Lake Powell Pipeline Project

Water Needs Assessment

April 2016

FINAL

Prepared for:
Utah Division of Water Resources

Prepared by:

 Table of Contents
Executive Summary .............................................................................................................................1
ES-1

Introduction ................................................................................................................................ 1

ES-2

The Districts ............................................................................................................................... 1

ES-3

Water Demand Forecast............................................................................................................. 2
ES-3.1 WCWCD .................................................................................................................................... 2
ES-3.2 KCWCD ..................................................................................................................................... 4
ES-3.3 Conservation and Climate Change ............................................................................................ 7
ES-3.4 Per Capita Water Use ................................................................................................................ 7

ES-4

Conclusion ................................................................................................................................. 8

Chapter 1 – Overview ...................................................................................................................... 1-1
1.1

Introduction ............................................................................................................................ 1-1

1.2

Study Area ............................................................................................................................. 1-1

1.3

The Potential Recipients ........................................................................................................ 1-2

1.4

1.3.1

Washington County Water Conservancy District ................................................................... 1-2

1.3.2

Kane County Water Conservancy District .............................................................................. 1-4

Summary Description of the Lake Powell Pipeline Project ................................................... 1-5

Chapter 2 – Methodology ................................................................................................................ 2-1
2.1

Introduction ............................................................................................................................ 2-1

2.2

Service Areas ......................................................................................................................... 2-1

2.3

2.4

2.5

2.2.1

Washington County Water Conservancy District ................................................................... 2-3

2.2.2

Kane County Water Conservancy District .............................................................................. 2-3

Water Demand Forecast Methodology .................................................................................. 2-5
2.3.1

Projecting Population ............................................................................................................. 2-5

2.3.2

Estimating Per Capita Water Use........................................................................................... 2-8

2.3.3

Factors Influencing Per Capita Use ....................................................................................... 2-8

2.3.4

Conservation ........................................................................................................................... 2-9

2.3.5

Forecasting Water Demand .................................................................................................. 2-10

Water Supplies ..................................................................................................................... 2-10
2.4.1

Surface Water Sources .......................................................................................................... 2-11

2.4.2

Groundwater Sources ........................................................................................................... 2-12

2.4.3

Demand Timing .................................................................................................................... 2-12

Agricultural Conversion for M&I Supply............................................................................ 2-14

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 2.6

Calculating Water Conservation .......................................................................................... 2-15
2.6.1

Demand Hardening .............................................................................................................. 2-16

2.7

Integrated Water Resources Plans ....................................................................................... 2-17

2.8

Coordination with Local Stakeholders................................................................................. 2-18

Chapter 3 – Water Demand ............................................................................................................ 3-1
3.1

3.2

3.3

Introduction ............................................................................................................................ 3-1
3.1.1

WCWCD Projected Population .............................................................................................. 3-1

3.1.2

KCWCD Population Projections ............................................................................................ 3-1

Per Capita Water Use ............................................................................................................. 3-2
3.2.1

WCWCD 2010 Per Capita Water Use .................................................................................... 3-2

3.2.2

KCWCD 2010 Per Capita Water Use ..................................................................................... 3-3

Projected Water Demand ....................................................................................................... 3-4
3.3.1

Required Source-Sizing Standards ......................................................................................... 3-4

3.3.2

WCWCD Water Demand Forecast ......................................................................................... 3-4

3.3.3

KCWCD Water Demand Forecast .......................................................................................... 3-5

Chapter 4 – Water Supply Conditions ........................................................................................... 4-1
4.1

Introduction ............................................................................................................................ 4-1

4.2

Washington County ............................................................................................................... 4-1

4.3

4.2.1

WCWCD Water Supply Overview ........................................................................................... 4-1

4.2.2

Water Quality Effects on WCWCD Future Supplies ............................................................... 4-2

4.2.3

WCWCD Existing Supplies ..................................................................................................... 4-3

4.2.4

Total Washington County Municipal and Industrial Water Supplies ................................... 4-13

4.2.5

WCWCD Planned Water Supplies ........................................................................................ 4-15

4.2.6

WCWCD Water Sources not Feasible for Development ....................................................... 4-23

4.2.7

Summary of Planned and Potential WCWCD Water Supply Projects .................................. 4-26

Kane County Water Conservancy District ........................................................................... 4-26
4.3.1

Kane County Water Supply Overview................................................................................... 4-26

4.3.2

Kane County Existing Water Supplies .................................................................................. 4-27

4.3.3

KCWCD Future Supplies – Planned..................................................................................... 4-31

4.3.4

Kane County Future Supplies – Potential............................................................................. 4-34

4.3.5

Summary of Potential Developable Kane County Water Supplies ....................................... 4-35

Chapter 5 – Water Conservation Programs .................................................................................. 5-1
5.1

Introduction ............................................................................................................................ 5-1
5.1.1

5.2

Historical Conservation and Goals ........................................................................................ 5-2

Washington County ............................................................................................................... 5-2
5.2.1

Washington County Water Conservancy District Programs .................................................. 5-3

5.2.1.1 Water Conservation Demonstration Gardens......................................................................... 5-4

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 5.3

5.4

5.2.2

Programs Offered by Cities in Washington County................................................................ 5-8

5.2.3

Conservation Savings ............................................................................................................. 5-9

5.2.4

Future Goals and Water Conservation Programs .................................................................. 5-9

Kane County ........................................................................................................................ 5-11
5.3.1

Current Conservation Program ............................................................................................ 5-11

5.3.2

Conservation Savings ........................................................................................................... 5-13

5.3.3

Future Goals ......................................................................................................................... 5-14

Conclusions.......................................................................................................................... 5-16

Chapter 6 – Water Resources Planning ......................................................................................... 6-1
6.1

Introduction ............................................................................................................................ 6-1

6.2

WCWCD Integrated Water Resources Plan .......................................................................... 6-2

6.3

KCWCD Integrated Water Resources Plan ........................................................................... 6-6

6.4

Conclusion ........................................................................................................................... 6-10

References Cited...............................................................................................................................R-1
Glossary ............................................................................................................................................ G-1
Abbreviations and Acronyms ...................................................................................................A&A-1
List of Preparers ........................................................................................................................... LP-1

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 List of Tables
Table ES-1
Table ES-2
Table 2-1
Table 3-1
Table 3-2
Table 3-3
Table 3-4
Table 3-5
Table 4-1
Table 4-2
Table 4-3
Table 4-4
Table 4-5
Table 4-6
Table 4-7
Table 4-8
Table 4-9
Table 4-10
Table 4-11
Table 4-12
Table 4-13
Table 4-14
Table 5-1
Table 5-2
Table 5-3
Table 5-4
Table 5-5
Table 5-6
Table 5-7
Table 5-8
Table 6-1
Table 6-2
Table 6-3

Existing and Future Reliable Culinary Supplies for Washington County ...................................... 3
2010 Residential Per Capita Water Use .......................................................................................... 8
Projected Future Period Virgin River Flow .............................................................................. 2-12
WCWCD Population Projections ............................................................................................... 3-1
Population Projections for KCWCD Groups .............................................................................. 3-2
WCWCD Total M&I Water Demand Forecast........................................................................... 3-5
KCWCD (Kanab City and Johnson Canyon) M&I Water Demand Forecast ............................. 3-6
Kane County Groups M&I Water Demand with Conservation Forecast ................................... 3-6
WCWCD Existing Projects and Water Uses .............................................................................. 4-4
Water Quality of St. George Reuse Effluent and Utah Water Quality Limits ............................ 4-9
Reliable Culinary Water Supplies – Washington County ......................................................... 4-13
Washington County Secondary Untreated Use 2010 – Reliable Supply .................................. 4-14
Virgin River below Washington Fields – Percent Exceedance for Daily Streamflow, 19402006 .......................................................................................................................................... 4-23
Future Planned and Potential WCWCD Water Supply Projects ............................................... 4-26
Reliable Culinary Water Supplies – Kane County.................................................................... 4-28
Reliable Water Supplies – East Fork Virgin River ................................................................... 4-28
Reliable Water Supplies – Alton Town .................................................................................... 4-29
Reliable Water Supplies – KCWCD ......................................................................................... 4-29
Reliable Water Supplies – Wahweap Creek ............................................................................. 4-29
Municipal Groundwater Supplies Potentially Available for Development .............................. 4-31
Kane County Groups – 2007 Estimated Agricultural Water Use ............................................. 4-34
Developable KCWCD Supplies ................................................................................................ 4-36
Conservation Goals1.................................................................................................................... 5-2
WCWCD Water Conservation Programs (WCWCD 2007; WCWCD 2008b; WCWCD 2010) 5-4
WCWCD Conservation Programs ............................................................................................ 5-10
Conservation Program Projected GPCD Reduction Percentage to Year 2060 ......................... 5-11
KCWCD Increasing Block Rate Structure for Residential Customers ..................................... 5-12
KCWCD (Kanab City and Johnson Canyon) Conservation Programs ..................................... 5-12
Kanab City Conservation Management Plan ............................................................................ 5-13
KCWCD Conservation Measures Considered .......................................................................... 5-15
WCWCD Summary of Existing and Future Supplies ................................................................. 6-5
WCWCD Integrated Water Resources Plan Data ....................................................................... 6-6
Kane County Integrated Water Resources Plan Data ................................................................. 6-8

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 List of Figures
Figure ES-1
Figure ES-2
Figure ES-3
Figure ES-4
Figure ES-5
Figure ES-6
Figure 1-1
Figure 2-1
Figure 2-2
Figure 2-3
Figure 2-4
Figure 2-5
Figure 2-6

Lake Powell Pipeline Participating Water Conservancy District Service Areas ........................ 1-2
WCWCD Supply and Total Demand .............................................................................................. 3
KCWCD Supply and Demand – Kanab City, Johnson Canyon ..................................................... 5
East Fork Subbasin Supply and Demand – Orderville Town and Glendale ................................... 5
Alton Town Supply and Demand ................................................................................................... 6
Wahweap Creek Subbasin Supply and Demand ............................................................................. 6
Water Needs Assessment Study Area ......................................................................................... 1-1
Lake Powell Pipeline Participating Water Conservancy District Service Areas ........................ 2-2
Basins in KCWCD’s Service Area ............................................................................................. 2-4
Historical Population Projections for Washington County ......................................................... 2-6
Historical Population Projections for Kane County .................................................................... 2-7
Monthly M&I Water Use Pattern (Percentage of Total Annual Use ........................................ 2-13
Monthly M&I Secondary Untreated Water Use Pattern (Percentage of Total Annual Secondary
Untreated Use) .......................................................................................................................... 2-14
Figure 2-7 State of Utah Duty Values ........................................................................................................ 2-15
Figure 3-1 WCWCD 2010 Per Capita Water Use ........................................................................................ 3-2
Figure 3-2 KCWCD (Kanab City and Johnson Canyon) 2010 Per Capita Water Use ................................. 3-3
Figure 3-3 Four Kane County Subbasins 2010 Per Capita Water Use ......................................................... 3-4
Figure 3-4 WCWCD Projected Demand ...................................................................................................... 3-5
Figure 3-5 KCWCD (Kanab City and Johnson Canyon) Projected Demand ............................................... 3-6
Figure 3-6 East Fork Virgin River Subbasin Total M&I Water Demand Forecast ...................................... 3-7
Figure 3-7 Alton Town Total M&I Water Demand Forecast ....................................................................... 3-7
Figure 3-8 Wahweap Creek Total M&I Water Demand Forecast ................................................................ 3-8
Figure 4-1 WCWCD Existing Water Supplies ............................................................................................. 4-5
Figure 4-2 WCWCD Owned and St. George Secondary Untreated Sources and Infrastructure ................ 4-11
Figure 4-3 WCWCD Existing and Future Water Supplies ......................................................................... 4-16
Figure 4-4 WCWCD Existing and Potential Secondary Untreated Infrastructure and Customers ............ 4-20
Figure 4-5 Washington County Irrigated Lands ......................................................................................... 4-22
Figure 4-6 Daily Streamflow for Virgin River below Washington Fields ................................................. 4-24
Figure 4-7 Virgin River below Washington Fields Flow Exceedance Curve ............................................ 4-25
Figure 4-8 KCWCD Existing Water Supplies ............................................................................................ 4-30
Figure 4-9 KCWCD Potential Water Supplies ........................................................................................... 4-33
Figure 4-10 Kane County Water-Related Land Use ..................................................................................... 4-35
Figure 5-1 Culinary Per Capita Water Use for WCWCD ............................................................................ 5-9
Figure 5-2 KCWCD (Kanab City and Johnson Canyon) Average per Capita Water Use from 2000 to 2010514
Figure 5-3 Four Subbasins Average per Capita Water Use from 2000 to 2010 ......................................... 5-14
Figure 6-1 WCWCD Supply and Demand – Total ....................................................................................... 6-3
Figure 6-2 KCWCD Supply and Demand – Kanab City Johnson Canyon .................................................. 6-8
Figure 6-3 East Fork Subbasin Supply and Demand – Orderville Town and Glendale ............................... 6-9
Figure 6-4 Alton Town Supply and Demand ............................................................................................... 6-9
Figure 6-5 Wahweap Creek Subbasin Supply and Demand ....................................................................... 6-10

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 Executive Summary
ES-1

Introduction

This Water Needs Assessment (Assessment) evaluates the need for future water supplies by the
Washington County Water Conservancy District (WCWCD) and the Kane County Water
Conservancy District (KCWCD) (collectively the “Districts”). WCWCD and KCWCD are
participants in the Lake Powell Pipeline (LPP) Project. The LPP would deliver Utah’s Colorado
River water from Lake Powell to the service areas of WCWCD and KCWCD shown in Figure
ES-1.
WCWCD requested 82,249 acre feet (ac-ft) per year and KCWCD requested 4,000 ac-ft per year
from the LPP Project.
This Assessment is designed to:
 Estimate the Districts’ demand and supply, taking into account conservation and possible
effects of climate change, to determine the validity of their requests
 Determine the likely timing of the need for the LPP supply

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 Figure ES-1

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Lake Powell Pipeline Participating Water Conservancy District Service Areas

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 The Assessment is the basis of the purpose and need for the project and partially fulfills project
objectives outlined in Study Plan 19: Water Supply and Climate Change, which was approved by the
Federal Energy Regulatory Commission on January 21, 2009.
Information on the topics summarized here can be found in each chapter:
 Chapter 1 – Introduction
 The Districts’ histories and functions that form the basis for their requests for project
water
 The Lake Powell Pipeline project description
 Chapter 2 – Methodology
 Determination of service areas
 Estimation of demand
o Population projections
o Per capita water use estimates
 Determination of existing water supplies
 Estimation of agricultural conversions for future water supplies
 Conservation measure analysis
 Chapter 3 – Demand
 Projected populations and per capita usage
 Role of water conservation
 Water demand forecast
 Chapter 4 – Supply
 Current municipal supplies
 District planned water projects
 District potential water projects
 Chapter 5 – Water conservation programs
 Chapter 6 – Integrated supply and demand time lines
Each chapter provides an introduction summarizing information covered in that chapter.
Accordingly, those who desire to obtain the main conclusions of this report may do so by reading
this executive summary, Chapter 1,Chapter 1 – and the introductory section of each chapter.
Those desiring to understand calculations and other information supporting the conclusions will
find details in the chapter content.

ES-2

The Districts

The Districts are public agencies created by the state to provide and manage water within their
specified service areas. Each district has a unique set of circumstances giving rise to the need for the
Lake Powell Pipeline water.
WCWCD is the primary water supplier for the major municipalities in the county serving over 85
percent of the county’s population, thousands of second homes, 5.6 million tourists each year,
10,000 Dixie State College students and a 245-bed hospital complex. WCWCD has developed an
innovative water contract that allows for greater conservation and facilitates the transition of these
communities to more desert-wise landscapes. WCWCD and its customers have active conservation
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 programs and are committed to the fulfillment of realistic and practical water conservation
achievements that reflect the water-wise standards promoted in its service area for the past 20 years.
However, given limitations on Virgin River supply and diversions to the district’s off-stream
reservoirs, as well as water quality limitations unique to the Virgin River, local supplies will not
meet long-term demand.
KCWCD was formed in 1992. It has a very limited customer base and limited supply sources at
present. Although KCWCD encompasses all of Kane County, much of the district will not be served
by the Lake Powell Pipeline. The only substantial community in Kane County, the City of Kanab,
has developed its own water supply system, and intends to continue to meet the needs of M&I
customers within its current city boundaries, and within future annexation areas as well. Existing
KCWCD water supply customers include rural developments located in the Cedar Mountain and
Johnson Canyon areas. KCWCD owns and operates wells in the Johnson Canyon area to meet these
demands and intends to use Lake Powell Pipeline supplies to meet future demands. The Lake Powell
Pipeline would traverse Kane County on its way to Washington County enabling KCWCD to
conveniently tap into the pipeline for a reliable long-term supply.

ES-3
ES-3.1

Water Demand Forecast

WCWCD

Total M&I demand for WCWCD is expected to increase from 50,380 ac-ft per year in 2010 to
184,250 ac-ft per year in 2060 (DWRe 2014c). With feasible local project developments estimated to
add about 13,670 ac-ft per year, without the LPP, WCWCD demand will exceed supply by about
85,520 ac-ft per year in 2060, with the shortfall starting in about 2028 (Figure ES-2). The LPP is the
only water source available to meet this demand. The full LPP supply will meet demand through
2060, the end of the study period.

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 Figure ES-2

WCWCD Supply and Total Demand

These estimates take into account anticipated effects of conservation efforts on demand and climate
change on supply. WCWCD’s per capita water use dropped 26 percent between 2000 and 2010 and
is expected to drop another 12 percent from 2010 values by 2060. There is no practical water
conservation program that could offset reasonably anticipated demand over the study period.
Climate change effects are estimated to reduce the supply by up to 23 percent in the months of May
through July (Reclamation 2014, 50th percentile).
The total reliable water supply for Washington County is summarized in Table ES-1 below. The
13,670 ac-ft of future supplies include local projects to deliver additional culinary, or potable water
prior to construction of the LPP project. The LPP would offer an additional 82,249 ac-ft for culinary
use and add 17,120 ac-ft of reuse water that would not otherwise be available.
Table ES-1

Existing and Future Reliable Culinary Supplies for Washington County
Washington County Water Supply
WCWCD

Other
Suppliers

LPP

Total

Current Supply
Future Culinary
Future
Reuse/Secondary
Untreated Supply

32,225
13,670

35,452
---

--82,249

67,677
95,919

17,380

---

28,830

46,210

TOTAL

63,275

35,452

111,079

209,806

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 ES-3.2

KCWCD

KCWCD’s service area encompasses all of Kane County. This document includes a brief assessment
of four groups in Kane County primarily based on the four major subbasins. While the entire county
is considered part of KCWCD’s service area, KCWCD currently provides most of its water retail
connections in the Cedar Mountain area, which is outside of the basins covered in this study. Within
the study area KCWCD provides all of the retail water connections in the Johnson Canyon subbasin,
which also serves all of the water needs between Johnson Canyon and the Kanab City limits
including a connection to Kanab City to provide a backup water system to their residents. This
service area contains the largest future developable private properties in this study area and will
receive LPP water in the future. For this reason, Kanab City is grouped with the Johnson Canyon
subbasin in this Assessment and Alton Town is represented alone in the Kanab Creek subbasin.
Throughout this document, when referring to the four subbasins, Kanab City and the Johnson
Canyon subbasin are included along with Alton Town and the East Fork and Wahweap subbasins.
Total M&I demand for the areas served by KCWCD (Johnson Canyon and Kanab City) is expected
to increase from about 1,535 acre-feet per year in 2010 to 3,435 acre-feet per year in 2060 (DWRe
2014c). The remaining communities within Kane County are expected to increase demand from 733
ac-ft per year in 2010 to 1,750 acre-feet per year in 2060. A combination of existing and new
groundwater supplies is sufficient to meet future needs beyond the planning horizon for the
Wahweap Creek subbasin. The East Fork Virgin River subbasin and Alton Town would rely on
transfers of agricultural water to meet future demand deficits rather than groundwater within the
planning period.
The KCWCD (Kanab City and Johnson Canyon subbasin) reliable supplies are estimated at 2,516
acre-feet per year. When the estimated effects of climate change (Reclamation 2014) are applied to
these supplies and a 10 percent planning reserve is added, the reliable supply drops to 2,102 ac-ft per
year by 2060. KCWCD reliable supplies are projected to be in deficit by 2035 when they would be
exceeded by total water use. KCWCD will use LPP water to meet future demands beyond the
reliable supply.
Figure ES-3 through Figure ES-6 show the relationship between supply and demand, and the
sequential timing of new projects brought on line to meet the forecasted total water demand.

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 Figure ES-3

Figure ES-4

KCWCD Supply and Demand – Kanab City, Johnson Canyon

East Fork Subbasin Supply and Demand – Orderville Town and Glendale

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 Figure ES-5

Figure ES-6

Alton Town Supply and Demand

Wahweap Creek Subbasin Supply and Demand

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 ES-3.3

Conservation and Climate Change

Two factors that influence water demand and supply are conservation and climate change.
Conservation has been a hallmark of WCWCD’s focus since 1995. Several conservation measures
have been implemented since 1995 and all municipal customers that are part of the Regional Water
Supply Agreement have been required to comply. Because of this, a culture of conservation has
begun to develop in the county and between 2000 and 2010 WCWCD achieved 26 percent reduction
in per capita water use. WCWCD has already exceeded the statewide established goal of 25 percent
reduction by 2025.
KCWCD and the City of Kanab have active conservation plans for the Johnson Creek and Kanab
Creek areas. The water conservation programs address conservation education, maintenance of the
water distribution system and water sources, as well as increasing block rate structures. Kanab City’s
conservation approach has been to provide an efficient culinary water supply system to its
customers. KCWCD completed the construction of the Jackson Flat reservoir for the Kanab
Irrigation Company which has significantly enhanced the pressurized irrigation system. Current and
future conservation programs for both districts are discussed in detail in Chapter 5.
The U.S. Bureau of Reclamation conducted a statistical analysis of climate change projections of
future streamflow at the Virgin River at Littlefield USGS streamflow gauge. Median streamflow is
projected to decline between 10 and 35 percent relative to historical streamflow during the months of
May through July (Reclamation 2014). This analysis was incorporated into the Virgin River Daily
Simulation Model for WCWCD to estimate reliable supplies (DWRe 2014a). The reduction
associated with climate change also was applied to the Kane County subbasins’ reliable supply.
Climate change is anticipated to cause the runoff season to shift one month earlier in the year.
Furthermore, warmer temperatures are anticipated to cause winter precipitation to shift from snow to
rain (see Study Report 19 - Water Supply and Climate Change). The impacts of these changes
may reduce the ability to capture water in WCWCD storage. WCWCD’s off-stream storage system
is highly dependent upon stream discharge rates, the season of that water, and the rate at which the
water occurs in the river. The water rights in the system dictate that water is stored in the winter and
spring, when agriculture water is not being used for irrigating. Winter and spring water discharge is
based on snowmelt in the mountains. If snow precipitation is limited then the potential for storage is
limited. Rain precipitation often causes intense, abrupt storm events. If river flow exceeds the Quail
Creek diversion pipeline capacity, water cannot be stored and is lost. Therefore, more storage will
not help overcome the impacts of climate change for WCWCD.
ES-3.4

Per Capita Water Use

Per capita residential water usage in WCWCD and KCWCD for 2010 is shown in Table ES-2,
below. Total per capita water use rates, reported in Chapter 3, are addressed in this Assessment
because of their value in project planning. By estimating total per capita water use rates and
permanent population served, water managers can plan for the likely needs of the future. With the
conservation goals applied to the total use, managers have some assurance that sufficient water will
be available to fulfill estimated demands as they may be redistributed among various users over
time.
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 Table ES-2

2010 Residential Per Capita Water Use
Culinary
(gpcd)
143
141

District
WCWCD
Kane County Subbasins
KCWCD (Kanab City and Johnson
139
Canyon)
Source: DWRe 2013b; DWRe 2013d; DWRe 2014c

Secondary
untreated
(gpcd)
12
36

Total
(gpcd)
155
177

15

154

Total water use numbers calculated in this study do not provide valid comparisons to other water
users in the United States. The factors that contribute to the total per capita numbers are a unique
combination applicable to southwest Utah. For example:
 This Assessment reports all water use consistent with State of Utah policy, whereas
communities in other states may eliminate commercial, institutional, industrial or secondary
water use and/or subtract return flows from wastewater to calculate per capita water use.
 The population numbers used to compute per capita water use do not include the large numbers
of non-permanent residents; thus, their water usage is attributed to the total per capita usage of
the residential population, inflating these numbers.
 The growing season in southwest Utah is long, summers are hot and precipitation occurs
outside of peak demand periods, particularly in the WCWCD service area, increasing the need
for outdoor irrigation water, unlike areas where precipitation or cooler temperatures reduce the
demand for system water.

ES-4

Conclusion

Given available information and taking into account various parameters applicable to this Water
Needs Assessment, results set forth in this report are sufficient to support long-range regional water
supply planning. This Assessment shows that in the near future, projected water demands will
exceed existing supplies in the Districts’ services areas, causing them to employ a variety of
approaches to meet these demands. Conservation will play a vital role in minimizing the need for
additional water, but development of new water sources, including LPP water, will be critical in
maintaining a safe and reliable supply of water for communities in Southern Utah.

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 Chapter 1 – Overview
1.1 Introduction
The Lake Powell Pipeline Study Water Needs Assessment was conducted to evaluate the need for
future water supplies by the Lake Powell Pipeline (LPP) project participants and is the basis of the
Purpose and Need for the project. Study areas generally included only those areas that could be
served with project water. The potential project recipients, WCWCD and KCWCD, are public
agencies, each with unique circumstances governing water needs. The Lake Powell Pipeline project
is a project of the State of Utah that includes water delivery and hydroelectric power generation
components.

1.2 Study Area
The study area for this Assessment, shown in Figure 1-1, is limited to the areas that are potential
recipients of water from the Lake Powell Pipeline, which are:
 All of WCWCD service area
 Portion of KCWCD service area that could be served with water from the LPP
Figure 1-1

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 1.3 The Potential Recipients
1.3.1

Washington County Water Conservancy District

The WCWCD is a public non-profit agency, charged under state law with conserving, developing,
managing and stabilizing water supplies within the county to establish a safe, sustainable water
supply for human use and for a healthy natural environment in the Virgin River basin. The WCWCD
seeks to meet its goals by reference to estimates of water demand derived from the plans established
by local and state elected representatives of the people as well as state water and wildlife agencies.
As a political subdivision of the state, WCWCD operates under the Water Conservancy District Act
(§ 17B-2a-1001 et seq.), Limited Purpose Local Government Entities – Local Districts (Utah Code
Ann. § 17B-1-101 et seq.), Open and Public Meetings Act (Utah Code Ann. § 52-4-1 et seq.) and
other statutes generally applicable to public agencies. WCWCD has the limited purposes and powers
set forth in Utah law applicable to limited purpose local government entities and has no general
police powers or governing authority.
Washington County is located in the southwest corner of Utah adjacent to both Nevada and Arizona.
The county has diverse topography and climate resulting from a wide range of elevations but is
generally characterized by a desert landscape. Most Washington County residents live in fairly
narrow corridors along the Virgin and Santa Clara rivers. Washington County is one of the fastest
growing counties in the state, and Utah is one of the fastest growing states in the country. While
conservation will be an important factor in meeting the demand created by the anticipated growth,
the water saved through conservation cannot offset the total demand created over time. Furthermore,
changes from traditional landscapes to xeric landscapes increase the ambient temperature. This
increase in temperature will result in an increased use of air conditioning. According to Tamim
Younos, a professor of water resources at Virginia Tech, it can take an average of 25 gallons of
water to produce 1 kilowatt-hour of electricity (IEEE 2008). While not considered in this analysis,
this could increase the average per capita per day indoor water use, reducing the benefits of this form
of conservation. Because local water projects and conservation together will not meet demand over
time, it is essential that an additional supply is developed.
In addition, given risks posed by drought, climate change and the demand hardening that
accompanies conservation, the ability to tap into Lake Powell, an on-stream reservoir that gathers
water from the entire upper basin of the Colorado River, would add important diversity of supply not
available from the off-stream reservoirs that currently tap the Virgin River to supply Washington
County. Furthermore, the long range reliability of the Lake Powell supply avoids the drastic
economic losses that can occur if businesses see a risk of unstable water supplies and cease to
maintain and invest in the area.
The WCWCD operates in compliance with state and federal law and regulations pertaining to system
design, capacity and water quality, and the WCWCD’s water deliveries are constrained by factors
imposed by the Endangered Species Act. Its plans take into account data and studies prepared by the
state and relied upon by its professional consultants with expertise in the area of study. The plans set
forth by its municipal customers are an important basis for estimating reasonable demand
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 expectations. Thus, WCWCD seeks to respond to the will of the residents of the county as
represented by elected public officials.
In 2006, the WCWCD adopted a unique approach to water sales, designed to enhance conservation
opportunities for its municipal customers (WCWCD 2006). The Regional Water Supply Agreement
(RWSA), in contrast to the take-or-pay contracts traditionally relied upon by utilities, is an “allrequirements” contract serving the following Washington County cities (see Figure ES-1 for
locations):
 St. George
 Washington
 Hurricane
 Ivins
 LaVerkin
 Toquerville
 Santa Clara
 Leeds
Conservation is emphasized through several contract provisions.
 The RWSA requires municipal customers to pay only for the water that is delivered to them,
eliminating disadvantages to conservation caused by traditional “take-or-pay” contracts that
require blocks of water to be paid for whether or not they are used.
 Impact fees, paid by new development for capital costs of facilities necessary to supply water,
are increased with increasing irrigated area, thus encouraging new development to minimize
outdoor use of water. Lots in excess of 10,000 square feet pay for the additional area unless a
water conservation agreement is recorded to limit irrigated landscape.
 A conservation provision requires municipal customers to maintain or implement
 water conservation plans,
 water conservation rate structures,
 time of day water use ordinances,
 landscape ordinances.
 Municipal customers are also required to
 promote secondary untreated water irrigation systems,
 participate in planning to ensure maximum use of reuse water and
 use secondary untreated water on all municipal facilities for which such use is feasible.
The RWSA requires the WCWCD to acquire, construct, and operate its water system to meet
anticipated municipal demand. The RWSA pays for water through three different charges. Impact
fees are paid by new growth to address demand for new public water facilities. Municipal customers
pay a wholesale delivery charge based on metered delivery and a water development surcharge to
ensure a steady funding mechanism during economic fluctuations.
Municipal customers retain their existing water resources, rights and facilities, except to the extent
they choose to integrate them with WCWCD’s water supplies, which requires additional contracts
with the District. The wholesale delivery charge covers operation, maintenance, repair and
replacement. The District’s Capital Facilities Plan (CFP), which is approved by the municipal
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 customers, determines the components of the system necessary to provide adequate water to meet
the current and future needs of the customers. The CFP includes the LPP as a future system
component.
The only source available to augment Virgin River basin groundwater supplies traditionally relied
upon for municipal use has been development of Virgin River basin surface water, requiring the
construction of storage and transmission facilities. The WCWCD’s first project, the Quail Creek
diversion and off-stream reservoir, was completed in 1985. The construction of Sand Hollow
reservoir in 2002, integrated with the Quail Creek project, brought the average annual yield of
Virgin River water of the reservoirs to 24,922 ac-ft per year. In addition Sand Hollow Reservoir
operates as a groundwater recharge system, currently storing over 100,000 ac-ft, available as a
drought reserve.
The WCWCD’s ability to develop water in the Virgin River basin is limited by several factors:
 Water quality is compromised by the LaVerkin hot springs, coming in at about 10 cubic feet
per second at 10,000 parts per million of total dissolved solids (TDS).
 The district is faced with water quality issues such as arsenic and brackish water (geology).
 Due to the contamination of the Virgin River by the hot springs water, the district’s diversion
structure is located several miles upstream from the springs and the water is delivered to the
off-stream reservoirs through several miles of pipeline.
 The capacity of the pipeline limits the amount of water that can be diverted from the river.
 Diversion must be avoided when the natural flows are compromised by mud and debris during
floods that might damage facilities or negatively impact water quality in the system. As a result
of these limitations on diversions from the Virgin River, the river has maintained virtually the
same hydrograph including flood stage flows for the past 100 years.
 The district’s water use is subject to the major, primary agricultural diversion rights on the
Virgin River, dating between 1890 and 1904, belonging to the St. George and Washington
Canal Company (1890-1900), the Hurricane Canal Company (1904) and LaVerkin Canal
Company (1891). These three companies combined are entitled to about 190 cfs of Virgin
River flow, which exceeds the typical summer flows in this stretch of river emphasizing the
challenge faced by having only one water source, the Virgin River Basin.
 The district also allocates water for riparian habitat and wildlife conservation demands,
including instream flow protection.
Because water quality issues have prevented use of Virgin River water downstream of the La Verkin
hot springs for culinary or potable water use, the WCWCD and its municipal partners have
developed secondary untreated water systems to maximize the use of this water supply for outdoor
irrigation. Many secondary untreated systems were constructed years ago, with limited delivery pipe
sizes, and are often used continuously to make the most use of this water. Golf courses in
Washington County rely on secondary untreated water.
1.3.2

Kane County Water Conservancy District

KCWCD was formed in 1992. It has a limited customer base and limited supply sources at present.
The KCWCD boundary encompasses all of Kane County. The county extends from Lake Powell and

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 the Colorado River on the east to Washington County on the west. The main communities can be
seen in Figure ES-1 and include:







City of Kanab
Orderville Town
Alton Town
Glendale Town
Big Water
Johnson Canyon

Although KCWCD encompasses all of Kane County, much of the county will not be served by the
Lake Powell Pipeline. Existing KCWCD water supply customers include rural developments located
in the Cedar Mountain and Johnson Canyon areas. KCWCD owns and operates wells in the Johnson
Canyon area to meet these demands. KCWCD has a connection to the Kanab City water supply and
intends to use Lake Powell Pipeline supplies to meet future demands there and in the Johnson
Canyon subbasin. This document includes a brief assessment of four groups in Kane County
primarily based on the four major subbasins. Kanab City is grouped with the Johnson Canyon
subbasin in this Assessment and Alton Town is represented alone in the Kanab Creek subbasin.
Throughout this document, when referring to the four subbasins, Kanab City and Johnson Canyon
subbasin are included along with Alton Town and the East Fork and Wahweap subbasins.
The Utah State Institutional Trust Lands Administration (SITLA) administers a large tract of land in
east Kane County within the KCWCD service area. The eastern part of KCWCD, including Big
Water, drains to Lake Powell. It is therefore in the Southeastern Colorado River Basin as defined by
the State of Utah, and is in the Upper Colorado Basin as defined by the Colorado River Compact.

1.4 Summary Description of the Lake Powell Pipeline Project
In 2006 the Utah State Legislature passed the Lake Powell Pipeline Development Act (Utah Code
Ann. § 73-28-101 et seq.), which authorized the Board of Water Resources to build the LPP to meet
a portion of southwestern Utah’s future water demands. The Act specifies the powers of the state
Board of Water Resources, which is charged with construction of the project, establishes a
management committee to consult with the board and approve expenditures, establishes contractual
requirements, allocates the water to specified entities, establishes terms for delivery and payment
and authorizes transfer of title under specified conditions.
The LPP would transport a portion of Utah’s Colorado River water from Lake Powell to Washington
and Kane counties. The pipeline would consist of approximately 140 miles of buried 69-inch
diameter pipe from Lake Powell to Sand Hollow Reservoir near Hurricane and St. George. Pumping
facilities near Glen Canyon Dam and booster pumping stations along the pipeline alignment would
provide the approximately 2,000-foot lift needed to transport the water over the high point in the
pipeline. The 2,630-foot drop between the high point and end of the pipeline would be utilized to
generate hydropower by new hydroelectric generation facilities. The power sales from the
hydroelectric generation facilities would offset a portion of the pumping costs. The Districts have

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 requested allotments of water from the LPP project based on their own assessments of future water
needs. These requests are summarized as follows.
 WCWCD – 82,249 ac-ft/yr
 KCWCD – 4,000 ac-ft/yr

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 Chapter 2 – Methodology
2.1 Introduction
This chapter describes the data and methodology used in this Assessment, including:
 Determination of potential LPP service areas.
 Water demand forecasts based on
 Population forecasts, based on officially adopted forecasts provided by the Utah
Governor’s Office of Management and Budget (GOMB).
 Forecasts of per capita water use and total water needs to 2060, the adopted study period.
 Estimates of reliable yields of existing and future water supply projects.
 Confirmation by Maddaus Water Management (MWM) that conservation goals are attainable
 Integrated water resources plans
 Coordination efforts with stakeholders.

2.2 Service Areas
This Assessment evaluated which portions of the Districts’ service areas could be provided water
from the LPP. Figure 2-1 is a map showing the boundaries of the two districts and the proposed
alignment of the LPP.
Because portions of the Districts’ service areas are distant from the proposed LPP alignment, there
may be economic and engineering limitations to supplying project water to all areas. However,
indirect use of LPP water may be possible in some seemingly remote areas through exchanges and
substitute supply agreements. As a result of these potential partnerships, the majority of each
district’s service area was evaluated in this assessment. WCWCD and KCWCD demands and water
supply projects were evaluated independently.

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 Figure 2-1

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 2.2.1

Washington County Water Conservancy District

The majority of WCWCD system water is delivered to municipal customers who serve over 85
percent of the population of the county. In this Assessment, 33 retail water systems were evaluated
in WCWCD’s service area. Enterprise was not included in the analysis because of its distance from
the LPP and unlikeliness of exchange agreements involving LPP water taking place.
2.2.2

Kane County Water Conservancy District

KCWCD’s service area encompasses all of Kane County. The county extends from Lake Powell and
the Colorado River on the east to Washington County on the west. This document includes a brief
assessment of four groups in Kane County primarily based on the four major subbasins. While the
entire county is considered part of KCWCD’s service area, the district currently only serves
residences in the Johnson Canyon subbasin and areas between Kanab City and Johnson Canyon.
KCWCD also provides backup water and has a supply connection to Kanab City, which can be used
to deliver additional water in the future as needed. The Duck Creek and Cedar Mountain area has
several residences that are used as second homes. Because of its location, water use in this area does
not return to the Kanab/Virgin River basin or the Colorado River basin and was therefore excluded
from analysis in this document. The KCWCD pipeline proposed as part of the Lake Powell Pipeline
would terminate at the mouth of Johnson Canyon, where it would be connected to the existing
KCWCD and the Kanab City treatment and distribution systems. For this reason, Kanab City is
grouped with the Johnson Canyon subbasin in this Assessment and Alton Town is represented alone
in the Kanab Creek subbasin.
Strictly speaking, the four subbasins analyzed in this assessment within Kane County, Figure 2-2,
include:
 East Fork Virgin River – Orderville, Glendale and Alton
 Kanab Creek – Alton Town and Kanab City
 Johnson Canyon – Johnson Canyon
 Wahweap Creek – Church Wells and Big Water

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 Figure 2-2

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 2.3 Water Demand Forecast Methodology
In 2014, the Utah Division of Water Resources (DWRe) published population and water use
projections for each water basin in Utah. With the exception of Enterprise, all of WCWCD’s service
area was included in the Kanab Creek/Virgin River Basin. KCWCD’s service area encompasses
portions of the East Fork Virgin River, Kanab Creek, Johnson Canyon and Wahweap Creek Basins.
2.3.1

Projecting Population

The Utah Governor’s Office of Management and Budget (GOMB; formerly the Governor’s Office
of Planning and Budget) has developed population projections for southwest Utah since the late
1960s. These forecasts are sanctioned for use by state and other agencies for planning purposes. The
most recent projections, issued in 2012, use the estimated 2010 populations as a baseline to predict
populations every decade to 2060. The projections are provided by county and also by listed cities
and towns within each county. DWRe compared city and town boundaries used in the GOMB
projections to the municipal service area boundaries for which they collect water usage data and
adjusted the baseline populations to reflect the population within these municipal service area
boundaries. DWRe applied the GOMB growth rates to the baseline populations in the adjusted area
boundaries.
Because future population depends on birth rate, mortality, immigration, and emigration, each of
which are affected by many factors, there is a high degree of uncertainty in population models,
especially those projecting beyond just a few years. In Figure 2-3 and Figure 2-4, ten historical
population projections made by GOMB are plotted with actual population data estimated by the
Census Bureau for Washington and Kane counties, respectively (GOMB 2005, GOMB 2008,
GOMB 2012a, GOMB 2012b, & U.S. Census 2015). The GOMB projections have frequently
underestimated, and in 2005 and 2008 overestimated, population growth for Washington County.
The projections for Kane County, likewise, have failed to accurately estimate actual population.
Although inaccuracy is inherent to all population models, projections which under or overestimate
population can have detrimental consequences for the entities using them for long-term planning.

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 Figure 2-3

Historical Population Projections for Washington County

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 Figure 2-4

Historical Population Projections for Kane County

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 2.3.2

Estimating Per Capita Water Use

Per capita water use is essentially the amount of water used by a given population. The per capita
usage outlined in this report is intended to help state and local entities plan for the future, taking into
account the unique circumstances they face.
The following assumptions were made in determining the base per capita water use for the entities
within the Districts’ service areas:
 Water use by both permanent and non-permanent residents was divided by the permanent
resident population to calculate per capita use.
 This Assessment reports all customer level water use consistent with State of Utah policy,
whereas communities in other states often do not include commercial, institutional, industrial
or secondary water use, and may also subtract return flows from wastewater to calculate per
capita water use.
 This Assessment reports all municipal and industrial (M&I) water use, including customer
level residential, commercial, institutional and industrial culinary and secondary water use,
whereas other communities report only residential water use.
 This Assessment reports both culinary and secondary untreated water use; whereas other
communities report only culinary water use.
 Per capita water use includes M&I use but not agricultural use.
 Water use forecasts were developed for total, culinary or potable, and secondary untreated use.
 WCWCD – Average per capita water use for Washington County was assumed to be
representative of per capita water use for WCWCD. Enterprise was not included because it is
located in the Cedar/Beaver Basin and would not be served by Lake Powell Pipeline project
because of its remote location.
 KCWCD – Average per capita water use for Kanab City and the Johnson Canyon subbasin
was assumed to be representative of per capita water use for the KCWCD as this is the only
area that will be served by KCWCD facilities. Per capita water use for three other groups is
provided for informational purposes.
DWRe separated 2010 M&I water use estimates into residential, commercial, institutional and
industrial use categories. Residential water use was further broken down by indoor and outdoor use.
Secondary untreated water systems are not available in all areas, so many homes and businesses use
culinary water to meet outdoor watering needs. Reliable use records are available for culinary water
because cities meter and bill customers for this water. However, while some secondary untreated
water use is metered, most is not; and therefore, DWRe estimated secondary untreated use using
available lot size, efficiency and climate data.
2.3.3

Factors Influencing Per Capita Use

Local climate, culture and economic makeup influence water consumption. The pioneer culture of
home gardening has persevered over time. The warm climate in southwest Utah provides a long
growing season for shade trees, home vegetable gardens and other landscaping. Precipitation occurs
outside of much of the summer growing season. System demands in southwest Utah are increased by
the growing season coupled with a high evapotranspiration (ETo) rate and minimal offsetting
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 precipitation. Annual per capita water use data were analyzed to determine trends in water use
considering net evapotranspiration data from Coral Canyon (DWRe 2013e) as an indicator of annual
weather conditions.
The pleasant climate, plentiful recreational opportunities, and the scenic beauty of southwest Utah
attract millions of tourists each year. During their stays, these tourists consume water and contribute
to the calculated per capita usage in both WCWCD and KCWCD. Washington County has a large
tourism population associated with conventions, golfing, athletic events, and visits to nearby national
parks and recreation areas. Washington and Kane County share the world renowned Zion National
Park. Kane County is a gateway to Lake Powell, Bryce Canyon, and the Grand Staircase-Escalante
National Monument. Average annual tourist visits for the two counties exceed six million per year.
The Washington County Convention and Tourism Office (WCCTO) estimates 5.6 million tourists
visit Washington County each year (WCCTO 2015). This estimate was derived by multiplying the
number of hotel rooms with the average occupancy rate and an estimate of three people per room.
Using that methodology, Kane County likely receives 440,000 tourists per year. There are 155 new
hotel rooms in Kanab City currently under construction and scheduled for opening in early 2016
(KCWCD 2015). Kane County also has about 2.5-3 million people that ‘pass through’ the county on
the way to and from tourist destinations such as Zion, Bryce, Grand Canyon, and Lake Powell.
Dixie State University (DSU) and Dixie Applied Technology College (DXATC) are within
WCWCD’s service area. Some students at these two institutions are permanent residents of
Washington County, and consequently are included in the population data for the county, but the
many are not. In 2007, over 2,000 DSU students, or 36 percent, were not residents of Washington
County. The net non-permanent student population for Washington County will inflate commercial,
institutional and industrial (CII) per capita water use compared to locations without student
populations. The student population in Kane County is negligible and will have minimal effect on
calculated per capita water use.
Although estimates of per capita water use only consider the permanent population, there are a
number of part-time, second home owners that reside during the winter months in both districts.
Second-home owners make up approximately 30 percent of Washington County’s total parcels, and
most second-homes are within major city limits and could potentially be served by the LPP
(Washington County Assessor 2015). These properties maintain outdoor landscaping year round,
equipped with timer-controlled irrigation systems, creating an irrigation demand that is attributed to
permanent population in the per capita numbers. DWRe estimates that water use by second homes
contributes an additional 36.4 gpcd in WCWCD. Second home use is included in the CII water use
category in the DWRe per capita estimates. Kane County has more second homes than primary with
56 percent of the residents being classified as second homes (Kane County Assessor 2015). The
majority of Kane County second-home owners live in the Cedar Mountain area, which is outside the
study area. This area is not analyzed in this assessment. The DWRe estimates an additional 15.7
gpcd of second home water use in KCWCD (Kanab City and Johnson Canyon; DWRe 2013d). This
use is also grouped in the CII water use category in the per capita estimates.
2.3.4

Conservation

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 The historical conservation achieved in the Districts’ service areas has been based on water use data
provided by DWRe (DWRe 2014c). Annual per capita water use data were analyzed to determine
trends in water use. Future water conservation efforts were evaluated in a detailed water
conservation study, conducted for each of the districts by Maddaus Water Management (Appendix
B, MWM 2015a, MWM 2015b). This analysis reviewed water use data (billing data), evaluated
existing water conservation measures, considered potential future water conservation measures and
selected a program considered likely to be implemented in the future. The analysis relied on a model
developed by MWM that analyzes water use at the end-use level (e.g., individual appliances and
fixtures) and considers factors such as individual unit water savings, year of implementation, unit
costs, and market penetration. Meetings with local water user representatives were held to select
preferred conservation measures.
2.3.5

Forecasting Water Demand

Total projected water demand was determined for the two Districts for the period from 2010 to 2060
by multiplying the projected population for each of the Districts by the projected total per capita
water use with conservation. Separate culinary and secondary untreated water use demands were
estimated to determine the potential secondary untreated supply that could be utilized by the
Districts.

2.4 Water Supplies
The best estimate of reliable supply represents the approximate annual volume of water that is
reliably available to meet peak demands, reported in the DWRe Water Use Projections (WCWCD
2014; DWRe 2014c). Reliable yield for future projects was based upon information provided by the
Districts. Reliable yield for the Virgin River was based upon the Virgin River Daily Simulation
Model prepared by DWRe 2014a.
Key documents that were reviewed to determine existing water supplies included:
 Capital facilities plans for the Districts and cities within the Districts;
 Basin plans developed by the Utah Board of Water Resources for the Kanab Creek/Virgin
River Basin; and
 DWRe municipal and industrial water use reports (DWRe 2013b; DWRe 2013g; WCWCD
2014).
When different references reported different values for yields of existing water supplies, in general
the most recent report was considered to provide the most reliable information.
Water supplies that meet the EPA’s secondary untreated Maximum Contaminant Level (MCL) for
drinking water of Total Dissolved Solids (TDS) less than 500 mg/L are deemed usable for culinary
purposes in this Assessment. The EPA’s secondary untreated MCLs are guidelines which address
aesthetic concerns in culinary water, such as taste, color and odor. The EPA does not establish
MCLs for secondary untreated water; therefore, an upper limit of 1,000 mg/L TDS was assumed for

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 M&I secondary untreated water use in this report, which is the maximum TDS level for the least salt
tolerant residential ornamental landscape.
Water supply planning typically uses the estimated reliable yield for a water supply. In particular,
the hydrology of surface water supplies in the Virgin River reveals that averages rarely occur and
most years yield well below average supplies. Reliance on average or maximum yields or flows
would significantly overestimate supplies and underestimate shortages. Reliable yield estimated by
the DWRe was used to estimate yield for the existing water supplies within the Districts.
2.4.1

Surface Water Sources

WCWCD relies heavily on surface water supplies. For WCWCD, average annual yield with a
maximum annual surface water shortage of 10 percent using the critical historical drought period
was used to represent reliable surface water supplies. In other words, the WCWCD would have to
address a water shortage in 1 out of every 10 years.
Kane County primarily relies on groundwater; however, the supply for the Kanab Irrigation
Company water, providing water to the Kanab City irrigation and secondary water users, comes
from surface water streamflow from the Kanab Creek. These flows are affected dramatically by
drought conditions and have a direct impact on Kanab City groundwater demands, as residents use
these sources when irrigation flows are reduced.
A recent study by the U.S. Bureau of Reclamation, in coordination with the DWRe describes the
potential impact of climate change on future streamflow in the Virgin River (Reclamation 2014).
This study evaluated 112 streamflow projections at the Virgin River at Littlefield USGS streamflow
gauge, developed using global General Circulation Model output of 112 future projections of
temperature and precipitation data. The results of the study display statistics representing the range
of variability among the 112 climate change projections. Table 2-1 below shows the projected future
simulated monthly percent changes in flow for the Virgin River at Littlefield. This analysis was
incorporated into the Virgin River Daily Simulation Model for estimating reliable supply at the
WCWCD diversion structure (DWRe 2014a). As shown, future flows during the summer months
(May through August) are projected to be lower while the fall and winter months are projected to be
similar or greater than the base period. Furthermore, due to warmer temperatures, the future climate
is anticipated to shift the seasonal runoff one month earlier, have more severe storm events and
cause winter precipitation in the West to fall more as rain than snow (see Study Report 19), which
will all affect surface water flows. While a decrease in flow hurts the system, a shift in the runoff
and a shift from snow to rain may cause an even greater loss to supply.

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 Table 2-1

Projected Future Period Virgin River Flow

10th
percentile

30th
percentile

50th
percentile

70th
percentile

90th
percentile

(1)

(1)

(1)

(1)

(1)

88%
98%
104%
117%
136%
January
83%
98%
109%
139%
167%
February
80%
103%
126%
161%
226%
March
58%
79%
100%
124%
158%
April
41%
59%
72%
91%
119%
May
51%
59%
66%
75%
98%
June
75%
83%
90%
95%
104%
July
79%
86%
93%
98%
119%
August
84%
92%
97%
105%
123%
September
88%
93%
97%
104%
118%
October
90%
94%
98%
102%
111%
November
89%
94%
99%
104%
114%
December
Annual
72%
86%
97%
114%
141%
Sum
Notes:
(1)
Percentiles are relative to the distribution of the 112 climate change simulations
(2)
Monthly percentages are Future Period (2025-2054) relative to Base Period (1950-1999)

2.4.2

Mean
110%
123%
141%
107%
77%
70%
90%
95%
100%
101%
100%
101%
104%

Groundwater Sources

Reliable yields of groundwater supplies were assumed to be equal to those estimated in the DWRe
reports regarding M&I water supply and uses, which are 50 percent of the maximum pumping
capacity of wells, when pump capacity is the limiting factor (unless otherwise indicated by the well
owner) (DWRe 2013g). Springs are equal to their respective reliable yields.
2.4.3

Planning Reserves

Planning reserves provide water districts protection against variations in supply and demand.
Although not reflected in either the supply or demand in this analysis, WCWCD has a goal of
maintaining a planning reserve equal to the estimated supply for 15 years into the future, so that new
projects are brought online in advance of need. This allows for time that might be needed for
planning, obtaining approvals, final design and construction of large water projects.
A 10 percent planning reserve was added to the existing reliable groundwater supplies for Kane
County entities to avoid using water supplies up to the maximum and to provide a buffer against
annual variability in water supplies affected by precipitation runoff and groundwater aquifer
recharge. This reserve is applied to the reliable supply estimates after the climate change reductions
are considered and results in a 10 percent decrease in reliable supply.
2.4.4

Demand Timing

Water use is not constant from month to month. Monthly M&I water use patterns for each District,
as a percentage of total annual use, are presented in Figure 2-5. For both districts, the largest amount

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 of water is used from April through October, during the irrigation season. Throughout the rest of the
year water use is fairly constant.
Total annual secondary untreated water use was distributed monthly throughout the irrigation season
(April through October) using data obtained from the cities (St. George Water Services Department
2004; Alpha Engineering 2006). Figure 2-6 shows the monthly secondary untreated water use
pattern, estimated assuming no outdoor water use in January through March, November, and
December.
Monthly secondary untreated demand variations were used to estimate the portion of potential
secondary untreated supply that could be used without storage capacity. Potential secondary
untreated supply is generated throughout the year as treated wastewater, but the secondary untreated
demand occurs only during the irrigation season. Without storage of potential wintertime secondary
untreated supply, wastewater generated during winter months could not be utilized to meet
secondary untreated demands. Monthly water use patterns were used to estimate potential secondary
untreated supplies described in Chapter 4.
Figure 2-5

Monthly M&I Water Use Pattern (Percentage of Total Annual Use)

Source: St. George Water Services Department, 2004; Alpha Engineering, 2006.

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 Figure 2-6

Monthly M&I Secondary Untreated Water Use Pattern (Percentage of Total Annual
Secondary Untreated Use)

Source: St. George Water Services Department, 2004; Alpha Engineering, 2006.

2.5 Agricultural Conversion for M&I Supply
As municipal development occurs over existing agricultural lands, water will be converted from
agricultural to municipal uses. To estimate the amount of water that might be obtained from these
conversions, the State of Utah duty of water values were used. Water quality concerns and
groundwater sustainability were not considered in this computation.
None of the agricultural water in the Kanab and Johnson Canyon area can be planned on for future
conversion to M&I. Most all of the agriculture water supplies in the Kanab City area are provided by
the Kanab Irrigation Company who holds title to the water rights. This unique situation is created
because most of the water available in the area being irrigated is not available from surface or
ground water on or nearby the property as there are no surface flows and the groundwater is
extremely brackish. As a result, the irrigation water is piped from streamflows about ten miles north
of the area being served. Kanab irrigation company water rights are held for irrigation purposes and
individuals cannot change uses as they hold shareholder rights only. Kanab Irrigation Company
policy is not to allow for any conversions to M&I as properties are developed, but to transfer
irrigation to other parcels which are readily available. The Irrigation Company and Kanab City
culinary water compete for the same resources and irrigation water reduces the residential demands
for the culinary water so conversions will not likely provide any net gain in the system.
Additionally both Kane County and Kanab City general and land use plans give strong support to
preserving and strengthening agriculture and open space preservation associated with agricultural
uses. Current trends have shown an increase in agricultural lands by approximately 20% over the last
five years. There are no estimated reductions in agricultural lands as both plans and local production
needs for these resources will continue to increase rather than decrease.
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 The duty of water multiplied by the irrigated acreage determines anticipated irrigation water use.
The duty of water is established by the Utah State Engineer for irrigated agricultural land, as shown
in Figure 2-7 (DWRi 2008b). The Virgin River Basin and the Kanab Creek Basin are depicted in the
figure as numbers 81 and 85, respectively. As shown, the Virgin River Basin is a combination of
duty values of 3, 4, 5 and 6. The portion of Washington County most likely to be developed has a
duty value of 6 ac-ft per year per acre of irrigated land.
Figure 2-7

State of Utah Duty Values

2.6 Calculating Water Conservation
Information on the water conservation programs currently being implemented by the Districts and
the cities within their service areas was obtained from published water conservation plans submitted
to the DWRe and from interviews with water conservation coordinators and water resource planners
at the various entities. No effort was made to field-verify the implementation of specific
conservation measures described in the water conservation plans.
Documentation of recent water use reductions that could be attributed to state and local water
conservation programs was expressed in terms of per capita water use rates as determined from

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 review of information provided by the entities or the state. The historical conservation achieved in
the Districts’ service areas was based on water use data provided by DWRe (DWRe 2014c).
Projected conservation for the two districts was based on water conservation projections by the Utah
Division of Water Resources (DWRe 2014c). Water conservation demand management alternatives,
general and site-specific conservation programs, and other water efficiency measures targeted to
achieve these projections were developed by Maddaus Water Management (MWM), in close
cooperation with MWH and each District (Appendix B, MWM 2015a, MWM 2015b). Results of the
conservation studies were compared to the State’s water conservation goals.
Studies of potential future water savings resulting from implementation of conservation programs
were performed for each District independently. The studies included collecting billing data to
analyze actual water use at the customer level; selecting potential conservation measures suitable for
the community; combining selected measures into comprehensive water conservation programs; and
coordinating with the communities in the selection of conservation measures likely to succeed in this
area and the overall desired program. MWM’s Demand Side Management Least Cost Planning
Decision Support System (DSS Model) prepares long-range water demand and conservation water
savings projections. The DSS Model is an end-use model that separates total water production (i.e.,
water demand in the service area) into specific water end uses (e.g., toilets, faucets, irrigation).
Development of the model was based on extensive experience with conservation programs in other
communities, published information on conservation measure effectiveness, and locally specific
information provided by the water users. Conservation programs were developed for each District,
and the local stakeholders selected the program they felt was most reasonable for their conditions.
The impacts of the water conservation programs on water demand were evaluated from 2016
through 2025 with respect to the targets, and from 2016 to 2060 for long-term planning.
In MWM’s Technical Conservation Analysis for Kane County (MWM 2015a), the water
conservation projections include use from the Duck Creek and Cedar Mountain areas. This
assessment does not include these areas. Because of this, the current and future per capita water use
estimates are much higher than is reported by DWRe and shown in this document. The programs to
be followed to achieve conservation and the feasibility of achieving the stated percent reductions
apply to the areas analyzed in this assessment as well as the entire Kane County as analyzed by
MWM.
Conservation is essential in meeting future water needs. Changes in technology, demographics,
community values, and other factors may have unanticipated effects on water use. Conservation
above the levels used in these reports is encouraged by WCWCD; however, the conservation goals
used are prudent for planning. These goals have been vetted by Division of Water Resources, each
district, community participants, and Maddaus Water Management. They exceed current state goals,
utilize available technologies, and, importantly, are believed to be achievable within the timeframe
that additional water supplies will be needed in Washington County.
2.6.1

Demand Hardening

Water providers currently rely on demand management – or emerging conservation measures – to
get through drought periods when water supplies are well below normal. When conservation
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 measures have consistently reduced water use to the point it has become “normal” use, there are
fewer short term options for reducing non-essential uses to save water for essential uses. This
decrease in flexibility of water use is referred to as “demand hardening.” Demand hardening
requires that reliable yield estimates are factored to meet all projected demands, because there is
little potential to reduce demands when actual yields are less than the estimated yield.

2.7 Integrated Water Resources Plans
Integrated water resources plans consist of integrating demand forecasts with existing and potentially
available supplies in a strategic manner. New supply sources were added sequentially in priority
when demand exceeds supply based on factors such as qualitative unit cost, current status of project
development, and preferences expressed by the Districts. Because detailed cost estimates for future
water supply projects were not developed for this analysis, any cost comparisons between water
supply sources were qualitative only.
There are a number of factors that introduce significant uncertainty into integrated water resource
plans. These include:
 Actual future conservation efforts may exceed or fall short of the goals assumed in this study.
A conservation analysis conducted by Maddaus Water Management evaluated the potential for
implementing specific conservation measures in the study area.
 Changes from traditional landscapes to xeric landscapes increase the ambient temperature.
This increase in temperature will result in an increased use of air conditioning which could
result in an increase in the average per capita per day indoor water use, reducing the benefits
of this form of conservation.
 The rate at which urban development occurs in areas of existing irrigated agriculture will affect
the rate at which agricultural supplies are converted to M&I supplies without buy and dry
programs. This in turn could affect the timing of other new supplies including LPP.
 The existing mix of culinary and secondary untreated water use was assumed to change in the
future. Complex economic factors, outdoor landscaping practices, and regional and local water
use policies will probably affect the ratio of secondary untreated water use to total water use
substantially.
 Advanced water treatment processes (e.g., reverse osmosis) are currently financially and
environmentally prohibitive to provide culinary water from local surface waters. Technological
breakthroughs in treatment processes or brine disposal methods could make advanced water
treatment feasible for southwestern Utah in the future and may allow use of some secondary
untreated water resources currently planned to offset culinary demand available for direct
culinary use.
 The conservation goals of each district were applied to 2010 per capita usage to project future
demand. While this estimation method is appropriate for a 50-year projection, per capita use
is affected by several factors, such as economic makeup, infrastructure design, and climate,
which are likely to deviate from current conditions.
 The economic composition of each district is likely to change as population increases thus
varying the residential to CII usage ratio. As cities grow, commercial, industrial and
institutional uses often increase. It is likely that southwest Utah will remain a popular location
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 for second homes and tourism, but it is unknown if either component will increase as more and
more baby boomers retire or taper off as the area becomes more populated.
 Possible effects of climate change on demand, such as an increase in per capita water use with
decreased precipitation, were not included in this analysis because of uncertainties in effects
of climate change on use.

2.8 Coordination with Local Stakeholders
Several meetings were held to involve local stakeholders in the development of the first draft of this
assessment. In May 2007, stakeholder meetings were held with representatives from the public (e.g.,
cities within the Districts’ service areas, local citizens, and environmental groups), and additional
meetings were held with the Districts in July 2007, September 2007, and January 2008. These
meetings informed stakeholders on the Districts’ current water supply operations and issues
associated with current and future supplies.
For the conservation assessment performed by MWM (MWM 2010a, MWM 2010b, MWM 2015a,
MWM 2015b), meetings were conducted to collect water use and reuse data and existing
conservation program information. The initial meetings occurred in 2010 and an update of the
conservation technical analysis was completed in 2015. The update included additional meetings
with the WCWCD Water Conservation Plan Update Work Group and several meetings and
communications with KCWCD. KCWCD also held meeting with all municipalities in the county to
participate in the development of the KCWCD conservation plan. MWM presented several potential
conservation measures that could be considered for implementation in each community and the
stakeholders screened the potential conservation measures to a short list of specific conservation
measures that were further evaluated in the conservation assessment. The conservation coordinators
and water resource planners for each entity selected the preferred conservation program in a
workshop with MWM.

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 Chapter 3 – Water Demand
3.1 Introduction
As southwestern Utah’s population steadily continues to grow, demand for water will consequently
increase, approaching an estimated 189,435 acre-feet per year by 2060 in LPP service areas.
Increased conservation efforts are expected to reduce per capita usage, but both districts must be
capable of supplying enough water to meet Utah design standards for source sizing. In Chapter 3,
population and per capita water use projections are used to predict future water demands for
WCWCD and KCWCD.
Per capita water use in WCWCD’s service area is expected to decrease by 35 percent from 2000 to
285 gpcd total and 136 gpcd residential by the end of the study period (2060) with conservation.
Even with this per capita use reduction, overall water demand will approach 184,250 ac-ft per year
in WCWCD’s service area by 2060 (DWRe 2014c).
The four KCWCD subbasins are projected to have a total population of 17,074 by 2060. Per capita
water use is expected decrease 30 to 35 percent from 2000 baseline levels to 271 gpcd by the end of
the study period (2060) with conservation. Thus, water demand will approach 5,185 ac-ft per year
within the four subbasins of KCWCD by 2060 (DWRe 2013b; DWRe 2014c).
3.1.1

WCWCD Projected Population

The average annual growth rate in Washington County is projected to be 3.6 percent until 2030
when it is expected to gradually decrease. By 2060, WCWCD’s service population is anticipated to
exceed 575,000. Population projections for WCWCD and the six largest cities in their service area
are shown in Table 3-1.
Table 3-1
City/District
Hurricane
Ivins
La Verkin
Santa Clara
St. George
Washington
WCWCD
Annual Growth Rate
Source: DWRe 2014c.

3.1.2

WCWCD Population Projections

2010
13,300
6,410
4,060
6,500
72,750
18,760
138,530
-

2020
18,950
9,130
5,780
9,260
103,640
26,730
196,480
3.6%

Population
2030
2040
27,020
35,800
13,020
17,250
8,250
10,930
13,200
17,500
147,780 195,810
38,110
50,490
279,270 369,370
3.6%
2.8%

2050
45,510
21,930
13,890
22,240
248,920
64,190
468,990
2.4%

2060
56,020
27,000
17,100
27,380
306,420
79,020
576,850
2.1%

KCWCD Population Projections

Population projections for the four groups within KCWCD boundaries are summarized in Table 3-2.
Only Kanab City and Johnson Canyon is expected to be served by the Lake Powell Pipeline. The

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 other groups are shown for informational purposes only. Cities and towns within each of the four
groups were previously described in Section 2.2.2.
Table 3-2

Population Projections for KCWCD Groups
Year

Group
East Fork Virgin
River Subbasin
Alton Town

Paramet
er(2)
Pop.
AGR
Pop.
AGR
Pop.
AGR
Pop.
AGR

2010

2020

2030

2040

2050

2060

960
120
4,780
680
-

1,130
1.59%
140
1.59%
5,610
1.60%
800
1.59%

1,380
2.05%
170
2.05%
6,890
2.05%
980
2.05%

1,700
2.06%
210
2.06%
8,460
2.06%
1,200
2.06%

2,060
1.95%
260
1.95%
10,290
1.95%
1,460
1.95%

2,500
1.93%
310
1.93%
12,480
1.94%
1,770
1.93%

Kanab City and
Johnson Canyon
Wahweap Creek
Subbasin
Notes:
(1)
Source DWRe 2013a, DWRe 2013b, DWRe 2014c
(2)
Pop. = population projection; AGR = annual growth rate.

2010 to
2060
AGR
1.92%
1.92%
1.92%
1.92%

3.2 Per Capita Water Use
The 2010 estimated per capita water use of both districts was used as the baseline to project future
water demands. As described in Section 2.3, DWRe calculates per capita water use by dividing the
total water use in an area by the permanent population. Water usage is also divided into culinary or
potable and secondary untreated categories.
3.2.1

WCWCD 2010 Per Capita Water Use

In 2010 the per capita water use in the WCWCD service area was estimated to be 325 gpcd. Figure
3-1 shows that 270 gpcd was culinary water and 55 gpcd was secondary untreated water (DWRe
2013a; DWRe 2013d). Residential use contributed 156 gpcd, and commercial, institutional and
industrial (CII) use contributed 169 gpcd. CII includes use from second homes.
Figure 3-1

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 3.2.2

KCWCD 2010 Per Capita Water Use

In 2010 the per capita water use in the KCWCD service area (Kanab City and Johnson Canyon
subbasin) was estimated to be 287 gpcd (DWRe 2014c). Figure 3-2 shows that 272 gpcd was
culinary water and 15 gpcd was secondary untreated water. Residential use contributed 153 gpcd,
and CII use contributed 133 gpcd. The per capita water use for the four subbasins in Kane County
(all groups) was estimated to be 309 gpcd (DWRe 2013b; DWRe 2013d; DWRe 2014c). Figure 3-3
shows that 260 gpcd was culinary water and 49 gpcd was secondary untreated water. Residential use
contributed 177 gpcd, and CII use contributed 133 gpcd. CII includes use from second homes.
Figure 3-2

KCWCD (Kanab City and Johnson Canyon) 2010 Per Capita Water Use

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 Figure 3-3

Four Kane County Subbasins 2010 Per Capita Water Use

3.3 Projected Water Demand
Annual water demand was calculated by DWRe using population projections and anticipated per
capita water usage assuming 30 to 35 percent conservation by 2060. Projections were given for
WCWCD and each of its major water systems as well as for the entities of Kane County that reside
within the Kanab/Virgin River Basin. The annual demand was forecast in 10-year increments out to
2060 and includes a breakdown of culinary and secondary untreated use (DWRe 2014c). Demand
was forecast using the currently mandated design standards per equivalent residential connection
(ERC), as described in Section 3.3.2.
3.3.1

Required Source-Sizing Standards

Per capita water use is anticipated to decline resulting from increased conservation, but ultimately,
the quantity of water municipalities must be capable of providing their customers is dictated by
design standards for source sizing. Utah Division of Drinking Water (DDW) requires sources to
meet both average and peak day demands (DDW citation, R309-510). A minimum of 0.45 ac-ft per
year of source water is required per equivalent residential connection (ERC) statewide to meet
indoor demands. The ERC could influence the demand needs in the future as the requirement may be
more than the per capita use after conservation measures have been taken.
The current rule requires extensive data collection of both average and peak flows before DDW will
consider reducing the quantity of source water supplied per ERC. DDW is evaluating current indoor
and outdoor requirements across the state, but unless requirements are reduced, both Districts must
provide enough source water to meet the DDW standard.
3.3.2

WCWCD Water Demand Forecast

Water demand forecasts for total M&I water use for WCWCD are shown in
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 Table 3-3 (DWRe 2014c). Figure 3-4 projects both secondary untreated and culinary demands out
to 2060
Table 3-3

WCWCD Total M&I Water Demand Forecast
Per Capita Use
with
Conservation
(gpcd)
325
311
295
295
295
285

Year
Population
2010
138,530
2020
196,480
2030
279,270
2040
369,370
2050
468,990
2060
576,850
Source: DWRe 2014c

Figure 3-4

3.3.3

Total Projected
Water Demand
with
Conservation
(ac-ft/yr)
50,380
68,450
92,220
122,010
154,940
184,250

WCWCD Projected Demand

KCWCD Water Demand Forecast

Water demand forecasts for total M&I water use are shown in Table 3-4 and plotted for KCWCD
(Kanab City and Johnson Canyon subbasin) in Figure 3-5. KCWCD currently serves only the
Johnson Canyon subbasin but anticipates serving this area as well as Kanab City with water from the
Lake Powell Pipeline in the future.

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 Table 3-4

KCWCD (Kanab City and Johnson Canyon) M&I Water Demand Forecast

Population
Year
2010
4,780
2020
5,609
2030
6,888
2040
8,463
2050
10,287
2060
12,484
Source: DWRe 2014c

Figure 3-5

Per Capita Use
with
Conservation
(gpcd)
287
272
256
256
256
246

Total Projected
Water Demand
with
Conservation
(ac-ft/yr)
1,535
1,709
1,971
2,422
2,944
3,445

KCWCD (Kanab City and Johnson Canyon) Projected Demand

Water demand forecasts for total M&I water use are plotted for the three other groups in Kane
County in Figure 3-6 through Figure 3-8. The approximate total M&I water demands for each of
the groups throughout the study period with conservation is shown in Table 3-5.
Table 3-5

Kane County Groups M&I Water Demand with Conservation Forecast
Projected Water Demand (ac-ft/yr)

Group
2010
East Fork Virgin River Subbasin
467
Alton Town
28
Wahweap Creek Subbasin
238
Source: DWRe 2013b; DWRe 2014c

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2020

2030

2040

2050

2060

538
32
267

641
39
311

786
47
382

954
57
464

1,137
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 Figure 3-6

East Fork Virgin River Subbasin Total M&I Water Demand Forecast

Figure 3-7

Alton Town Total M&I Water Demand Forecast

80
Projected Water Demand with Conservation

Water Demand (ac‐ft per year)

70
60
50
40
30
20
10
0
2010

2015

2020

2025

2030

2035

2040

2045

2050

2055

2060

Year

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 Figure 3-8

Wahweap Creek Total M&I Water Demand Forecast

600
Projected Water Demand with Conservation
Water Demand (ac‐ft per year)

500

400

300

200

100

0
2010

2015

2020

2025

2030

2035

2040

2045

2050

2055

2060

Year

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 Chapter 4 – Water Supply Conditions
4.1 Introduction
Existing supplies are currently used to meet water needs and are assumed to be available on a
sustainable basis in the future. Planned supplies are projects now in the planning or implementation
process. Projects identified in this chapter include both culinary or potable and secondary untreated
supplies that have previously been evaluated by the Districts or by DWRe. The LPP project is
included because it is considered to be a key potential component of future water supply plans for
the Districts. WCWCD has requested 82,249 ac-ft per year of LPP water and KCWCD has requested
4,000 ac-ft per year.
In Washington County, water quality of the Virgin River below the LaVerkin hot springs is a
significant issue affecting potential supplies, which are therefore not planned for implementation
within the study period; these supplies could be part of a longer term water supply portfolio if
identified problems are resolved. Certain sources not feasible for development in Washington
County are discussed in Section 4.2.6.
Groundwater supplies in the Johnson Wash area (KCWCD service area) are of poor quality and are
not likely to be suitable for culinary purposes (Appendix A, MWH 2015). Some ground water is
potentially available in the East Fork Virgin River subbasin and the Wahweap Creek subbasin. The
quality of this water is assumed to be suitable for future needs.
Agricultural water supplies are considered only as potential M&I sources through transfers and
conversions. Irrigated acreage and agricultural water use are not expected to increase in the future
based on the Virgin River Basin Plan and Kanab Creek Basin Plans (DWRe 1993).

4.2 Washington County
4.2.1

WCWCD Water Supply Overview

Washington County water supplies come from a combination of groundwater (springs and wells)
and surface water (direct diversions and reservoirs). The Navajo Sandstone Aquifer and shallow
alluvial aquifers provide groundwater resources. Surface water sources consist of the Virgin River
and its tributaries. In 2010, approximately 20 percent of the developed culinary water supplies for
public community water systems in Washington County were from groundwater sources and 80
percent were from surface water sources (DWRe 2013a). Groundwater supplies developed by public
drinking water systems are generally of high quality and can be used directly for culinary uses after
disinfection. Surface water supplies are used directly to meet secondary untreated water demands or
are treated to meet culinary demands. The cities and towns in Washington County have historically
developed independent water collection and treatment systems; however, since WCWCD’s first
project in the mid-1980s, the major municipal water systems have become increasingly integrated.

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 Groundwater sources within the WCWCD service area are considered to be fully appropriated and
closed to further appropriations at this time by the State Engineer (DWRi 2008a), with the exception
of the Canaan Gap drainage east of the Hurricane Cliffs and the Beaver Dam Wash drainage, which
are open to small underground water appropriations for domestic filings. New diversions and uses
must be accomplished by change applications filed on previously approved water rights. Changes
between surface and underground sources are reviewed for hydrologic connection to avoid
interference with existing water rights.
4.2.2

Water Quality Effects on WCWCD Future Supplies

Water quality, primarily arsenic and dissolved solids concentration, limits current and future use of a
substantial portion of Washington County’s water supplies. Arsenic concentrations of groundwater
in the Navajo Sandstone Aquifer often exceed the maximum contaminant level (MCL) set by EPA,
and many groundwater sources must be either treated or blended with low arsenic concentration
water in order to be used for culinary purposes. The concentration of total dissolved solids (TDS) of
a water source also limits what uses are appropriate. A large portion of Virgin River water is
unsuitable for culinary and even landscape irrigation use because of the high TDS discharge from
the La Verkin hot springs.
In 2000, EPA lowered the primary MCL for arsenic in drinking water from 50 micrograms per liter
(µg/L) to 10 µg/L. Many local wells that recover water from the Navajo Sandstone Aquifer naturally
exceed this limit. Consequently, several high-production, culinary wells in Washington County were
converted to secondary untreated wells because of the new arsenic limit. Other wells require
blending with waters containing less arsenic in order to comply with the new MCL. Because future
recharge and recovery projects will likely occur in the Navajo Sandstone Aquifer, arsenic
concentration will continue to be a challenge, and additional treatment processes will be needed to
use the affected groundwater for culinary purposes.
La Verkin hot springs discharge water with 10,000 mg/L concentration of TDS at a rate of about 10
cubic feet per second into the Virgin River near the La Verkin Bridge, thus rendering all downstream
water unsuitable for culinary use or landscape irrigation. Virgin River water, diverted by the St.
George and Washington Canal Company at the Washington Fields agricultural diversion, has an
average TDS of approximately 1,500 mg/L due to the La Verkin hot springs discharge (USEPA
2008). Because TDS at the agricultural diversion exceeds 2,500 mg/L when base river flows are low,
agricultural users of this water must utilize flood irrigation to prevent salts from building up in the
soil, an approach unsuitable for M&I purposes.
The high cost, high energy demand, and lack of an environmentally sound alternative for disposal of
the waste brine stream is a deterrent to reverse osmosis (RO) treatment of the Virgin River water
supply. As technology improves over time and the costs of water treatment decline, it may become
economically feasible to treat high TDS water for culinary use without the adverse environmental
effects currently of concern. The proposed LPP project would import higher quality water much
more economically and would avoid the environmental impacts associated with RO treatment.
The TDS and hardness concentrations in Lake Powell water are similar to those of the existing
WCWCD supplies, and addition of the water as a new supply would likely have a minimal effect on
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 overall water quality in the area. Current TDS concentrations of the water supply in the WCWCD
service area ranges from 100 to 800 mg/L, with average of about 450 mg/L. TDS concentrations of
untreated Lake Powell water within the top 100 feet ranges from 350 to 600 mg/L, depending on
seasonal fluctuations in water quality. Total hardness of the water supply in the WCWCD service
area ranges from approximately 100 to 400 mg/L as calcium carbonate, compared to the hardness of
untreated Lake Powell water of 240 to 320 mg/L as calcium carbonate. The design and operation of
the Lake Powell Pipeline intake at Lake Powell would allow water diversion from the top 100 feet of
Lake Powell to optimize water quality of the supply that would be conveyed through the pipeline.
If adequate storage and additional water supplies were available, it may become possible to blend
high TDS Virgin River water with a lower TDS supply from another source (e.g., reuse water and
excess Santa Clara Project Water) to create water suitable for secondary untreated M&I purposes.
An increase in the use of highly saline water for secondary untreated water use purposes may still
have a detrimental effect on the water quality of local surface and groundwater supplies as a result of
return flows and infiltration of a portion of the water used for irrigation. These effects must be
carefully considered in connection with use of high TDS water as a future supply so as not to
decrease the quality of the culinary supply or cause adverse environmental effects in receiving
waters.
4.2.3

WCWCD Existing Supplies

Because most of the readily available water in the county has been developed and most of the county
is closed by the State Engineer to the acquisition of new water rights, the municipalities are
generally relying upon the District for future water supplies, most of which will be provided through
large water projects that require a regional funding base.
Reliable supply for surface water sources was calculated with the Virgin River Daily Simulation
Model (DWRe 2015a, DWRe 2015b) for a 90 percent reliability level (i.e., maximum surface water
shortage of 10 percent in any given year that would be made up with groundwater supply). The
Virgin River Daily Simulation Model was run with climate change reductions on supply based on
the 50th percentile climate change scenario as defined by Reclamation (Reclamation 2014) and
described in Section 2.4.1. Reliable secondary untreated supply is assumed to be equivalent to
current secondary untreated use (DWRe 2013a). The yield estimates used for Washington County
are considered reliable because recharged groundwater supplies can be used to supplement surface
water supplies to fully meet demands during extreme drought years. Additionally, operational
flexibility is continually being enhanced by the District in order to avert water supply shortages.
Climate change may have a larger impact on WCWCD’s supplies than is seen by the predicted
streamflow reductions in Reclamation 2014. Due to warmer temperatures, the future climate is
anticipated to shift the seasonal runoff one month earlier, have more severe storm events and cause
winter precipitation in the West to fall more as rain than snow (see Study Report 19). While a
decrease in flow hurts the system, a shift in the runoff and a shift from snow to rain may cause an
even greater loss to supply. WCWCD’s water rights dictate that water is stored in the winter and
spring, when the agriculture water rights are not being used for irrigation. Winter and spring water
discharge in the system is based on snowmelt in the mountains. If snow precipitation is limited then
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 the potential for storage is limited. The Quail Creek Pipeline’s capacity also limits the ability to
capture and move water into storage. If snow melts quickly, the period of time to capture water in a
fixed capacity pipeline is limited. If precipitation comes in abrupt rain events causing streamflow to
exceed the pipeline capacity, that water is lost and the system’s storage is not improved.
Table 4-1 summarizes the reliable yield for WCWCD projects for culinary and secondary untreated
purposes. Culinary supplies can also be used to meet secondary untreated water demands if
necessary. Figure 4-1 shows the general location of water supply projects described below.
Table 4-1

WCWCD Existing Projects and Water Uses
Reliable Culinary Quality
Water Yield (ac-ft/yr)(1)
24,922
4,000
875
250
2,000

Reliable Secondary untreated
Quality Water Yield (acft/yr)(4)
0
0
0
0
0

Project
Quail Creek and Sand Hollow Reservoirs(2)
Sand Hollow Non-Recharge Groundwater(3)
Cottam Well Field
Kayenta Water System (Ence Wells)
Crystal Creek Pipeline
Toquerville Secondary untreated Water
0
178
System
Total
32,047
178
Notes:
(1)
Source of data: WCWCD 2008a; WCWCD 2014.
(2)
Reliable yield for Quail and Sand Hollow Reservoirs includes yields from Kolob and Meadow Hollow Reservoirs.
(DWRe 2014a).
(3)
Supply utilizes water rights and natural basin recharge.
(4)
DWRe 2013a. Assumed reliable supplies are equivalent to current secondary untreated water use.

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 Figure 4-1

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WCWCD Existing Water Supplies

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 4.2.3.1

WCWCD System Facilities

Quail Creek and Sand Hollow System. Quail Creek and Sand Hollow reservoirs are a combined
system, receiving Virgin River water from the Quail Creek Diversion structure through a pipeline
network. Water delivery to these off-stream reservoirs is limited by the capacity and operational
requirements of the diversion structure and pipeline system. Quail Creek Reservoir has a capacity of
40,000 ac-ft and supplies raw water to the Quail Creek Water Treatment Plant. Sand Hollow
Reservoir has a 50,000 ac-ft capacity with an active pool of about 30,000 ac-ft and a drought pool of
20,000 ac-ft reserved for extreme drought. The drought pool is included in the reliable yield for Sand
Hollow Reservoir. In addition, the reservoir serves as a groundwater recharge facility to the Navajo
Sandstone Aquifer which currently stores about 100,000 ac-ft with an estimated future capacity of
about 300,000 ac-ft. Water may be delivered from Sand Hollow to Quail Creek Reservoir or directly
to the Quail Creek Water Treatment Plant.
Kolob Reservoir. Kolob Reservoir, 5,585 ac-ft, on a tributary of the Virgin River, was built in 1957
and later acquired by WCWCD. Water from the reservoir is released to the Virgin River for
diversion at the Quail Creek diversion structure.
Crystal Creek Pipeline. Water is diverted from Crystal Creek and conveyed through a 12-mile
pipeline to Kolob Reservoir to augment deliveries to Quail Creek and Sand Hollow reservoirs. The
yield for the Crystal Creek Pipeline was assumed to be “new water” that would otherwise not be
diverted from the Virgin River because it utilizes excess capacity in Kolob Reservoir.
Gunlock Reservoir. Gunlock Reservoir, 10,884 ac-ft, was built on the Santa Clara River in 1970 for
storage and delivery to irrigation companies in Gunlock, Santa Clara and Ivins. Most of the water
stored in Gunlock Reservoir is diverted through the Gunlock to Santa Clara Pipeline to meet
secondary untreated water demands. The Gunlock to Santa Clara Pipeline is described in Section
4.2.3.4.
Meadow Hollow Reservoir. Meadow Hollow Reservoir, 600 ac-ft, is located on Spring Creek and
La Verkin Creek in Iron County and was built in 1948 for irrigation purposes.
Ash Creek Reservoir. Ash Creek Reservoir receives snowmelt and peak flow runoff from the Ash
Creek drainage basin. The reservoir seldom fills, does not retain water, and the storage capacity has
been restricted significantly because of dam safety concerns by the Utah State Engineer. The Ash
Creek Pipeline is currently being built to convey water from Ash Creek Reservoir to the proposed
Toquer Reservoir near Anderson Junction.
4.2.3.2

Culinary Water Systems

Quail Creek Water Treatment Plant. The Quail Creek Water Treatment Plant is an integral
component of WCWCD’s water system. This 60 million gallon per day (mgd) plant can receive
water from three sources: Quail Creek Reservoir, Sand Hollow Reservoir and the Virgin River and
delivers culinary water to RWSA municipal customers described in Section 1.3.1. Located just

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 below Quail Creek Reservoir, this conventional filtration plant will eventually be expanded to treat
80 mgd
Sand Hollow Wells. The Sand Hollow well field includes 13 wells that draw water from prereservoir groundwater rights and from water recharged to the Navajo Sandstone Aquifer by Sand
Hollow Reservoir. Water is chlorinated and pumped to two storage tanks with a total of 3 million
gallons of storage capacity prior to delivery to RWSA municipal customers and Sky Ranch and Cliff
Dwellers retail customers.
An evaluation of aquifer storage and recovery at Sand Hollow is presented in the Groundwater
Resources Technical Report, (DWRe 2016). Currently it is estimated that there is approximately
106,000 ac-ft stored in the aquifer that could be used for this purpose (USGS 2013). Most of the
recharged water stored in the Navajo Sandstone Aquifer would be reserved for use during dry
periods to compensate for any deficit between annual supply and demand.
Cottam Wells System. The Cottam Well system delivers water from two wells via pipeline to
Toquerville, La Verkin and Virgin and, if needed, to Hurricane and Leeds. This system also supplies
water to about 20 customers in WCWCD’s retail system, Casa de Oro, near Leeds.
Kayenta (Ence Wells) Water System. The Kayenta Wells (also known as the Ence Wells) are two
wells with a total pumping capacity of 310 gallons per minute located within the incorporated
boundary of Ivins. They provide water to the residential community of Kayenta.
Regional Pipeline Transmission System. The Regional Pipeline transmission system (pipeline,
500,000 gallon tank and two pump stations) conveys water from the Quail Creek Water Treatment
Plant and Sand Hollow Wells to St. George, Santa Clara, Washington and Ivins.
Retail Water Systems. The WCWCD delivers retail water to the residential communities of Sky
Ranch and Cliff Dwellers, south of Hurricane, the Casa de Oro subdivision near Leeds and certain
areas on Kolob plateau.
4.2.3.3

Secondary Untreated Water Systems

Secondary untreated water is non-potable water that may be used for outdoor landscape irrigation.
Secondary untreated water is a significant factor in assessing WCWCD service area supplies because
of the significant amount of untreated water that cannot be economically used any other way. Water
quality is compromised by the LaVerkin hot springs, as described in Section 4.1.2. Historically
secondary untreated water was available in certain communities based upon surface water diversions
developed by irrigation companies. Today, secondary untreated water deliveries may be provided
from these untreated water sources and from treated municipal reuse water. In all cases,
infrastructure, including main delivery lines and lateral pipelines, can limit the ability to deliver
secondary untreated water to neighborhoods and communities. Meeting outdoor irrigation or
industrial demands with secondary untreated water allows higher quality potable supplies to be
reserved for culinary purposes. Because of the value of secondary untreated water in offsetting
demand on culinary systems, and because of the limited infrastructure, secondary untreated water is

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 delivered to public parks, golf courses and other areas over the entire 24 hour period the water is
available regardless of time of day water restrictions.
4.2.3.3.1

Toquerville Secondary Untreated Water System

WCWCD, Toquerville City and the Toquerville Irrigation Company created the Toquerville
Secondary Water System (TSWS) by contract in 1998, relying upon the water available from
Toquerville Springs. WCWCD purchased irrigation company water rights (except those belonging to
the municipality) and converted the open ditch irrigation system to a pressurized system that
distributes water to residents of the Toquerville area. The secondary untreated supply of TSWS was
assumed to be equal to the reliable use of the system in 2010 which was 178 ac-ft per year (DWRe
2013d).
4.2.3.3.2

Gunlock to Santa Clara Pipeline

Secondary untreated water on the Santa Clara River is stored in the Gunlock and Ivins Reservoirs
and delivered through the Gunlock to Santa Clara pipeline. The Gunlock to Santa Clara Project,
constructed in 2004, replaced four previous diversions and converted the old flood irrigation system
to a pressurized system, with a pipeline from Gunlock Reservoir to Ivins Reservoir and beyond to
deliver secondary untreated water in Ivins and Santa Clara and to the Shivwits Band of Paiute
Indians. Ivins Reservoir also stores reuse water. The pipeline provides secondary untreated M&I
water to golf courses, parks and residences. The Santa Clara secondary untreated system is
supplemented by the wells. The Santa Clara River constitutes an abrupt hydrology that is highly
variable thereby making it difficult to accurately estimate reliable supply, but WCWCD estimates
reliable yield of the system to be approximately 2,500 ac-ft per year of secondary untreated water
supply (WCWCD 2008a).
4.2.3.3.3

St. George Secondary Untreated Systems

St. George has a wastewater treatment plant, reuse plant, and an extensive secondary untreated
distribution system.
St. George Wastewater Treatment Plant
The St. George Wastewater Treatment Plant (WWTP) produces Type II effluent using an extended
aeration treatment process that uses physical and biological processes to treat sewage (City of St.
George 2009b). The current design capacity of the WWTP is about 17 million gallons per day
(mgd). The wastewater effluent is either treated by the reuse plant or discharged to the Virgin River.
St. George Reuse Treatment Plant
St. George completed a reuse plant in 2006 that treats water from the WWTP for reuse as secondary
untreated water, in conjunction with the Shivwits Band of Paiute Indians water rights settlement on
Santa Clara River water, under which St. George agreed to deliver 2,000 ac-ft of reuse water
annually to the Band. Utah water law specifies that original water rights owners retain ownership
after the first-use water has been treated for reuse so the St. George treatment plan relies upon
agreements reached with WCWCD and municipal entities to distribute the reclaimed water.

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 The reuse plant filters and chlorinates WWTP water producing Type I effluent that can be used for
secondary untreated purposes where human exposure is likely. Current capacity of the reuse plant is
7 mgd with two filters treating 3.5 mgd each. The plant is designed to expand to 10.5 mgd capacity
with the addition of a third filter. The typical effluent of the WWTP is good quality which enhances
efficiency of the reuse plant. The average water quality of the reuse effluent in comparison to the
Utah’s water quality limits are displayed in Table 4-2 below.
Table 4-2

Water Quality of St. George Reuse Effluent and Utah Water Quality Limits
Constituent
Turbidity (NTU)
pH
Residual Chlorine (mg/L)
E Coli (#/L)
BOD (mg/L)
TSS (mg/L)
Notes:
(1)
City of St. George 2009b.
(2)
DAS 2014.

Reuse
Effluent(1)
0.5-0.8
7.7
1.7-2.4
1
2.0-2.6
1.3-2.4

Utah Constituent Limit(2)
2
6-9
<1
0
5
5

Demand for reuse water exists only during the irrigation season; as a result the reuse plant is only
operated from late March to late October. There is currently no storage for reuse water. When supply
exceeds secondary untreated demand, the reuse plant is shut down, and wastewater effluent is
discharged to the Virgin River. Because of this limitation, the current maximum annual yield from
the reuse facility is approximately 5,800 ac-ft per year, with 3,900 ac-ft per year committed to
Shivwits Band of Paiute Indian Reservation and area golf courses. In 2007, approximately 2,460 acft of reuse water was treated and distributed (City of St. George 2009a).
Currently reuse water has better water quality (approximately 1,200 ppm TDS) than the Virgin River
water available for secondary untreated use (approximately 2,500 ppm TDS) and thus would
improve secondary untreated water quality. But over time, increases in total dissolved solids and
other constituents in the return flows, after repeated reuse treatment, could degrade water quality
where reuse water is used or stored.
Secondary Untreated Distribution Sources
Secondary untreated water from the St. George and Washington Canal Company system and the
Gunlock to Santa Clara pipeline system is currently being used to offset demand on culinary supplies
in certain areas of St. George. In 2010, WCWCD worked with the Canal Company to replace 22.6
miles of the St. George and Washington Canal and its laterals, which had a long history of leakage
and evaporation losses, with pipeline. The pipe can facilitate pressurization for residential sprinkler
system in the Washington Fields area. Springs located northeast of downtown called the East/West
City Springs feed a small ditch system in downtown St. George. This system primarily serves
residential customers. Secondary untreated water and reuse water are intermixed in Santa Clara
secondary untreated systems. Springs in western Washington City supply water for a private
secondary untreated system called the Sandburg System, serving 3 schools, 2 parks, and a ball field
in northeast St. George and western Washington City.

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 Most of the secondary untreated water delivery system is pressurized and interconnected with the
exception of the small ditch system in downtown St. George and the Sandburg system mentioned
above. The network of distribution lines within the system runs from Gunlock Reservoir to
Washington Fields as can be seen in Figure 4-2.

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 Figure 4-2

WCWCD Owned and St. George Secondary Untreated Sources and Infrastructure

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 Secondary Untreated Customers
Several churches, golf courses, parks, and schools are served by the secondary untreated systems.
Approximately eight golf courses, ten parks, sixteen schools, six churches and eight subdivisions, an
RV park, the St. George WWTP, and the city power yard are all supplied with secondary untreated
water.
Two private ditch companies also provide water in the St. George service area. Bloomington Water
Company provides water to residential lots near the Bloomington Hills golf course. Cottonwood
Irrigation supplies water to Dixie State College.
Secondary untreated customers are generally charged based on a water rate structure that is intended to
encourage use of this supply to offset culinary demand, rather than to recover full cost of delivery.
4.2.3.3.4

Hurricane City Secondary Untreated System

The original Hurricane canal diversion was merged into WCWCD’s Quail Creek diversion in 1985.
The district is responsible to transmit water rights belonging to the Hurricane Canal Company,
12,000 to 15,000 ac-ft of water per year, based upon its 1890 water right priority.
4.2.3.3.5

La Verkin City Secondary Untreated System

The original La Verkin diversion was merged into WCWCD’s Quail Creek diversion in 1985 and
the WCWCD is responsible to transmit the associated 2,650 ac-ft of water rights. In February 2007
the City of La Verkin acquired these water rights along with the La Verkin Bench Canal Company
secondary untreated water system. The original pressurized irrigation distribution system was
installed around 1985 and facilities are being used at or near capacity, although there are sufficient
water rights to support an expanded infrastructure.
4.2.3.3.6

Ivins City Secondary Untreated System

The Ivins Irrigation Company system receives water from the Santa Clara project and delivers within
Ivins City and to agricultural users in the area. Ivins City owns shares in the company and seeks to
maximize the distribution and efficiency of this source to offset culinary demand. The city has
required new developments to install dry secondary untreated lines for a future secondary untreated
system.
4.2.3.3.7

Santa Clara City Secondary Untreated System

The Santa Clara Canal Company and St. George Clara Canal Company are private companies in
which WCWCD, St. George City, Ivins Irrigation Company and Santa Clara City own shares. A city
park and cemetery are served by the secondary untreated system.
4.2.3.3.8

Washington City Secondary Untreated System

Washington City owns and operates a secondary untreated irrigation system within the “old” section
of town north of the Virgin River. The secondary untreated system is comprised of irrigation districts
which utilize different sources of secondary untreated water. The irrigation infrastructure consists of
a network of small, unconnected low pressure ditches, pipes, gates, and valves. None of the existing
infrastructure would be usable for a pressurized irrigation system.
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 4.2.4

Total Washington County Municipal and Industrial Water Supplies

Total reliable existing and near-term supply for Washington County is approximately 67,677 ac-ft
per year, made up of culinary (potable) and secondary untreated (non-potable) supplies.
4.2.4.1

Culinary Water Supplies

The total reliable culinary water supply in Washington County, including WCWCD, is
approximately 59,172 ac-ft per year. Table 4-3 shows the reliable culinary water supplies developed
by each public community water system in Washington County.
Table 4-3

Reliable Culinary Water Supplies – Washington County

Water Supplier

Angell Springs SSD
Apple Valley Water Company
Cedar Point Water Company
Central Culinary Water(3)
Dammeron Valley Water Works(2)
Diamond Ranch Academy
Diamond Valley Acres Water Co.
Dixie Deer SSD
Gunlock SSD
Harmony Farms Water Users
Harmony Heights
Hildale/Colorado City
Homespun Village Water Company
Hurricane City Water System(3)
Ivins City(3)
Kayenta Water Users Association(3)
La Verkin City(3)
Leeds Domestic Water Users Assoc.
Mountain Springs Water Co.
New Harmony Town Water
Pine Valley Irrigation Co.
Pine Valley Mt. Farms Water Co. (2)
Rockville Pipeline Co.
Santa Clara Municipal Water System(3, 4)
Springdale Culinary Water
St. George, City of(3, 5)
Toquerville Water Dept. (3)
Veyo Culinary Water Association
Virgin Water Department(3)
Washington County WCD(6)

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Springs

Reliable Culinary Water Supply (ac-ft/yr)
Wells
Surface

40
0
0
0
0
28
0
0
43
0
0
42
0
1,614
48
0
661
80
0
28
91
0
31
97
205
1,200
363
240
0
0

17
160
123
100
426
56
465
110
32
145
42
1,362
11
1,854
177
0
0
339
124
724
24
185
41
1,274
129
11,113
0
41
0
5,125

4-13

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
498
0
0
0
0
26,922

Total(1)

57
160
123
100
426
84
465
110
74
145
42
1,404
11
3,468
226
0
661
418
124
752
114
185
72
1,371
832
12,313
363
280
0
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 Water Supplier

Springs

Reliable Culinary Water Supply (ac-ft/yr)
Wells
Surface

Total(1)

Washington County WCD-Hurricane Valley
0
0
0
0
Retail
Washington Municipal Water System(3)
0
1,904
0
1,904
Winchester Hills Water Company(2)
0
267
0
267
Zion Canyon Water System
540
33
0
573
Totals
5,350
26,402
27,420
59,172
Notes:
(1)
Wells are limited to 50% of their maximum capacity for reliable supply when well/pump capacity is the limiting
factor. Springs and surface water supplies are equal to their respective maximum capacities.
(2)
Reliable water supply is considered to be equal to calculated water use.
(3)
Has contract with WCWCD for additional water supply
(4)
Reliable well supply is calculated based on Santa Clara's 24.7% ownership of wells in Snow Canyon Compact yield.
(5)
Reliable well supply is calculated based on St. George’s 63.3% ownership of wells in Snow Canyon Compact yield.
However, St. George has more well water rights available for additional supply, if needed.
(6)
See Table 4-2
Source: DWRe 2014c.

4.2.4.2

Secondary Untreated Water Supplies

A number of irrigation companies deliver secondary untreated water to M&I systems in Washington
County. While these 2010 secondary untreated water use data are considered reliable due to the
significant validation process followed by DWRe, reliable data for previous years are not available
with enough frequency to assess possible trends in use within the county or on a per capita basis.
Total secondary untreated use in Washington County, including systems owned by WCWCD, is
approximately 8,505 ac-ft per year (DWRe 2013a, Table 4-4).
Table 4-4

Washington County Secondary Untreated Use 2010 – Reliable Supply

Washington County Water Supplier
Central Canal & Irrigation Co.
Gunlock Irrigation Co.
Hurricane City Water System
Ivins Irrigation
La Verkin Bench Canal Co.
Leeds Water Company
New Harmony Town Water
Pine Valley Irrigation Company
Rockville Ditch Co.
Santa Clara Municipal Water System
Springdale Culinary Water
City of St. George, Various Irrigation
Companies
Toquerville Secondary System(1)
Virgin Canal Company
Washington Municipal Water System
County Totals

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Residential
Use
15
30
136
81
243
50
15
20
60
15
82

Commercial
Use
0
0
1,079
0
0
0
0
0
0
0
0

Institutional
Use
0
0
901
0
0
0
8
0
2
0
20

Industrial
Use
0
0
45
0
0
0
0
0
0
0
0

Total
Secondary
Untreated
Use
15
30
2,161
81
243
50
23
20
62
15
102

760
175
40
100
1,822

1,080
0
0
314
2,473

2,850
3
2
378
4,164

0
0
0
0
45

4,690
178
42
792
8,505

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 Washington County Water Supplier
Notes:
(1)
Included in WCWCD reliable supply
(2)
Source: DWRe 2013a

4.2.5

Residential
Use

Commercial
Use

Institutional
Use

Industrial
Use

Total
Secondary
Untreated
Use

WCWCD Planned Water Supplies

While municipal customers of the district may make improvements to their individual systems to
improve efficiencies, major future water supplies will be developed by WCWCD. This section
briefly describes water development projects currently planned or being implemented by WCWCD.
4.2.5.1

Culinary Water System Expansion

The Lake Powell Pipeline project is considered a planned source of future water supplies. Figure 4-3
shows the general location of the planned projects. Direct wastewater reuse delivery for culinary
water supply is not considered to be a viable option in this study because of limitations in treatment
technology, treatment cost, permit-ability and public acceptance.
4.2.5.1.1

Ash Creek Pipeline/Toquer Reservoir

The Ash Creek Project will be completed in the near term. A collection system is being planned and
constructed to replace the current open ditches on Leap Creek (partially complete), Wet Sandy Creek
(complete) and South Ash Creek (planned). Water will be carried from the existing points of
diversion and the Ash Creek Reservoir to the proposed 3,640 ac-ft Toquer Reservoir near Anderson
Junction. Water stored in the reservoir will be delivered through a pipeline to the Toquerville
Secondary untreated Water System, offsetting demand on the high quality Toquerville Spring water,
thus maximizing its availability for culinary use. Water from the Ash Creek Pipeline also could be
integrated into the Quail Creek Pipeline. Water developed by the Ash Creek Project would be a new
water resource because the source water currently infiltrates into the ground to unknown locations.
The Ash Creek Pipeline will be sized to meet full demands during the summer irrigation period, but
yield will be limited by secondary untreated demand levels. The simulated yield of the pipeline
would be 2,840 ac-ft per year with 90 percent reliability according to the Virgin River Daily
Simulation Model from 50th percentile climate change scenario results (DWRe 2014a). The supply is
categorized as culinary supply due to offset of demand for culinary quality water.

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 Figure 4-3

Lake Powell Pipeline Project
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WCWCD Existing and Future Water Supplies

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 4.2.5.1.2

Well Field Expansions

Sand Hollow Recharge/Recovery. Additional local groundwater will be developed at the Sand
Hollow well field to achieve the maximum allowable yield capacity, although the major portion of
the recharged groundwater will be reserved as a drought buffer. The Sand Hollow recharge and
recovery source will need arsenic treatment or blending and transmission upgrades for use as a
culinary supply.
Cottam Wells. The system will be optimized with additional wells for maximum yield over time.
Sullivan Well Field. The Sullivan Well field will be developed to tie into the Cottam well system or
deliver to developments in the Leeds area in the future.
Ash Creek Recharge/Recovery and Toquer Wells. The first Toquer Well was drilled in September
2015. Other wells will be developed in the area to take advantage of existing water rights and aquifer
recharge provided by the Ash Creek Project.
Pintura Wells, Diamond Valley Wells and Kayenta (Ence) Wells. The WCWCD is planning
groundwater development in the Pintura area, along the Ash Creek Corridor and in Diamond Valley
area, to be completed before construction of the Lake Powell Pipeline. Additional yield from the
Kayenta (Ence) Well system is anticipated to be developed after the Lake Powell Pipeline.
4.2.5.1.3

Additional Conveyance Infrastructure

WCWCD anticipates completion of additional water supply pipelines that will not generate new
yield, but will increase the flexibility of the water supply portfolio. For example, the Sand Hollow
Regional Pipeline will distribute water taken out of the Sand Hollow well field. This pipeline is part
of a regional water supply project that will tie into existing water lines to provide water to the cities
of St. George and Washington and will provide a redundant water supply to existing city facilities.
4.2.5.1.4

Warner Valley Reservoir

Warner Valley Reservoir will store water to serve secondary systems. A capacity of 55,000 ac-ft has
been assumed based on preliminary planning work. The reservoir will store water diverted from the
Virgin River at the Washington Fields Diversion, water from the St. George reuse plant and
available water from the Gunlock to Santa Clara Pipeline. The reservoir will firm the yields from
Virgin River diversions that may otherwise be lost downstream, facilitate use of reclaimed water and
allow for blending of high TDS water with better quality water. The storage provided by Warner
Valley Reservoir would be especially important in light of the anticipated reduced yields from the
Virgin River caused by projected climate change (DWRe 2014a). Environmental review for the
Warner Valley Reservoir has not yet formally commenced, so the project may be constructed prior
to or after completion of the LPP.
4.2.5.1.5

Lake Powell Pipeline

WCWCD has requested the delivery of 82,249 ac-ft of water per year from the LPP project.
Approximately 13,200 acre-feet of the LPP water would be diverted from the pipeline in Apple
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 Valley and treated for future M&I use in the Apple Valley area. Approximately 69,000 acre-feet of
the LPP water would flow into Sand Hollow Reservoir at full demand and use. The LPP water from
Sand Hollow Reservoir would be treated and distributed to the District’s municipal customers. Water
from LPP is fully consumable so wastewater generated from LPP water use would be treated and
stored for reuse in secondary untreated supply systems.
4.2.5.2

Additional Secondary Untreated Water System Expansion

WCWCD and the several cities within the WCWCD service area propose to expand secondary
untreated systems in their communities to offset culinary water use. Expansion of secondary
untreated water infrastructure, including water distribution pipelines and storage tanks, would allow
greater use of reuse water. It is prohibitively expensive to add secondary untreated delivery systems
in already-developed communities. Expansion may be justified where trunk lines can meet large
secondary untreated demands at golf courses, cemeteries, parks, and other large outdoor irrigation
needs. Some cities are requiring secondary untreated water systems to be installed in new
developments where it may be practicable to deliver secondary untreated water in the future. The
following sections discuss the potential for further development of the secondary untreated systems
in the study area.
4.2.5.2.1

St. George City

The St. George wastewater reuse plant could be maximized to its 10 mgd design capacity (11,200
ac-ft per year). The plant’s current reuse capacity is 7.0 mgd or 7,800 ac-ft per year, but due to lack
of storage, this supply can only be used to meet secondary untreated demands during the irrigation
season from April through October. Thus, the usable supply is 50 percent, or 3,900 ac-ft per year.
Assuming storage facilities would be implemented, a future maximized 10 mgd plant capacity would
result in an additional 7,300 ac-ft per year of future supply.
Any reuse capacity above the 10 mgd design capacity would require new treatment facilities. In
theory, wastewater reuse could be increased to approximately 40,000 ac-ft per year in 2060
(including the 11,200 ac-ft per year given above). This estimate is based upon the wastewater
effluent rate for communities served by the St. George wastewater treatment plant (St. George,
Washington, and Santa Clara) using the indoor water use projections and assumes 15% losses in the
collection system and a 90% plant recovery. This estimate may be high as it does not consider
limitations placed by return flow commitments, secondary untreated demand timing and the
infrastructure available to store and deliver the supply.
Storage capacity is a significant limiting factor in maximizing reuse water supplies because demand
sets the limit on the amount that can be used at any one time without storage for the excess supply.
The existing reuse line extends southeast from the treatment plant along the Southern Corridor to the
intersection with River Road and will be extended eastward as the Southern Corridor is extended.
Reuse water may serve the Ledges common areas and golf course on Highway 18 once additional
pump stations are installed. This assessment assumes that St. George will require all new
development to install secondary untreated water systems, where feasible, by 2020.
4.2.5.2.2

Hurricane City

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 The City, in cooperation with the Hurricane Canal Company contracted to create a Pressurized
Water Master Plan in 2007 to expand the secondary untreated system in the Hurricane Valley area.
The canal system is gradually being replaced with pipe as agricultural uses change and residential
areas develop in this area. Another 3 MG reservoir adjacent to the existing reservoir is proposed for
additional storage. Hurricane is expected to require all new development to install secondary
untreated water systems, where feasible.
4.2.5.2.3

Ivins City

All subdivisions constructed since the 1990s in Ivins City have been required to install secondary
untreated irrigation pipelines to connect to a future municipal irrigation system. Ivins City currently
owns shares in the Ivins Irrigation Company, St. George Clara Canal Company and the Santa Clara
Field Canal Company, which own rights for secondary untreated water. It is unclear how this system
will be phased into the City, whether by transferring the Ivins Irrigation Company system to the city
or by development of an independent system. Future municipal irrigation system demands at 2060
are projected to be 3,100 ac-ft per year, with a peak day demand of 4,700 ac-ft per year.
4.2.5.2.4

La Verkin City

The City of La Verkin Secondary Water Master Plan (LaVerkin City 2010a) discusses the future
secondary untreated system needs. The Plan outlines recommendations for improvements to the
secondary water system to meet secondary untreated water demands through buildout conditions.
According to the Plan, secondary untreated water right usage at buildout would be 1,070 ac-ft per
year. Secondary untreated water use projections at 2060 are 1,024 ac-ft per year (DWRe 2014c).
4.2.5.2.5

Toquerville City

By 2060 the existing TSWS secondary untreated system could be used to full capacity, which could
be as much as 2,063 ac-ft per year, the total original water rights of the system.
4.2.5.2.6

Washington City

Washington City’s 2005 Secondary Water Master Plan (Washington City 2005) estimates potential
secondary untreated water demand through 2025 and recommends a future pressurized secondary
untreated water system. The Plan considered water resource recovery facilities (WRRFs) also known
as scalping plants in conjunction with their wastewater system improvements. Preliminary
calculations show that on average the amount of water recovered from the scalping plant could take
care of the secondary untreated irrigation needs of the community. In October 2006 the City adopted
an ordinance requiring all new development within the city to install distribution infrastructure
within new developments. The projected secondary untreated demand in 2060 is 3,343 ac-ft per year
(DWRe 2014c)
The locations of future secondary untreated lines were estimated conceptually for this assessment
based on areas of potential development that may include secondary untreated pipeline
infrastructure, which can be seen in Figure 4-4. Potential secondary untreated water customers
include any future developments.

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 Figure 4-4

WCWCD Existing and Potential Secondary Untreated Infrastructure and Customers

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 4.2.5.3

Agricultural Conversion for M&I Supply

As agricultural lands are developed, water will be converted from agricultural to municipal uses. No
“buy and dry” programs have been established by WCWCD. Approximately 90 percent of irrigated
agricultural water supply in the Kanab Creek/Virgin River Basin originates from surface water
sources (DWRe 1993), and as described in Section 4.2.2, poor water quality limits cost-effective use
of this water by secondary untreated systems. Figure 4-5 outlines the relative location of irrigated
croplands to urban areas to help gain a better understanding of the acreage that could potentially be
converted from agricultural to municipal uses.
Within Washington County, most conversion of agricultural water use to M&I would likely occur
within the Washington Fields area south of St. George and Washington cities. DWRe (2011a)
performed an analysis of the Virgin River basin which included an estimate of the Washington
Fields agricultural water that could be converted to M&I use, following historical trends. The study
estimated that 12,880 ac-ft per year could be converted for secondary untreated M&I purposes with a
90 percent reliability. This value includes some existing irrigation supplies that have already been
converted. Using the M&I Water Use Report data (DWRe 2013g) for secondary untreated water
supplies, it was estimated that about 2,800 ac-ft per year of Washington Fields was included in the
12,880 ac-ft per year value. Thus, the remaining irrigation water available for conversion to
secondary untreated M&I use is about 10,080 ac-ft per year.
The majority of agricultural supply that would be converted to M&I supply as a result of
development has high TDS concentrations that would either require blending with lower TDS
supplies or very costly (RO) treatment to reduce overall TDS. In the future, water from agricultural
conversions made in the Washington Fields area could be placed in a future storage facility, allowing
efficient management of this water for secondary untreated and other purposes in the area. Blending
with reuse water and Santa Clara River stored water could reduce the overall TDS.
WCWCD intends to use stored water for use in M&I pressurized secondary untreated supply
systems in the future. Water could also be managed for environmental uses such as providing target
flows in the Virgin River for the endangered woundfin minnow and Virgin River chub.

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 Figure 4-5

Washington County Irrigated Lands

Source: Modified from (DWRe 1999)
Map Color Code: Green = Irrigated Cropland, Orange = Non-Irrigated Cropland, Blue = Water, Black = Urban

Lake Powell water in the top 100 feet ranges from 350 to 600 mg/L TDS. As described in Section
4.2.2, blending untreated Lake Powell water with agricultural water (1,500 mg/L) at about 2:1 would
result in an overall supply with 735-900 mg/L TDS, which is assumed to be acceptable for
secondary untreated use in this report.
RO treatment is not under consideration at this time for secondary untreated use because of
environmental, technical, and economic feasibility issues. For purposes of discussion, assuming a
TDS concentration of 1,500 mg/L for the agricultural supply and 100 percent removal of TDS, 2,470
ac-ft per year of the total 7,400 ac-ft per year supply would have to be treated with RO to meet 1,000
mg/L, leaving an average annual yield of 6,900 ac-ft per year for secondary untreated use.
The following issues affect the feasibility of advanced treatment of agricultural conversions.
 High cost of advanced water treatment options such as reverse osmosis
 High energy requirements associated with reverse osmosis
 Lack of an environmentally acceptable alternative for disposal of brine created from the reverse
osmosis process

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  High TDS of water supply may require substantial portions of the water supply to be treated
to achieve the final desired TDS for secondary untreated M&I uses
4.2.6

WCWCD Water Sources not Feasible for Development

The projects described in this section are not currently part of the long-term water supply portfolio of
WCWCD, largely because of practical, economic and environmental reasons. The technical and
environmental challenges are discussed below.
4.2.6.1

Virgin River Water

After numerous studies by various state and federal agencies, the DWRe and WCWCD have
concluded there is no additional Virgin River water available to be developed for water supply in
Washington County because of variable streamflow, poor water quality, lack of current storage
options, minimum streamflow requirements, and the potential for sedimentation of possible reservoir
sites. An evaluation was completed for this analysis to confirm the above conclusion that there is no
additional Virgin River water available for development.
The studies described here have looked for additional water downstream from existing diversions. A
large portion of the available water supply occurs during short periods of high streamflow, which
cannot be economically diverted with standard river diversion and conveyance facilities. Even if an
alternative diversion structure and conveyance system could be built, the high TDS would disqualify
the supply for M&I use (including secondary untreated water use) as discussed in Section 4.2.2.
Another factor, the lack of available storage sites, is discussed below.
Simulated daily streamflow for the Virgin River downstream of the Washington Fields diversion
from 1941 to 2006 is shown in Figure 4-6. Streamflow exceedance information for the same
location and period of record is summarized in Table 4-5 and Figure 4-7 (DWRe 2008b), which
shows the frequency of various streamflow values. For example, Table 4-5 and Figure 4-7 indicate
that 50 percent of daily streamflow values are greater than or equal to 25 cfs. The majority of annual
flow volume occurs during infrequent higher flows, which decreases the potential for capturing these
flows and developing additional Virgin River water. The simulated historical daily streamflow
ranges from 0 to 21,100 ac-ft per day (0 to 10,600 cfs), with higher flows generally occurring during
spring runoff and in response to short intense rainfall events. The variability of streamflow would
require a large diversion structure and storage facility to give a reliable annual supply and thus
eliminates this source of Virgin River water as a technically and economically feasible project.
Table 4-5

Virgin River below Washington Fields – Percent Exceedance for Daily Streamflow,
1940-2006
Percent Exceedance
1
5
10
20
30
40
50
60

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Streamflow (cfs)
1,280
403
175
43
43
43
25
13

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 Percent Exceedance
70
80
90
100

Figure 4-6

Streamflow (cfs)
7.3
7.1
0.0
0.0

Daily Streamflow for Virgin River below Washington Fields

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 Figure 4-7

Virgin River below Washington Fields Flow Exceedance Curve

100,000

Streamflow (cfs)

10,000

1,000

100

10

1

0
0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Percent Exceedance

Potential storage locations within the Virgin River Basin were investigated by the DWRe (DWRe
1988; DWRe 1992). Of the 96 potential sites considered, DWRe screened out all but 16 sites based
on geologic flaws, potential storage capacity, onsite field reviews, and detailed characteristics such
as cost and environmental considerations. An on-stream dam would have a detrimental effect on
aquatic habitat at the location of the reservoir, and would also have serious sedimentation and
erosion issues. Of the 16 sites remaining after DWRe’s analysis, only two of the reservoir sites were
deemed to be potentially feasible sites for storage of additional Virgin River water. DWRe yield
modeling of the Virgin River indicates that reservoir capacity for Virgin River water would need to
be about 5 ac-ft of reservoir storage capacity per 1 ac-ft of reliable yield, because of the variability of
streamflow in the Virgin River.
4.2.6.2

Groundwater Development

The Virgin River groundwater basin in Washington County (the Navajo Sandstone aquifer) is
considered to be over-appropriated by the Utah Division of Water Rights (DWRi 2008a). The
groundwater budget for the Navajo Sandstone aquifer presented in the Virgin River Basin Plan
(DWRe 1993) was updated with current groundwater pumping information from the Virgin River
M&I Use Report for municipal demands (DWRe 2013g), and with projected agricultural
groundwater pumping for 2005 from the Virgin River Basin Plan (DWRe 1993). The updated
groundwater budget confirmed the aquifer is fully utilized and there are no new supplies available
for development.
The USGS has completed modeling for WCWCD in the Sand Hollow area, including an analysis of
natural infiltration to the Sand Hollow Basin. The USGS concluded natural recharge to the Sand
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 Hollow groundwater is 790 ac-ft per year, which has already been accounted for in the Sand Hollow
groundwater yield described in Section 4.2.3.1 (USGS 2013).
4.2.7

Summary of Planned and Potential WCWCD Water Supply Projects

Table 4-6 summarizes the water supply projects currently planned by WCWCD to meet the
demands of existing and future water users in Washington County and those that could be
considered potential long-term projects if certain technical, environmental or cost concerns were
resolved. Individual projects would supply either culinary or secondary untreated water to District
customers. Each project would have limitations in the areas it could deliver water to economically.
Table 4-6

Future Planned and Potential WCWCD Water Supply Projects
Estimated Reliable Culinary
Supply
(ac-ft/yr)
2,840
3,000
600
750
600
400
480
5,000
0
0

Estimated Reliable Secondary
untreated Supply
(ac-ft/yr)
0
0
0
0
0
0
0
0
7,300
10,080

Project
Ash Creek Pipeline(1)
Sand Hollow Recharge and Recovery(2)
Cottam Well Maximization
Sullivan Wells
Pintura Well
Diamond Valley Well
Kayenta (Ence) Wells(3)
Westside Arsenic Treatment(4)
Maximize Existing Wastewater Reuse(3,5)
Agricultural Conversion from
Development(3,6)
Lake Powell Pipeline
82,249
0
Potential Future LPP Reuse(3)
0
28,830
Total Potential Yield from Future
95,919
46,210
Projects
Notes:
(1)
Ash Creek Pipeline yields 2,840 ac-ft/yr based on Virgin River Modeling (DWRe 2014a).
(2)
Arsenic Treatment or blending and transmission upgrades must first occur.
(3)
To be implemented post-Lake Powell Pipeline
(4)
Includes Gunlock to Santa Clara Pipeline and Snow Canyon Wells. Moved to future reliable supply due to extent of
treatment needed for culinary supply.
(5)
See Section 4.2.5.2.1.
(6)
The estimated supply is 12,880 ac-ft/yr with 90% reliability (DWRe 2011a). However, it was estimated that
approximately 2,800 ac-ft/yr of this supply is currently in use and has been accounted for in the reliable secondary
untreated supply.
(7)
Source of data DWRe 2014c

4.3 Kane County Water Conservancy District
This section describes existing and future planned and potential water supplies for entities within the
Kane County.
4.3.1

Kane County Water Supply Overview

KCWCD is a relatively new water conservancy district, formed in 1992. It has a limited customer
base and limited supply sources at present. While the entire county is considered part of KCWCD’s
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 service area, existing KCWCD customers are rural developments located in the Cedar Mountain and
Johnson Canyon areas. KCWCD owns and operates its own wells in the Johnson Canyon area to
meet these demands. The only substantial community in Kane County – the City of Kanab – has
developed its own water supply system over time, and may continue to meet the needs of M&I
customers within its current city boundaries, and within future annexation areas as well.
All existing M&I supplies in Kane County are derived from groundwater resources (wells and
springs). Most existing water supplies in Kane County are derived from groundwater from the
Navajo Sandstone Aquifer. This groundwater is of high quality, and is used directly for culinary
purposes after disinfection. Because of its proximity to Zion National Park and the Grand Staircase –
Escalante National Monument, Kane County is a partner in an agreement with WCWCD and others
that limits its well production and groundwater development by prohibiting removal of water
supplies from the Monument.
Kane County encompasses parts of four different watershed basins: (1) Kanab Creek/Virgin River,
(2) Southeastern Colorado River, (3) Western Colorado River, and (4) Sevier River. Surface and
groundwaters are considered to be fully appropriated at this time in the Kanab Creek/Virgin River
and Southeastern Colorado River Basins. New diversions and uses must be accomplished by change
applications filed on owned or acquired existing rights.
The Navajo Sandstone Aquifer is the primary water source for the Kanab and Johnson Wash
drainages. The water from the Navajo Sandstone Aquifer is usually of good quality. However,
throughout the Kanab Creek and Johnson Wash drainage areas both good and poor water quality is
found. The groundwater at lower elevations of the basins tends to have poorer quality due to soluble
minerals that are discharged from some geological formations (DWRe 1993). Available data suggest
that groundwater quality in wells drilled in the Johnson Wash area is of poor quality and generally
not favorable for culinary use (Appendix A, MWH 2015). As a result, the water from the lower
elevations of the basins can only be used as secondary untreated water unless treated by advanced
processes such as RO.
Both surface water and groundwater supplies are anticipated to be affected by climate change in the
future. As discussed at the beginning of Chapter 4, existing supply yields are anticipated to decline
from 3 percent in 2020 to 7.2 percent in 2060 based on the statistical analysis of streamflow
projections conducted by the U.S. Bureau of Reclamation (Reclamation 2014).
Water supply is of the utmost importance to Kane County. The Kane County Resource Management
Plan (Kane County 2011) states that “Water is the life blood of Kane County. Water quality and
availability has historically determined the level, type, and location of existing growth. This pattern
would continue into the future except for the fact that new distribution systems have made water
more available throughout the county. The county encourages and supports the efficient
management and use of its water resources. The future of the county is completely dependent on
available water. The county not only needs a county-wide distribution system to assist any area in
time of need, but a redundant supply to avoid simply running out of water at some future date.”
4.3.2

Kane County Existing Water Supplies

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 A summary of the reliable culinary water supply sources for all of Kane County is provided in Table
4-7 and existing reliable supplies are described separately for each of the four groups. Fredonia,
Arizona, receives its water supply from Kane County, but it is not located within the county and is
not included in the population or water demand values reported in Chapter 3. Therefore, Fredonia
supplies are not included in the existing reliable culinary supply total for Kane County. The National
Park Service Bullfrog Recreation Site and the Cedar Mountain residential area would not be served
by the Lake Powell Pipeline and are not located within any of the four subbasins considered.
Therefore it is also not included as reliable culinary water supplies for KCWCD. There is currently
no aquifer recharge in Kane County recovered for water supply (DWRe 2011b). The reliable
supplies will reduce with time based on climate change projections. Also, a ten percent planning
reserve is incorporated into the future reliable supply quantities in the integrated water resource
plans discussed in Chapter 6. The planning reserve helps to avoid using water supplies up to the
maximum and to provide a buffer against annual variability in water supplies affected by
precipitation runoff and groundwater recharge. Those shown in this section have not yet been
reduced and do not include a reduction to accommodate the planning reserve.
Table 4-7

Reliable Culinary Water Supplies – Kane County
Reliable Culinary Water Supply (ac-ft/yr)
Springs
Wells(1)
Surface
Total(1)
34
0
0
34
0
225
0
225
0
506
0
506
105
15
0
120
105
2,182
0
2,287
0
150
0
150
79
384
0
463
323
3,462
0
3,785

Water Supplier

Alton(2)
Church Wells Special Service District(3)
Glen Canyon Special Service District #1 (Big Water) (3)
Glendale Town Corp.(2)
Kanab Municipal Water System(2,4)
Kane County WCD (Johnson Canyon) (2,4)
Orderville Town Water System(2)
Total Kane County Reliable Supply
Notes:
(1)
Wells are limited to 50% of their “maximum” capacity for reliable supply when well/pump capacity is the limiting
factor. Springs and surface water supplies are equal to their respective “maximum” capacities.
Sources: (2)DWRe 2013b; (3)DWRe, 2014b
(4)
Kanab City and Johnson Canyon would be served by KCWCD LPP supplies in the future

4.3.2.1

East Fork Virgin River Subbasin

Public community water systems in the East Fork Virgin River subbasin include the towns of
Glendale and Orderville. Reliable culinary and secondary untreated water supplies for the basin are
summarized in Table 4-8. The total reliable water supply for the basin is the combined culinary and
secondary untreated supply of 842 ac-ft per year (DWRe 2013d). Annual total culinary use for 2010
was 208 ac-ft per year or 36 percent of the reliable culinary water supply.
Table 4-8

Reliable Water Supplies – East Fork Virgin River

Water Source

Glendale Town Corp.
Orderville Town Water System
Total

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Reliable Supply (ac-ft/yr)
Secondary
Culinary
Untreated

120
463
583

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89
170
259

Total

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 4.3.2.2

Alton Town

Reliable culinary and secondary untreated water supplies for Alton Town is summarized in Table 49. The total reliable water supply is the combined culinary and secondary untreated supply of 50 acft per year (DWRe 2014c). Annual total culinary use for 2010 was 28 ac-ft per year or 56 percent of
the reliable culinary water supply. Fredonia, AZ and Kanab City are in the same hydrologic subbasin
as Alton Town. However, while Fredonia receives its water supply from Kane County, it is not
located within the county and is not included in the population or water demand values reported in
Chapter 3. Further, Kanab City will be served by KCWCD LPP water supply in the future and was
therefore grouped with Johnson Canyon. Therefore, Fredonia and Kanab City supplies are not
included in the existing reliable culinary supply total for Kanab Creek Subbasin, and only Alton
Town is listed.
Table 4-9
Water Source

Reliable Water Supplies – Alton Town
Reliable Supply (ac-ft/yr)
Secondary
Culinary
Untreated

Alton Town
Total

4.3.2.3

34
34

Total

16
16

50
50

KCWCD (Kanab City and Johnson Canyon Subbasin)

The two public community water systems to be served LPP water in the future by KCWCD are
Kanab City and the Johnson Canyon subbasin. Reliable culinary and secondary untreated water
supplies for this group are summarized in Table 4-10. The total culinary reliable water supply for
the basin is 2,437 ac-ft per year and secondary untreated supply of 80 ac-ft per year (DWRe 2014c).
Annual total culinary use for 2010 was 1,535 ac-ft per year or 61 percent of the reliable culinary
water supply.
Table 4-10
Water Source

Reliable Water Supplies – KCWCD
Reliable Supply (ac-ft/yr)
Secondary
Culinary
Untreated

Kanab City
Johnson Canyon
Total

4.3.2.4

2,287
150
2,437

80
0
80

Total

2,367
150
2,517

Wahweap Creek Subbasin

Public community water systems in the Wahweap Creek subbasin include two public community
water systems. Reliable culinary and secondary untreated water supplies for the basin are
summarized in Table 4-11. The total reliable water supply for the basin is the combined culinary and
secondary untreated supply of 736 ac-ft per year (DWRe 2013b). Annual total culinary use for 2010
was 233 ac-ft per year or 32 percent of the reliable water supply.
Table 4-11

Reliable Water Supplies – Wahweap Creek
Reliable Supply (ac-ft/yr)
Secondary
Culinary
Untreated

Water Source

Glen Canyon Special Service District #1 (Big Water)
Church Wells Special Service District
Total

506
225
731

5
0
5

Total

511
225
736

Figure 4-8 shows the general location of the existing Kane County supply sources.
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 Figure 4-8

Lake Powell Pipeline Project
Final Aquatic Resources Study Report

KCWCD Existing Water Supplies

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 4.3.3

KCWCD Future Supplies – Planned

4.3.3.1

Groundwater

M&I water suppliers in Kane County anticipate using additional groundwater production to meet
increased future water demands. The State Engineer has determined that no new groundwater
permits will be issued within the project area in Kane County. A review of existing records
determined that the total of adjudicated municipal groundwater rights in the four subbasins within
Kane County is approximately 13,990 ac-ft per year (MWH 2013). Total reliable culinary supply
from wells for Kane County in the Kanab Creek/Virgin River Basin (minus Fredonia, AZ) and the
Southeast Colorado Basin was reported to be 3,460 ac-ft per year in 2010 (Table 4-12). Thus,
municipal well users could increase their supply by approximately 10,530 ac-ft per year and remain
within their permitted withdrawal rates. Groundwater quality data from wells in the Johnson Wash
area near the mouth of Johnson Canyon have shown that most wells in this area are not suitable for
culinary use. The wells that have acceptable quality penetrate below alluvial deposits. These wells
are of low to moderate production potential (Appendix A, MWH 2015). Therefore, while the water
right may be available, the quality of the water or production of the wells may not be sufficient to
fulfill the right. The Kanab City Water Conservation Plan (Kanab City 2013) states that there is
potential for additional groundwater development in all of Western Kane County by drilling wells at
favorable locations. Care must be taken to avoid discharging more groundwater than can be
recharged over time. If overdrafts would occur, the Department of Water Rights would curtail the
amount of well water rights shown in the table below, preventing them from being fully realized.
Table 4-12 depicts the groundwater potentially available by study area group. Alton Town did not
have any groundwater data in the sources reviewed.
Table 4-12

Municipal Groundwater Supplies Potentially Available for Development

Group

East Fork Virgin River
Subbasin
Alton Town
KCWCD (Kanab City and
Johnson Canyon Subbasin)
Wahweap Creek Subbasin
Total
Notes:
(1)
MWH 2013
(2)
See Table 4-7; DWRe 2013b

Municipal
Groundwater
Rights (acft/yr)(1)

Current Reliable
Culinary Supply
from Wells (acft/yr)(2)

985

400

0

0

0

10,250

2,330

7,920

2,755
13,990

730
3,460

2,025
10,530

Legally Available
for Development
(ac-ft/yr)

585

There are substantial water quality issues that would limit the use of any additionally available
groundwater supply. Water quality diminishes from the upper portions of the four subbasins to the
lower portion of the subbasins. For example, TDS concentrations increase in the lower part of the
Kanab Creek subbasin to an extent that any available additional supplies near the City of Kanab
would only be of sufficient quality for secondary untreated use. An analysis of published online
water quality data showed that wells within the Johnson Wash area produce groundwater that exceed
the State of Utah’s Secondary untreated Maximum Contaminant Levels (MCL) for drinking water in
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 total dissolved solids (TDS), electrical conductivity (EC), sulfate (SO4) associated with gypsum, and
sodium (Na). Sediments derived from erosion of Johnson Canyon are likely to include deposits
originating from the Moenkopi Formation exposed in the lower (southerly) extent of the canyon.
These exposures include the Shnabkaib Member, which are high in soluble gypsum and evaporites,
and could be the source of high TDS, SO4, and Na concentrations in the Johnson Wash area
groundwater (Appendix A, MWH 2015).
4.3.3.2

Lake Powell Pipeline

KCWCD has requested delivery of 4,000 ac-ft of water annually from the LPP. The planned delivery
point for Lake Powell Pipeline water to KCWCD would be to a proposed water treatment plant in
Johnson Canyon. From this point, LPP water could be delivered into the Kanab City water supply
system. KCWCD would be allowed 4,000 ac-ft per year of depletions to the Upper Colorado River
Basin based on Colorado River Compact requirements and the agreement between KCWCD and
DWRe for diversion of Lake Powell water supply.
The proposed Lake Powell Pipeline would have a limited service area within KCWCD. Although
KCWCD has no current intention of doing so, the proposed pipeline alignment is conveniently
located to also serve the Big Water, and SITLA areas. Big Water currently has its own groundwaterbased supplies, yet KCWCD could agree to provide LPP water in the future, either in addition to
groundwater development when demand exceeds the allowable groundwater supply, or in lieu of
groundwater development to allow additional groundwater resources to be developed in
communities that are not located near the LPP. In this way LPP water would free up use of
additional groundwater in the more remote and rural parts of Kane County. Although extremely
unlikely, KCWCD could conceivably construct a pipeline from the LPP to the Orderville/Glendale
area to meet future demands in that region of the County. The Lake Powell Pipeline would never
serve the Sevier River Basin because of its remote location relative to the pipeline alignment.
KCWCD would either store LPP water in a new surface reservoir for treatment in a future water
treatment facility or use it to recharge groundwater aquifers such as in the Johnson Canyon area to
extend the life of the groundwater basin. Lake Powell water would have lower TDS (approximately
350 to 600 milligrams per liter) relative to groundwater in the lower portions of the Kanab Creek and
Johnson Canyon subbasins (up to 1,200 milligrams per liter TDS). Consequently, if Lake Powell
water was used to recharge the aquifers at these points of currently high TDS groundwater, the Lake
Powell water may improve the local groundwater quality at the recharge locations.
4.3.3.3

Jackson Flat Reservoir

KCWCD completed Jackson Flat Reservoir south of Kanab in spring 2012. Jackson Flat Reservoir is
a 4,228 ac-ft facility to supply secondary untreated and agricultural irrigation water to commercial,
institutional and industrial (CII) users that are currently served by well water. The reservoir stores
surface water diversions that had typically been used by the Kanab Irrigation Company
(approximately 7,500 ac-ft per year) in order to maximize the efficiency of the use of these
agricultural diversions. Diversions are being stored in the reservoir throughout the year and are
available during irrigation season when demands are highest. Locations of potential future water
supplies for KCWCD are shown in Figure 4-9.

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 Figure 4-9

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KCWCD Potential Water Supplies

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 4.3.4

Kane County Future Supplies – Potential

In addition to development of new groundwater, existing agricultural water supplies could be
converted to M&I use, either through growth over currently irrigated lands or through “buy and dry”
programs. Agricultural land exists in Kane County. There is no agricultural water use in the
Wahweap Creek subbasin which is located in the Southeast Colorado River Basin. Most of the
agricultural in the Kanab Creek subbasin is occurs near Kanab City. However, as previously
mentioned in Section 2.5, none of the agricultural water in the Kanab City or Johnson Canyon area
will likely be available for conversion toe M&I in the future. The Kanab irrigation company water
rights are held for irrigation purposes only. Kanab Irrigation Company policy is not to allow for any
conversions to M&I as properties are developed, but to transfer irrigation to other parcels which are
readily available. Therefore, the irrigated lands and diversions attributed to the KCWCD group have
a 0 percent agricultural water potentially developable for M&I use. Alton Town had no data in the
sources reviewed. There is agriculture around Alton Town. For the purposes of this study it was
assumed a minimal amount of irrigated land could be converted near Alton Town in the future if no
other supply were available, resulting in 50 ac-ft per year of water supply.
There were a total of approximately 19,167 acres of agricultural land in 2013 within Kane County,
of which 5,755 were irrigated acres and 13,412 were non-irrigated agricultural acres (DWRe 2014b).
Irrigated agricultural acreage in 2013 and the associated agricultural water use (based a duty of water
5.0 ac-ft per year per acre; Section 2.5) are shown in Table 4-13. In order to calculate the amount of
water available from potential agricultural water rights conversions to M&I use, it was assumed that
the entire agricultural diversion right would be able to be transferred to M&I use (i.e., not just the
consumptive use portion). The consumptive use for the new M&I water right was assumed to be no
greater than the existing agricultural consumptive use. Although Table 4-13 indicates that there is a
total of 13,052 ac-ft per year of agricultural water use, it would not be reasonable to assume that all
agricultural water use would be transferred to M&I. It was assumed that 20 percent of existing
irrigated agricultural land could potentially be either developed for M&I purposes of purchased
through “buy and dry” programs in the East Fork Virgin River Subbasin and that none would be
available in the Kanab City and Johnson Canyon group. Thus, there would only be a total of
approximately 1,153 ac-ft per year of water supply available to M&I from existing irrigated
agricultural.
Table 4-13
Group

Kane County Groups – 2007 Estimated Agricultural Water Use
Irrigated Lands (acres)(1)

Agricultural Water
Diversions
(ac-ft/yr)(2)

20% Agricultural Water
Potentially Developable
(ac-ft/yr)

1,150

5,750

1,150

50
1,460

250
7,300

50
0

--

--

--

East Fork Virgin River
Subbasin
Alton Town
KCWCD (Kanab City and
Johnson Canyon Subbasin)
Wahweap Creek Subbasin

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 Notes:
(1)
Source of irrigated land data: DWRe 2008c; DWRe 2013f; DWRe 2014b
(2)
Based on duty of water of 5.0 ac-ft/yr per acre of irrigated agricultural land (DWRi 2008b, Section 2.5). Also assumed
that the entire agricultural water right would be able to be converted (diversions) and not just the consumptive use
portion (depletions) and 20% could be transferred to M&I.

Figure 4-10 outlines the relative location of irrigated croplands to urban areas. Irrigated croplands
are represented by the areas shaded in green, while urban areas are colored black. The significant
irrigated lands are located in the Johnson Wash and East Fork Virgin River floodplains. Agricultural
conversions in the East Fork Virgin River area could supply future M&I demands in Orderville and
Glendale. While no irrigated lands are shown for Alton Town in Table 4-13, Figure 4-10 shows that
some of the area around Alton Town would be available for agricultural conversion. This water
would be needed for future supply once demand exceeds current reliable supplies.
Figure 4-10

Kane County Water-Related Land Use

Source: Modified from DWRe, 1999.
Notes: Map Color Code: Green = Irrigated Cropland, Orange = Non-Irrigated Cropland, Blue = Water, Black = Urban

4.3.5

Summary of Potential Developable Kane County Water Supplies

Table 4-14 summarizes the potential developable supplies to meet future demands in Kane County.
KCWCD previously owned approximately 30,000 ac-ft per year of additional water rights referred to
as the Andalex water rights. However, the District recently leased these rights to a proposed nuclear
power plant project in Emery County off the Green River. The water rights were leased on a 40-year
term with a 30-year renewal option. The lease payment for the rights is planned to be used by the
District to help pay for the District’s portion of the cost for the Lake Powell Pipeline project.

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 Table 4-14

Developable KCWCD Supplies

Maximum Potential Yield (ac-ft/yr)

Source
New
Groundwater
Production

Agricultural
Water
Conversion

Lake Powell
Pipeline
Total
Potential
Yield

East Fork
Virgin
River Basin

585

Alton Town

KCWCD
(Kanab City
and Johnson
Canyon)

Wahweap
Creek Basin

0

7,920

2,025

1,150

50

0

--

0

0

4,000

0

1,735

100

11,920

2,025

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Comments

Assumed 20% of irrigated agricultural water use could
be transferred to M&I. Estimate is based on full
conversion of agricultural diversions to M&I diversions
assuming no increase in consumptive use. No
agriculture is expected to transfer to M&I in the
KCWCD group and a minimal amount was assumed
for Alton Town.
KCWCD has requested 4,000 ac-ft from LPP Supply
and plans to serve Johnson Canyon and Kanab City.

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 Chapter 5 – Water Conservation Programs
5.1 Introduction
Water conservation is an important component of any future water supply plan, particularly for
communities in the arid southwest United States. Utah is one of the five fastest growing states in the
nation and is the second driest state in the country (only Nevada is drier). The population growth rate
coupled with the semi-arid climate makes water conservation vital to maximize the benefits of
Utah’s limited water resources. This chapter describes existing water conservation plans adopted by
the Districts and the cities within their service areas and their recent effectiveness in reducing per
capita water use and conservation programs adopted for future implementation. For the purpose of
this report, water conservation is defined as reductions in municipal, commercial, and industrial per
capita water use, because these are the demand sectors that would be served by supplies from the
Lake Powell Pipeline. The information in this chapter is the basis for the assumptions for future
water conservation used in the water needs forecast analysis described in Chapter 3.
In 1998 and 1999 the Utah legislature passed and then revised the Water Conservation Plan Act,
requiring water agencies with more than 500 drinking water service connections to submit water
conservation plans to the Utah Division of Water Resources by April 1999. The water conservation
plans are intended to outline conservation goals, programs and methods for implementing the
programs and guide the water agencies in their water conservation activities for the next five years
(DWRe 2003). Water conservation plans evaluated in this document include:










Kane County (KCWCD 2007)
Kanab City (Kanab City 2013)
Santa Clara (Santa Clara City 2009)
Hurricane City (Hurricane 2009)
LaVerkin (LaVerkin City 2010b)
St. George (City of St. George 2008)
Washington City (Washington City 2010)
Ivins City (Ivins City 2008)
Washington County Water Conservancy District (WCWCD 2010)

In 2000 the state of Utah set a statewide water conservation goal of reducing the 1995 per capita
water demand from public community systems by at least 25 percent before 2050 (DWRe 2003).
Then, in 2002, the state revised the goal to be at least a 25 percent reduction by the year 2050 from
the baseline year 2000. DWRe estimates that an 8 percent reduction occurred from 1995 to 2000. In
2013, the state again revised its conservation goal to a 25 percent reduction of 2000 water use by
2025. DWRe estimated that the state of Utah achieved an 18 percent water use reduction between
2000 and 2010 (DWRe 2010).

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 5.1.1

Historical Conservation and Goals

From 2000 to 2010, total per capita water use decreased 26 percent in WCWCD’s service area. In
the KCWCD service area of Kanab City and the Johnson Canyon subbasin a reduction of 24 percent
has been obtained (DWRe 2014c). Together, the four subbasins in Kane County have conserved 21
percent during the same time period. Both districts aspire to reduce 2000 per capita use 30-35
percent by 2060, exceeding the state goal of 25 percent reduction by 2025. The programs they have
included in their water conservation plans have been evaluated and shown to be a practical method
for achieving these goals.
Maddaus Water Management (MWM) concluded that 30 to 35 percent reduction by 2060 is
attainable if additional conservation measures are implemented in each district’s service area.
Descriptions of these measures and results of the model are discussed in depth in the following
sections. Based on this analysis, and the notable conservation already realized by both districts, the
total per capita use reduction goals listed in Table 5-1 are assumed when calculating future water
demands.
Table 5-1

Conservation Goals1

KCWCD
(Kanab City and
Year
WCWCD
Johnson
Canyon)
2010
26%
24%
2025
33%
32%
2060
35%
35%
(1)
Percent reduction in total per capita water use from 2000.
(2)
Source: DWRe 2014c.

All Subbasins
Combined
21%
28%
31%

5.2 Washington County
Water use in the WCWCD service area reflects a strong trend towards increased conservation. The
older parts of communities reflect the pioneer lots established at the time of settlements with gardens
and trees, forming a narrow ribbon of green in the valleys. New developments have limited irrigated
area, less turf and more desert-wise landscaping. From 2000 to 2010, conservation savings are
estimated at about 26 percent (DWRe 2014c).
Given the long growing season, the annual precipitation of about 8 inches (WRCC 2013), with little
falling during the peak demand season, the ever-increasing reduction in water use reflects the
substantial efforts devoted to water conservation in Washington County. This achievement is
magnified when considering that about 27 percent of the homes in Washington County are second
homes, whose use is attributed to the resident population. Additional uses that are uniquely
combined in the county include millions of tourists each year and Dixie State University’s
nonresident students, which add a substantial water use factor onto the relatively small local
population (Section 2.3.3). Per capita water use numbers will continue to decline as development
density increases with urbanization.

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 As the first water conservancy district in Utah to adopt a water conservation plan, WCWCD has
been a leader in conservation in Utah and continues to enhance its conservation programs. Seven
cities have also adopted water conservation plans: St. George, Santa Clara, Washington, Hurricane,
Ivins, Toquerville and LaVerkin. Additionally, WCWCD’s 2006 Regional Water Supply Agreement
described in Section 1.3.1, includes a number of conservation requirements for its municipal
customers.
In August of 1993, WCWCD approved a “Long Term Framework for Water Resource Management,
Development, and Protection Plan” stating the District’s intent to develop a water conservation plan.
The same month the District formed a Water Conservation and Drought Management Committee,
comprised of realtors, landscape professionals, irrigators, and concerned citizens, with the objective
of examining water conservation practices that could be implemented within the County. This
committee’s recommendations were incorporated into the Washington County Water Management
and Conservation Plan (WCWMCP) which was adopted in May 1996. In 1998, the state of Utah
imposed a water conservation plan requirement on water districts and retailers, currently codified at
Utah Code Ann. § 73-10-32 (2014). The WCWMCP was revised in 2003 and again in 2010. The
most recent conservation plan update occurred in 2015.
Between 1996 and 2010, WCWCD spent $12.6 million on water conservation efforts, and the
district currently budgets about $250,000 per year for water conservation programs directly, in
addition to a full-time water conservation manager and two full-time horticulturists for its
demonstration gardens.
5.2.1

Washington County Water Conservancy District Programs

Conservation activities began in Washington County with the first Water Fair in 1995. After the
adoption of the original WCWMCP in 1996, WCWCD hired a conservation coordinator and began
implementing additional water conservation programs. The goal of each conservation plan is to
conserve water through the improvement of surface water quality, seepage and evaporation
reduction, drought management, watershed enhancement, irrigation practice improvements, public
education, and conservation ordinance establishment.
Table 5-2 gives a list of the various water conservation measures WCWCD has implemented since
1996 (WCWCD 2007; WCWCD 2008b; WCWCD 2010). Each measure is described in more detail
below.

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 Table 5-2

WCWCD Water Conservation Programs (WCWCD 2007; WCWCD 2008b; WCWCD
2010)
Category
Water Conservation Demonstration Gardens
Media
Education and Outreach
Conservation Education and Certification
Weather Station Link and Website
New Arrival Water Survival Kit
Rebates and Grants
Irrigation Upgrade Rebate Program
WaterSense Toilet Rebate Program
Water Efficient Technology Assistance Program
(WETAP)
Turf Replacement for Public Athletic Fields
Water Checks
On-going Studies to Maximize Use of Highly Saline Water
Water-Wise Plant List and Tagging (State Program)
Watershed Management and Enhancement
Secondary Untreated Water Systems
Conversion of Open Canals to Pipelines
Telemetry Project
Ordinances
Impact Fee
Water Rates

5.2.1.1

Water Conservation Demonstration Gardens

The Garden at Tonaquint Park. To educate the public and landscape professionals on water-efficient
landscaping, WCWCD, in cooperation with the City of St. George, constructed its first
demonstration garden in the fall of 2002 at Tonaquint Park. Self-guided tours, with the assistance of
pamphlets and kiosks, allow visitors to learn about the importance of soil composition and
fertilization; weather and climate; irrigation practices and technology; and plant design and
selection. The garden also displays five distinct landscaping themes: Desert Highlands; Urban
Desert; Desert Shrublands; a Native Garden; and Desert Oasis. To further assist the public with
water-efficient landscaping, a list of water-wise plants developed by WCWCD and Utah State
University Extension, is available at the garden and online. Monthly workshops are hosted at the
garden to give the public an opportunity to learn about water-wise practices from community
experts. This garden has received many local donations and grants from the Bureau of Reclamation.
Tonaquint Community Garden. Local St. George residents grow a variety of fresh produce in a oneacre garden organized in 44 plots in this community garden. This community garden is designed to
provide education to residents on how to nurture, maintain and protect a healthy landscape. An
onsite horticulturist along with volunteer master gardeners offer hands-on instruction on how to
plant and maintain food-producing plants in an arid, water limited environment. This garden is a
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 partnership with St. George City and WCWCD. It was built with a 75/25 percent grant from Natural
Resource Conservation District. Education is coordinated with Utah State University Extension.
Red Hills Desert Garden. Opened in May of 2015 in partnership with the City of St. George and the
Virgin River Program, this interactive garden focuses on desert landscapes, with more than 170 plant
varieties demonstrating the beauty of water smart landscapes. The 4.5-acre garden area uses, on
average, five million gallons of water less per year than traditional turf. The garden provides
information on designing, installing and maintaining a desert landscape that’s compatible with the
local climate and also offers views of endangered fish species and prehistoric dinosaur tracks.
5.2.1.2

Media

WCWCD launched its first conservation media campaign in 2000. Current efforts include print,
broadcast and online advertising campaigns, a district website, brochures, fact sheets, flyers, and
newsletters, with water saving tips and other water conservation information. WCWCD participates
in the Governor’s Conservation Team SlowtheFlow media campaign, started in 2002 to instill a
conservation ethic state-wide, using a unified conservation message. WCWCD also engages in
conservation related activities for “Water Week,” designated by the state in 2007 as the first full
week in May.
5.2.1.3

Education and Outreach

WCWCD organizes an annual water fair that reaches approximately 1,900 elementary school
students annually. The fair is hosted at Dixie State University where the students participate in
presentations and a water jeopardy game in which classes compete on knowledge about water
treatment, water properties, water infrastructure and water conservation. This program began in
1995.
USU and St. George worked with Irrisoft to create a website that reports ETo values based on data
from three weather stations. ETo values are used by landscape professionals and homeowners to
gauge the landscape irrigation needs.
Other educational outreach programs implemented by WCWCD include a garden fair, facility tours
and a water walk, in cooperation with the City of St. George. District staff members also serve as
resources to educators in a school outreach program. Using these events and activities, the district
educates people on the value of water, the importance of conservation and water issues facing the
state. WCWCD also partners with the United States Environmental Protection Agency (EPA) in the
WaterSense Program.
Qualified Water Efficient Landscaper (QWEL) classes are offered to train professional landscapers
and homeowners to implement water conservation practices. This course covers 12 sections on
landscape management involving design, plant selection, irrigation installation, irrigation scheduling
and irrigation audit. WCWCD hosts an annual Irrigation Association certification courses to train
and certify landscape professionals

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 5.2.1.4

New Arrival Water Survival Kit

Municipal customers of the WCWCD are given water conservation packets to hand out to new water
utility customers. The packets contain information about programs offered, water-wise landscaping
principles, local conservation resources and contact information for the water conservation
specialist.
5.2.1.5

Rebates and grants

Rebates for water saving irrigation upgrades have been offered to all water use categories to
encourage the use of Smart Water Applied Technology (SWAT) devices and high efficiency
technology. SWAT devices update irrigation controllers based on plant water needs, weather
information and soil moisture sensors. WaterSense-labeled-toilet rebates are offered to homeowners
and commercial properties. Rebates are given for replacing clothes or dish washers with water
efficient appliances. The Water Efficient Technical Assistance Program (WETAP) offers a rebate to
businesses upgrading equipment to water efficient types. Also, WCWCD has offered matching
grants for public athletic fields irrigated by culinary or potable water when retrofitted with artificial
turf.
5.2.1.6

Water Checks

Water Checks were first offered by WCWCD in 2005 along with the state-wide “SlowtheFlow”
program. A WCWCD technician performs tests on the irrigation system, evaluates system efficiency
and application rate and provides appropriate recommendations to customers, including an irrigation
schedule.
5.2.1.7

Ongoing Studies to Maximize Use of Highy Saline Water

WCWCD is working with Brigham Young University and the state to identify water-wise plants and
irrigation practices that will thrive when irrigated with highly saline Virgin River water.
Identification of plants that can tolerate the saline water and also survive on low water consumption
could extend the use of a large quantity of water in secondary untreated water systems.
5.2.1.8

Water-Wise Plant List and Tagging (State Program)

WCWCD was a sponsor of the state’s Water-Wise Plant Tagging Program. This program assists
Utah citizens in identifying water-wise plants at participating plant nurseries. The plants must be 1)
water-wise, 2) adaptable to Utah’s arid climate and cold winters, 3) available in the industry, 4)
relatively easy to maintain in the landscape and 5) have desirable landscape characteristics which
function under limited water availability. Tags are placed on plants that meet the five specified
criteria to assist in identifying appropriate plants for use in the region.
5.2.1.9

Watershed Management and Enhancement

The Virgin River Watershed Management Plan (VRWAC 2006) addresses watershed concerns of
water quality and water quantity as they affect drinking water supplies, threatened/endangered/native
species and riparian corridor health. WCWCD was a major partner and contributor to the Plan and
assisted in its development by working with Utah Department of Environmental Quality (UDEQ) to
address water quality impairments through Total Max Daily Loads (TMDL) for the Virgin River and
its tributaries. They were also influential in several programs to improve streamflow within the
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 watershed including the Virgin River management and Recovery Program as well as contributing to
the integrated approach of managing water supply and watershed health put forth in the Plan.
5.2.1.10

Secondary Untreated Water Systems

Municipalities and WCWCD, pursuant to the RWSA, are maximizing the use of secondary untreated
water systems to serve new development, thus offsetting demands on culinary water sources
(WCWCD 2006). One conservation method that reduces irrigation water use is the conversion of
open canals and flood irrigation to pipelines and pressurized systems. This reduces water losses from
seepage and evaporation in secondary untreated systems. The Toquerville Secondary untreated
Water System was the first open ditch system to be connected to a piped system. WCWCD
purchased water rights from the Toquerville Irrigation Company’s shareholders and converted the
open-ditch irrigation system to a pressurized system which distributes irrigation water from
Toquerville Springs to Toquerville residents. The Gunlock to Santa Clara pipeline has replaced four
diversions and converted flood irrigation to a pressurized system. The pipeline delivers irrigation
water to Ivins, Santa Clara, and the Shivwits Band of Paiute Indian Reservation. Also, WCWCD was
instrumental in converting the largest and longest open canal system in the county, the St. George
and Washington Canal system, from approximately 22.6 miles of open ditch to enclosed pipeline
(including main canal and laterals). Finally, upon completion of the district’s Ash Creek Project,
another 6.3 miles of open ditch will have been converted to enclosed pipelines (including the ditch
from South Ash Creek to Pintura and the Wet Sandy Ditch.
5.2.1.11

Telemetry Project

To minimize water loss, aid in water management, and enhance the accuracy of measuring water
right allocations, a telemetry project that monitors diversions along the Santa Clara River and Virgin
River has been implemented (WCWCD 2008b). The project monitors diversions along both rivers to
minimize water loss and enhance the accuracy of measuring water right allocations.
5.2.1.12

Ordinances and Impact fees

All municipal customers of the district have time-of-day watering restrictions to discourage
excessive water use. Impact fees, applicable to all new development (new platted lots and building
permits) within the service areas of municipal customers, are based on the size of the irrigable
portion of the lot, with a pro rata increase for irrigated areas over a certain size (WCWCD 2008b).
5.2.1.13

Water rates

To encourage the reduction of water consumption, many cities have adopted inclining block-rate
structures. Block rate structures consist of fixed amounts of water sold at a unit price. Increased
block rate structures are based on the idea that consumers will use less water if the unit rate of water
increases with increased volume consumption. Inclining block-rate structures are more effective in
encouraging customers to reduce their water use when there is a significant price difference between
each tier. WCWCD and the following cities have adopted increasing block rate structures:
Springdale, Hurricane Valley, La Verkin, Ivins, Washington, Santa Clara, St. George, Enterprise,
and Hurricane, where the price of water is stepped up based upon increased usage. In addition,
WCWCD completes a water budget for each of its golf course customers and charges a 50 percent
surcharge for usage in excess of the budget amount.
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 5.2.2

Programs Offered by Cities in Washington County

The conservation efforts of the individual cities in Washington County are consistent with those of
WCWCD with a primary focus on public awareness and education. St. George City employs a water
conservation coordinator and the seven major cities in Washington County have written conservation
plans. These plans implement a wide range of conservation measures, several in partnership with
WCWCD. To encourage water conservation, Washington County municipalities are:
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Charging increasing block-rate structures to encourage efficient water use
Implementing time-of-day watering ordinances to discourage irrigation water waste
Restricting use of culinary water for large irrigators and homeowners
Prohibiting use of culinary water for washing paved areas, non-commercial car washing, filling
of private swimming pools, and irrigation of city parks or schools
Offering free residential outdoor water audits
Providing water audit programs for commercial and industrial users
Integrating drought management plans into rate schedules
Offering rebates for water efficient toilets and washing machines
Giving rebates to coin-operated laundromats and multi-family housing complex laundries
that upgrade to water efficient washing machines
Promoting of indoor water-saving fixtures
Offering incentives for efficient landscape/irrigation installations or rehabs
Rebating pressure regulating valve installations on irrigation systems
Converting of public facility irrigation systems to secondary untreated water where feasible
Installing additional meters and radio read systems to better account for water losses
Replacing old pipes and meters to significantly reduce water loses
Upgrading SCADA systems to better manage and identify water losses
Purchasing leak detector to decrease water loss
Educating students, teachers and scout troops about water conservation, water quality, water
supplies, and water shortages
Participating in WCWCD’s annual water fair
Presenting to Chamber of Commerce and service clubs on water conservation
Teaching customers to read and understand their water bills
Providing water use comparisons and water savings tips with customer’s water bills
Distributing conservation information by newsletters, public awareness programs,
conservation pamphlets, checklists, and lawn water guides
Publishing lists of low water plant species to promote more efficient of landscape design
Providing training on efficient irrigation systems
Offering awards for water-conserving landscape
Hosting workshops for industry professionals such as landscapers, builders, plumbers, and
irrigation contractors
Increasing public awareness of conservation practices through radio and newspaper
education
Identifying effective conservation programs with Alliance for Water Efficiency’s Water
Conservation Tracking Tool
Promoting xeriscape, especially in new developments
Requiring installation of secondary untreated water irrigation systems in new developments

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  Implementing water conservation principles in planning, development and management of
new projects
5.2.3

Conservation Savings

As previously shown in Table 5-1, total per capita water use decreased 26 percent in WCWCD’s
service area between 2000 and 2010 (DWRe 2014c). The overall culinary water conservation
savings for WCWCD from 2000 to 2010 was determined by DWRe to be 15 percent utilizing actual
data for the 6-cities between 2000 and 2010 (DWRe 2013c). Reduction in regional per capita water
use can result from conservation actions, changes in housing density, housing types, landscaping, lot
sizes, climate, water pricing, drought policies, regional economic conditions (e.g., recessions),
percentage of non-permanent residents, hotel occupancy, and commercial, institutional and industrial
(CII) uses. ETo data were analyzed to help determine the effects weather may have had on water use
in a particular year. High ETo in hot and dry years could result in increased water demands for
outdoor irrigation. The opposite is true for wet and cool years when water use can decline. Figure 51 shows the relationship between net ETo and per capita culinary water use for the six cities, as
monitored by the Governor’s Water Conservation Team.
Figure 5-1

5.2.4

Culinary Per Capita Water Use for WCWCD
(6 Cities; DWRe 2009b, DWRe 2013c, DWRe 2013e)

Future Goals and Water Conservation Programs

Future water conservation savings were estimated through a detailed water conservation study,
originally conducted for WCWCD by Maddaus Water Management in 2010 (MWM 2010b) and
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 updated in 2015 (Appendix B, MWM 2015a). This analysis reviewed water use data (billing data),
evaluated existing water conservation measures, considered potential future water conservation
measures and selected a program considered likely to be implemented in the future. The analysis
relied on a model developed by MWM that analyzes water use at the end-use level (e.g., individual
appliances and fixtures) and considers factors such as individual unit water savings, year of
implementation, unit costs, and market penetration. Meetings with local water user representatives
were held to select preferred conservation measures.
Twenty-eight conservation measures were selected for evaluation in the DSS Model. Based on water
savings potential and cost-effectiveness, 23 of these conservation measures were included in the
2015 conservation plan update. The details of the study and each conservation measures are included
in Appendix B, MWM 2015a. Table 5-3 lists the measures selected for implementation.
Table 5-3

WCWCD Conservation Programs

Measure Name

Category

Real Water Loss Reduction
Conservation Pricing
Public Information Program
Water Budgeting/Monitoring
Billing Report Educational Tool
Efficient Outdoor Use Education and Training
Program
Distribute Retrofit Kits
Single Family (SF) Water Surveys
Toilet Leak Detection
Multifamily Washer Rebate
High Efficiency Toilet (HET) Rebates
CII Surveys
CII Rebates to Replace Inefficient Equipment
Replace Spray Nozzles
High Efficiency Urinal Rebate (<.5 gallon)
School Building Retrofit
Install High Efficiency Fixtures in Government
Buildings
Irrigation Water Surveys (Water Checks)
Xeriscape Demonstration Gardens
Train Landscape Maintenance Workers
Financial Incentives for Irrigation Upgrades
Smart Irrigation Controller Rebates

General Measures
General Measures
General Measures
General Measures
General Measures
General Measures
Residential Measures (Indoor)
Residential Measures (Indoor)
Residential Measures (Indoor)
Residential Measures (Indoor)
Residential Measures (Indoor),
Commercial Measures (Indoor)
Commercial Measures (Indoor)
Commercial Measures (Indoor)
Commercial Measures (Indoor)
Commercial Measures (Indoor)
Commercial Measures (Indoor)
Commercial Measures (Indoor)
Irrigation Measures (Outdoor)
Irrigation Measures (Outdoor)
Irrigation Measures (Outdoor)
Irrigation Measures (Outdoor)
Irrigation Measures (Outdoor)

Table 5-4 summarizes the projected GPCD reductions and percent conservation anticipated with the
selected program. Results show that by 2060 WCWCD could reduce its 2010 GPCD levels by 12
percent by 2060. The estimated water savings include those anticipated from enforcement of current
plumbing codes that require use of low-flow plumbing fixtures in new homes and remodels. The
conservation savings shown in Table 5-4 were factored into the demand projections used to compare
future supply and demand in Chapter 6.

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 Table 5-4

Conservation Program Projected GPCD Reduction Percentage to Year 2060

Year
2010
2020
2025
2030
2040
2050
2060

Conservation Plan
with Plumbing Code
(GPCD)
325
306
298
294
291
288
285

Conservation Plan
with Plumbing Code
(% Reduction)
0%
6%
8%
10%
10%
11%
12%

5.3 Kane County
The Kane County Water Conservancy District and the City of Kanab have developed conservation
plans for the Johnson Creek and Kanab Creek areas. The goal of these plans is to make sure that
future culinary water needs are met. As with other parts of Utah, many of the homes in Kane County
are secondary untreated homes. As a result, water use increases during the summer months, holidays,
and weekends.
The City of Kanab adopted a water conservation plan in 1999 and revised it in 2009. The water
conservation plan addresses past water conservation measures, opportunities to develop and
implement management conservation measures, and short and long term goals for efficient water
use.
5.3.1

Current Conservation Program

5.3.1.1

KCWCD (Kanab City and Johnson Canyon)

The Johnson Canyon area has year-round residence with both outside and inside usage. The
conservation efforts in this area focus on management, household usage and outside usage.
Management conservation measures include the facilitation of water rights transfers and acquisition
of new water rights (KCWCD 2011). The efficiency of KCWCD’s culinary water distribution
system will be sustained through maintenance and system upgrades. The Johnson Canyon system is
currently monitored by employees of KCWCD, but the installation of a SCADA system is possible
in the future to automate and monitor the system (KCWCD 2011).
KCWCD is educating the public on water conservation methods that can be implemented to reduce
household water use. KCWCD has adopted an inclining block-rate structure in their Johnson Canyon
area. Inclining block rate structures are based on the idea that consumers will use less water if the
unit rate of water increases with increased volume consumption. Table 5-5 shows the increasing
block rate structures that are used to discourage excessive water use in the Johnson Canyon area
(KCWCD 2011).

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 Table 5-5

KCWCD Increasing Block Rate Structure for Residential Customers

Water System

Level

Consumption

Rate

Johnson Canyon
Johnson Canyon
Johnson Canyon
Johnson Canyon
Johnson Canyon

-1 - Base Minimum Fee
2
3
4

Residential Standby
0-15,000 gal/mo
15,001-25,000 gal/mo
25,001-45,000 gal/mo
45,001+ gal/mo

$15.00
$35.00
$1.00/1,000 gal
$1.25/1,000 gal
$1.50/1,000 gal

Kanab City’s conservation approach has primarily been to provide an efficient culinary water supply
system to its customers, and the city has completed system upgrades to improve the efficiency
including completion of a pressurized irrigation system. Kanab City’s short and long term goals for
efficient water use include public education, maintenance and upgrades of the culinary water system,
use of reclaimed municipal wastewater for irrigation of parks, golf courses and other large turf areas,
source protection zones and well management. Other conservation implementations include
residential water saving devices and practices for consumers, requirements of new residential
construction to meet landscape or xeriscape ordinances, and impact fees and water rates based on
usage and best management practices on golf courses and parks. Table 5-6 lists the conservation
programs in greater detail.
Table 5-6

KCWCD (Kanab City and Johnson Canyon) Conservation Programs

Category

Education and Outreach
Water Distribution
System
Residential Water
Systems
Residential Water
Systems

Title

Description

Public Education
Maintenance
Water Saving Devices
New Construction
Requirements

Water Rates

Impact Fees, Increasing Block
Rate Structure

Commercial and
Industrial Water
Systems

Best Management Practices

Water Source

Protection

Teach children and adults about conservation methods to
minimize water use.
Maintain an efficient culinary water system through
maintenance and system upgrades.
Flow restrictors for showers and faucets, toilet dams, leak
protection kits, and lawn watering guides.
New residential construction must meet model landscape
or xeriscape ordinances.
Impact fees and water rates based on water usage are
used in Kanab City. An increasing block rate structure is
currently used in the Johnson Canyon area.
Best Management Practices for golf courses and parks
including bubblers on trees, timed night watering,
upgrade in sprinkler efficiency, use of low-pressure
nozzles, minimization of well overflow, and immediate
fixing of water leaks.
Maintain source protection zones and protect recharge
and watershed areas.

Source: Kanab City 2013; KCWCD 2011

Kanab City also has a four stage conservation approach, with the four stages of conservation based
on four levels of water shortages or reduction in supply from drought or equipment failure. Kanab
City has a conservation management plan, with detailed requirements and restrictions for each of the
four levels of water shortages. The management plan describes conservation requirements for indoor
and outdoor water practices for each of the four levels of shortages, which are generally described in
Table 5-7.

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 Table 5-7
Conservation Stage

Stage 1

Stage 2

Stage 3

Stage 4

Kanab City Conservation Management Plan
Supply/Demand Relationship

Conservation Action

Supply 2-3% greater than total daily
demand, or drought or equipment failure
results in 2-3% reduction in supply
Culinary demand greater than supply by 13%, or drought or equipment failure results
in 5% reduction in supply
Culinary demand greater than supply by
5%, or drought or equipment failure results
in 10% reduction in supply
Culinary demand greater than supply by
10%, or drought or equipment failure
results in 25% reduction in supply

Voluntary restrictions on nonessential water
use, with reduction goal of 2-3% of daily
peak use.
Mandatory restrictions on nonessential
water use, with reduction goal of 5-10% of
daily peak use.
Mandatory restrictions on nonessential
water use, with reduction goal of 10-25% of
daily peak use.
Water rationing plan for all available
culinary water resources, with reduction
goal of 25-60% of daily peak use.

Source: Kanab City 2013

5.3.2

Conservation Savings

The historical water use patterns for Kane County were analyzed based on water production and
consumption data provided by KCWCD. However, much of the water use data available to KCWCD
contains many errors. The best assumptions have been made to include all water uses, with
knowledge that in some areas the water numbers are being reported in multiple data sets. Current
population data also is limited to the census records that do not account for the actual use by Kane
County's large transient tourist and second home users. As a result the current measures of GPCD
are not fairly comparable to other areas.
For the purposes of this document, estimates of past water use were made based on the Kanab
Creek/Virgin River Basin M&I water supply and use reports from the Utah Division of Water
Resources. These were used to estimate the trend in per capita water use in KCWCD (Johnson
Canyon and Kanab City).
5.3.2.1

KCWCD (Kanab City and Johnson Canyon)

Between 2000 and 2010, the time period in which KCWCD began providing culinary water to the
Johnson Canyon area, the total water use decreased by 24 percent (DWRe 2014c). Culinary water
use dropped 20 percent and secondary untreated water use dropped 56 percent. Average per capita
water use for the KCWCD service area (Kanab City and Johnson Canyon) is shown in Figure 5-2
(DWRe 2006a, DWRe 2009a, DWRe 2014c).

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 Figure 5-2

5.3.2.2

KCWCD (Kanab City and Johnson Canyon) Average per Capita Water Use from 2000
to 2010

Four Subbasins

Between 2000 and 2010, the total water use for the four subbasins combined decreased by 21
percent (DWRe 2014c). Average per capita water use for the four subbasins combined is shown in
Figure 5-3 (DWRe 2006a, DWRe 2006b, DWRe 2008a, DWRe 2009a, DWRe 2014c)
Figure 5-3

5.3.3

Four Subbasins Average per Capita Water Use from 2000 to 2010

Future Goals

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 Kanab City, Johnson Canyon and the remainder of Kane County have begun to make significant
conservation savings in recent years. Future community-wide conservation savings will be achieved
by implementing both passive and active measures. Passive measures are codes and standards that
force consumers to update appliances and fixtures to increase conservation savings. Active measures
are those in which KCWCD will invest to promote conservation, such as incentives and educational
programs.
MWM completed a Conservation Technical Analysis Memorandum (Appendix B, MWM 2015a) to
identify programs and projects to most effectively improve water use efficiency. This Conservation
Technical Analysis builds on the 2010 Water Conservation Technical Analysis prepared by MWM
and MWH (MWM 2010a). In this analysis, MWM included uses from all of Kane County, including
the Duck Creek and Cedar Mountain area. For this reason, the estimates of gallons per capita day
are higher than what is shown by the DWRe and used in this analysis. A study of the potential
conservation measures readily available to Kane County entities yielded three potential water
conservation programs. Of these, Program B was selected by KCWCD for future implementation.
MWM (2015a) performed an analysis of potential conservation measures and programs for Kane
County. This task included a review of KCWCD’s current water conservation measures,
identification of current and new measures that may be appropriate for the local entities, and
screening of these measures to a short-list for detailed evaluation (benefit-cost analysis). The shortlist was further evaluated and scored during screening workshops based on water use characteristics,
economies of scale, demographics, and other factors that are unique to Kane County.
To more precisely estimate Kane County’s water use, Maddaus Water Management (MWM)
employed its DSS Model. Using data provided by KCWCD for population and demand in 2013 and
the historical and projected water use estimates provided by the State (DWRe 2014c), MWM was
able to estimate water use projections for multiple water use categories and develop conservation
strategies to help the district achieve its water use goals (Appendix B, MWM 2015a).
A total of 24 individual measures were evaluated using the DSS Model. Based on the modeling
results from Maddaus Water Management’s DSS model. Program B was chosen as the only costeffective combination of measures. To achieve the desired level of water efficiency county-wide, all
utilities must participate in Program B and implement the applicable measures with their share of the
overall customer participation rates assumed in the DSS model. Table 5-8 lists the ten conservation
measures selected under Program B. Measures are categorized as education, or incentives.
Table 5-8

KCWCD Conservation Measures Considered
Measure Name

Category

Distribute Retrofit Kits
Toilet Leak Detection
Public Information Program
Rotating Sprinkler Nozzle Rebates
Replace Spray Nozzles
Xeriscape Demonstration Gardens
Billing Report Educational Tool
Educate Builders on New Home Water Sense
Standards

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Incentives
Incentives
Education
Incentives
Incentives
Education
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 Measure Name

Category

Twenty Gallon Challenge
Efficient Outdoor Use Education and Training
Programs

Education
Education

5.4 Conclusions
WCWCD has been a leader in water conservation for many years. It developed its water
conservation program in 1996 before it was required by the State of Utah and has continued to
expand the program and add measures to increase water conservation. Based on a review of
historical water use, total per capita water use decreased from 2000 to 2010 by 26 percent (DWRe
2014c). WCWCD has exceeded the state goal of 25 percent reduction by 2025 and aims to reduce
2000 per capita use 35 percent by 2060. Maddaus Water Management (MWM) concluded that this
reduction is attainable if additional conservation measures are implemented in the district’s service
area (Appendix B, MWM 2015b).
Kane County has also had significant conservation savings for the 2000-2010 period with a
reduction of 24 percent within the KCWCD service area of Kanab City and Johnson Canyon (DWRe
2014c) and 21 percent for the four subbasins in Kane County combined. MWM (2015a) performed
an analysis of potential conservation measures and programs for Kane County. This task included a
review of KCWCD’s current water conservation measures, identification of current and new
measures that may be appropriate for the local entities, and screening of these measures to a shortlist for detailed evaluation (benefit-cost analysis). The short-list was further evaluated and scored
during screening workshops based on water use characteristics, economies of scale, demographics,
and other factors that are unique to Kane County. KCWCD intends exceed the State goal of 25
percent by 2025 and to further reduce 2000 per capita use 30 percent by 2060 through these
conservation measures.

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 Chapter 6 – Water Resources Planning
6.1 Introduction
The integrated water resources plans for each district define the magnitude and timing of future
water project development in relation to future water demands. They show a likely scenario of how
supplies could be developed in a logical sequence to meet demands. These plans are designed to
determine whether the Lake Powell Pipeline Project would be needed within the planning horizon
(present to 2060), and if so, when.
WCWCD: It is estimated the LPP would need to be brought online in 2028 when the projected
demand with conservation nears 81,273 ac-ft, exceeding the total reliable supply. Total reliable
supply for WCWCD is 67,677 ac-ft per year with an additional 13,670 ac-ft per year of culinary or
potable supply projects planned for completion prior to 2060. A portion of the culinary supplies can
be used to meet secondary untreated demands as necessary until their full yield is needed to fulfill
culinary requirements.
KCWCD: The KCWCD (Kanab City and Johnson Canyon) reliable supplies are projected to be in
deficit by 2035 when they would be exceeded by total water use. Supplies are projected by DWRe
(2014b), reduced by the Reclamation projected climate change median streamflow reductions
(Reclamation 2014) and again reduced to account for a 10 percent planning reserve buffer.
Criteria for bringing new water projects online, and the strategies for implementing new projects,
vary among water utilities and can change substantially over time in response to many factors
including hydrology, economics, and politics. The evaluation in this study is necessarily simplified
and is intended primarily to assess the need for the Lake Powell Pipeline Project in the context of
long-term growth. Each district’s short-term planning objectives and priorities may change from the
concepts outlined in this study over time, but the effects of any short-term changes in local water
development would not affect the need for the LPP within the planning horizon (2010 – 2060).
The following general assumptions were used in preparing integrated water resource plans for each
district.
 Service Area. The districts’ service areas include cities that have developed their own water
supplies. These cities have various policies – formal and informal – on how they want to
participate with their water conservancy district in meeting future demands. Some plan to rely
entirely on the district to meet all increased demands in the future (e.g., RWSA municipal
customers of the WCWCD), while others currently anticipate meeting increased future needs
on their own. For purposes of this study, total supplies and demands throughout Washington
County and within Kanab City and the Johnson Canyon subbasin of Kane County have been
considered when determining the need for and timing of new water sources, based upon the
following assumptions:

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  The benefits of regionalization in seeking new water sources will encourage water
suppliers to work together rather than individually
 Local projects implemented by individual water suppliers in already over-appropriated
basins (e.g. virtually all of the Virgin River basin) will increase the need for regional
supplies.
 Unconstrained Distribution Systems. The required infrastructure would be provided to
distribute new water sources to the areas of need.
 Total Water Use. Total water use (culinary and secondary untreated) has been used to forecast
water demand timing.
 Sequential, Prioritized Project Implementation. Although districts could simultaneously
implement multiple projects, the uncertainties of timing cannot be addressed in this analysis.
New projects have been sequenced based on current capital facility plans, qualitative unit cost,
current status of project development, ease of implementation, and stated preferences of the
districts.
 Supply Reductions. The U.S. Bureau of Reclamation projected climate change median
streamflow reductions (Reclamation 2014) were incorporated into WCWCD water supply
modeling and applied to the reliable supply estimates for Kane County. Also, a ten percent
planning reserve is incorporated into the reliable supply quantities to avoid using water
supplies up to the maximum and to provide a buffer against annual variability in water supplies
affected by precipitation runoff and groundwater recharge.
 Project Certainty. Future water projects have a reasonable certainty of being implemented
within the study period. More speculative or uncertain projects, due to technical, cost or
environmental concerns, have not been included.
 Lake Powell Pipeline Supplies. LPP requests have been used as LPP supplies (82,249 ac-ft
per year for WCWCD and 4,000 ac-ft per year for KCWCD).
Assumptions specific to each individual district are described in the following sections.

6.2 WCWCD Integrated Water Resources Plan
Figure 6-1 shows the timing of supply and demand. LPP would be needed in approximately 2028.
The full yield of secondary untreated supply projects would be available to meet any M&I demand
(i.e., both culinary and secondary untreated demand) when the projects are complete. The portion of
the culinary supplies above the demand line would be needed when the demand line crosses the
supply line, so this portion of culinary supply could be used to meet secondary untreated demand
until the entire culinary supply is needed to meet culinary demands.

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 Figure 6-1

WCWCD Supply and Demand – Total

More details regarding the yields of these supplies are summarized in Table 6-1. Specific
assumptions used to develop the integrated water resources plan are presented in Table 6-2. The
difference between the projected 2060 demand of 184,250 ac-ft per year and reliable supplies
(67,677 ac-ft per year) is about 116,573 ac-ft per year. Approaches for meeting this projected
demand are discussed below and include planned projects. The suggested order of implementation of
all planned and potential projects is based on a comparison of conceptual unit cost, current status of
project development, and preferences expressed by the WCWCD during meetings held with the
district for the analyses completed for this report.
The total yield of WCWCD culinary projects planned before bringing the LPP online is 13,670 ac-ft
per year. These projects are described in detail in Section 4.2.5. The Ash Creek Project is the first
culinary water supply source because it makes culinary-grade quality water available that currently
is used to meet secondary untreated demands. Other future culinary supplies include well field
expansions and upgrades.
Another source of water available to WCWCD to meet total water demands would be agricultural
water conversions from M&I development (10,080 ac-ft/yr). This potential project has substantial
feasibility or economic constraints that preclude it as a viable option as a culinary M&I supply.
However, water from agricultural conversions could supply secondary untreated demands. It was
assumed that agricultural conversions would begin immediately and continue to increase annually
until the full yield is attained. Conversions made in the Washington Fields area would need to be

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 stored in a future storage facility to attain maximum yield. For planning purposes, it is assumed that
this storage can be permitted, designed, and constructed in about 6 years, prior to the LPP.
Water reuse up to the existing St. George reuse plant capacity is the next increment of secondary
untreated supply. Assuming storage facilities would be implemented, a future maximized 10 mgd
plant capacity would result in 7,300 ac-ft per year of future supply. Additional reuse plant expansion
beyond existing plant capacity could be implemented as another source of secondary untreated
supply and would accommodate reuse of LPP water. Plant expansion could be phased in over time to
meet demand in response to population growth and water use, improvements in treatment
technologies, and improved public acceptance of water reuse.
Timing for new secondary untreated water sources assumes demand along with construction of
separate secondary untreated water distribution systems. A portion of the culinary supplies can be
used to meet secondary untreated demands as necessary until their full yield is needed to fulfill
culinary requirements.

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 Table 6-1

WCWCD Summary of Existing and Future Supplies

Reliable Culinary Quality
Reliable Secondary untreated
Existing Project
Water Yield (ac-ft/yr)(2)
Quality Water Yield (ac-ft/yr)(2)
Quail Creek and Sand Hollow Reservoirs(3)
24,922
0
Sand Hollow No-Recharge Groundwater(4)
4,000
0
Cottam Well Field
875
0
Kayenta (Ence Wells) Water System(8)
730
0
Crystal Creek Pipeline
2,000
0
Toquerville Secondary untreated Water
0
178
System(5)
(6)
Ash Creek Pipeline
2,840
0
Sand Hollow Recharge and Recovery(7)
3,000
0
Cottam Well Maximization
600
0
Sullivan Wells
750
0
Pintura Well
600
0
Diamond Valley Well
400
0
Westside Arsenic Treatment(9)
5,000
0
Other Washington County Providers
27,125
8,327
Maximize Existing Wastewater Reuse(8,10)
0
7,300
Agricultural Conversion from
0
10,080
Development(8,11)
Lake Powell Pipeline
82,249
0
Potential Future LPP Reuse(8)
0
28,830
Total
155,091
54,715
Notes:
(1)
Source of data: WCWCD 2014; DWRe 2013a; DWRe 2013d. Average yield with up to 10 percent shortage
assumed to represent reliable yield for WCWCD projects.
(2)
Culinary quality water was assumed to be able to meet culinary demands first, and then secondary untreated
demands with any portion of the culinary supply that is not fully utilized.
(3)
Reliable yield model for Quail and Sand Hollow Reservoirs includes yields from Kolob and Meadow Hollow
Reservoirs. Current supply from 50th percentile climate change scenario with 10% shortage (DWRe 2014a).
(4)
Supply utilizes existing water rights and natural basin recharge.
(5)
DWRe 2013d. Assumed reliable supplies are equivalent to current secondary untreated water use.
(6)
Ash Creek Pipeline yields 2,840 ac-ft/yr based on a 90% reliability level under the 50th percentile climate change
scenario.
(7)
Arsenic Treatment or blending and transmission upgrades must first occur.
(8)
To be implemented post-Lake Powell Pipeline (Ence Well post-LPP portion equal to 480 ac-ft/yr)
(9)
Includes Gunlock to Santa Clara Pipeline and Snow Canyon Wells. Moved to future reliable supply due to extent of
treatment needed for culinary supply.
(10
See Section 4.2.5.2.1.
(11)
The estimated supply is 12,880 ac-ft/yr with 90% reliability (DWRe 2011a). However, it was estimated that
approximately 2,800 ac-ft/yr of this supply is currently in use and has been accounted for in the reliable secondary
untreated supply.

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 Table 6-2

WCWCD Integrated Water Resources Plan Data

Supply Source

Average
Annual
Yield in 2060
(ac-ft/yr)

Type of Supply
(Culinary or
Secondary
untreated)

Existing Supplies

67,677(1)

Culinary and
Secondary untreated

Timing

Start
Date
-

Comments
Combined culinary and
secondary untreated
supply.

Future Supplies

Agricultural
Conversions from
Development

10,080(2)

Ash Creek
Pipeline and Well
Improvements

(4)

13,670

Secondary untreated

Begin when
needed; phase in
over time

2010

Culinary

As needed PreLPP, 480 ac-ft
Kayenta Wells
post-LPP

2010

Lake Powell
Pipeline

82,249

Culinary

When needed

2028

Maximize Existing
Wastewater Reuse
Capacity of 10
mgd

7,300(3)

Secondary untreated

When needed

2055

Future LPP Reuse

28,830(4)

Secondary untreated

When needed

2055

Consists of multiple
projects and water rights
changes. Linear annual
increase to meet
secondary untreated
demand; full yield
requires additional
storage.
Culinary supply indirectly
by supplying secondary
untreated supply grade
water to offset current
culinary use.
Can be used to meet
culinary and/or secondary
untreated supply as
needed. 82,249 ac-ft/yr
used in 2060.
Treatment capacity and
distribution system can be
phased as needed to meet
secondary untreated
demand; requires
additional storage.
Phased in as needed to
meet secondary untreated
demand; requires
additional storage.

Notes:
(1)
Includes WCWCD reliable water supply based on WCWCD 2014 which includes WCWCD existing projects and
water uses. Includes other existing municipal supplies.
(2)
The estimated supply is 12,880 ac-ft/yr with 90% reliability (DWRe 2011a). However, it was estimated that
approximately 2,800 ac-ft/yr of this supply is currently in use and has been accounted for in the reliable secondary
untreated supply. It was assumed that agricultural conversions from development would be developed moderately until
additional storage is available.
(3)
See Section 4.2.5.2.1.
(4)
WCWCD 2014

6.3 KCWCD Integrated Water Resources Plan

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 KCWCD’s service area encompasses all of Kane County. This document includes a brief assessment
of four groups in Kane County primarily based on the four major subbasins. Although KCWCD
encompasses all of Kane County, much of the county will not be served by the Lake Powell
Pipeline. Existing KCWCD water supply customers include rural developments located in the Cedar
Mountain and Johnson Canyon areas. KCWCD owns and operates wells in the Johnson Canyon
area. KCWCD has a connection to the Kanab City water supply and intends to use Lake Powell
Pipeline supplies to meet future demands there and in the Johnson Canyon subbasin. For this reason,
Kanab City is grouped with the Johnson Canyon subbasin in this Assessment and Alton Town is
represented alone in the Kanab Creek subbasin. Throughout this document, when referring to the
four subbasins, Kanab City and Johnson Canyon subbasin are included along with Alton Town and
the East Fork and Wahweap subbasins.
Kane County reliable water supplies were discussed in Section 4.2. The Reclamation projected
climate change median streamflow reductions were interpolated for the years 2010 to 2060 to give a
downward sloping reduction in streamflow based on the future period projections (Reclamation
2014). The reductions were applied to the reliable supply for the four Kane County subbasins.
Furthermore, a 10 percent planning reserve was added to the reliable supply estimates, based on
similar planning reserves used by water districts in western states, to avoid using water supplies up
to the maximum and to provide a buffer against annual variability in water supplies affected by
precipitation runoff and groundwater aquifer recharge. Table 6-3 shows the yield of the current
reliable and future supplies when the climate change median streamflow reductions are applied to
the existing reliable supply and the 10 percent planning buffer is applied. The future groundwater
rights shown for KCWCD is assumed to be available in the future, however care will have to be
taken to drill in favorable locations throughout Western Kane County so that withdrawals do not
exceed recharge rates. If drawdowns become evident, the Department of Water Rights would limit
these rights.
The KCWCD (Kanab City and Johnson Canyon subbasin) deficit would likely occur in 2035 as total
use would exceed the reliable supply. KCWCD shows a 2040 deficit of 266 acre-feet. Figure 6-2
shows the supply and demand for KCWCD where the lines of the graph cross in approximately
2035, indicating KCWCD would need a new supply starting in 2035. The LPP would traverse Kane
County on its way to Washington County. Therefore, there is an opportunity for KCWCD to
participate in the LPP simply out of convenience. Tapping into the pipeline would add a reliable
supply to their system that would stretch local supplies further into the future. LPP deliveries could
be used for culinary supplies, saving local groundwater for use as secondary untreated water and
preserving aquifer levels within the county. KCWCD has also considered using LPP deliveries to
recharge aquifers supporting local well fields to sustain natural supplies and keep water levels high.

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 Table 6-3

Kane County Integrated Water Resources Plan Data
Average Annual Yield in 2060 (ac-ft/yr)
East Fork
Virgin River
Subbasin

Supply Source
Alton Town
703
42
Existing Supplies
Future Supplies(1)
New Groundwater
489
0
Agricultural Conversion
960
42
Lake Powell Pipeline
0
0
Notes:
(1)
Climate Reduction (7.2%) + 10% Planning Reserve
(2)
Combined culinary and secondary untreated supply
(3)
KCWCD requested 4,000 ac-ft/yr from LPP

KCWCD
(Kanab City
and Johnson
Canyon

Wahweap
Creek
Subbasin

2,102

615

6,615
0
3,341

1,690
0
0

Figure 6-2 through Figure 6-5 show graphically the relationship between supply and demand, and
the sequential timing of new projects brought on line to meet the forecasted total water demand in
each of the four groups. A combination of existing and new supplies is sufficient to meet all future
needs within the planning horizon for each group.
The KCWCD (Kanab City and Johnson Canyon subbasin) reliable supplies are projected to be in
deficit by 2035 when they would be exceeded by total water use. As previously discussed, KCWCD
will use LPP water to meet future demands beyond the reliable supply due to the poor quality of
groundwater available.
Figure 6-2

KCWCD Supply and Demand – Kanab City Johnson Canyon

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 Figure 6-3

East Fork Subbasin Supply and Demand – Orderville Town and Glendale

Figure 6-4

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Alton Town Supply and Demand

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 Figure 6-5

Wahweap Creek Subbasin Supply and Demand

6.4 Conclusion
Demand projections to 2060 for each county were provided by the State of Utah Department of
Water Resources (DWRe 2014c). Entities in both counties are implementing conservation measures
and have committed to future programs developed through a detailed water conservation study
conducted by Maddaus Water Management (Appendix B; MWM 2015 a; MWM 2015b). Each
district is expected to exceed the State of Utah’s water conservation goal of reducing per capita use
from 2000 usage by 25 percent by year 2025. Existing reliable supplies for each water district have
been evaluated and it is determined that they are being efficiently and fully utilized. The future of the
climate in the area is expected to change in ways that are unfavorable to the estimated yields of the
reliable supplies. Given the available information, the results shown in this report are suitable for
long-range regional water supply planning purposes. This Assessment shows that in the near future,
projected water demands will exceed existing supplies for WCWCD and KCWCD and as water
suppliers, they will be required to employ a variety of approaches to meet these demands.
Conservation will play a vital role in minimizing the need for additional water, but development of
new water sources, including Colorado River water from the Lake Powell Pipeline, will be critical in
maintaining a safe and reliable supply of water for communities in Southern Utah. The no project
alternative is not a good use of water resources and is not appropriate for water supply planners.

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 References Cited
Alpha Engineering. 2006. Capital facilities plan and development impact fee analysis. Prepared for
Kanab City. December 2006.
City of St. George. 2008. Water Conservation Plan Update. January.
__________. 2009a. Water Reuse Data Collection Meeting with MWH. February 24.
__________. 2009b. WW Effluent Summary for Report.xlsx. June 11.
DAS (see Utah Department of Administrative Services)
DWRe (see Utah Division of Water Resources)
DWRi (see Utah Division of Water Rights)
GOMB (see Utah Governor’s Office of Management and Budget)
Hurricane City. 2009. Hurricane City Water Management and Conservation Plan.
IEEE Spectrum. 2008. “How Much Water Does it Take to Make Electricity?” by Willie D. Jones.
Accessed online at http://spectrum.ieee.org/energy/environment/how-much-water-does-ittake-to-make-electricity.
Ivins City. 2008. Water Conservation Plan. December
Kanab City. 2013. Water Conservation Plan. October.
Kane County. 2011. Kane County Resource Management Plan. November 28.
Kane County Assessor. 2015. Email to Lisa Fardal, MWH engineer from Kane County Assessor
office. November 19.
Kane County Water Conservancy District (KCWCD). 2007. Water management and conservation
plan. July 11.
Kane County Water Conservancy District (KCWCD). 2011. Water management and conservation
plan. January.
Kane County Water Conservancy District (KCWCD). 2015. Personal communication with Dirk
Clayson, KCWCD and Brian Liming, MWH via email. November 12, 2015.

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 KCWCD (see Kane County Water Conservancy District)
LaVerkin City. 2010a. LaVerkin City Secondary untreated Water Master Plan. Prepared by Sunrise
Engineering. May.
LaVerkin City. 2010b. LaVerkin City Water Management and Conservation Plan.
Maddaus Water Management (MWM). 2010a. Technical Memorandum No. 2 – Conservation
Technical Analysis. Prepared for Kane County Water Conservation District and MWH. March.
Maddaus Water Management (MWM). 2010b. Technical Memorandum No. 2 – Conservation
Technical Analysis. Prepared for Washington County Water Conservation District and MWH.
August.
Maddaus Water Management (MWM). 2015a. Final Technical Memorandum–Technical
Conservation Analysis. Prepared for Kane County Water Conservation District and MWH.
February.
Maddaus Water Management (MWM). 2015b. Technical Memorandum– Technical Conservation
Analysis. Prepared for Washington County Water Conservation District and MWH. August.
MWH 2013. Kane County Subbasin Water Permits Database Review. Conducted by Alicia DuPree,
MWH Engineer. April 9.
MWH 2015. Lake Powell Pipeline Project, Groundwater Quality Near Johnson Wash. Technical
Memorandum prepared by Patrick Naylor, P.G., P.E., MWH. See Appendix A.
St. George City. (See City of St. George)
St. George Water Services Department. 2004. Annual Water Report. QCWTP Production Per Fiscal
Year 2001-2004.
Santa Clara City. 2009. Water Management and Conservation Plan. Prepared by Sunrise Engineering.
December.
United States Bureau of Reclamation (Reclamation). 2014. Virgin River Climate Change Analysis
Statistical Analysis of Streamflow Projections. Katrina Grantz. March 26.
United States Census Bureau (U.S. Census). 2015. Fact Finder. Available online at
http://factfinder.census.gov/faces/tableservices/jsf/pages/productview.xhtml?src=bkmk
United States Environmental Protection Agency (USEPA). 2008. STORET water quality data for
Virgin River Utah gaging stations. Accessed January 9.

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 United States Geological Survey (USGS). 2013. Scientific Investigations Report 2013–5057. Marston,
T. and V. M. Heilw. Assessment of Managed Aquifer Recharge at Sand Hollow Reservoir,
Washington County, Utah, Updated to Conditions in 2012.
USEPA (see United States Environmental Protection Agency)
USGS (see United States Geological Survey)
Utah Department of Administrative Services (DAS). 2014. Rule R317-2. Standards of Quality for
Waters of the State. Date of Enactment or last Substantive Amendment: July 2, 2014.
Utah Division of Water Resources (DWRe). 1988. Inventory of Reservoirs and Potential Dam Sites
in the Virgin River Basin. December.
__________. 1992. Preliminary Analysis of Potential Dam Sites in the Virgin River Basin.
Preliminary Draft Subject to Revision. January.
__________. 1993. Kanab Creek/Virgin River Basin state water plan. August.
__________. 1999. Water-related land use summary report. March.
__________. 2003. Utah’s municipal and industrial water conservation plan. July.
__________. 2006a. Municipal and industrial water supply and uses in the Kanab Creek/Virgin River
Basin (Data collected for the year 2002). July.
__________. 2006b. Municipal and industrial water supply and uses in the Southeast Colorado River
Basin (Data collected for calendar-year 2005). September.
__________. 2008a. Municipal and industrial water supply and uses in the Southeast Colorado River
Basin (Data collected for the year 2005). June.
__________. 2008b. Virgin River Daily Simulation Model. Virgin River Base Case – 86 cfs with Sand
Hollow optimized 10 percent; SA4, No Lake Powell Pipeline. August 11.
__________. 2008c. Sub-basin Irrigated Lands. KCWCD_Irrigated_Land_Area_from DWRe.xls.
Provided by Todd Adams, DWRe Assistant Director via email to Steve Smith, MWH
engineer.
__________. 2009a. Municipal and industrial water supply and uses in the Kanab Creek/Virgin River
Basin (Data collected for the year 2005). January.
__________. 2009b. Draft Governor’s Conservation Team water use data. Provided by Todd
Adams, DWRe Assistant Director. November.

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 __________. 2010. Municipal and Industrial Water Use in Utah. December.
__________. 2013a. Kanab Creek Virgin River MI 2010 Public Community System Use and
Supplies.xlsx. Email from Todd Adams, DWRe, to Alicia DuPree, MWH engineer.
February 19.
__________. 2013b. Southeast Colorado Basin LPP MI Use and Supply.xlsx. Email from
Eric Klotz, DWRe, to Alicia DuPree, MWH engineer. February 20.
__________. 2013c. M&I Statewide Summary. Provided by Eric Klotz, DWRe. June 12.
__________. 2013d. Kanab/Virgin River Basin DW and WR database query. MWHVirginData.xlsx.
Provided by Eric Klotz, DWRe. June 26.
__________. 2013e. Coral Canyon net evapotranspiration rate for 2009 and 2010. 091613
Evapotranspiration Coral Canyon.pdf. Email from Eric Millis, DWRe, to Brian Liming,
MWH engineer. September 16.
__________. 2013f. Personal communication via email from Aaron Austin, DWRe GIS Analyst to
Lisa Fardal, MWH engineer. October 23.
__________. 2013g. State of Utah Municipal and Industrial Water Supply and Use Study Summary
2010. December.
__________. 2014a. Virgin River Daily Simulation Model Flow Results—90 percent reliability
under current conditions with 50th percentile climate change scenario flows. Provided by
Todd Adams, DWRe Assistant Director. March 29.
__________. 2014b. Kanab Creek/Virgin River Basin 2013 Inventory Report. March.
__________. 2014c. Kanab/Virgin River Basin GPCD Projections and Use to 2060. 111214
KanabVirgin_UseProjections.xlsx. November.
__________. 2015a. Virgin River Daily Simulation Model Flow Results. Provided by Todd
Adams, DWRe Assistant Director. September.
__________. 2015b. Virgin River Daily Simulation Model (Documentation). April.
__________. 2016. Final Groundwater Resources Technical Report. April.
Utah Division of Water Rights (DWRi). 2008a. Ground Water Policy Map. Available online at
http://www.waterrights.utah.gov/gisinfo/maps/agwpol.pdf
Utah Division of Water Rights (DWRi). 2008b. Duty Values. Available online at
http://www.waterrights.utah.gov/gisinfo/maps/aduty.pdf.
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 Utah Governor’s Office of Management and Budget (GOMB). 2005. 2005 Baseline economic and
demographics projections. Subcounty population projections.
__________. 2008. Detailed Demographic and Economic Projections.
__________. 2012a. Population Estimates for the State of Utah and Utah counties 1940 to 2011.
Available
online
at
http://www.governor.utah.gov/dea/popestimates.html.
All_UPEC_Data.xls
__________. 2012b. Total Population by Area, Governor’s Office of Planning and Budget 2012
Baseline Projections. Available online at http://governor.utah.gov/dea/projections.html.
Households by Area (1).xlsx
Virgin River Watershed Advisory Committee (VRWAC). 2006. Virgin River Watershed Management
Plan. February.
Washington City. 2005. Washington City Secondary Water Master Plan. DRAFT. Prepared by Sunrise
Engineering. March.
Washington City. 2010. Water management and Conservation Plan. May.
Washington County Assessor, 2015. Data from District Abstract.pdf. State and Locally Assessed
District Totals. Washington County. As of 10/12/2015.
Washington County Convention and Tourism Office (WCCTO). 2015. Personal communication via
phone between Karry Rathje of WCWCD and Roxie Sherwin, Director of Washington County
Convention and Tourism Office. May.
Washington County Water Conservancy District (WCWCD). 2006. Regional Water Supply
Agreement. April 23, 2006.
__________. 2007. Draft WCWCD water conservation status report. May, 1.
__________. 2008a. Meeting with MWH, regarding yield estimates for WCWCD supplies. January
9.
__________. 2008b. Email from Barbara Hjelle, WCWCD Assistant Manager, to Steve Smith, MWH
Engineer. Re: WCWCD Conservation Efforts, 1995 to 2007. July 7.
__________. 2010. Washington County Water Management and Conservation Plan - Revised.
December 31.
__________. 2014. Washington County Water Conservancy District’s Reliable Supply. DRAFT.
September 29.
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 WCWCD (see Washington County Water Conservancy District)
Western Regional Climate Center (WRCC). 2013. Historical Climate Information, data for St George
COOP site. Available online at http://www.wrcc.dri.edu/index.html.
WRCC (see Western Regional Climate Center)

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 Glossary
Acre-foot – a volumetric unit of water used in water supply planning, which is equivalent to water
spread over an acre of area with a depth of 1 foot (325,851 gallons)
Annual Growth Rate – the yearly compounding increase in a value, used in this report to represent
the yearly rate of growth for population projections
Aquifer – an underground water-bearing geologic formation
Buy and Dry – the conversion of agricultural water rights for other uses, typically through purchase
by municipal and industrial water providers, with a resulting dry-up of irrigated land
Conservation – reduction in per capita water use typically achieved through water savings measures
such as water reuse, efficient lawn watering practices, and low flow water fixtures
Culinary Water – water supply that meets drinking water quality standards and can be used to meet
all water demands (synonymous with potable water)
Groundwater – water contained in an aquifer, and sometimes extracted for water supply (typically
extracted through a groundwater well)
Integrated Water Resources Plan – a balance of forecasted water demands and existing and future
water supply projects, typically prepared for planning the timing and volume of future potential
water supplies
Maximum Annual Supply – the yearly volume of water that could be delivered at the maximum
daily flow rate of a given water supply
Maximum Contaminant Level (MCL) – the greatest level of a particular contaminant within a
water source that is considered to be a threshold for making the water source available for beneficial
use (e.g., a drinking water MCL for total dissolved solids)
Non-Potable Water – water supply that does not meet drinking water standards, which can be used
to meet demands that do not require drinking water quality (e.g., irrigation and lawn watering)
(synonymous with secondary untreated water)
Per Capita Water Use – the average rate of water consumption per person, typically calculated in
gallons per person per day
Permanent Population – the number of residents living in an area that occupy their residences yearround (i.e., not including tourists or part-time residents)

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 Potable Water – water supply that meets drinking water standards, which can be used to meet all
water demands (synonymous with culinary water)
Prior Appropriation Doctrine – a water administration system typically used in the western United
States, which prioritizes water rights by the date that the rights were first administered (i.e., through
seniority of the rights)
Reliable Annual Supply – the annual volume of water that is readily available to meet peak
demands (in this report, reliable supply is based on the Utah Division of Water Resources definition
– the portion of the maximum potable water supply that can be used to meet annual water demands)
Secondary Untreated Water – water supply that does not meet drinking water standards, which can
be used to meet demands that do not require drinking water quality (e.g., irrigation and lawn
watering) (synonymous with non-potable water)
Sustainable Yield – the volume of groundwater that can be withdrawn from an aquifer on an
average annual basis without depleting the long-term storage of the aquifer, which is generally equal
to the amount of recharge to the aquifer
Water Reuse – the use of treated wastewater for a beneficial use, such as lawn and golf course
irrigation or industrial water; potable water reuse refers to the use of treated wastewater to meet
culinary demand
Yield – the amount of water can be delivered from a particular supply, typically given in terms of
annual supply

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 Abbreviations and Acronyms
BOD
CFP
CII
DATC
DWRe
DWRi
ET
GOMB
GOPB
GPCD
KCWCD
LPP
M&I
MCL
MG
mgd
mg/l
MWM
NEPA
RWSA
SITLA
SWAT
TDS
TMDL
TSS
USGS
WCWCD
WCWMCP

Biochemical oxygen demand
Capital Facilities Plan
Commercial/Industrial/Institutional
Dixie Applied Technology Courses
Utah Division of Water Resources
Utah Division of Water Rights
Evapotranspiration
Utah Governor’s Office of Management and Budget (formerly GOPB)
Utah Governor’s Office of Planning and Budget
Gallons per capita per day
Kane County Water Conservancy District
Lake Powell Pipeline
Municipal and Industrial
Maximum contaminant level
Million gallons
Million gallons per day
Milligrams per liter
Maddaus Water Management
National Environmental Policy Act
Regional Water Supply Agreement
Utah State Institutional Trust Lands Administration
Smart Water Applied Technology
Total dissolved solids
Total Maximum Daily Load
Total suspended solids
United States Geological Survey
Washington County Water Conservancy District
Washington County Water Management and Conservation Plan

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 List of Preparers
Name

Degree(s)

MWH Americas, Inc. Consultant Team
M.S. – Water Resources Engineering
Chip Paulson MWH, Inc.
B.A. – Applied Mechanics and Engineering
Science
M.S. – Civil and Environmental Engineering
Brian Liming MWH, Inc.
B.S. – Ecosystems Analysis
M.S. – Civil Engineering
Steven Smith MWH, Inc.
B.S. – Civil Engineering
Alicia (Duran) DuPree MWH,
B.S. – Environmental and Civil Engineering
Inc.
M.S. – Bioresource Engineering
Lisa Fardal MWH, Inc.
B.A. – Biology; Environmental Studies
Kazu Clarke MWH, Inc.
Maddaus Water Management Consultant Team
M.S. – Civil Engineering
Bill Maddaus, MWM
B.S. – Civil Engineering
M.B.A
Michelle Maddaus, MWM
B.S. – Civil and Environmental Engineering

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LP-1

Role

Project Management
Report QA/QC Review
Phase 1 Analysis
Phase 2 Analysis
Phase 2 Analysis
Word Processing and Formatting
Water Conservation Analysis
Water Conservation Analysis

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