United States Department of the Interior NATIONAL PARK SERVICE Carlsbad Caverns National Park 3225 National Parks Highway REPLY REFER TO: Carlsbad, NM 88220 505-785-2232 TRANSMITTED VIA ELECTRONIC MAIL - NO TO FOLLOW November 1, 2016 Memorandum To: Paul Murphy, Project Lead, Bureau of Land Management, Carlsbad Field Of?ce From: Doug Neighbor, Superintendent, Carlsbad Caverns National Park Subject: National Park Service Comments on the Conditions of Approval Proposed for the Chevron U.S.A., Inc. Hayhurst Master Development Plan, Environmental Assessment DOI- BLM-NM-P020-2016-1434-EA On August 29, 2016, the National Park Service (N PS) reviewed and provided comments on the referenced Environmental Assessment (EA), completed in support of the Chevron USA, Inc. Hayhurst Master Development Plan (MDP). These comments are provided as an attachment for reference. In our August comment letter, the NPS raised concerns regarding potential signi?cant adverse effects on ecosystems in nearby Carlsbad Caverns National Park (NP) as a result of excess nitrogen deposition from project-related nitrogen oxide emissions. Accordingly, the NPS recommended that mitigations are necessary to address these predicted signi?cant impacts. We also provided comments on mitigation measures to protect dark night skies in the park. In response to these comments, the Bureau of Land Management (BLM) arranged several follow-up meetings to discuss NPS air resource concerns among representatives from the NPS, the BLM, Chevron and Arcadis (the consultant providing the air quality analysis on behalf of the project). The BLM also provided a response to comments document to the NPS, which proposed several Conditions of Approval (COAs) aimed at mitigating the signi?cant air resource effects. The mitigations described in the response to comments document also addressed dark night skies, however these mitigations are not incorporated as COAs into the Decision Record/Finding ofNo Signi?cant Impact (FONSI). The NPS appreciates the efforts made by BLM and the project proponent to address impacts on air resources in Carlsbad Caverns NP and concurs that such measures are necessary to reduce the potential for signi?cant adverse effects. We also applaud decision to incorporate these air resource COAs into the Decision Record. We recommend that a few changes to the COAs would ensure their effectiveness in addressing any potential adverse effects on park resources from excess nitrogen deposition. These changes are important because even with the proposed NOX mitigation, nitrogen deposition in the park is predicted to exceed the NPS Deposition Analysis Threshold (DAT) for a period of ten years during the drilling phase. We believe these changes will better address NPS concerns related to nitrogen deposition. Air Resource COAs The air resource COAs phase?in the use of engines that are compliant with Tier 4 or equivalent emission standards by year 2020, and cap the annual allowable NOX emissions associated with the project at these levels. As requested by the NPS, these COAs were incorporated in the Decision Record released by BLM. Speci?c NPS recommended changes to these COAs are provided in red text, along with the rationale for each change below. We believe the following revisions to the emission caps for drilling and completion (mobile) engines provided in the second COA are appropriate: 0 During the drilling phase, the operator?s yaw?emit NOX emissions will not exceed ef?263 tons per year (tpy) er?less from nonroad (mobile sources) between Year 1 and Year 3 and 220?7 179 tpy eeless from nonroad (mobile sources) for the remainder of the drilling phase. The recommended revision to the emissions cap for project years four through 11 from Tier 4 drilling and completion engines is based on the difference between the Tier 4 emissions factor for ?large generator sets? greater than 750 hp, (0.5 g/hp-hr, hereafter referred to as ?gen sets?), which phased-in during 2015 and the emission factor for ?all other equipment? (2.6 g/hp- hr, hereafter referred to as ?mechanical rigs?), which phased-in during 2011 . After review of the revised DAT table provided by Arcadis on September 15, 2016 in conjunction with the original emission inventory provided to the NPS in August of 2016, it appears the project proponent assumed drill rig engines would meet the 2.6 g/hp?hr requirement, which is consistent with either the use of mechanical rigs or gen set engines that were manufactured prior to 2015. We recommend it is appropriate to assume that Tier 4 drill rig engines can comply with the 2015 gen set emission factor of 0.5 g/hp-hr, which will reduce the NOX emissions by roughly 100 tpy relative to the 2.6 g/hp?hr assumption. (Note: For the reasons provided below, this estimate does not incorporate the reduced fuel use assumptions provided by Arcadis.) We believe waiting until project year four to implement this requirement for Tier 4 engines allows the operator time prepare for the transition to newer generator sets. The revised emissions information provided by Arcadis on September 15, 2016 included both the Tier 4 phase-in assumptions (2.6 NOx/hp-hr mechanical rigs), along with signi?cant reductions in fuel use assumed for each drilling and completions operation. Based on the original emissions Source: Table ILA-2 and table Control of Emissions of Air Pollution From Nonroad Diesel Engines and Fuel; Final Rule, Fed. Reg. 69, No. 124, 38958 (Tuesday, June 24, 2004) (to be codified at 40 CFR Parts 9, 69, et a1.) inventory provided to the NPS, the assumed reduction in fuel use signi?cantly reduces the assumed hours of operation for each drill rig and completion engine (from 355 to 199 hours/well for drill rig engines and from 261 to 42 hours/well for completion engines). This effectively reduces the emissions by approximately 58 tpy relative to a similar Tier 4 scenario that does not incorporate the reduced fuel use. We question the reduced fuel use assumptions as they result in drill time estimates that are much lower on average than what is assumed for many BLM emission inventories for similar drilling operations horizontal wells) in WY, UT and C02. As such, the NPS did not factor these assumptions into our estimate for emissions from drill rigs powered by Tier 4 generator sets. We would also like to note that the NPS conducted a Level 2 near?eld visibility assessment using the VISCREEN model and the NPS revised emission estimates described above. This assessment indicated that there may be a visible plume in Carlsbad Caverns NP under stable atmospheric conditions early morning hours). This visibility impact assessment highlights the need to mitigate emissions not only to reduce nitrogen deposition impacts, but also to prevent potential near?eld visibility impacts. Finally, we recommend that the emissions tracking mechanism should apply to equipment associated with all phases of development, including drilling and completions, and should be independent of the production emissions cap. The tracking mechanism is essential to ensuring actual emissions are consistent with mitigation measures assumed in the revised air analysis provided in the EA. As such, we believe detailed requirements associated with this tracking mechanism should be incorporated into the COAs, as recommended below. 0 The operator?s emissions will not exceed emit 214 tpy eHess?efNQx?emissiens during production operations, as defined 1n the emission inventory analyzed 1n the Environmental Assessment. - An emissions tracking mechanism will be developed and employed to ensure compliance with the annual NOX emission caps. The operator will submit an equipment list with associated emissions and operating parameters with each Application for Permit to Drill, as well as an annual emissions inventory demonstrating that the production-related and drilling?related emissions are within the limits of the air quality analysis presented within the Environmental Assessment. The annual inventory will provide a list of all equipment operating in the field (including mobile sources) along with associated operating parameters that are relevant to the emissions calculations fuel use, hours of operation, etc). The methods and format for the annual emissions inventory will be developed and approved by the BLM in consultation with the NPS prior to the close of the first annual period of operations approved under EA The annual emissions inventory will be submitted to the BLM within three months after the close of each calendar year and will be made available to the NPS. 2 For example, see the drilling hours per well assumed in emission inventories for other BLM project and planning assessments, including the Bull Mountain project in CO, the Moneta Divide, Cross Bow, Converse County, and Labarge projects in WY and the Moab MLP in UT, which range from 396 to 1560 hours of drill rig operation per well drilled. Night Sky COAs We appreciate BLM's consideration ofthe cumulative impacts of arti?cial light from oil and gas development on night skies. We applaud the inclusion of additional lighting mitigation measures such as full cutoff shielding, a best practice measure that increases ef?ciency and helps prevent . waste light that could diminish the natural darkness of night skies in the area. However, we note that the night sky mitigations were not incorporated as COAS in the Decision Record/Finding of No Signi?cant Impact (FONSI). Please advise the NPS ofthe mechanism through which these mitigations will be implemented. In closing, we again commend efforts to address air resource and night sky impacts to Carlsbad Caverns NP. We believe that this type of mitigation is necessary for all projects moving forward when considering potential cumulative impacts from oil and gas to this park. The Permian Basin has seen a shift towards increasing oil and gas development within in the last several years and has become the leading basin in the nation terms of ongoing drilling, with the number of active drill rigs outpacing previous top contenders, including the Bakken and the Eagle Ford regions3. In short, although the rate of oil and gas development has generally slowed around the country, deveIOpment new well drilling) in the Permian is continuing. Simultaneously, while the oil and gas source sector continues to expand in this region, we are not seeing significant reductions in other nearby stationary sources. We believe innovative approaches to reducing emissions from drilling equipment (including consideration of hydraulic fracturing ?eets) will be necessary. As such, we would like to discuss options to reduce emissions from drilling and hydraulic fracturing operations for future consideration, and could provide a list of specific references to address. This may be best achieved in the context of the revised Carlsbad Field Office Resource Management Plan that is under development. If you have any questions regarding these comments, please contact Andrea Stacy with the NPS Air Resources Division at 303-969-2816, Randy Stanley with the intermountain region?s night sky program at 303-987?6890, or Rodney Horrocks with Carlsbad Caverns NP at 575-785-3105. Sincerely, awaJW/?? Doug Neighbor, Superintendent, Carlsbad Caverns National Park Cc: Mark Foust, Acting Deputy Regional Director, Chiefof Operations, Intermountain Region, National Park Service 3 Permian Basin Drives First-quarter Growth in Oil?directed horizontal Drilling Rigs, EIA, (2014), available at: Attachments: 1. National Park Service Comments on the Chevron U.S.A., Inc. Hayhurst Master Development Plan, Environmental Assessment United States Department of the Interior NATIONAL PARK SERVICE Carlsbad Caverns National Park 3225 National Parks Highway IN REPLY REFER TO: Carlsbad, NM 88220 505?785?2232 TRANSMITTED VIA ELECTRONIC MAIL NO HARDCOPY TO FOLLOW August 29, 2016 Memorandum To: Paul Murphy, Project Lead, Bureau of Land Management, Carlsbad Field Of?ce From: Doug Neighbor, Superintendent, Carlsbad Caverns National Park Subject: National Park Service comments on the Chevron U.S.A., Inc. l-Iayhurst Master Development Plan, Environmental Assessment DOI-BLM-NM-P020-2016-1434-EA The National Park Service has reviewed the referenced Environmental Assessment (EA) completed in support of the Chevron U.S.A., Inc. Hayhurst Master Development Plan (MDP). We appreciate the opportunity to comment on this MDP and discuss the potential impacts to park resources in Carlsbad Caverns Nation Park. The western boundary of the project area is located approximately 17 km from the eastern boundary of Carlsbad Caverns National Park (NP), a Clean Air Act Class I area administered by the NPS. As such, we have a number of comments regarding the potential air resource impacts to resources in Carlsbad Caverns NP as a result of this proposed development. We also have a number of concerns associated with cumulative night sky impacts to this park. In summary: 0 The NPS concludes that as proposed, the project will result in significant adverse effects to the desert ecosystems in Carlsbad Caverns NP due to excess nitrogen deposition (associated with 744 TPY additional emissions from oil and gas drilling and production equipment). As a result, we do not believe the project impacts are congruent with the issuance of a Finding of No Signi?cant Impact. 0 We would like to explore emission mitigation options that may be feasible for this project to eliminate the significant impacts to park resources. a We have signi?cant concerns regarding the cumulative impacts to night skies. We recommend the BLM implement additional BMPs to further mitigate existing and future impacts to night skies 1n Carlsbad Caverns NP. 0 In the future, we recommend that similar projects, particularly ones in proximity to NPS areas follow the collaborative process outlined in the 2011 Air Quality Memorandum of Understanding (MOU) Among the US. Department of Agriculture, US. Department of the Interior and the US. Environmental Protection Agency Regarding Air Quality Analyses and Mitigation for Federal Oil and Gas Decisions Through the National Environmental Policy Act Processl. These comments are discussed in greater detail below. Background Carlsbad Caverns National Park is located in the Guadalupe Mountains, a mountain range that extends from west Texas into southeastern New Mexico, and is situated in the northern portion of the Chihuahuan Desert, the largest and wettest of the North American deserts. Carlsbad Caverns was set aside as a unit of the National Park System in part to preserve and protect the Chihuahuan Desert ecosystem it contains. In addition, other primary purposes of the park are to preserve and prdtect the world- class cave resources and portions of the Captain Reef, which provides opportunity to experience extraordinary scenic vistas (Carlsbad Caverns General Management Plan, 1996). Elevations within the park rise from 3,595 feet (1,095 meters) in the lowlands to 6,520 feet (1,987 meters) atop the escarpment, with scattered woodlands in the higher elevations and a variety of grassland and desert shrubland habitats covering the remaining majority of the park. The park spans two different ecoregions: the ?Temperate Sierras? and the ?North American Deserts.? Much of the park?s backcountry is designated Wilderness, over 33,000 acres, providing outstanding opportunities for solitude and primitive recreation. As such, the park provides a diverse and remote range of habitats. In 1995, the park became a World Heritage Site, demonstrating the outstanding universal value of the park?s natural resources. The park IS also a designated Class I area under the Clean Air Act, giving the federal land manager (FLM) for these areas an ?af?rmative responsibility? to protect the air quality and AQRVs in this park from the deleterious effects of air pollution. Nitrogen Deposition Impacts Based on a CALPUFF modeling analysis using one year of meteorological data, the MDP would result in annual nitrogen deposition of 00122?00159 kg/ha/yr over a ten year period. This Available at: 2 In considering inclusion of Carlsbad Caverns NP as a world heritage site, the UNESCO advisory body summary notes: ?Vegetation communities range from desert to coniferous forest. Some 800 plant species have been identi?ed, of which three are internationally threatened: Sneed pincushion cactus, Lee pincushion cactus and Lloyd's hedgehog cactus. The faunal inventory includes 64 mammals, 331 bird and 44 herpetofauna species. The caves are noted for their migratory bat species, especially the Mexican free-tailed bat whose population is estimated at one million individuals. Various species of fungi and bacteria growing in the caves are of particular scienti?c and medical interest.? The advisory body also identi?ed potential oil and gas development along the park?s boundaries as a ?serious threat? to the site. amount of annual deposition is roughly 144?229% of the NPS Deposition Analysis Threshold (DAT), a threshold used to determine signi?cance/insigni?cance of new sources of emissions. After year ll of the project, the deposition would drop to 0.0053 kg/ha/yr for the remaining life of the project (representing production emissions alone), a level which is just over the NPS DAT. We have concluded that this constitutes a signi?cant adverse effect to park resources based on (1) the current modeled/monitored estimates of cumulative annual deposition loading in Carlsbad Caverns NP and the presence of vegetation types within the park which published science indicates are highly sensitive to excess nitrogen deposition, (2) the magnitude of predicted additional nitrogen deposition as a result of the project emissions, (3) the other site- speci?c factors outlined under Context/Criteria for Evaluating a DATExceedance? below the proximity of the project to the park, the duration of the impact). As discussed here and elsewhere, we recommend NOX mitigation is necessary to address the signi?cant impacts. (1) Park Ecosystems and Current Conditions The Chihuahuan Desert is the most biologically diverse desert in the Western Hemisphere and one of the most diverse in the world. Carlsbad Caverns is ecologically signi?cant in that it contains one of the few protected portions of the northern Chihuahuan Desert ecosystem (GMP, 1996). Many plant and animal species located in the pgl?k are at the limits of their geographic range and the park?s biodiversity is quite high. However, these systems are threatened by external stresses, including nitrogen deposition. Woodland, shrubland, and grassland vegetation types in the North American Deserts Ecoregion, such as those found in Carlsbad Caverns, are known to be highly sensitive to deposition. Nitrogen deposition in these ecosystems may increase the presence of non-native plant species and alter ?re regimes. Critical loads are a tool established by scientists to assist the NPS and other land managers in determining annual levels of cumulative deposition below which park ecosystems would be protected from undesirable change or damage. Critical loads are cumulative deposition thresholds speci?cally linked to the plant and animal communities or species present in a given area or ecosystem indicators). A critical load is de?ned as ?the quantitative estimate of an exposure to one or more pollutants below which signi?cant harmful effects on speci?ed sensitive elements of the environment do not occur according to present knowledge.? The current estimated annual level of total nitrogen (N) deposition at Carlsbad Caverns National Park (CAVE) ranges from 2.7 kg/ha/yr to 3.5 kg/ha/yr,4 which is at or just over the minimum critical load for increases in invasive and lichen community shifts (3.0 kg/ha/yr) in these ecoregionss. When current deposition levels are at or near the critical load, it indicates that negative ecosystem changes may already be occurring in the park. Consequently, the NPS is concerned about additional deposition inputs. Herbaceous vegetation critical loads in arid areas are generally based on the potential spread of invasive grass species due to excess nitrogen. Bromus rubens (red brome), and 3 4 National Atmospheric Deposition Program, 2014. Total Deposition Maps, [version]. [accessed 0305/2016] 5 See Cl. ecoregion 'l'ticnlOl2pdl?. 3 Avena?trua (Wild Oats), are two species of invasive grass found within Carlsbad Caverns NP. Research studies have demonstrated that both species grow faster under conditions of excess nitrogen deposition. Fertilization studies to show change through arti?cially increasing levels of and gradient studies show change across the landscape as deposition increases (Brooks 2003, Allen et al. 2009, Rao et al. 2011). Research at Joshua Tree National Park and in the Mojave Desert has shown that at a deposition rate of 3.0 ng/halyr and above, the excess nitrogen can stimulate additional biomass growth from B. rubens suf?ciently to increase ?re risk through the desert ecosystem which is not adapted to large wild?res (Rao et al. 2010). The growth of invasive grasses also has a direct impact on the richness and diversity of native vegetation (Brooks 2000, Allen et al. 2009, Rao et al. 2011) due to competition for Space and nutrients. Maintaining native plants and natural biodiversity is important when considering the park?s status as a Class I area, maintaining the wilderness character of backcountry areas designated as wilderness (which are difficult to treat for non-natiVe invasives) and in maintaining habitat that is crucial to the species diversity which is noted in the park?s initial consideration as a UNESCO World Heritage site. Additionally, the invasive grass ciliaris, buffel grass, is present in counties adjacent to CAVE, but has yet to be found within the park boundaries. C. ciliaris is an aggressive invader and has been shown to have a positive growth response to increased soil N, allowing it to spread faster into disturbed areas (Lyons et al. 2012, Marshall et al. 2012) when excess nitrogen deposition occurs. Finally, increased atmospheric concentration and deposition can have a toxic effect on sensitive lichen species accustomed to low nitrogen levels, and lead to an increase in species of weedy lichens adapted to higher nitrogen levels (Pardo et al. 201 1, Root et al. 2013). The change in lichen composition removes and/or provides lower quality of food and nesting material for small mammals and birds that inhabit the region. This is important as the park provides habitat for numerous bird species. The park?s draft Natural Resource Condition Assessment states: ?The unique ecosystems and physical formations in Carlsbad Caverns NP provide bird Species with a wealth of habitat types and food sources. While the park is most notable for its expansive cave formations and habitats, a habitat type that is heavily utilized by cave swallows (Petrocheiidon?dva?, the park is also home to several stretches of grassland habitats as well as the desert riparian oasis in the Rattlesnake Springs Unit. Of particular note are the rugged and remote high elevation mesic vegetation communities in Carlsbad Caverns NP (West 2012). The park has con?rmed the presence of 362 bird species within the park and another ?ve species have been identified as probably occurring in the park (N PS 2016). Among the con?rmed species are several birds designated as species of concern by at least one agency. Four bird species in park are listed under the Endangered Species Act (BSA) as either threatened or endangered: the southwestern willow flycatcher (endangered), yellow?billed cuckoo (Coccyzus amertcamrs; threatened), lesser prairie chicken (threatened), and the Mexican spotted owl (Srrix occidentalr's lucida; threatened). The Rattlesnake Springs area of CAVE is of particular importance to several bird species of conservation concern, especially riparian obligate species such as the Bell?s vireo (Vireo bclh'i; state?threatened Species) and the yellow-billed cuckoo. The southwestern willow ?ycatcher has also been observed in this habitat type, and may potentially breed there (Powell 2009).? (2) Deposition Due to Project Emissions Given the proximity of the proposed development area to Carlsbad Caverns NP and the magnitude of the anticipated annual emissions, the modeled deposition from this proposal signi?cantly exceeds the NPS DAT, indicating that this project may exacerbate existing deposition impacts to park ecosystems resulting from an estimated exceedance of the critical load. It is important to note that the DAT is a tool for evaluating the signi?cance of a project?s contribution to deposition in a given area. A project contribution to deposition that is below the DAT is considered insigni?cant. A project contribution to deposition that is above the DAT is scrutinized more closely. (3) Context/Criteriafor Evaluating a DAT Exceedance Factors such as the magnitude of the exceedance, any proposed mitigation, the 1eso111ce(s) impacted and their signi?cance to park protection, regional changes in emissions and other considerations speci?c to the area impacted are all consideled when determining whether an exceedance of the DAT ls adverse. Speci?cally, 1n this circumstance: - Regional air quality modeling analyses (including the recently completed Carlsbad RMP analysis) predict that air quality is unlikely to improve in near- term within the life of this project) and that cumulatively, oil and gas development makes a signi?cant contribution to air quality and AQRV impacts in this region. 0 As demonstrated above, the NPS believes that the ecosystems in Carlsbad Caverns NP may be at a tipping point for harmful effects associated with nitrogen deposition it is estimated that deposition is at the CL value for this region). - Carlsbad Caverns is ecologically signi?cant in that it contains one of the few protected portions of the northern Chihuahuan Desert ecosystem (GMP, 1996). As such, ecological impacts from deposition in this park are given signi?cant weigh. a The magnitude of the annual DAT exceedances due to MDP?associated activities are signi?cant, the predicted project-caused deposition is almost two and a half times the DAT threshold. In addition, as described below, if any potential sources are missing from the inventory, the deposition impacts may be underestimated. - The duration of DAT exceedance is projected to last many years (at least a decade or more) 5 For more information on how the NPS evaluates depositiou impacts, see the Federal Land Managers? lnteragency Guidance for Nitrogen and Sulfur Deposition Analyses (November 2011), Natural Resource Report 1/465, available at: CL Guidance The proximity of the project to the park. In this circumstance, considering all of these factors, we recommend that additional mitigations are necessary to avoid signi?cant impacts associated with nitrogen deposition in Carlsbad Caverns NP from activities approved under this EA. Emissions rWitigatt'on Equipment associated with the drilling, completion and production operations are anticipated to emit 744 TPY of in the maximum emission year, which is estimated to be project year 9. Of these emissions, roughly 70% are attributable to the drilling operations (including drilling and completion), 15.5% are attributable to the compressors (7 total) and roughly 13.7% are attributable to the separator heaters located at centralized tank batteries (the remainder is other miscellaneous small equipment). We have provided a list of potential mitigation measures that primarily target emissions from drilling and compression engines and separator heaters, and would like discuss the feasibility of implementing these measures with the BLM and the operator. We recommend that any mitigation measures implemented to avoid significant impacts are implemented at Conditions of Approval (COAs) through this EA and in subsequent applications for permits to drill (APDS). Finally, we have questions regarding the emission inventory assumptions that we would like to discuss with the BLM and the operator. (1 Reduction Options for Drilling and Completion Engines: These engines constitute the majority of the project emissions, therefore, our recommendations focus on these sources. Currently, the MDP proposes to use Tier [1 engines for drilling and completion operations. These engines would emit an estimated 522.7 TPY of in the maximum drilling years. We would like to discuss the feasibility of the following options for reducing emissions with the BLM and the operator: 0 Use of all Tier 4 compliant engines: It is important to clarify that we are speci?cally requesting the BLM and operator consider the feasibility of using Tier 4 compliant generator sets for all drilling and completion operations, this would require the use of generator sets in conjunction with electric motors to power equipment, rather than mechanical engines/rigs? If this option were implemented, engines would meet the 0.5 NOx/hp-hr and would reduce drilling and completion emissions by roughly 90%. This option was deemed feasible by the four corners air quality task force. We recognize that ?eet turnover would likely need to occur to fully implement these types of engines; however, due to the large reduction in emissions, we recommend that this option be considered. - Retrofit of Tier 2 engines with Selective Catalytic Reduction (SCR): We note that the addition of SCR systems to generator sets has been successfully demonstrated in the Jonah-Pinedale field in Wyoming, achieving 80% to 7 Mechanical engines have a emission factor of2.6 g/hp-hr. 6 upwards of 90% reductions in emissions from these enginesg. reduction requirements were implemented in response to concerns regarding visibility impairment in the nearby Wind River Wilderness, a Class I area managed by the USPS. Operators and control system manufacturers have been able to overcome dif?culties associated with installing SCR on engines used for drilling operations, including accommodating ?uctuating loads and exhaust temperatures, extreme swings in weather conditions and portability. This option was deemed feasible by the four corners air quality task force and we recommend that this technology be considered as part of a reduction strategy. 0 Use of natural gas-?red or dual-fuel engines: Both natural gas-?red and dual? fuel engines have proven to be feasible, cost effective options for drilling operations in various basins throughout the United States and Canada.91 We note that publicly available data shows that EQT, Apache Corporation, Chesapeake Energy, Statoil, Encana Corporation, Cabot Oil and Gas, Antero Resources, CONSOL Energy and Seneca Resources have all successfully employed natural gas?fired or dual??le] engines for drilling operations. Lique?ed Natural Gas (LNG) and dual-fuel engines have also been successfully employed in completion (hydraulic fracturing) operations.?12 This is most clearly highlighted by Chesapeake Energy?s move in 2011 to transition all of its hydraulic fracturing equipment to LNG. The use of natural gas??red and dual- fuel engines can achieve upwards of an 85% reduction in emissions (relative to Tier 1 engines) .14 We recognize that natural gas-fired and dual-fuel engines may not be suitable for all operational circumstances; however, given that they have been successfully implemented by numerous operators in a variety of areas and operations, we strongly recommend that their use he considered. - Electri?cation of drilling operations: This option would virtually eliminate emissions from the drilling phase and has been used successfully in the 8 See lntermountain Oil and Gas BMP Project, available at: the Four Corners Air Quality Task Force Report of Mitigation Options for the Oil and Gas Industry, available at: Report FINAL OilandGas.ndf. 9 David Hill, ?Encana Initiative Underscores Environmental, Economic Bene?ts Of Powering Rigs On Natural Gas,? The American Gas Reporter, Aug. 2011, '0 Charlie Riedl, ?Natural Gas Gaining Ground As Fuel,? The American Oil Gas Reporter, Oct. 2014, David G. Gallagher, ?Bifueling Big Step In Fracturing Future,? The American Oil Gas Reporter, July. 2013, 12 Kulkarni, P. Gas-Driven Hydraulic Fracturing and Drilling Cut Costs, Reduce Environmental Impact. Gulf Publising Company. ?3 Chesapeake Energy. (2011). Chesapeake energy corporation unveils bold plan to transform U.S. transportation fuels market and reduce OPEC oil imports [Press release]. Retrieved from 1 1-1 ?4 See Four Corners Air Quality Task Force Report of Mitigation Options for the Oil and Gas Industry, available at: Report FINAL OilandGas.ndf. 7 Marcellus shale by CONSOL Energy.? We recommend that electri?cation of drilling operations be considered for the I-layhurst project given that electric power may be available in the MDP area. I Phased drilling approach: One remaining option is to limit the number of drilling and/or fracturing operations that can occur simultaneously to a level that eliminates the signi?cant adverse effects of nitrogen deposition, as demonstrated through modeling. (2) Reduction Options for Compressors: As proposed, the compressors are well controlled at 0.5 g/bhp-hr NOX for the small compressors (1,380 bhp/unit) and 0.3 g/bhp-hr for the large compressors (5,000 bhp/unit). As such, we believe the only remaining option to reduce emissions from the compressors would be to electrify the compression. Based on the EA, the operator is already proposing to build a substation to power gas lift pump systems and chemical injectors. We request that BLM consider whether electrification of the compressors is feasible for this MDP area. (3) Reduction Options for Separator Heaters: In addition, we recommend that using the minimum temperature necessary and insulating separator heaters (heater treaters) can minimize NOX emissions through reduced fuel usage for this equipment. We recognize that quantification of emission reduction from this recommendation is difficult; however, this recommendation would be relatively easy to implement and likely cost neutral as a result of reduced fuel usage. (4) Additiona! Mitigation Measures: As noted, we would like the BLM and the operator to address these recommendations and speci?cally, their feasibility for operations in the MDP area. We welcome input regarding any additional options for emission reductions (or combination thereof) that may achieve the same level of control necessary to reduce the signi?cant adverse effects. (5) Conditions of Approved: We believe any NOX emission reductions identi?ed and agreed to would need to be implemented through COAs in the ?nal EA and subsequent APDs. If a ?mitigated? finding of no significant impact (FONSI) is the ?nal decision document, the COAs should also be referenced in and incorporated into the FONSI associated with the MDP to ensure they are carried into subsequent APDS. (6) Emission Inventory Assumptions: We have several questions regarding the emission inventory assumptions for fuel usage for drilling operations, and whether completion ?aring should be included in the inventory. These assumptions impact the estimated emissions from drilling rigs and completion operations. We note that while this is important for determining the level of impact, we do not anticipate that the answer to this question will affect the mix of sources we should focus on to achieve reductions. '5 Timothy Puko, ?Consol Energy to reduce air pollution of airport drilling with electric engines,? Pittsburgh Tribune-Review, Dec. 2013, 8 . The emissions inventory assumes that Drill Rigs operate 355 hours per well (or roughly 15 days assuming 24-hr operation) and that completion rigs will operate 261 hours per well (or roughly 11 days assuming 24-111' operation). However, page 2-15 of the EA states: well is expected to require 24 to 60 days to drill and an additional 34 to 47 days to complete.? We request two points of clarification regarding these assumptions: (1) The operating hours assumed in the inventory are calculated based on the fuel consumption for each engine type (gal/well). The footnotes in the inventory state that the gal/well estimates are based on ?historical fuel consumption records provided by Chevron.? Are the historical fuel consumption records speci?c to this area not part of a national or regional average) and for similar well types unconventional multi-lateral wells rather than conventional wells)? Please provide the additional information that was used to develop the fuel consumption estimates. (2) Recognizing that there will be some downtime during drilling, please explain the large discrepancy between the estimates disclosed on page 2-15 of the BA for drilling and completion time and those assumed in the emissions inventory. 0 The emissions inventory does not include any emissions associated with completions ?aring. Please clarify whether ?are devices will be used for any period of time during completion operations, or whether gas produced during completions will be routed to a gas gathering system. er A 0R Impacts If additional reductions were to be obtained, we believe that these could address other regional AQRV concerns, such as visibility impairment and increased ozone levels (recognizing that CALPUFF does not simulate ozone). In our recent review of the administrative DEIS for the Carlsbad FO (CFO) RMP, we noted that we have signi?cant concerns regarding the predicted cumulative ozone, nitrogen deposition and potential visibility impacts in Carlsbad Caverns NP. We have raised these concerns, and the need for associated mitigation, in previous communications including comments on the CFO RMP air quality technical support document (2013 through 2014). Additional reductions from this project will also address ongoing concerns regarding other adverse effects to AQRVs from cumulative oil and gas development. We would like to note that very little information regarding the visibility analysis methods for the Hayhurst project is provided in the EA. Additional time is necessary for the NPS to review the visibility modeling analysis, and note that generally, it is preferable to work through these steps well before the EA is released for public comment (see MOU comments below). As stated in our comments on the RMP, the FLMs do not agree with the visibility analysis methods utilized in the RMP assessment.16 It is unclear at this time whether similar deviations from FLM It appears the reported visibility results in table 4.2?1 15 ofthe RMP ADEIS were arbitrarily reduced, and do not re?ect the actual magnitude of modeled visibility impacts according to FLM recommended analysis procedures. Page 4-236 states: ?The absolute total number ofdays ofsigniticant visibility changes (greater than 0.5 delta-dv and greater than 1.0 delta-dv) calculated 9 recommend methods were used in the MDP analysis. As such, we cannot conclusively comment on the predicted visibility impacts from MDP-related activities. Air Quality MOU As noted above, this project falls under the scope of the MOU among the US. Department of Agriculture, U.S. Department of the Interior and the U.S. Environmental Protection Agency Regarding Air Quality Analyses and Mitigation for Federal Oil and Gas Decisions Through the National Environmental Policy Act Process. 17 We appreciate that BLM is now reaching out to the NPS regarding this project, and working to resolve NPS concerns. We believe that recent efforts are consistent with the goals of the MOU. However, for future projects that may impact Carlsbad Caverns (or any other NPS unit), we recommend that a technical workgroup is convened and the MOU procedures are implemented ?early in the planning process,? pre? scoping or well before the public comment period as specified in the MOU. The MOU establishes a collaborative process for analyzing and mitigating impacts to air resources for federal oil and gas planning, leasing and development. When implemented, we believe the MOU process can facilitate the resolution of many issues in advance of the public comment period. Night Sky Impacts We greatly appreciate BLM's inclusion of dark night skies in the affected environment, section 3.14, as well as the discussion of cumulative impacts and proposed mitigation measures. Given the number of proposed wells (up to 436 wells on 109 well pads) and the existing impacts from oil and gas development in the area of in?uence, we are concerned about cumulative impacts to night skies. Publicly available data show that sky glow in the area is growing, and more effective BMPs with mitigation of gas ?aring may be needed. The image below from the New World Atlas of Arti?cial Brightness shows extensive existing sky glow impacts from nearby oil and gas development extending across Carlsbad Caverns National Park and into Guadalupe Mountains National Park. The light sources from oil and gas development are very substantial?; light from this development essentially dwarfs light from the town of Carlsbad (See Figure 1 in Attachment 1 - the large orange area northeast of Carlsbad Caverns National Park). for base year 2008, base case 2017, and future RFD alternatives is 366 days (every day of a leap year). Therefore, to show relative impacts among the alternatives with respect to the base case emissions scenarios, the calculated delta-dv (change in visibility) was divided by 15 for each day before counting and reporting the number of days above the thresholds. This essentially equates to evaluating impacts for thresholds of 7.5 delta-dv and 15 delta-dv." 1? AQ MOU Section VB: ?When preparing an Environmental Assessment for a Federal oil and gas decision where air quality or AQRVs are issues warranting NEPA analysis, the Lead Agency will consider following the procedures established in this MOU and the Appendix." In Section the MOU list criteria for determining when air quality or AQRVs may be affected (and thus modeling should be implemented). One ofthese criteria is "proximity" to a Class 1 or sensitive Class 11 area. '3 For more information on oil and gas impacts to night skies in the Permian Basin Upgraded Rig Lighting improves Night Time Visibility While Reducing Stray Light and the Threat to Dark Skies in West Texas, SPE- 2015. Summary at: . 10 While ideally it is true that in the absence of existing impacts, ?implementation of BMPs for light ?xtures would minimize the potential for sky glow and glare," as stated in the Cumulative Impacts section, this may be questioned in areas where sky glow and glare are already extensive. Impacts on the bat population of Carlsbad Caverns National Park should be addressed. There is growing evidence of arti?cial light impacts on wildlife, as documented in a new NPS publication: ?Arti?cial night lighting and protected lands: Ecological effects and management approaches? We would appreciate addition of this reference to the EA. See also: Stone, E. L., S. Harris, and G. Jones. 2015. Impacts of arti?cial lighting on bats: a review of challenges and solutions. Mammalian Biology- ?ir Sangetierkunde 80:213?919. Therefore, we are concerned that more substantial BMPs may be necessary for both existing and future operations to minimize cumulative impacts that are already substantial. We reSpectfully recommend that full cutoff shielding is incorporated in the list of lighting mitigation measures, as follows: 0 Chevron will use minimal light necessary for site safety, security, and operations. a Light will be directed downward or only where needed. 0 Low-pressure sodium lamps, such as yellow LED lighting or equivalent, will be used to reduce sky glow and wildlife impacts. - Properly shielded (full cutoff preferred) and mounted light ?xtures would be used to reduce sky glow from upward pointing light, as well as trespass from light falling outside of desired area of illumination. The need for more effective BMPs also applies to gas ?aring. When there are hundreds of wells, even a few exposed gas ?ares can produce signi?cant impacts for miles. Letters by private citizens indicate that looking to the east from Carlsbad Caverns National Park, 25 or more exposed gas ?ares can now be seen lighting up the sky on any given night. As noted above, it is unclear whether completions flaring will be implemented. If ?aring will be utilized in the MDP area, we strongly recommend the following BMP for new and existing operations: - Produced or recycled gas will not be ?ared at night except for instances where flaring is necessary to protect operating personnel or to ensure the safe operation of surface facilities. Options to avoid nighttime ?aring of gas may include storage. In those instances when nighttime flaring of gas is required, a visual screen or enclosed combustion chamber ("combustor") will be used to prevent adverse impacts on nearby national parks. In closing, thank you for reaching out to the NPS regarding the proposed project and the predicted deposition impacts in Carlsbad Caverns NP. We believe the opportunity to discuss and ultimately implement and night sky mitigation options is invaluable to protecting resources at Carlsbad Caverns NP, a park that has been identi?ed as having numerous outstanding world-class resources through its international recognition. As stated previously, we do not believe the air resource impacts from the proposed project are congruent with the issuance of a FONSI. We also have signi?cant concerns regarding the cumulative impacts to night skies. ll We look felward to ?nding mutually agreeable solutions to resolve these issues, and recognize that such solutions should address the planning needs as well as the NPS concerns regarding signi?cant adverse effects. If you have any questions regarding these comments, please contact Andrea Stacy with the NPS Air Resources Division at 303?969~2816 or Randy Stanley with the intermountain region?s night sky program at 303-987-6890 or Rodney Horrocks with Carlsbad Caverns NP at 575-785-3105. Sincerely, WJW Doug Neighbor, Superintendent, Carlsbad Caverns National Park Cc: Collin Campbell, Deputy Regional Director, Chief of Operations, lntermountain Region, National Park Service Attachments: I. Maps and Figures 2. Citations Attachment 1: Maps ?1317343? 1'3- ?122% @1an [Carts-bf?; Caverns NatlonalPark- Vegetation 59' m3: . 77' Ecosystem Component (Critical Load - kyhaiyr) - Grassland (3.0 - 8.4) Shrubland (3.0.3.4) (3.0- 3.4) Other Io . 25' I Map 1: Locations in Carlsbad Caverns National Park having vegetation types characterized by the presence of plant communities expected to be most sensitive to deposition, based on nutrient critical load values compiled by Allen and Geiser (20] 1). l3 Arti?cial Sky 3d a a Signln la?cnd Map 2: Sky glow impacts from nearby oil and gas emit-lending across Carlsbad Caverns National Park and into Guadalupe Mountains National Park. 14 Attachment 2 Citations Allen, E. B., L. E. Rao, R. J. Steers, A.- Bytnerowitcz, and M. E. Fenn. 2009. Impacts of atmospheric nitrogen deposition on vegetation and soils in Joshua Tree National Park. Pages 78-100 in R. H. Webb, L. F. Fenstermaker, J. S. Heaton, D. L. Hughson, E. V. McDonald, and D. M. Miller, editors. The Mojave Desert: Ecosystem Processes and Sustainability. University of Nevada Press, Las Vegas. Brooks, M. L. 2000. Competition between alien annual grasses and native annual plants in the Mojave Desert. American Midland Naturalist 144:92-108. Brooks, M. L. 2003. Effects of increased soil nitrogen on the dominance of alien annual plants in the Mojave Desert. Journal of Applied Ecology 40:344-353. Lyons, K. G., B. G. Maldonado-Leah and G. Owen. 2012. Community and Ecosystem Effects of Buffelgrass (Pennisetum ciliare) and Nitrogen Deposition in the Sonoran Desert. Invasive Plant Science and Management 6:65-78. Marshall, V. M., M. M. Lewis, and B. Ostendorf. 2012. Buffet grass (Cenchrus ciliaris) as an invader and threat to biodiversity in arid environments: A review. Journal of Arid Environments 7811-12. Pardo, L. H., M. E. Fenn, C. L. Goodale, L. H. Geiser, C. T. Driscoll, E. B. Allen, J. S. Baron, R. Bobbink,'W. D. Bowman, C. M. Clark, B. Emmett, F. S. Gilliam, T. L. Greaver, S. J. Hall, E. A. Lilleskov, L. Liu, J. A. K. J. Nadelhoffer, S. S. Perakis, M. J. Robin- Abbott, J. L. Stoddard, K. C. Weathers, and R. L. Dennis. 201 1. Effects of nitrogen deposition and empirical nitrogen critical loads for ecoregions of the United States. Ecological Applications 21:3049-3082. Rao, L., R. Steers, and E. Allen. 201 1. Effects of natural and anthropogenic gradients on native and exotic winter annuals in a southern California Desert. Plant Ecology 212: 1079-1089. Rao, L. E., E. B. Allen, and T. Meixner. 2010. Risk-based determination of critical nitrogen deposition loads for ?re spread in southern California deserts. Ecological Applications 20:1320-1335. Root, H.T., L.H. Geiser, ME, Fenn, S. Jovan, M.A. I-Iutten, S. Ahuja, K. Dillman, D.Schirokauer, S. Berryman, .A. McMurray. 2013. A simple tool for estimating throughfall nitrogen deposition in forests of western North America using lichens. Forest Ecology and Management 306: 1?8.