water Commissioner. However, the IPTDS has been called out by the senior Cameo call, which Hydrological Decision Support Tools 13 typically occurs in an intermittent manner during July through August of below-average years, Year (Figure 4). 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec Figure 4: Historical occurrence of the Cameo Call, a collection of water rights near Grand Junction senior to IPTDS water rights Diversions by the IPTDS are the primary cause of human-caused shortages, or aggravations to natural shortages, to the CWCB’s 32 cfs instream flow right on the Upper Roaring Fork as measured as the Roaring Fork Near Aspen gage (09073400) during November through March, although most of the shortages during November through March are natural shortages, which are aggravated by IPTDS diversions. During these months, Roaring Fork ditches are not diverting and natural flows are already relatively low, typically close to the 32 cfs ISF right for the Upper Roaring Fork. Hydrological Decision Support Tools 14 2.1.2 Grizzly Reservoir Grizzly Reservoir is located on Lincoln Creek and is operating by Twin Lakes as part of the IPTDS collection system. The reservoir has a storage capacity of approximately 400 AF. It provides storage for water available to the Colorado River Water Conservation District and Pitkin County pursuant to the 95CW321 decree and several related agreements. It is also used by the public as a recreational reservoir. Water available from Grizzly Reservoir for West Slope uses, including releases to maintain minimum stream flows, comes from diversions made under Twin Lakes’ IPTDS 1994 priority water rights, which do not divert reliably in every year, as mentioned above. 2.1.3 Salvation Ditch The Salvation Ditch is owned and operated by the Salvation Ditch Company and diverts water from the Upper Roaring Fork for irrigation uses on McClain Flats. The point of diversion is approximately 100 feet downstream of the USGS stream gauge above Aspen. The Salvation Ditch’s water right has an appropriation date of August 2, 1902, which is senior to the IPTDS water rights and the Cameo rights but is junior to the downstream Wheeler Ditch water right. The Ditch normally diverts from May through October. Diversions have ranged from as low as 3,400 AF per year to as high as 8,400 AF per year, averaging approximately 5,000 AF per year over the most recent 20 years (Figure 5). Because of the relatively senior priority of its water right and the relatively large inflows to the Roaring Fork downstream of the Salvation Ditch’s headgate, the Ditch’s diversions are normally not limited by the Cameo call or by the demands of downstream Roaring Fork ditches, including demands of the Wheeler Ditch, a senior right located approximately 1.5 miles downstream of the Salvation Ditch’s headgate. The Roaring Fork typically gains sufficient flow between the Salvation and Wheeler Ditch headgates that the Wheeler Ditch does not normally call out the Salvation Ditch. Salvation Ditch representatives have reported that the Ditch occasionally voluntarily reduces its diversions during critical dry spells to help support instream flows and downstream junior water users. Diversions by the Salvation Ditch are the primary cause of Hydrological Decision Support Tools 15 shortages to the Upper Roaring Fork between the Salvation Ditch headgate and the confluence with Castle Creek, although diversions by the Wheeler Ditch have caused aggravations to 35 shortages in this reach. 0 5 10 Discharge ( cfs ) 15 20 25 30 Maximum 0.95 Quantile Mean Median 0.25 Quantile Minimum Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 5. Historical reported diversion patterns for the Salvation Ditch. 2.1.4 Hunter Creek Collection System – Frying Pan Arkansas Project The Hunter Creek Collection System portion of the Frying Pan Arkansas (FryArk) project is comprised of diversion dams at three locations - Hunter Creek, No Name Creek and Midway Creek. A series of tunnels convey the diverted water to the Boustead Tunnel, which delivers FryArk project diversions to Turquoise Lake in the Arkansas basin. FryArk diversions from the Hunter Creek system are subject to bypass requirements as needed to meet the CWCB’s instream flow rights on Midway Creek, No Name Creek and on several segments of Hunter Creek. While the water rights of the FryArk project are junior to the Cameo rights, they are insulated from Cameo calls by replacement releases from Ruedi Reservoir. Daily diversions Hydrological Decision Support Tools 16 typically occur from mid-May through early July and typically peak at around 200 cfs (Figure 6). Annual diversions have averaged approximately 10,000 AF per year and have ranged from a low 350 of approximately 2,800 AF (2002 and 2012) to a high of approximately 16,500 AF (2011). 0 50 100 Discharge ( cfs ) 150 200 250 300 Maximum 0.75 Quantile Mean Median 0.25 Quantile Minimum Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 6. Historical reported diversion patterns for the Hunter Tunnel. 2.1.5 Wheeler Ditch The Wheeler Ditch diverts from the Roaring Fork within the City of Aspen at a point about 1.5 miles downstream of the Salvation Ditch. It is owned by the City of Aspen and is used to irrigate lands associated with Aspen’s storm water management facilities. The Wheeler Ditch is senior to the Salvation Ditch and to the Cameo rights and has never been called out by downstream Roaring Fork irrigation rights. Diversions have averaged about 4 cfs (Figure 7) and typically run from early May through late October (annual average ~1300 AF). Beginning in 2013, the City of Aspen has operated the Ditch to reduce diversions at times during the irrigation season when Hydrological Decision Support Tools 17 the CWCB’s instream flow reach is not satisfied in the reach immediately below the Wheeler 14 Ditch headgate. 0 2 4 Discharge ( cfs ) 6 8 10 12 Maximum 0.95 Quantile Mean Median 0.25 Quantile Minimum Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 7. Historical reported diversion patterns for the Wheeler Ditch. 2.1.6 Red Mountain Extension Ditch The Red Mountain Extension Ditch diverts from the lower reach of Hunter Creek and supplies water for irrigation to parcels located mainly on McClain Flats. The ditch diverts from early May to mid-October and a typical rate of 12 cfs (Figure 8). Historical annual diversions average about 3,600 AF per year and have ranged from about 800 AF to about 5,600 AF. The Red Mountain Extension Ditch’s water rights are senior to the Cameo call. Hydrological Decision Support Tools 18 25 0 5 Discharge ( cfs ) 10 15 20 Maximum 0.95 Quantile Mean Median 0.25 Quantile Minimum Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 8. Historical observed diversion patterns into the Red Mountain Extension Ditch. 2.1.7 City of Aspen Water Supply System The City of Aspen owns and operates its own water utility. The utility provides both treated and raw water supply to customers within its service area, as to other users via service contracts. Aspen’s treated water system is supplied primarily by surface diversions from Castle Creek (Figure 9), supplemented by diversions from Maroon Creek and pumping of three municipal wells situated in the downtown Aspen area. These supplemental sources are used at times when surface supplies from Castle Creek are insufficient to meet Aspen’s demands while maintaining minimum stream flows below Aspen’s Castle and Maroon Creek diversions. Aspen’s diversions from Castle and Maroon Creek are conveyed by pipelines to Thomas Reservoir (13 AF capacity), which provides short-term storage and supplies Aspen’s water treatment plants located adjacent to the reservoir. Some of the water delivered to Thomas reservoir is released for raw water irrigation and snowmaking. Aspen has committed to Hydrological Decision Support Tools 19 operating its diversions to support the CWCB’s instream flow rights below its points of diversion 50 in all but extraordinary circumstance. 0 10 Discharge ( cfs ) 20 30 40 Maximum 0.95 Quantile Mean Median 0.25 Quantile Minimum Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 9. Historical reported diversion patterns into the Midland Flume, which carries water to Thomas Reservoir. The City of Aspen also operates the Maroon Creek hydropower project (Figure 10), a run-ofriver project that diverts water from Maroon Creek above Willow Creek and returns the diverted water to Maroon Creek at a downstream location without depletion. Several ditch systems that divert from the Roaring Fork and Castle Creek to provide raw water for the downtown mall, fountains, aesthetic features, irrigation of street trees and private properties, the municipal golf course, Marolt Open Space and the Red Butte cemetery. Aspen’s combined diversions from Castle and Maroon Creek for uses other than Maroon Creek hydropower have averaged about 5,200 AF per year. Hydrological Decision Support Tools 20 100 0 20 Discharge ( cfs ) 40 60 80 Maximum 0.95 Quantile Mean Median 0.25 Quantile Minimum Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Figure 10. Historical diversion patterns reported for the Maroon Ditch, which supplies flow to the Maroon Hydropower Plant. Aspen’s municipal water supply system operates without a significant amount of available surface storage, which is unusual for municipal water supply systems of similar size. Aspen owns conditional storage rights on Castle and Maroon Creek, which Aspen is considering developing. In recognition of the problematic aspects of building a significant new reservoir on Castle or Maroon Creek, Aspen has contracted to purchase two adjoining parcels of land near Woody Creek for potential use as an alternate off-channel water storage reservoir for its conditional water rights. 3. Decision Support Tool Development To provide estimates of streamflow at additional points intermediate to or above locations where historical data is available and at points above and below surface water diversions, this Hydrological Decision Support Tools 21 project employed a variety of methodologies. Regression models, point-flow spreadsheet models, and water rights simulation models were created to provide different types of information about patterns of streamflow. Development of each required approximating the administration of Colorado Water Law in order to produce daily timestep estimates of water availability, water demand, patterns of local use, and discrepancies between use needs and water supply. These decision support tools enable retrospective analysis of surface water hydrology in the upper Roaring Fork and will allow City and County staff and their consultants to test “what-if” water use and management scenarios in a consistent and data-driven manner in the future. Notably, daily hydrological simulation models may be useful to the City’s ongoing efforts to understand impacts of climate change on its water supplies and its future ability to simultaneously meet municipal demands, contract obligations, and the needs of the environment. 3.1 Point Flow Model Development The simplest method for estimating streamflows at locations where observed data records do not exist is to create an additive water balance model in a spreadsheet. This approach, sometimes termed ‘point-flow’ modeling relies on observed streamflows, reported surface water diversions, and some knowledge of network structure, stream gains and losses, and return flow timing and allocation. In the upper Roaring Fork watershed, this modeling approach was used to characterize hydrological regime behavior on 13 stream segments. The model estimated daily streamflows using only historical streamflow observations from USGS and CDWR and records of daily water diversion available from CDWR in the HydroBase system. This approach yielded streamflow time series of different lengths, covering different periods of time at different locations in the watershed. The long streamflow records available on the Roaring Fork River above Aspen and on Hunter Creek above the Red Mountain Ditch enabled computation of streamflow at upstream and downstream points between 1975 and 2013. Limited streamflow records on Castle Creek and Maroon Creek, conversely, limited estimates of streamflow in those drainages to the period between 1975 and 1995. The spreadsheet model computes daily flow percentiles for each day in the calendar year using the full record of estimated flows on each reach. Users may define different drought or flood conditions of Hydrological Decision Support Tools 22 interest by selecting daily flow percentiles for model output that correspond to ‘Dry’, ‘Average’, and ‘Wet’ conditions. The primary purpose of point flow model development is to allow stakeholders and water managers to understand how historical patterns of streamflow and water use impacted water availability for environmental needs in low-flow periods. To do this, the model allows users to assign low-flow thresholds for each reach. Thresholds may correspond to CWCB ISF rights, to Fryingpan-Arkansas Project Operating Principals, to recommendations made in special studies, or to user-defined values. Daily flows on each reach are compared against thresholds to calculate the magnitude, timing and duration of environmental water use shortages under the selected hydrological year types. The model generates estimates of shortages under natural (no-use) conditions, and existing (historical-use) conditions. Calculating both provides users with important information for placing estimates of environmental use shortages in context with limitations imposed by natural water availability. Total Dry Year Shortages: Total Days Below Threshold (Count) Total Days Above Threshold (Count) Summer Days Below Threshold (Count) Total Shortage (af) Summer Shortage (af) Roaring Fork River below Lost Man Creek Lincoln Creek below New York Creek Roaring Fork River above Difficult Creek Roaring Fork River at North Star Roaring Fork River below Wheeler Ditch Hunter Creek below Red Mountain Ditch Roaring Fork River below Hunter Creek 301 64 150 3418 1145 195 170 44 1144 97 196 169 45 2780 1693 176 189 25 2776 145 262 103 111 6107 3330 304 61 153 14193 6691 224 141 88 3673 2362 Figure 11. Example output from the point flow spreadsheet model. The largest limitations of the point-flow model are its reliance on historical records and its focus on low-flow thresholds. This is particularly true where patterns of water use changed significantly over the last 40 years and where historical water management is no longer an appropriate proxy for understanding current or future use. It is also problematic on reaches where the primary question of interest involves the impact of water management on peak flow timing, duration, and magnitude. Therefore, outputs from the point flow model are best suited for understanding the historical context that shapes the current condition of riparian areas, aquatic biota, and other elements of riverine landscapes impacted by low-flow alteration. Different tools are required to help managers and stakeholders understand the impact of Hydrological Decision Support Tools 23 Castle Mid current or future water management actions (or climate change) on all components of hydrological regime behavior. 3.2 Water Rights Simulation Model Development Understanding the complex interplay between inflow hydrology and the exercise of surface water diversion rights under Colorado water law requires a water rights allocation and accounting model. Gauge records, diversion histories, and, optionally, rainfall/runoff simulations provide the inputs necessary to build a functioning simulation model for local streams and rivers. Hydrological simulations for the Roaring Fork River and its tributaries were initially produced by modifying the State of Colorado Stream Simulation Model (StateMod) developed by the Colorado Water Conservation Board (CWCB) for the Colorado River Basin.12 The basic CWCB StateMod model simulates inflows, surface water diversion, crop usage, ground- and surface-water return flows, reservoir operations, in-stream demands, reservoir operations, and augmentation plans on a monthly time step. For computational efficiency, the model combines multiple simulation objects (such as diversions or instream flow points) into aggregated modelling nodes. The CWCB model was refined for this project. Aggregated simulation nodes in the upper Roaring Fork watershed were disaggregated (or split apart into separate objects) and the simulation time step was refined downward from monthly to daily. Updated data records provided by Colorado Decision Support System (CDSS) databases, the local Water Commissioner, and municipal water managers were integrated into the model to produce a more robust and accurate simulation of local water allocation and accounting. Diversions were updated with ditch capacities, return flow locations, and estimates of ditch loss. The refined StateMod model characterized the impacts of management actions and changing hydrological conditions on average daily streamflow at numerous locations across the watershed (Figure 12). In order to accommodate important administrative actions on the mainstem Colorado River, the model actually includes rivers and diversion locations across the entire Colorado River basin. Hydrological Decision Support Tools 24 Figure 12. Portion of the StateMod simulation network covering the upper Roaring Fork watershed. Several conversations with local water managers and City of Aspen staff subsequent to refinement of the StateMod model indicated some dissatisfaction with complexities and steep learning curve associated with use of StateMod. These potential users of the decision support tools developed under the Roaring Fork River Management Plan indicated a strong preference for more user-friendly modeling environment. In response, we developed a MODSIM-DSS model for the upper Roaring Fork watershed. The MODSIM model network included the mainstem Roaring Fork River, major tributaries, and major surface water diversions (Figure 13). Simulations covered the period between 1975 and 2013. The hydrological variability observed Hydrological Decision Support Tools 25 over this period provides a baseline for expected hydrological behavior on top of which climate change or water management scenarios can be built. Cameo_Call Upper Roaring Fork Watershed Hydrological Simulation Model Network Salvation_Ditch Flow Through Node Red_Mountain_Ditch Consumptive Demand Non-Storage Node Flow Direction Reservoir Network Sink Hunter_Tunnel Stapleton_Brothers _Ditch Hunter_Near_Aspen Marolt_Ditch Herrick_Ditch Hunter_Creek_Inflow SI_Johnson_Ditch Wheeler_Ditch Nellie_Bird_Ditch Holden_Ditch Riverside_Ditch Willow_Ditch Willow_Creek_Inflow Maroon_Ditch Herrick_Diversion Midland_Flume_Ditch Castle_COA_Intake RF_blw_Lost _Man Difficult_Creek_Inflow Conundrum_Creek_Inflow West_Maroon Creek_Inflow Roaring_Fork_Inflow Castle_Creek_Inflow East_Maroon_Creek_Inflow Twin_Lakes_Tunnel_2 Lincoln_Creek_blw_Grizzly Twin_Lakes_Tunnel_1 Lincoln_Creek_Inflow Figure 13. MODSIM-DSS simulation network for the upper Roaring Fork Watershed 3.2.1 Inflow Hydrology Where suitable diversion records and long observed streamflow data sets exist, inflow hydrology over the period of interest can be computed directly. This is the case on Hunter Creek above Red Mountain Ditch and on the Roaring Fork River at the North Star Preserve. At both of these locations, calculating natural flows involved adding historical transmountain diversion records to the observed streamflows. Flows were then distributed among the upstream tributaries and contributing basins using the watershed area ratio approach. On the Roaring Fork River, 16% of the flows were allocated to the mainstem above the IPTDS diversion, 11% to the confluence with Ptarmigan Creek, 26% to Lincoln Creek and its tributaries above the Hydrological Decision Support Tools 26 IPTDS collection system, 4% to lower Lincoln Creek, 15% to the segment tributaries near Tagert Lakes, and 28% to Difficult Creek. In the Hunter Creek drainage, 40% of the naturalized flow was allocated to Hunter Creek and its tributaries above the FryArk collection system and 60% was 500 allocated between those collection points and the downstream USGS gauge. ● rf.streamflow$castle.abv.aspen.move2 rf.streamflow$X09074800 ● ● ● ● ● ● ● ● ● ● ● 400 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 300 ● ● ● ● ● ● ● ● ● 200 Streamflow [cfs] ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ●● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● GoF's: ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ●● ●● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ●● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ●● ● ● ● ● ● ● ●● ● ●● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ●● ● ● ● ● ●● ● ●● ● ●● ● ● ● ●● ● ● ● ●● ●● ● ● ●● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ●● ● ●● ● ●● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ●●● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ●● ●● ●● ●● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ●● ● ●● ● ●● ● ● ● ● ● ●● ● ● ● ●● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ●● ●● ●● ●● ● ●● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ●● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ●● ●● ● ● ●● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ●● ● ● ● ●● ● ● ● ●● ● ● ● ●● ●● ● ● ● ● ●● ● ● ● ●● ●● ● ● ●● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ●● ● ● ●● ●● ●● ● ● ● ● ●● ●● ● ● ● ● ●● ● ●● ● ● ●● ● ● ●● ● ● ●● ● ●● ● ●● ●● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ●● ● ● ● ● ● ● ● ●● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ●● ●● ● ● ●● ●● ● ● ● ● ● ●● ● ●● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ●● ● ● ● ●● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ●● ● ● ●● ● ● ● ●● ● ●● ● ●● ● ● ● ● ● ● ●● ● ● ● ●● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ●● ● ●● ● ● ● ● ● ● ●● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ●●● ● ●● ● ● ● ● ● ●● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ●● ● ●● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ●● ● ● ● ● ● ●● ●● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ●● ● ● ● ● ● ● ●● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ●● ● ●●● ●● ●● ● ● ● ● ●● ● ● ● ● ●● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ●● ● ● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ●● ● ●● ● ●● ●● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ●● ●● ●● ● ● ● ● ●● ● ● ● ●● ● ●● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ●● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ●● ● ●● ● ● ● ●● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ●●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ●● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ●● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ●● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ●●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ME = −0.26 MAE = 9.75 RMSE = 18.03 NRMSE = 32.1 PBIAS = −0.7 RSR = 0.32 rSD = 1.05 NSE = 0.9 mNSE = 0.73 rNSE = 0.93 d = 0.97 md = 0.86 rd = 0.98 r = 0.95 R2 = 0.9 bR2 = 0.86 KGE = 0.95 VE = 0.75 0 100 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● Oct 01 1974 Jan 01 1980 Jan 01 1986 Jan 01 Jan 01 1992 1998 Time Jan 01 2004 Jan 01 2010 Figure 12. MOVE.2 model for streamflows at USGS gauge on upper Castle Creek. Black line is observed data, blue is simulated. Calculation of natural flows on Castle Creek and Maroon Creek over the period of interest required extension of the observed records at the historical USGS gauges on each creek. Records on Castle Creek (USGS-09074800) were extended by applying the Maintenance of Variance 2 (MOVE.2) function in the smwrStats package in the R statistical computing Hydrological Decision Support Tools 27 environment. The naturalized flow records from the USGS gauge at North Star Preserve was selected as the reference data set. The function was applied using a lognormal distribution and a lag of 3 days. Flows on Maroon Creek were also filled by applying the MOVE.2 methodology. Prior to filling, diversions at the Herrick Ditch were added to the observed flows at the Maroon Creek gauge (USGS-09075700). The naturalized flow records from the USGS gauge at North Star Preserve was selected as the reference data set. The function was applied using a lognormal distribution and a lag of 5 days. The fitted streamflows for each location (Figure 12, 13) (Table 3) were deemed suitable for inclusion in the model and were subsequently used as the upstream boundary condition for each creek. ● rf.streamflow$maroon.abv.aspen.move2 rf.streamflow$X09075700 ● ● ● ● ● ● ● ● ● ● 600 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 400 Streamflow [cfs] ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ●● ● ●● ●● ●● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ●● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● GoF's: ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ●● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ●● ● ●● ●● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ●● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ●● ● ●● ● ●● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ●● ●● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ●● ●● ●● ● ● ● ● ●● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ●● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ●● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ●● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ●● ● ●● ●● ● ● ● ●● ● ●● ● ● ●● ● ●● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ●● ●● ● ● ● ●● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ●● ● ●● ● ● ●● ● ● ●● ● ●● ● ● ● ● ● ● ●● ●● ●● ● ● ● ● ●● ●● ● ● ● ●● ● ● ● ●● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ●● ● ● ●● ● ●● ● ● ● ●● ● ● ● ●● ● ●● ●● ● ● ●● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ●● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●●● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ●● ● ●● ● ● ●● ●● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ●● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ●● ● ● ● ●● ● ● ●●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ●● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ●● ● ●● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ●● ●● ●● ● ●● ● ●● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ●● ● ●● ● ●● ● ● ●● ● ● ●● ● ●● ●● ● ●● ● ●● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ●● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●●● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ●● ● ● ● ● ●● ● ● ● ● ● ●● ●● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ●● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ●● ● ● ●●● ● ● ● ● ●● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ●● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ●● ●● ●●● ● ●● ●● ● ● ● ●● ● ● ● ● ●● ● ● ● ●● ● ● ●●● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ●● ● ● ● ● ● ●● ● ●● ● ●● ● ● ● ● ● ● ●● ● ●● ●● ●● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ●● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ●● ●● ● ● ● ●● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ●● ●● ● ●● ● ● ● ●● ● ● ● ● ● ●● ●● ● ● ● ●●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ●● ● ●● ● ● ● ●● ● ● ●● ● ●● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ●● ●● ●● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ●●● ● ●● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ●● ● ● ●● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ●●● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ●● ● ● ● ●● ● ●● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ●● ● ● ● ●● ● ●● ● ●● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ●● ● ● ● ● ●● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ●●● ● ●●● ● ● ●● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ●●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ●● ● ●● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ●● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ●● ● ●● ● ●● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ●●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ●● ●● ● ● ● ●● ●● ● ●● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ●●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ●● ● ● ●● ● ● ● ●● ●● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ●● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ●● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ●● ● ● ● ●● ● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ●● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ●● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●● ● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ME = 3.46 MAE = 23.28 RMSE = 44.59 NRMSE = 55.3 PBIAS = 5.7 RSR = 0.55 rSD = 1.22 NSE = 0.69 mNSE = 0.56 rNSE = 0.79 d = 0.93 md = 0.79 rd = 0.95 r = 0.88 R2 = 0.78 bR2 = 0.75 KGE = 0.79 VE = 0.61 0 200 ●● ● ● ● ● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● Oct 01 1974 Jan 01 1980 Jan 01 1986 Jan 01 Jan 01 1992 1998 Time Jan 01 2004 Jan 01 2010 Figure 13. MOVE.2 model for streamflows at USGS gauge on upper Maroon Creek. Black line is observed data, blue is simulated. Hydrological Decision Support Tools 28 Table 3. Goodness-of-fit measures applied to assess model fit. Abbreviation Measure Description me Mean Error mae Mean Absolute Error rmse Root Mean Square Error nrmse Normalized Root Mean Square Error PBIAS Percent Bias pbiasfdc PBIAS in the slope of the midsegment of the Flow Duration Curve RSR Ratio of RMSE to the Standard Deviation of the Observations, RSR = rms / sd(obs). ( 0 <= RSR <= +Inf ) rSD Ratio of Standard Deviations, rSD = sd(sim) / sd(obs) NSE Nash-Sutcliffe Efficiency ( -Inf <= NSE <= 1 ) mNSE Modified Nash-Sutcliffe Efficiency rNSE Relative Nash-Sutcliffe Efficiency d Index of Agreement ( 0 <= d <= 1 ) md Modified Index of Agreement rd Relative Index of Agreement cp Persistence Index ( 0 <= PI <= 1 ) r Pearson product-moment correlation coefficient ( -1 <= r <= 1 ) r.Spearman Spearman Correlation coefficient ( -1 <= r.Spearman <= 1 ) Coefficient of Determination ( 0 <= R2 <= 1 ). R2 Gives the proportion of the variance of one variable that is predictable from the other variable R2 multiplied by the coefficient of the regression line between bR2 Kling-Gupta efficiency between KGE sim and obs ( 0 <= KGE <= 1 ) Volumetric efficiency between VE sim and obs ( 0 <= bR2 <= 1 ) sim and obs ( -Inf <= VE <= 1) Stream gains and tributary contributions below the inflow locations on Castle Creek and Maroon Creek were estimated using the watershed area ratio approach. Total surface water flows for the Maroon Creek watershed were estimated as 165% of the filled gauge record from upper Maroon Creek. Seventy percent of this flow was allocated back to Maroon Creek above the Herrick Ditch, 25% for Willow Creek above the Willow Ditch, 3% above the Maroon Hydropower Plant outfall, and 2% on the short segment above the confluence with the Roaring Fork River. A limited streamflow record on lower Castle Creek (USGS-09075400) provided opportunity for a more refined approach to distributing flows in that drainage. Flows for the entire Castle Creek drainage were first estimated as 230% of the filled record from the gauge on upper Castle Creek. These flows were then modified to match downstream flow records by raising them to the 0.94 power. The final estimated flows were distributed back to points in the Hydrological Decision Support Tools 29 Castle Creek drainage such that 96% accrued to Castle Creek above the Midland Flume and 4% accrued at the confluence with Keno Gulch. Synthetic regional groundwater inflows contributing to streamflows on the Roaring Fork River and its tributaries above Brush Creek were computed by conducting a baseflow separation on the time series of naturalized streamflows on the Roaring Fork River at North Star Preserve. Daily baseflow values over the period of interest were estimated by applying a Lynne-Hollick (LH) baseflow filter from the hydroStats package in the R statistical computing environment. The LH filter was set to 0.985 and the number of burn-in days was set to 30. Estimated baseflows were distributed to the major tributary watersheds in the upper Roaring Fork located below the USGS gauge above Aspen using the watershed area ratio approach such that 40% of the flows accrued to the mouth of Castle Creek, 30% to the mouth of Maroon Creek, 20% to the mouth of Hunter Creek, and 10% to the Roaring Fork below the Wheeler Ditch. Groundwater contributions to streamflow are notoriously difficult to measure directly. However, first principals in watershed hydrology and limited direct measurement of streamflow gains on the Roaring Fork River through the City of Aspen suggest that inclusion of some estimate of groundwater contribution to streamflow should make simulations more accurate. In fact, inclusion of these baseflows as a proxy for regional groundwater contributions greatly assisted in calibration of simulated low flows to observed streamflows at the CDWR gauge in the Roaring Fork Gorge (CDWR-ROABMCCO). Using the approaches outlined above, estimates of regional groundwater and flow on Castle Creek and Maroon Creek require only the naturalized flow record from the USGS streamgauge in the North Star Preserve (USGS-09073400). Use of this gauge as the index station was intentional, as this gauging station is included in numerous regional and state-sponsored assessments of the impact of climate change on streamflows. Incorporating climate change impacts in future application of the model is thus simplified. Impacts on groundwater and tributary flows (excepting Hunter Creek) may be rapidly estimated through reapplication of the above methodologies to the predicted streamflow timeseries for USGS-09073400. Hydrological Decision Support Tools 30 3.2.2 Water Demands Water demands for transmountain diversions were set equal to the 95th percentile of weekly historical diversions measured between 2000-2015. The same approach was used for the Wheeler Ditch, Nellie Bird Ditch, Salvation Brothers Ditch and Riverside Ditch where diversions are not strongly tied to crop water requirements. A special study commissioned by the City of Aspen (Wilson Water Group, 2016) provided water demands at the Midland flume for treated municipal supply, snowmaking, etc. Hydropower demands on Maroon Creek were assumed equal to the absolute decreed rate for the Maroon Ditch. Irrigation water demands associated with most other diversions in the system were extracted from StateCU and the StateMod model described previously. The general approach calculated Irrigation Water Requirement (IWR) based on the irrigated acreages associated with each diversion structure, observed precipitation and air temperature between 1975-2013, and the type of crop irrigated at each location. The efficiency of water conveyance and delivery system was then estimated by comparing the IWR to the historical diversion record (Table 4). Infiltration fractions were then estimated by subtracting the irrigation efficiency from 1.0 (Table 5). The maximum diversion rate for each structure was set equal to the absolute adjudicated water right. Table 4. Irrigation efficiencies evaluated for MODSIM diversion nodes. Values calculated as [Irrigation Water Requirements] – [Historical Diversions]. Month Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Salvation Ditch 0.03 0 0 0 0 0 0.34 0.19 0.13 0.11 0.06 0.05 Red Mountain Ext. Ditch 0.06 0 0 0 0 0 0.6 0.35 0.19 0.16 0.09 0.1 Hydrological Decision Support Tools Midland Flume 0.26 0 0.1 0.1 0.12 0.14 0.44 0.55 0.62 0.61 0.56 0.44 Holden Ditch 0 0 0 0 0 0 0 0.01 0.07 0.07 0.05 0.01 Herrick Ditch 0.01 0 0 0 0 0 0.17 0.16 0.07 0.05 0.02 0.02 Willow Creek Ditch 0.02 0 0 0 0 0 0 0.24 0.15 0.14 0.07 0.04 31 Table 5. Infiltration fractions applied to MODSIM diversion nodes calculated as 1 – [Irrigation Efficiency]. Month Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Salvation Ditch 0.97 1 1 1 1 1 0.66 0.81 0.87 0.89 0.94 0.95 Red Mountain Ext. Ditch 0.94 1 1 1 1 1 0.4 0.65 0.81 0.84 0.91 0.9 Midland Flume 0.74 1 0.9 0.9 0.88 0.86 0.56 0.45 0.38 0.39 0.44 0.56 Holden Ditch 1 1 1 1 1 1 1 0.99 0.93 0.93 0.95 0.99 Herrick Ditch 0.99 1 1 1 1 1 0.83 0.84 0.93 0.95 0.98 0.98 Willow Creek Ditch 0.98 1 1 1 1 1 1 0.76 0.85 0.86 0.93 0.96 3.2.3 Water Rights Administration The water rights extension in MODSIM was used to simulate administration of water in the upper Roaring Fork watershed according to Colorado water law. Each water right at each diversion structure was given a negative cost value corresponding the administration number assigned by DWR such that increasing negative values represent more senior water rights (Table 6). Bypass flows maintained by the City of Aspen at the Maroon Ditch and Midland Flume for environmental benefit were included as separate water demands and given a slightly higher priority than the most senior right at the corresponding structure, even though these bypasses are not decreed uses of water and cannot, technically, be administered with the same priority as the diversion right. Therefore, use of the model for evaluating some scenarios may require modification of this priority setting; particularly where upstream junior water rights have claim to bypassed flows. Bypass requirements at TMDs were treated as water demands with a higher priority than the associated structure to ensure they are always met (to the degree that they can be given native inflow hydrology). Effects of administration of the Cameo Call on the IPTDS was handled by extracting the simulated call for water in the StateMod model described previously. In this way, the impacts of ‘big-river’ administration are accounted for in the model Hydrological Decision Support Tools 32 without requiring simulation of streamflows, reservoir operations, diversions, etc. across the entire Colorado River basin directly. Table 6. Diversion structures and water rights included in the MODSIM model. Structure WDID 3800749 3801790 3800981 3801091 3800963 3800904 3800755 3800755 3800755 3800854 3801026 3801101 3804617 3800869 3800869 3801101 3801101 3801101 3800749 3800749 3800904 3800755 3801026 3801026 3801790 3801790 3801790 3801790 3801790 3801790 3800981 3800854 3801594 3802049 3802023 3802050 3802015 3802027 3802111 3802000 3802000 3802039 3801763 Absolute Rate 9 1 58 10 3 4 4 19 30 3 8 3 625 60 100 3 30 4 52 4 1 2 6 2 13 6 4 1 1 1 1 65 270 32 8 10 12 14 55 14 16 15 322 Unit cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs Hydrological Decision Support Tools Adjudication Date 10/1/1890 5/15/1884 8/2/1902 9/1/1882 6/1/1888 6/9/1885 1/10/1926 3/1/1902 8/27/1950 7/10/1889 6/30/1904 7/1/1885 8/23/1930 11/16/1885 5/11/1889 5/1/1887 4/15/1891 12/22/1989 8/1/1951 12/22/1989 4/30/1989 5/1/1932 9/22/1960 6/1/1977 11/27/1888 4/3/1909 9/3/1915 6/11/1990 12/11/2001 10/15/2004 12/26/1989 8/12/1892 7/29/1957 1/14/1976 1/14/1976 1/14/1976 1/14/1976 1/14/1976 11/8/1985 2/26/1975 1/31/1979 1/14/1976 8/25/1936 Admin. Number 31648.1488 12554.0000 20041.1921 11932.0000 30941.1403 30941.1294 30941.2777 30845.1905 36763.0000 15799.1444 30523.1990 12966.0000 30941.2945 15515.1310 15515.1438 13635.0000 15514.1508 51125.0000 37552.3710 51125.0000 52230.5089 30941.3007 40442.0000 46751.4654 14211.0000 25618.2164 30941.2399 51296.0000 56247.5550 56536.0000 51129.0000 32907.1557 39291.0000 46034.0000 46034.0000 46034.0000 46034.0000 46034.0000 49620.0000 45712.0000 47147.0000 46034.0000 MODSIM Cost -295 -480 390 -490 -340 -350 -320 -360 -280 -410 -370 -470 -310 -430 -420 -460 -440 -120 -270 -120 -100 -300 -250 -170 -450 -380 -330 -100 -90 -80 -110 -290 -260 -220 -220 -220 -220 -220 -150 -240 -160 -220 -310 33 3.2.4 Baseline simulation Model Performance Simulations yielded a 38-year data set extending from 1975 to 2013. Model performance was evaluated by comparing simulation results against measured streamflows at several gauging stations (Figure 14). Goodness-of-fit measures provided indications of times and locations where simulation results most accurately reflected observed conditions (Table 3). The revised model performed well at mainstem Roaring Fork River locations, particularly during low flows. A lack of long-term historical records and difficulty in simulating the operation of the IPTDS produced some uncertainty below the IPTDS diversion point on the upper Roaring Fork River near Lost Man Creek. Difficulty simulating IPTDS and FryArk responses to reservoir operations on in the Arkansas Basin may cause artificially high peak flows in some years in the simulation model. Roaring Fork Gorge 3000 GoF's: simulated ME = 39.07 observed 2500 MAE = 60.76 RMSE = 121.76 NRMSE = 33 2000 RSR = 0.33 rSD = 1.15 1500 NSE = 0.89 mNSE = 0.74 rNSE = 0.96 d = 0.98 1000 Discharge (cfs) PBIAS = 13.4 md = 0.88 rd = 0.99 500 r = 0.97 R2 = 0.94 bR2 = 0.84 0 KGE = 0.8 VE = 0.79 Oct 01 1996 Jan 01 1999 Jan 01 2001 Jan 01 2003 Jan 01 2005 Jan 01 2007 Jan 01 2009 Jan 01 2011 Jan 01 2013 Figure 14. Simulated and observed streamflows in the Roaring Fork Gorge at CDWRROABMCCO. Hydrological Decision Support Tools 34 3.2.5 Scenario Development The most appropriate application of the decision support tools developed here requires development of paired pre- and post-condition simulations. The pre- and post-condition scenarios discuessed here represent: 1) the ‘natural’ condition that would exist in the absence of human water use or management activities, and 2) the ‘current’ condition as it is affected by existing patterns of water use and administration. In the context of the Roaring Fork River Management Plan, these two scenarios provide useful information for understanding the degree to which water management activities altered the natural hydrological template—an important driver of ecological and geomorphological conditions. Appropriate application of simulation results relies on comparative analysis of the modeled pre- and post-condition scenario results and not their individual characterization as precise estimates of historical or future conditions. In the future, local stakeholders and water managers may build upon these scenarios as a means for developing simple or complex impact assessments of climate change, reservoir development, water rights leasing, etc. on patterns for flow throughout the upper Roaring Fork watershed. 4. Hydrological Regime Behavior Hydrology in the upper Roaring Fork watershed is dominated by snowmelt runoff and impacted by patterns of water use at all times of the year. Peak flows increase with increasing watershed size. The summer and fall are typically characterized by a short recession of peak flows followed by a period of stable low flows between early fall and late spring. The IPTDS and the FryingpanArkansas Project impact peak flow timing and magnitude on downstream river segments. The IPTDS completely dewaters portions of the upper Roaring Fork River for significant periods each year. Late summer water depletions in the lower watershed on the mainstem Roaring Fork create some discontinuities in longitudinal patterns in flow magnitude and low-flow duration. The effects are most prominent on lower Hunter Creek and on the Roaring Fork River between the North Star Preserve and the confluence with Castle Creek. Identification of locations across the watershed where management activities appear to impact the hydrological regime most Hydrological Decision Support Tools 35 significantly provides indication of stream reaches where additional management actions may propagate positive or negative changes to measures of river health and resiliency. 4.1 Hydrological Alteration Hydrological simulation results elucidate the convergence of climate, stream network structure, and patterns of water use that dictate the ability of local streams and rivers to meet the full array of existing uses in different year types. Understanding the ability of the Roaring Fork River and its tributaries to meet both human and ecosystem begins with characterization of the range of hydrological conditions throughout the watershed and the degree to which these conditions are impacted by management activities. An analysis of hydrological regime behavior at locations throughout the Roaring Fork watershed considered 30 measures of hydrological behavior (Table 7). Metrics characterizing flow magnitude, duration, and rate of change were derived through statistical examination of the entire 38-year simulation period at each node in the modelling network. Results covered a range of wet, average, and dry hydrological conditions. Three flow percentiles (0.75, 0.5, 0.25) were selected to approximate moderate-wet, average, and moderate-drought conditions. Indices of hydrological alteration were computed by first characterizing hydrological regime behavior under each scenario at each simulation node using the IHA package in the R statistical computing environment. Output yielded measures of the metrics presented in Table 7 for each year in the simulation period. Annual values where then summarized into three aggregated sets corresponding to each of the threshold flow percentiles identified above. The percent change in each measure of hydrological behavior was subsequently derived by comparing results from the existing conditions scenario to the results from the natural conditions scenario (Table 8, 9, 10). Hydrological Decision Support Tools 36 Table 7. Measures of hydrological regime behavior assessed throughout the upper Roaring Fork watershed. Variable Units Description April cfs April mean daily discharge August cfs August mean daily discharge December cfs December mean daily discharge February cfs February mean daily discharge January cfs January mean daily discharge July cfs July mean daily discharge June cfs June mean daily discharge March cfs March mean daily discharge May cfs May mean daily discharge November cfs November mean daily discharge October cfs October mean daily discharge September cfs September mean daily discharge 1 Day Max cfs Daily mean dischage, maximum daily obs of daily mean discharges 1 Day Min cfs 1 day minimum for daily mean discharge 3 Day Max cfs Maximum of 3-day means of daily discharge 3 Day Min cfs Minimum of 3-day means of daily discharge 7 Day Max cfs Maximum of 7-day means of daily discharge 7 Day Min cfs Minimum of 7-day means of daily dischrage 30 Day Max cfs Maximum of 30-day means of daily discharge 30 Day Min cfs Minimum of 30-day means of daily discharge 90 Day Max cfs Maximum of 90-day means of daily discharge 90 Day Min cfs Minimum of 90 day means of daily discharge Base index ratio Ratio of 7-day minimum flow to mean annual flow (7 day min / mean annual) Zero flow days count Number of no-flow days Max Julian day Date of peak flow, in Julian days 1-365 from January 1 Min Julian day Date of minimum flow, in Julian days 1-365 from January 1 High pulse length days Mean duration of high pulses High pulse number count Mean number of high pulses within each water year Low pulse length days Mean duration of low pulses Low pulse number count Mean number of low pulses within each water year Fall rate cfs/day Mean of all negative differences between consecutive daily flow values Reversals count Number of hydrologic reversals (dropping flow changing to rising and vice-versa) Rise rate cfs/day Mean of all positive difference between consecutive daily flow rates Hydrological Decision Support Tools 37 Hunter Creek below No Name Creek Lower Hunter Creek Castle Creek at Keno Gulch Lower Castle Creek Maroon Creek above Willow Creek Maroon Creek below Willow Creek Lower Maroon Creek 0% 0% -30% -25% 0% -18% 0% -9% 0% 0% -26% -24% 0% -16% 0% -47% -62% -54% -29% -29% -29% -8% 0% 0% -26% -21% 0% -14% 0% -60% -58% -60% -29% -33% -40% -8% 0% 0% -27% -27% 0% -20% 0% -78% -52% -66% -31% -39% -37% -20% -11% -16% -8% -8% -5% -52% -2% -85% -58% -72% -41% -46% -46% -26% -28% -38% -3% -7% -4% -22% -2% -75% -53% -64% -30% -53% -50% -18% 0% -50% -7% -23% -11% -50% -6% -68% -53% -61% -31% -44% -47% -16% 0% -100% -13% -34% -11% -65% -7% -62% -58% -60% -29% -37% -41% -16% 0% -100% -16% -56% -21% -63% -15% -59% -60% -60% -30% -41% -46% -12% 0% -66% -19% -19% -18% -50% -14% -56% -59% -57% -30% -30% -30% -7% 0% 0% -23% -23% 0% -36% -3% -50% -57% -53% -27% -27% -27% -7% 0% 0% -26% -26% 0% -26% -1% -85% -59% -72% -41% -44% -44% -26% -1% -42% -60% -45% -24% -26% -28% -85% -59% -73% -41% -44% -44% -25% -39% -59% -47% -25% -26% -28% -85% -59% -73% -41% -45% -44% -26% -40% -59% -49% -27% -28% -28% -85% -59% -73% -41% -44% -44% -27% -38% -59% -48% -26% -28% -28% -83% -59% -71% -40% -46% -45% -24% Roaring Fork at Mill Street -8% -60% -51% -28% -29% -29% Roaring Fork at Aspen Club -62% -53% -29% -29% -29% -43% Roaring Fork at North Star Preserve -45% Roaring Fork at Tagert Lakes Roaring Fork below Maroon Creek Mean January Flow Mean February Flow Mean March Flow Mean April Flow Mean May Flow Mean June Flow Mean July Flow Mean August Flow Mean September Flow Mean October Flow Mean November Flow Mean December Flow Annual 1 Day Max Annual 1 Day Min Annual 3 Day Max Annual 3 Day Min Annual 30 Day Max Annual 30 Day Min Annual 7 Day Max Annual 7 Day Min Annual 90 Day Max Annual 90 Day Min Baseflow Index Fall Rate High Pulse Duration High Pulse Count Low Pulse Duration Low Pulse Count Flow Reversals Rise rate Annual Volume Roaring Fork above Lincoln Creek 25th Flow Percentile (Dry Year) Lower Lincoln Creek Table 8. Simulated hydrological alteration during moderately dry conditions -8% -7% -9% -9% -44% -59% -51% -28% -28% -29% +147% -4% -50% -40% -46% -35% -36% -30% -21% 0% 0% -9% -39% -2% -5% -2% -14% 0% -100% -13% -68% 0% -18% 0% -35% -39% -2% -5% -2% -14% -2% 0% -100% -16% -65% 0% -18% 0% -32% -37% -2% -5% -3% -18% -2% 0% -99% -19% -32% -0% -13% -0% -34% -39% -2% -5% -2% -14% -1% 0% -100% -16% -61% 0% -17% 0% -26% -34% -4% -13% -5% -29% -3% 0% -13% -22% -18% -0% -17% -0% +30% -100% -1% -49% +5% -1% +2% -17% 0% 0% 0% 0% -20% +15% 0% -33% 0% -25% -3% -3% 0% 0% 0% 0% 0% 0% 0% 0% +25% 0% +67% 0% +6% +9% -9% +41% 0% +13% +50% -50% 0% +200% +100% +33% +50% 0% 0% -5% -7% 0% -7% +11% -6% +19% +57% +16% +27% +24% +16% +25% -35% 0% +14% +14% +50% +2% -33% -17% -33% +25% +25% +25% -50% -6% -100% +13% -44% -10% -14% -33% -33% -40% -17% -29% -21% -14% 0% +6% 0% 0% 0% -50% 0% -77% -59% -67% -38% -45% -44% -21% -21% -35% -8% -15% -6% -34% -3% -25% +23% +23% 0% Hydrological Decision Support Tools -8% -7% -5% -2% +1% 38 Maroon Creek above Willow Creek Maroon Creek below Willow Creek Lower Maroon Creek -26% -26% 0% -26% 0% 0% -27% -27% 0% -21% 0% -53% -60% -56% -31% -30% -30% -9% 0% 0% -27% -27% 0% -24% 0% -63% -59% -61% -33% -33% -41% -10% 0% 0% -20% -20% 0% -36% 0% -79% -55% -67% -40% -45% -44% -22% -24% -28% -5% -12% -2% -47% -2% -85% -59% -73% -41% -45% -45% -24% -32% -39% -2% -6% -3% -17% -2% -80% -57% -68% -39% -52% -50% -23% -7% -36% -5% -9% -6% -32% -4% -73% -57% -64% -31% -57% -61% -24% 0% -61% -10% -22% -15% -66% -8% -66% -56% -61% -30% -39% -41% -16% 0% -77% -15% -23% -19% -61% -9% -60% -57% -58% -26% -34% -39% -11% 0% -38% -20% -20% -18% -53% -16% -59% -59% -59% -31% -32% -32% -9% 0% 0% -20% -20% 0% -40% -55% -59% -57% -30% -30% -30% -8% 0% 0% -24% -24% 0% -33% 0% -85% -59% -73% -42% -44% -44% -24% -1% -2% -12% -1% -38% -58% -48% -26% -27% -27% -7% -30% -30% -3% -17% -2% -85% -59% -73% -42% -44% -44% -25% -1% -2% -12% -1% -43% -61% -51% -28% -29% -29% -7% -26% -32% -3% -18% -3% -85% -59% -73% -41% -45% -44% -22% -2% -2% -14% -1% -50% -59% -54% -30% -30% -32% -9% -27% -33% 0% -20% 0% -86% -59% -73% -41% -44% -44% -24% -2% -2% -12% -1% -47% -60% -53% -29% -29% -31% -8% -24% -33% -1% -19% -2% -83% -59% -71% -40% -46% -45% -24% -3% -52% -59% -55% -30% -30% -30% -9% +149% -33% -2% +52% +18% +29% +27% +14% -50% -50% -33% -25% -25% -50% -50% 0% 0% 0% -100% 0% -13% +17% +33% +33% -34% -9% -13% -43% -50% -50% -30% -33% -33% -78% -58% -69% -38% -44% -43% -21% -2% -5% 0% -74% -36% -37% 0% -100% -29% -35% 0% -7% +38% -100% 0% 0% -2% -34% -38% 0% -50% 0% -100% 0% -25% +17% 0% 0% +25% -8% -100% +1% 0% +67% +67% +33% 0% -36% -39% -17% 0% Hydrological Decision Support Tools 0% -36% -39% Lower Castle Creek Lower Hunter Creek 0% 0% Castle Creek at Keno Gulch Hunter Creek below No Name Creek 0% -9% Roaring Fork at Mill Street -9% -60% -55% -30% -30% -30% Roaring Fork at Aspen Club -60% -56% -31% -30% -30% -50% Roaring Fork at North Star Preserve -53% Roaring Fork at Tagert Lakes Roaring Fork below Maroon Creek Mean January Flow Mean February Flow Mean March Flow Mean April Flow Mean May Flow Mean June Flow Mean July Flow Mean August Flow Mean September Flow Mean October Flow Mean November Flow Mean December Flow Annual 1 Day Max Annual 1 Day Min Annual 3 Day Max Annual 3 Day Min Annual 30 Day Max Annual 30 Day Min Annual 7 Day Max Annual 7 Day Min Annual 90 Day Max Annual 90 Day Min Baseflow Index Fall Rate High Pulse Duration High Pulse Count Low Pulse Duration Low Pulse Count Flow Reversals Rise rate Annual Volume Roaring Fork above Lincoln Creek 50th Flow Percentile (Avg. Year) Lower Lincoln Creek Table 9. Simulated hydrological alteration during average conditions. -4% -5% -6% -4% -10% -3% -22% -2% -26% -27% 0% -23% 0% -15% -21% +5% +20% +20% 0% -43% 0% +50% 0% 0% +33% +162% 0% +33% -19% +13% 0% 0% +67% +67% +33% -2% 0% -5% -21% 0% 0% -25% -36% -2% -4% +2% +20% +20% -8% -14% +16% +3% 0% -50% 0% -6% -6% -5% 0% 0% +11% -23% 0% 0% -9% +50% 0% +6% 0% +14% 0% -40% 0% -5% -28% -3% 39 Lower Hunter Creek Maroon Creek above Willow Creek Maroon Creek below Willow Creek Lower Maroon Creek -31% -31% -31% -9% 0% 0% -23% -23% 0% -33% 0% -56% -30% -30% -32% -8% 0% 0% -24% -24% 0% -29% 0% -53% -59% -56% -31% -31% -31% -9% 0% 0% -23% -23% 0% -31% 0% -69% -57% -63% -34% -38% -32% -10% 0% -1% -17% -17% 0% -46% 0% -83% -58% -71% -41% -44% -43% -26% -29% -32% -4% -8% -2% -28% +1% -86% -59% -73% -41% -44% -44% -24% -35% -39% -2% -4% -2% -12% -1% -84% -59% -72% -40% -49% -48% -19% -23% -37% -3% -9% -4% -18% -2% -74% -55% -65% -37% -61% -57% -20% 0% -42% -8% -19% -9% -49% -6% -70% -52% -56% -29% -50% -53% -21% 0% -61% -11% -18% -13% -69% -10% -69% -56% -63% -35% -42% -45% -13% 0% -18% -14% -14% -13% -59% -8% -65% -60% -63% -34% -35% -34% -9% 0% 0% -18% -18% 0% -49% -2% -59% -60% -60% -31% -32% -32% -9% 0% 0% -21% -21% 0% -41% -2% -82% -59% -73% -42% -44% -43% -27% -1% -2% -10% -1% -50% -57% -53% -29% -29% -35% -27% -29% -4% -27% 0% -85% -59% -73% -42% -44% -43% -27% -1% -1% -10% -1% -51% -59% -55% -29% -29% -34% -26% -28% -1% -27% 0% -86% -59% -73% -41% -44% -44% -24% -2% -1% -53% -59% -56% -31% -30% -31% -86% -59% -73% -42% -44% -43% -25% -53% -60% -56% -30% -30% -34% -85% -59% -73% -41% -45% -45% -23% -31% -31% -31% -8% -9% -9% -8% -55% -59% -56% +136% -5% +48% +14% +26% +20% +16% -67% -33% -40% +139% -29% -29% -29% -25% +70% +106% -15% -52% -52% 0% 0% +8% -71% -7% -92% 0% -31% -7% -56% -40% -80% -59% -9% -37% -38% 0% -100% -37% -38% 0% -89% -35% -39% 0% -31% -36% -39% 0% -71% -31% -37% 0% -0% +28% -61% 0% -3% -4% -2% -12% -25% -28% 0% -27% 0% -1% -2% -10% -1% -26% -27% 0% -27% 0% -2% -3% -18% -2% -5% -3% -6% -24% -24% -0% -31% -0% -19% -19% +7% +20% +3% +9% -47% 0% -4% -1% -2% 0% 0% 0% -8% 0% -36% -6% -6% 0% 0% +25% 0% +17% -7% 0% 0% +65% -50% +34% -32% -59% +9% -11% 0% +17% +27% +27% +14% +14% +14% +1% +3% -2% -0% 0% -5% -13% -6% 0% 0% +12% -33% 0% -7% -11% -3% -28% -2% 0% 0% -11% +7% +2% 0% -18% +5% -10% +0% -3% -1% -2% -43% -34% -27% -18% -26% -71% -39% -45% -44% -21% -25% -33% Hydrological Decision Support Tools Lower Castle Creek Hunter Creek below No Name Creek -57% -59% Castle Creek at Keno Gulch Roaring Fork below Maroon Creek -59% -56% Roaring Fork at Mill Street Roaring Fork at North Star Preserve -55% Roaring Fork at Aspen Club Roaring Fork at Tagert Lakes Mean January Flow Mean February Flow Mean March Flow Mean April Flow Mean May Flow Mean June Flow Mean July Flow Mean August Flow Mean September Flow Mean October Flow Mean November Flow Mean December Flow Annual 1 Day Max Annual 1 Day Min Annual 3 Day Max Annual 3 Day Min Annual 30 Day Max Annual 30 Day Min Annual 7 Day Max Annual 7 Day Min Annual 90 Day Max Annual 90 Day Min Baseflow Index Fall Rate High Pulse Duration High Pulse Count Low Pulse Duration Low Pulse Count Flow Reversals Rise rate Annual Volume Roaring Fork above Lincoln Creek 75th Flow Percentile (Wet Year) Lower Lincoln Creek Table 10. Simulated hydrological alteration during moderately wet conditions. 0% +100% +100% +50% -35% +1% 40 5. Conclusions Effective and informed discussions about water issues in future community and/or stakeholder groups settings must be supported by reliable data and communication tools that speak to a diverse audience. Furthermore, any discussion that contemplates a change to water use or management should be supported by conceptual models, data products and simulation tools that help participants understand the likely outcomes of any given action. To this end, the project team developed a pair of hydrological and water rights simulation tools. These tools will allow City and County staff and their consultants to test “what-if” water use and management scenarios in the upper watershed. Consideration of simulation results using an ecological evaluation framework, also developed for this effort by the project team, will help place hydrological change in the appropriate ecological context and help users predict the degree to which any management action will impact river health. In addition to their use to further assess and refine the management opportunities listed previously, simulation tools may be used to inform other parallel efforts. The daily hydrological simulation models may be useful to the City’s ongoing efforts to understand impacts of climate change on its water supplies and its future ability to simultaneously meet municipal demands, contract obligations, and the needs of the environment. Any effort to build climate change scenarios into the hydrological simulation models would also benefit future discussions about water management for river health but must be proceeded by an agreement among City departments regarding the types of and theoretical basis for selected climate change scenarios. 6. References Johnson, B., Beardsley, M., & Doran, J. (2016). FACStream Manual 1.0: Functional Assessment of Colorado Streams. Retrieved from http://nebula.wsimg.com/bcd02501d43f467a7334b89eefea63d1?AccessKeyId=70CECFD07F5CD51B8510&di sposition=0&alloworigin=1 Poff, N. L., Allan, J. D., Bain, M. B., Karr, J. R., Prestegaard, K. L., Richter, B. D., Stromberg, J. C. (1997). The natural flow regime. BioScience, 47(11), 769–784. Wilson Water Group. (2016). City of Aspen Water Supply Availability Study, 2016 Update. Prepared for City of Aspen. Hydrological Decision Support Tools 41 P.O. Box 1524 Carbondale, CO 81623 (970) 903-7561 lotichydrological.com MEMORANDUM TO: April Long, Stormwater Manager, City of Aspen FROM: Seth Mason, Principal Hydrologist DATE: March 1, 2018 SUBJECT: URF-DSS Updates Following completion of the Roaring Fork River Management Plan, further revisions were completed for the Upper Roaring Fork Hydrological Decision Support System (URF-DSS). Version 2 of the model includes refinements to the distribution of inflows in the section of the Roaring Fork watershed above the City of Aspen. This version allocates naturalized flows at the USGS stream gauge near Stillwater Drive (USGS-09073400) in the follow manner: 20% to the Roaring Fork River above the Independence Pass Transmountain Diversion System (IPTDS); 35% to the Lincoln Creek drainage above the IPTDS collection system in Lincoln Creek, Tabor Creek, and New York Creek; 7% to Ptarmigan Creek, 13% to tributary and groundwater gains at Tagert Lakes, and 25% to Difficult Creek. Modification of streamflow allocations in this manner improved model fit during peak flows. The ‘goodness-of-fit’ of simulated flows to observed flows was assessed with a variety of measures (Table 1) at several stream gauges (Figure 1, 2, 3). All model input files and supporting documentation were compiled for easy access and future revision in a public GitHub repository (https://github.com/lotichydrological/URF-DSS). Table 1. Goodness-of-fit measures applied to assess model accuracy. Abbreviation Measure Description me Mean Error mae Mean Absolute Error rmse Root Mean Square Error nrmse Normalized Root Mean Square Error PBIAS Percent Bias pbiasfdc PBIAS in the slope of the midsegment of the Flow Duration Curve RSR Ratio of RMSE to the Standard Deviation of the Observations, RSR = rms / sd(obs). ( 0 <= RSR <= +Inf ) rSD Ratio of Standard Deviations, rSD = sd(sim) / sd(obs) NSE Nash-Sutcliffe Efficiency ( -Inf <= NSE <= 1 ) mNSE Modified Nash-Sutcliffe Efficiency rNSE Relative Nash-Sutcliffe Efficiency d Index of Agreement ( 0 <= d <= 1 ) md Modified Index of Agreement rd Relative Index of Agreement cp Persistence Index ( 0 <= PI <= 1 ) r Pearson product-moment correlation coefficient ( -1 <= r <= 1 ) r.Spearman Spearman Correlation coefficient ( -1 <= r.Spearman <= 1 ) Coefficient of Determination ( 0 <= R2 <= 1 ). R2 Gives the proportion of the variance of one variable that is predictable from the other variable R2 multiplied by the coefficient of the regression line between bR2 Kling-Gupta efficiency between KGE sim and obs ( 0 <= KGE <= 1 ) Volumetric efficiency between VE sim and obs ( 0 <= bR2 <= 1 ) ( -Inf <= VE <= 1) sim and obs MEMORANDUM Page 2 of 5 Above Difficult Creek 1000 GoF's: simulated observed ME = −6.72 MAE = 11.79 RMSE = 22.88 800 NRMSE = 36 PBIAS = −16.3 600 rSD = 0.82 NSE = 0.87 mNSE = 0.67 rNSE = 0.9 400 Discharge (cfs) RSR = 0.36 d = 0.96 md = 0.83 200 rd = 0.97 r = 0.95 R2 = 0.9 bR2 = 0.71 0 KGE = 0.75 VE = 0.71 Oct 01 2000 Apr 01 2002 Oct 01 2003 Apr 01 2005 Oct 01 2006 Apr 01 2008 Oct 01 2009 Apr 01 2011 Oct 01 2012 Figure 1. Observed and simulated streamflows at the USGS stream gauge above Difficult Creek (USGS-09073300). MEMORANDUM Page 3 of 5 North Star 1200 GoF's: simulated 1000 observed ME = 2.2 MAE = 13.86 RMSE = 23.89 NRMSE = 23.2 800 RSR = 0.23 rSD = 1.06 600 NSE = 0.95 mNSE = 0.77 rNSE = 0.94 d = 0.99 400 Discharge (cfs) PBIAS = 3.1 md = 0.89 rd = 0.99 200 r = 0.98 R2 = 0.95 bR2 = 0.92 0 KGE = 0.93 VE = 0.8 Oct 01 2000 Apr 01 2002 Oct 01 2003 Apr 01 2005 Oct 01 2006 Apr 01 2008 Oct 01 2009 Apr 01 2011 Oct 01 2012 Figure 1. Observed and simulated streamflows at the USGS stream gauge above City of Aspen (USGS-09073400). MEMORANDUM Page 4 of 5 3000 Roaring Fork Gorge GoF's: simulated 2500 observed ME = 26.61 MAE = 50.29 RMSE = 96.8 2000 PBIAS = 9.8 RSR = 0.29 rSD = 1.14 1500 NSE = 0.92 mNSE = 0.76 rNSE = 0.97 d = 0.98 1000 Discharge (cfs) NRMSE = 28.5 md = 0.89 rd = 0.99 500 r = 0.98 R2 = 0.95 bR2 = 0.86 0 KGE = 0.83 VE = 0.82 Oct 01 2000 Apr 01 2002 Oct 01 2003 Apr 01 2005 Oct 01 2006 Apr 01 2008 Oct 01 2009 Apr 01 2011 Oct 01 2012 Figure 1. Observed and simulated streamflows at the CDWR stream gauge below Maroon Creek (CDWR-ROABMCCO). MEMORANDUM Page 5 of 5 Appendix PROCESS FOR EVALUATING ECOSYSTEM CONDITIONS Description of a generalized process for evaluating environmental impacts and/or environmental benefits from future water projects in the Roaring Fork River basin and an application to existing datasets under the Roaring Fork Management Plan Prepared For: City of Aspen And Lotic Hydrological, LLC Prepared By: William J. Miller Senior Aquatic Ecologist Miller Ecological Consultants, Inc. Bozeman, Montana and Greg Espegren Aquatic Specialist Eagle, Colorado January 29, 2018 Process for evaluating ecosystem conditions Page i Table of Contents Introduction ............................................................................................................................... 1 Background on techniques and methods for evaluation. ................................................................... 2 Summary of Current Conditions on all Focus Reaches ............................................................... 9 Summary of the current conditions for each reach based on the available data.............................. 13 Roaring Fork River: Lost Man Creek to confluence with Difficult Creek .......................................... 13 Lincoln Creek: Grizzly Reservoir to Roaring Fork River ................................................................... 14 Roaring Fork River: Difficult Creek to Salvation Ditch Diversion ..................................................... 15 Roaring Fork River: Salvation Ditch Diversion to Castle Creek ........................................................ 17 Hunter Creek: Fry-Ark Diversion to confluence with Roaring Fork River......................................... 18 Castle Creek: Conundrum Creek to Roaring Fork River .................................................................. 21 Maroon Creek: West Maroon Creek to Roaring Fork River ............................................................ 22 Process for future project evaluation ...................................................................................... 25 References ............................................................................................................................... 26 List of Tables Table 1. IHA parameters and their Ecosystem Influences (TNC 2009). ........................................ 5 Table 2. Basinwide IHA modeling using Lotic point flow hydrologic model to evaluate changes in hydrology between natural flows and existing depleted flows (25th percentile). ........... 10 Table 3. Basinwide IHA modeling using Lotic point flow hydrologic model to evaluate changes in hydrology between natural flows and existing depleted flows (50th percentile). ........... 11 Table 4. Basinwide IHA modeling using Lotic point flow hydrologic model to evaluate changes in hydrology between natural flows and existing depleted flows (75th percentile). ........... 12 List of Figures Figure 1. Conceptual relationship of ecosystem evaluation methods to project characteristics (after Stalnaker et al. 1995). ................................................................................................ 7 Figure 2. Example of steps for project evaluation and adaptive management approach for future project evaluations. Espegren and Rozaklis 2012 ...................................................... 8 Process for evaluating ecosystem conditions Page ii Introduction The process presented here is one task of the Upper Roaring Fork River Basin Management Plan. The goal for this task is to outline a general process and data requirements for evaluating environmental impacts from future water development projects or environmental benefits from future water leasing/conservation/improved water efficiency projects within the upper Roaring Fork River basin. The appendix also lists the data and study reports available at the time for evaluation of each river reach. This compilation serves as the starting point for any future evaluations of new projects. This task used current state of the science techniques and existing data to evaluate river reaches in the Upper Roaring Fork River Basin. The stream reaches evaluated in the project area are: Roaring Fork River: Lost Man Creek to Difficult Creek Lincoln Creek: Grizzly Reservoir to Roaring Fork River Roaring Fork River: Difficult Creek to Salvation Ditch Diversion Roaring Fork River: Salvation Ditch Diversion to Castle Creek Hunter Creek: Fry-Ark Diversion to Roaring Fork River Roaring Fork River: Castle Creek to Brush Creek Castle Creek: Conundrum Creek to Roaring Fork River Maroon Creek: West Maroon Creek to Roaring Fork River The existing data for these reaches ranges from hydrology only data to multi-year site specific studies. The process presented here outlines an approach that can be used for future evaluations using the range of available data with recommendations on future studies and refinements to the approach. The approach and existing data should be useful to an aquatic ecologist tasked with evaluation of future projects. The approach presented here used a multi-disciplinary approach where such data was available and a single resource approach in stream reaches without existing multi-disciplinary studies. The uppermost stream reaches were evaluated mainly with hydrologic analysis and supplemented with some additional data sets. The stream reaches closer to the City of Aspen have had more extensive studies completed in the past few years. Those studies included Process for evaluating ecosystem conditions Page 1 geomorphology, hydrology, aquatic habitat, aquatic biota and water quality data. The comprehensive suite of information in those reaches is the optimal data for evaluation of riverine ecosystem conditions and analysis of potential changes in the ecosystem due to a proposed project. Background on techniques and methods for evaluation. Evaluation of stream flow and effects on aquatic habitat and aquatic biota has been an ongoing science since mid 20th century. The 1970s saw an increase in interest in quantification of streamflow – habitat relationships, especially with the advance of digital computation techniques. Early evaluations focused on desktop hydrologic analysis (Tennant 1976) or simple single cross section hydraulic models. The limitations of these early methods in addressing multiple components or stream ecosystems was the impetus for advanced hydraulic models that incorporated more components of aquatic ecosystems (Bovee 1982, Bovee et al. 1998, Stalnaker et al. 1995). As computational capabilities increased with the advances in computer technology, even more complex techniques for multidimensional analyses were developed (Steffler and Blackburn 2002). All of these techniques have assumptions regarding response of biota to change in stream flow or stream habitat but do not specifically measure a biological response. A newer approach for aquatic ecosystem analysis focuses on multiple parameters that make up the aquatic ecosystem. These parameters include hydrology, biology, water quality, geomorphology and connectivity. This more comprehensive approach is the focus of newer methods or approaches developed since the early 2000s (Annear et al. 2004, Arthington 2006, Jowett et al. 2016, Poff et al. 2010, and Sanderson et al. 2012). Each of those efforts explains the importance of a multidisciplinary techniques and provides the detail to direct future evaluations in the Roaring Fork Basin. A parallel track of hydrologic techniques also emerged in the late 1990s and extended into the early 2000s (Richter et al. 1996, 1997, Poff et al. 1997, Mathews and Richter 2007). While hydrology data was the main driver for these techniques, some also included biological components. The hydrologic techniques have an underlying assumption of a biological response to the hydrologic regime based on observations from natural systems. The Indicators of Hydrologic Alteration (IHA) (Richter et al. 1996) is a technique that has been applied in many locations and includes 33 hydrologic parameters (Table 1). IHA uses single or multiple hydrologic data sets to determine changes in key hydrologic parameters over time for natural Process for evaluating ecosystem conditions Page 2 and altered stream flows. Comparison of the parameters provide data for decision makers to evaluate effects of proposed water projects. The specific technique chosen for evaluation of projects that affect aquatic ecosystems should be based on the complexity of the project and the issues, both social and environmental, of the project. Simple projects, such as a small diversion may only need a simple approach whereas a complex project that could affect several different stream reaches could require a very complex study and analysis (Figure 1). Espegren and Rozaklis (2012) presented a conceptual approach for adaptive management evaluation of new projects. The approach included a conceptual flow chart for hydrologic analysis, flow-ecology relationships, social considerations, and adaptive management. At each step, there are a range of data and analyses that could be applied. The flow chart is not intended as a “cook book approach” but as a conceptual pathway adaptable to each new project. There are many levels of techniques and analysis that could be applied at each of the main flow chart levels. Hydrologic models can range from simple threshold models such as the Tennant Method, R2Cross and Wetted Perimeter to complex multi-parameter models such as IHA and Range of Variability Analysis (RVA). Flow-Ecology models also can include a wide range from coarse scaled watershed wide models such Watershed Flow Evaluation Tool (WFET) to fine scaled site specific one and two dimensional hydraulic-habitat models such as PHABSIM and River2D. Biological inventories and biological response models can also be used for evaluations. The level of detail should be commensurate with the complexity of the project and issues. Biological data can include information for a number of species or trophic levels. Example data may include benthic macroinvertebrate data either qualitative or quantitative. Benthic macroinvertebrates have life cycles from weeks to a year or multiple years depending on the species. There are numerous metrics for interpretation of aquatic ecosystem function including number of taxa, species diversity, evenness, and density. Other aquatic biota inventories, in particular for fish species, can also be used to evaluate conditions. Many evaluations focus on sport fish species as species of interest. While these species may be important for recreational components of the ecosystem, non-game and native species provide a more holistic data set for ecosystem analysis. Terrestrial species, plant and animal, can also be an indicator of ecosystem function. Plant species, such as riparian communities, are more dependent on near stream hydrologic conditions and can be an indication of ecosystem function and hydrologic conditions. Mobile terrestrial and avian animal species may be less dependent on hydrologic conditions and therefore not as useful as an indicator of river conditions or the river corridor Process for evaluating ecosystem conditions Page 3 ecosystem. All of an aquatic ecosystem’s components can add value to evaluation of changes due to projects or natural causes, however, as the level of understanding of the flow ecology relationship decreases the level of uncertainty of the response increases. Process for evaluating ecosystem conditions Page 4 Table 1. IHA parameters and their Ecosystem Influences (TNC 2009). Process for evaluating ecosystem conditions Page 5 Table 1. Continued 3. Timing of ammal extreme water conditions Julian date of each ammal 1-day maximum Julian date of each annual 1-day miniimun Subtotal 2 parameters Compatibility with life cycles of organisms Predictabilityf'avoidability of stress for organisms Access to special habitats during reproduction or to avoid predation Spawning cues for migratory ?sh Evolution of life history strategies. behavioral mechanisms 4. Frequency and duration of high and low pulses Number of low pulses within each water year Mean or median duration of low pulses (days) Number of high pulses within each water year Mean or median duration of high pulses (days) Subtotal 4 parameters Frequency and magnitude of soil moisture stress for plants Frequency and duration of anaerobic stress for plants Availability of ?oodplain habitats for aquatic organisms Nutrient and organic matter exchanges between river and ?oodplain Soil mineral availability Access for waterbirds to feeding. resting. reproduction sites In?uences bedload transport. channel sediment textures. and duration of substrate disturbance (high pulses) 5. Rate and frequency of water condition changes Rise rates: Mean or median of all positive differences between consecutive daily values Fall rates: Mean or median of all negative differences between consecutive daily values Number of hydrologic reversals Subtotal 3 parameters Grand total 33 parameters Drought stress on plants (falling levels) Entrapment of organisms on islands. ?oodplains (rising levels) Desiccation stress on low-mobility streamedge (varial zone) organisms Process for evaluating ecosystem conditions Page Level of Controversy Incremental, multidimensional, multidisciplinary techniques Single discipline, single method techniques Level of Complexity Figure 1. Conceptual relationship of ecosystem evaluation methods to project characteristics (after Stalnaker et al. 1995). Process for evaluating ecosystem conditions Page 7 Figure 2. Example of steps for project evaluation and adaptive management approach for future project evaluations. Espegren and Rozaklis 2012 Process for evaluating ecosystem conditions Page 8 Summary of Current Conditions on all Focus Reaches The summary of current conditions relied on existing data and recent hydrologic modeling for the assessment. The hydrologic modeling was completed as another task on this project (See Appendix A). The model provided hydrologic data at specific points within each river reach. The data for natural flows were compared to the existing conditions at each point to determine the difference in flow conditions. These data were then summarized into the IHA parameters and presented for specific flow conditions. The data for natural flows and existing flows at the 25th, 50th, and 75th recurrence percentiles were then displayed with color coded values (Table 2, Table 3, Table 4). The color range was from dark green (indicating no or little difference) to dark red (indicating large differences). These color-coded values allow the visual assessment of hydrologic conditions for the upper Roaring Fork Basin. Process for evaluating ecosystem conditions Page 9 Table 2. Basinwide IHA modeling using Lotic point flow hydrologic model to evaluate changes in hydrology between natural flows and existing depleted flows (25th percentile). Process for evaluating ecosystem conditions Page 10 Table 3. Basinwide IHA modeling using Lotic point flow hydrologic model to evaluate changes in hydrology between natural flows and existing depleted flows (50th percentile). Process for evaluating ecosystem conditions Page 11 Table 4. Basinwide IHA modeling using Lotic point flow hydrologic model to evaluate changes in hydrology between natural flows and existing depleted flows (75th percentile). Process for evaluating ecosystem conditions Page 12 Summary of the current conditions for each reach based on the available data. Roaring Fork River: Lost Man Creek to confluence with Difficult Creek Reach Description The upper Roaring Fork River between Lost Man Creek and Difficult Creek is characterized by narrow riparian areas, steep gradients and bedrock channels. Channel gradients decrease near Tagerts Lake, but the river remains a single threaded cascade throughout most of this segment. The Colorado Natural Heritage Program (CNHP) delineates riparian areas throughout this reach as a Potential Conservation Area (PCA) due to their high biodiversity and the presence of rare and/or significant plant communities (Spackman et al 1999). Most of this segment flows immediately adjacent to Highway 82 and sees significant recreational use near Tagerts Lake, the confluence with Lincoln Creek, and at the Grottos. Flow magnitude, duration, and inter-annual variation are altered by trans-basin diversions (TMDs). These diversions collect flows from the Roaring Fork River and Lost Man Creek near Lost Man Reservoir and convey up to 322 cubic feet per second (cfs) of water through the Twin Lakes Tunnel #2 to Grizzly Reservoir. Grizzly Reservoir, in turn, acts as a forebay for diversions through the Twin Lakes Tunnel #1, which carries water under the divide to Twin Lakes in the Arkansas basin. The Colorado Water Conservation Board holds two instream flow (ISF) water rights in this stream reach. The first ISF runs from Independence Lake to the confluence with Lincoln Creek for 10 cfs. The second runs from Lincoln Creek to Difficult Creek for 15 cfs. However, both of these ISF rights are junior in priority to the TMD’s trans-basin diversions and, therefore, may not be satisfied immediately below the TMD diversion structure on the Roaring Fork River. Summary of Current Environmental Conditions Scientific data within this headwater stream reach is limited to the basin-wide, point flow hydrologic modeling that was developed for this project by Lotic Hydrological (see Appendix A). Output from Lotic’s point flow model was analyzed using IHA methodology (TNC 2009) to evaluate current hydrologic impacts within this reach. No secondary component data is available within this headwater stream reach. IHA analyses for the 25th percentile (dry year), 50th percentile (median year) and 75th percentile (wet year) modeling output were evaluated at two locations on this reach of the Roaring Fork River (Tables 2, 3, and 4). Results of the IHA analysis indicate that, regardless of year type, Process for evaluating ecosystem conditions Page 13 mean monthly flows in the Roaring Fork River above Lincoln Creek and at Tagerts Lake are reduced from 50% to over 70% in all months of the year. Annual peak flows and minimum flows are also reduced by 50% to 70% in all 3 year types. Annual volume of flow is reduced by 59% to 67% from natural flow conditions. These large flow reductions are presumed to result in reduced aquatic habitat quality and availability for both fish and aquatic invertebrate communities. In addition, diversion structures themselves may create barriers to upstream-downstream movement by aquatic organisms like trout. Recommendation The primary recommendation for this reach would be to maintain additional flow in the river. Daily flows that approach zero result in limited to no aquatic resources. A secondary recommendation would be to have a hydrograph shaped like a snow melt hydrograph with a pronounced peak flow during snow melt. A snow melt hydrograph would restore some geomorphic function to the reach depending on the discharge. Lincoln Creek: Grizzly Reservoir to Roaring Fork River Reach Description Lincoln Creek alternates between meandering alluvial channel forms near Grizzly Reservoir and steep bedrock canyons through Lincoln Gulch. Water from the upper portions of Grizzly Creek, Lincoln Creek, Tabor Creek, and New York Creek are captured by a collection system that diverts flows through series of canals to Grizzly Reservoir. From Grizzly Reservoir, up to 625 cfs of water is diverted through the Twin Lakes Tunnel #1 under the divide to Twin Lakes in the Arkansas basin. These TMDs alter flow magnitude, duration, and inter-annual variation. The Colorado Water Conservation Board holds an ISF water right on this reach of Lincoln Creek. The ISF runs from the confluence of Galena Creek downstream to the confluence with the Roaring Fork River for 8 cfs. However, this ISF right is junior in priority to the TMD’s trans-basin diversions at Grizzly Reservoir and, therefore, may not be satisfied immediately below the Grizzly Reservoir outlet structure. Summary of Current Environmental Conditions Scientific data within this headwater stream reach is limited to the basin-wide, point flow hydrologic modeling that was developed for this project by Lotic Hydrological (see Appendix A). Output from Lotic’s point flow model was analyzed using IHA methodology (TNC 2009) to Process for evaluating ecosystem conditions Page 14 evaluate current hydrologic impacts within this reach. No secondary component data is available within this headwater stream reach. IHA analyses for the 25th percentile (dry year), 50th percentile (median year) and 75th percentile (wet year) modeling output were evaluated (Tables 2, 3 and 4). Results of the IHA analysis indicate that, regardless of year type, mean monthly flows in Lincoln Creek below Grizzly Reservoir are reduced from approximately 43% to over 85% in all months of the year. Annual peak flows are reduced by approximately 85% and minimum flows are reduced by approximately 40% in all 3 year types. Annual volume of flow is reduced by 77% from natural flow conditions. These large flow reductions are presumed to result in reduced aquatic habitat quality and availability for both fish and aquatic invertebrate communities. In addition, Grizzly Reservoir may create barriers to upstream-downstream movement by aquatic organisms like trout. Recommendation The primary recommendation for this reach would be to maintain additional flow in the river. Daily flows that approach zero result in limited to no aquatic resources. A secondary recommendation would be to have a hydrograph shaped like a snow melt hydrograph with a pronounced peak flow during snow melt. A snow melt hydrograph would restore some geomorphic function to the reach depending on the discharge. Roaring Fork River: Difficult Creek to Salvation Ditch Diversion Reach Description The Roaring Fork River in this reach is mainly in a relatively wide alluvial valley with low gradient and higher sinuosity than upstream reaches. There is evidence of channel migration and channel modification due to prior land use activities. Land use in this reach includes federal, county and private lands. The valley floor is a combination of riparian and upland areas with both linear off-channel wetlands. The Northstar Preserve in this reach sees heavy recreational use mainly from flatwater rafting, paddle boards, tubing and other floatation devices. Process for evaluating ecosystem conditions Page 15 Summary of Current Environmental Conditions Scientific data for this reach includes data from the basinwide point flow model, qualitative assessments of riparian conditions, and qualitative assessments of geomorphology. River flow in this reach is impacted by upstream trans mountain diversions and to a lesser extent small local diversions. Geomorphology of the reach was evaluated by Ayres (2011) and Golder Associates (2015). River channel slope is controlled by a moraine at the downstream end of the valley. There are signs of some channelization and attempts to drain wetland areas from previous land use activities associated with agriculture in the mid-1900s. Riparian areas in this reach are rated as suboptimal and marginal with smaller percent of the area as optimal (Clark et al. 2008). Riparian areas in the upper section of this reach are rated higher than the downstream section. The downstream section just upstream of the Salvation Ditch diversion is within the more urbanized area at the east side of Aspen. The stream channel is incised with some sections of eroding banks and relatively low amounts of instream aquatic habitat. Habitat diversity is low with long sections of slow, shallow water without instream refuge cover. Longitudinal connectivity is impacted by the Salvation Ditch diversion structure. Lateral connectivity to the flood plain is impacted by channel incision with limited connection in local areas and at relatively high flows (ca. 800-1000 cfs). Water quality data is not available for this reach, however, the long sections of shallow, slow water may have higher water temperatures than natural flow conditions due to lower flows, especially in the warmest months of July and August. Stream flows were evaluated at the Northstar Preserve hydrologic node (Table 2, Table 3, Table 4). The CWCB holds an ISF in this reach for 32 cfs from January 1 – December 31. The hydrologic analysis shows that existing flows are lower than natural flows year-round. The largest decreases occur in May June and July in average and wet years. Recommendations Preliminary recommendations for this reach are to provide additional flow during runoff and late summer. Additional flow in May, June and July provide geomorphic benefits. Additional flow in late summer would provide benefits to instream habitat and potentially to water temperature. Enhancement of lateral connectivity would provide a benefit to riparian and aquatic species. Process for evaluating ecosystem conditions Page 16 Roaring Fork River: Salvation Ditch Diversion to Castle Creek Reach Description The Roaring Fork River in this reach is within the City of Aspen urban footprint. As such, the reach is heavily impacted by human activities and land use. The river is bordered by residential and commercial developments, foot paths, and parks that provide access to residents and visitors. There is a heavy human use on the lands bordering the river for the majority of this reach. The river has a steeper gradient than the reach immediately upstream in Northstar Preserve. It is confined by urbanization and has bank protection in the form of rip rap in several areas. Summary of Current Environmental Conditions The scientific data for this reach includes the point flow hydrology model, geomorphic characterization, riparian characterization, fish population inventories, benthic macroinvertebrate inventories, and 2-dimensional hydraulic habitat analysis. The majority of these studies and reports were completed within the past 5-8 years. The geomorphic characterization noted several stream structures as well as urban infrastructure that impacts river function (Ayres 2011). There are several instream structures that are impediments to longitudinal connectivity for aquatic biota. Channel stabilization structures have been installed in several locations to protect residential properties and urban infrastructure. The stabilization minimizes lateral channel migration. Lateral connectivity is very restricted and confined to protect structures in the urban area. The hydrograph comparison of median monthly flows for this reach shows a pronounced snow melt hydrograph for natural flows. The median monthly flows for existing conditions shows a much lower peak flow than under natural flows, however, the hydrograph still maintains a snow melt hydrograph shape (Miller 2011). The median peak flow during runoff is approximately 300 cfs and may be suitable for the confined urban channel through Aspen. The bank armoring to protect structures does not allow for channel migration so habitat maintenance would be the main function of high flows. The August and September flow duration analysis shows the existing flow regime to be as much as 60% lower at the higher exceedance levels. Process for evaluating ecosystem conditions Page 17 The biological data for this reach shows a macroinvertebrate community with an average of 22 taxa and diversity of 2.57 (Miller 2011). These values are somewhat lower than a stream in excellent condition. Macroinvertebrate population are likely influenced by low late summer and fall flows. August and September flows can regularly range as low as 15-20 cfs. The wetted area of the stream increases by 20% at flows of 30 cfs compared to 17 cfs (Miller 2011). The difference in area combined with elevated water temperature at low summer flows could be one of the reasons for the lower invertebrate values. The fish populations are dominated by brown trout (1534 fish/mile and 98 lbs/acre). Other species present include rainbow trout and mottled sculpin. Rainbow trout were present in low numbers (101 fish/mile and 12 lbs/acre). The low Rainbow Trout numbers may be the result of many factors and not limited to the flow regime. Recommendations The main limiting factor for the Roaring Fork from Salvation Ditch to Hunter Creek appears to be low summer and fall flows (See Tables 2-4). Keeping flows at or above 32 cfs (the CWCB ISF) during late summer would be beneficial. In addition, the removal or modification of impediments to longitudinal connectivity would be a benefit to the aquatic ecosystem. Hunter Creek: Fry-Ark Diversion to confluence with Roaring Fork River Reach Description Hunter Creek drains alpine and subalpine areas on the east side of the Roaring Fork River. Below its confluence with No Name Creek, Hunter Creek transitions from a step-pool and cascade morphology to a single-threaded meandering channel form where it traverses several high-valley meadows. Hunter Creek between No Name Creek and Red Mountain Ditch is designated by CNHP as a PCA (Spackman et al 1999). CPW considers the Hunter Creek watershed as a critical management zone for native cutthroat trout populations. A system of surface water diversions, canals, and tunnels divert up to 270 cfs from upper Hunter Creek, Midway Creek, and No Name Creek. Water is conveyed to the Hunter Tunnel and, eventually, to Turquoise Lake in the Arkansas basin. Process for evaluating ecosystem conditions Page 18 Minimum streamflow bypass requirements on the Hunter Creek collection system intend to protect aquatic life health on downstream reaches. However, water collection structures (e.g. ditches, canals, and diversion dams) may represent significant barriers to upstreamdownstream migration of fish and other aquatic organisms. Surface water diversions at the Red Mountain Ditch convey water to McClain Flats to supply irrigated agriculture and water amenities. These diversions can significantly reduce flows or dry up the creek during the late summer season, particularly in dry years. The CWCB holds ISF water rights on three reaches of Hunter Creek which were appropriated in 1975 and 1979. The first runs from the headgate of the Fry-Ark Project to the confluence with Midway Creek for 12 cfs total. The second ISF reach runs from the confluence of Midway Creek to the confluence of No Name Creek for 17 cfs total. The third ISF reach runs from the confluence with No Name Creek to the confluence with the Roaring Fork River for a total of 30 cfs. The CWCB also holds various ISF acquisitions on Hunter Creek. Summary of Current Environmental Conditions Scientific data within this reach of Hunter Creek is limited to the basin-wide, point flow hydrologic modeling that was developed for this project by Lotic Hydrological (see Appendix A). Output from Lotic’s point flow model was analyzed using IHA methodology (TNC 2009) to evaluate current hydrologic impacts within this reach. No secondary component data is available within this headwater stream reach. IHA analyses for the 25th percentile (dry year), 50th percentile (median year) and 75th percentile (wet year) modeling output were evaluated at two locations on Hunter Creek (Tables 2, 3 and 4). The first location was below No Name Creek confluence. IHA results at this location suggest that natural flow conditions are maintained during all months except May, June and July. Depletions during May, June and July are somewhat larger in wet and average years than in dry years. Peak flows are reduced by approximately 35% in this reach of Hunter Creek. The second hydrologic modeling point was located on lower Hunter Creek. IHA results at this location suggest that natural flows are maintained in this stream reach from November through April regardless of dry, average or wet year flow conditions. However, August and September flows are depleted by as much as 100% in dry years, 61% to 77% in average years, and 42% to 61% in wet years, respectively. Significant depletions are also seen in the months of May, June, July and October. Peak flows in this reach are depleted by approximately 37% to 39% and minimum flows may be reduced by up to 100% in all three year types. Process for evaluating ecosystem conditions Page 19 Summertime flow reductions of up to 100% are presumed to result in reduced aquatic habitat quality and availability for both fish and aquatic invertebrate communities. In addition, diversion structures on Hunter Creek may create barriers to upstream-downstream movement by aquatic organisms like trout. Recommendation The primary recommendation for this reach would be to maintain additional flow in the lower reach of Hunter Creek during the summer months, especially August and September. Daily flows that approach zero result in limited to no aquatic resources. Roaring Fork River: Castle Creek to Brush Creek Reach Description The Roaring Fork River in this reach is on the western edge of the City of Aspen urban footprint and has a more rural setting. As such, the reach is less heavily impacted by human activities and land use than the next upstream reach. The river is bordered by residential and commercial developments, foot paths, and parks that provide access to residents and visitors. There is a human use on the lands bordering the river for the majority of this reach. The river has a steeper gradient than the reach immediately upstream. It is confined by urbanization and a narrower valley bottom. Summary of Current Environmental Conditions The scientific data for this reach includes the point flow hydrology model, and riparian characterization The hydrograph comparison of median monthly flows for this reach shows a decrease in stream flow for all months with a reduction that ranges from 23% to 26% during runoff months (Table 3). The August and September flow analysis shows the existing flow regime to be from 20% to 26% lower than natural flows. The riparian quality conditions in this reach are characterized as optimal and suboptimal (Clark et al. 2008). Riparian potential is listed as 50% marginal, 45% suboptimal and 5% optimal. Recommendations The primary limiting factor for the Roaring Fork from Castle Creek to Brush Creek appears to be reduction in summer and early fall flows (See Tables 2-4). Process for evaluating ecosystem conditions Page 20 Castle Creek: Conundrum Creek to Roaring Fork River Reach Description Castle Creek drains a tributary subwatershed to the Roaring Fork River. The upper section of this reach has widespread development with an increase in development in the lower section of the reach inside the urbanized section in Aspen, Colorado. Castle Creek has several agricultural and municipal diversions along the reach. Summary of Current Environmental Conditions Scientific data available for this reach includes hydrology point flow model, geology, vegetation, aquatic habitat description and inventory, fish inventory, benthic macroinvertebrate inventory, and water temperature data. The majority of the reach is in moderate gradient, wider valley with widespread development. There are numerous diversions in the watershed. The City of Aspen gets the majority of the municipal water supply from Castle Creek via the Midland Ditch. CWCB has an ISF decree of 12 cfs from January 1 through December 31. The largest percent change in flow occurs during low flow months in late summer and through the winter. The percent change in these flows us generally 20 to 30 percent with the higher values occurring in dry year conditions. The highest percent change in flow is in short term (1 day and 3 day) minimum flows. The flow hydrograph in this reach still maintains a strong snowmelt runoff shape with average peak flow over 650 cfs (Miller and Swaim 2010). Riparian vegetation in this reach consists mainly of narrowleaf cottonwood, spruce, fir, and willow species (Miller and Swaim 2010). The riparian corridor is relatively robust in the upper portion of the reach and is less intact in several sections near and within Aspen, Colorado. Optimal riparian quality conditions occur in more than 90 % of the reach (Clark et al. 2008). Terrestrial wildlife potential is rated optimal for more than 60% of the reach. Aquatic habitat in this reach is over 70% riffle habitat followed by glide and pool habitat as second and third most abundant, respectively. Aquatic habitat is relatively consistent in these distributions throughout the reach (Miller and Swaim 2011, 2012, 2013). The majority of the stream substrate is boulder and cobble with patches of gravels. The dominance of larger substrate is indicative of the steeper gradient and high stream velocity that transports the Process for evaluating ecosystem conditions Page 21 smaller size substrate out of the reach. Longitudinal connectivity is blocked at the City of Aspen Castle Creek diversion structure and prevents fish species from moving upstream past this structure. Lateral connectivity is possible at the upper section of the reach during runoff. There is limited lateral connectivity in the section of the reach through the city. The macroinvertebrate community is relatively robust and show no difference between areas upstream of Aspen compared to areas within the city. The metrics of diversity, eveness and HBI all show a relatively pristine water quality (Miller and Swaim 2011, 2012, 2013). Total macroinvertebrate taxa ranged from 32 to 37 while EPT taxa ranged from 15 to 19. Fish species in this reach include trout (rainbow, brown and brook) and sculpin. Brown trout are not present upstream of the Castle Creek diversion for the City of Aspen. Trout density ranges from 44 to 105 trout/acre greater than 6 inches long (Miller and Swaim 2013). Trout biomass ranged from 12 to 49 pounds per acre in the reach. Water temperature in the reach mirrors ambient air temperature with the warmest water temperature occurring in late July and early August. Maximum water temperature in the lower portion of the reach was than 16.4 C (Miller and Swaim 2013). The maximum water temperature is below the threshold for acute temperature established by CDPHE. Recommendations The primary recommendation for this reach would be to provide a slightly higher minimum flow during late winter and early spring (March/April). Maroon Creek: West Maroon Creek to Roaring Fork River Reach Description Maroon Creek subwatershed flows parallel to Castle Creek. Maroon Creek has numerous water diversions along the reach. The City of Aspen Maroon Creek diversion structure blocks upstream fish passage in this reach. The section of the reach downstream from the diversion are bordered by residential development. Summary of Current Environmental Conditions Scientific data available for this reach includes hydrology point flow model, geology, vegetation, aquatic habitat description and inventory, fish inventory, benthic macroinvertebrate inventory, Process for evaluating ecosystem conditions Page 22 and water temperature data. The majority of the reach is steeper gradient, narrow valley with residential development in the lower section. There are numerous diversions in the watershed. The City of Aspen diverts water at the Maroon Creek diversion for municipal water supply and for the Maroon Creek hydro plant. This structure blocks upstream fish passage. CWCB has an ISF decree of 14 cfs from January 1 through December 31. CWCB has received donations of smaller amounts for ISF in the past few years. The largest percent change in flow occurs just downstream of Willow Creek tributary during low flow months in late summer and early fall due to upstream diversions. The percent change in these flows us generally 20 to 60 percent with the higher values occurring in dry year conditions. There is little difference in IHA characteristics between natural and existing conditions in lower Maroon Creek. The flow hydrograph in this reach still maintains a strong snowmelt runoff shape with average peak flow over 700 cfs (Miller and Swaim 2010). Riparian vegetation in this reach consists mainly of narrowleaf cottonwood, spruce, fir, and willow species (Miller and Swaim 2010). The riparian corridor is relatively robust in the upper portion of the reach and is less intact in several sections near and within Aspen, Colorado. Optimal riparian quality conditions occur in more than 90 % of the reach (Clark et al. 2008). Terrestrial wildlife potential is rated optimal for more than 80% of the reach. Aquatic habitat in this reach is predominately riffle habitat followed by glide and pool habitat as second and third most abundant, respectively. The lower section of the reach has the lowest percent riffle and higher percentages of pools and glides than the upper section of the reach (Miller and Swaim 2013). The majority of the stream substrate is boulder and cobble with patches of gravels. The dominance of larger substrate is indicative of the steeper gradient and high stream velocity that transports the smaller size substrate out of the reach. Longitudinal connectivity is blocked at the City of Aspen Maroon Creek diversion structure and prevents fish species from moving upstream past this structure. Lateral connectivity is possible at the upper section of the reach during runoff. There is limited lateral connectivity in the section of the reach through the city. The macroinvertebrate community is relatively robust and show no difference between upper and lower sections. The metrics of diversity, eveness and HBI all show a relatively pristine water quality (Miller and Swaim 2013). Total macroinvertebrate taxa ranged from 33 to 37 while EPT taxa ranged from 20 to 21. Process for evaluating ecosystem conditions Page 23 Fish species in this reach include trout (rainbow, brown and brook) and sculpin. Brown trout are not present upstream of the City of Aspen Maroon Creek diversion. Trout density ranges from 100 to 531 trout/acre greater than 6 inches long (Miller and Swaim 2013). Trout biomass ranged from 18 to 538 pounds per acre in the reach. Water temperature in the reach mirrors ambient air temperature with the warmest water temperature occurring in late July and early August. Maximum water temperature in the lower portion of the reach was than 14.7 C (Miller and Swaim 2013). The maximum water temperature is below the threshold for acute temperature established by CDPHE. Recommendations The primary recommendation for this reach would be to increase the minimum flow immediately downstream of Willow Creek in late summer. Process for evaluating ecosystem conditions Page 24 Process for future project evaluation The process illustrated by the previous sections can be used as a template for evaluation of future projects or when social or institutional issues include objectives that could impact (positive or negative) the Roaring Fork River and its tributaries. The general approach was presented in the Introduction of this appendix. The first step in any project evaluation should be a concise statement of the project goals and objectives to provide context for the type of analysis that would be needed. This is generally referred to as project scoping. This step provides the decision makers with information needed to judge the level of complexity and level of controversy associated with any project. Where the project fits on the scale from simple to complex and non-controversial to controversial can aid in determining the range of study or data needed for the assessment. Municipal decision makers can and should be assisted in the scoping by professionals in the specific disciplines that could be affected by the project. The result of the scoping should be a listing of potential data needs, studies and timeline for analysis. The range of studies and processes could include: • Hydrologic analysis – either from existing gage data or hydrologic modeling • Biological analysis – either from existing data or from new biological studies on aquatic, terrestrial and plant species as determined in project scoping. • Physical habitat analysis – either from existing data or from new studies in the project area. These studies may include disciplines of geomorphology, geology, and water quality. • Social and Institutional issues – This may be from the scoping process and include a public and stakeholder involvement during the project evaluation. It may also include a cost/benefit analysis associated with the project. The results from the above studies and processes would be used by the decision makers to determine the fate of a project. Process for evaluating ecosystem conditions Page 25 References Annear, T., I. Chisholm, H. Beecher, and 12 coauthors. 2004. Instream Flows for Riverine Stewardship revised edition, Instream Flow Council, Cheyenne, Wyoming. Arthington, A. H., S.E. Bunn, N. L. Poff, R.J. Naiman. 2006. The Challenge of Providing Environmental Flow Rules to Sustain River Ecosystems. Ecological Applications, 16(4) 13111318. Ayres Associates. 2011. Geomorphic Assessment of the Stability of the Roaring Fork River through the City of Aspen, Pitkin County, Colorado. Feb 11, 2011. Bovee, K.D. 1982. A Guide to Stream Habitat Analysis using the Instream Flow Incremental Methodology. Instream Flow Information Paper 12. U.S.D.I. Fish and Wildlife Service, Office of Biological Services. FWS/OBS-82/26. Bovee, K.D., B.L. Lamb, J.M. Bartholow, C.B. Stalnaker, J. Taylor, and J. Henriksen. 1998. Stream Habitat Analysis using the Instream Flow Incremental Methodology. U.S. Geological Survey, Biological, Resources Division Information and Technology Report, USGS/BRD-1998-004. Clarke, S., M. Fuller, and R.A. Sullivan. 2012. Roaring Fork Watershed Plan. Prepared for Reudi Water and Power Authority. Clarke, S. 2006a. Roaring Fork Watershed Streamflow Survey Report. Prepared for Roaring Fork Conservancy. Clarke, S. 2006b. State of the Roaring Fork Watershed. Prepared for Roaring Fork Conservancy. Clark, S., K. Crandall, J. Emerick, and 6 coauthors. 2008. State of the Roaring Fork Watershed 2008. Prepared for Reudi Water & Power Authority, prepared by Roaring Fork Conservancy. Espegren, G. 2011. Review of City of Aspen’s Castle Creek Hydroelectric Project Aquatic Resource Documents. January 14, 2011. Espegren, G. and L. Rozaklis. 2012. A Scientific/Social Framework for Managing Impacts of Water Diversions to Protect Stream Health in Pitkin County, Colorado. Prepared for Pitkin County Healthy Rivers and Streams. May, 2012. Golder Associates. 2014. Geomorphic Assessment, North Star Nature Preserve. Prepared for Pitkin County Open Space and Trails. Process for evaluating ecosystem conditions Page 26 Hickey, A., J.C. Emerick, and K.E. Kolm. 2000. Preliminary Hydrologic and Biological Characterization of the North Star Nature Preserve, Pitkin County, Colorado. Division of Environmental Science and Engineering, Colorado School of Mines, Golden, CO. Jowett, I., T. Payne, R. Milhous. 2016. SEFA System for Environmental Flow Analysis, Software Manual, Version 1.3. Mathews, R. and B.D. Richter. 2007. Applications of the Indicators of Hydrologic Alteration Software in Environmental Flow Setting. Journal of the American Water Resources Association. December 2007. Miller, W.J. 2011. Final Report Evaluation of River Health: Roaring Fork River near Aspen, Colorado. Submitted to Pitkin County Attorney. Miller Ecological Consultants, Inc, Fort Collins, CO. December 21, 2011. Miller Ecological Consultants, Inc. and Ayres Associates. 2011. Final Letter Report-Geomorphic Assessment of the Roaring Fork River and Impacts of Groundwater Changes on Wetlands, North Star Nature Preserve, Pitkin County, Colorado. Prepared for Pitkin County, Colorado. Miller Ecological Consultants, Inc., December 14, 2011. Miller, W.J. and K.M Swaim. 2010. Castle Creek Hydroelectric Plant Environmental Report. Prepared for the City of Aspen, Water Utilities, Aspen, Colorado. Miller Ecological Consultants, Inc., Fort Collins, CO. October 8, 2010. Miller, W.J. and K.M. Swaim. 2011. Castle and Maroon Creeks 2010 Aquatic Monitoring Report. Prepared for the City of Aspen, Water Utilities. Aspen, Colorado. Miller Ecological Consultants, Inc., Fort Collins, CO. June 6, 2011. Miller, W.J. and K.M. Swaim. 2012. Castle and Maroon Creeks 2011 Aquatic Monitoring Report. Prepared for the City of Aspen, Water Utilities. Aspen, Colorado. Miller Ecological Consultants, Inc., Fort Collins, CO. May 21, 2012. Miller, W.J. and K.M. Swaim. 2013. Castle and Maroon Creeks 2012 Aquatic Monitoring Report. Prepared for the City of Aspen, Water Utilities. Aspen, Colorado. Miller Ecological Consultants, Inc., Fort Collins, CO. September 11, 2013. Poff, N.L., J.D. Allen, M.B. Bain, J.R. Karr, K.L. Prestgaard, B.D. Richter, R.E. Sparks, and J.C. Stromberg. 1997. The Natural Flow Regime, a paradigm for river conservation and restoration. Bioscience 47(11) 769-784. Process for evaluating ecosystem conditions Page 27 Poff, N.L., B.D. Richter, A.H. Arthington, and 16 coauthors. 2010. The ecological limits of hydrologic alteration (ELOHA): a new framework for developing regional environmental flow standards. Freshwater Biology 55:147-170. Richter, B.D., J.V. Baumgartner, J. Powell, and D.P. Braun. 1996. A Method for Assessing Hydrologic Alteration within Ecosystems. Conservation Biology 10(4) 1163-1174. Richter, B.D. How Much Water Does a River Need? Freshwater Biology (1997) 37, 231-249. Roaring Fork Conservancy. 2006. Roaring Fork Watershed Water Quality Report. Sanderson, J., B. Bledsoe, N.L. Poff, T. Wilding, W. Miller, and N. Fey. 2012. Colorado Basin Roundtable Watershed Flow Evaluation Tool Study. Prepared for Northwest Colorado Council of Governments. March, 2012. Spackman, S., K. Fayette, J. Siemers, K. Murrell, and M. Sherman. 1999. Roaring Fork Watershed Biological Inventory 1997-1999. Colorado Natural Heritage Program, Colorado State University College of Natural Resources, Ft. Collins, Colorado. Stalnaker, C., B.L. Lamb, J. Henriksen, K. Bovee, and J. Bartholow. 1995. The Instream Flow Incremental Methodology, A Primer for IFIM. U.S. Department of Interior, National Biological Service, Washington, D.C. Biological Report 29, March 1995. Steffler, P. and J. Blackburn. 2002. River2D Two Dimensional Depth Averaged Model of River Hydrodynamics and Fish Habitat. University of Alberta, Alberta, Canada. Tennant, D.L. 1976. Instream Flow Regimens for Fish, Wildlife, Recreation, and Related Environmental Resources. Fisheries 1(4): 6-10. The Nature Conservancy. 2009. Indicators of Hydrologic Alteration, Version 7.1, User’s Manual, April 2009. Process for evaluating ecosystem conditions Page 28