PNWR__Draft_Environmental_Assesment_0001.pdf

Draft Environmental Assessment Proposed Upper Lake Dam Modernization and Water

Management Improvements Pahranagat National Wildlife Refuge

Prepared for:

U. S. Fish and Wildlife Service

Pahranagat National Wildlife Refuge Alamo, Nevada

Prepared by:

Harris Environmental Group

December 2023

Pahranagat National Wildlife Environmental Assessment

Table of Contents

I. PURPOSE AND NEED

Introduction

Description of the Proposed Action

Purpose and Need for Action

The Decision to be Made

II. ALTERNATIVES

Alternative A – No Action Alternative

Alternative B – Proposed Action

III. AFFECTED ENVIRONMENT

General Site Information

Resource Topics Eliminated from Detailed Analysis

Resource Topics Analyzed in Detail

Geology and Soils

Water Resources

Air Quality

Biological Resources

Cultural Resources

Public Use

Socioeconomics

IV. ENVIRONMENTAL CONSEQUENCES

Alternative A – No Action Alternative

Geology and Soils

Water Resources

Air Quality

Biological Resources

Cultural Resources

Upper Lake Dam Modernization and Improvements i

Public Use

Socioeconomics

Environmental Justice

Cumulative Impacts

Alternative B – Proposed Action

Geology and Soils

Water Resources

Air Quality

Biological Resources

Cultural Resources

Public Use

Socioeconomics

Environmental Justice

Cumulative Impacts

V. COORDINATION WITH OTHERS AND ENVIRONMENTAL COMPLIANCE

Tribal and Agency Consultation

Public/Stakeholder Availability

Environmental Compliance

Relationship to Statutes, Regulations, or other Plans

VI. ACRONYMS & ABBREVIATIONS

VII. REFERENCES

APPENDIX 1. BEST MANAGEMENT PRACTICES

APPENDIX 2. USFWS IPAC CONSULTATION

APPENDIX 3. CULTURAL RESOURCES CORRESPONDENCE

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List of Figures Figure 1: Pahranagat National Wildlife Refuge Study Region, Lincoln County, Nevada

Figure 2: Pahranagat National Wildlife Refuge Study Area, Lincoln County, Nevada

Figure 3: Pahranagat National Wildlife Refuge Soils, Lincoln County, Nevada

Figure 4: Pahranagat National Wildlife Refuge Study Area Wetlands, Lincoln County, Nevada

Figure 5: Northern extent of the proposed Upper Lake Dam with respect to wetlands

Figure 6: Southern extent of the proposed Upper Lake Dam with respect to wetlands

Figure 7: Location of open water springs on the PNWR

List of Tables

Table 1: Acreage of the Proposed Action area with respect to NWI wetland type

Table 2: Lincoln County Water Withdrawals, Estimated by Type in 1995. Source: Nevada Division of Water Planning 1997

Table 3: National Ambient Air Quality Standards (EPA 2021a)

Table 4: Global Warming Potential of GHGs

Table 5: USFWS and NDOW Priority Species

Table 9: Amount of habitat potentially affected by wetland type

Table 10: Laws and regulations

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I. PURPOSE AND NEED

Introduction This Draft Environmental Assessment (EA) has been prepared to assist the U.S. Fish and Wildlife Service (USFWS) in evaluating the alternatives and environmental impacts of modernizing the current, aged, infrastructure responsible for receiving and holding summer water rights that is used to maintain lacustrine (shallow open water wetlands) and palustrine (emergent vegetation wetlands) ecosystems on the Pahranagat National Wildlife Refuge (PNWR) in Lincoln County, Nevada. In 1963, 3,916 acres of lakes, marshes, meadows, and desert uplands were designated by the USFWS as the PNWR; this has since been expanded to 5,382 acres as a refuge and breeding ground for migratory birds and other wildlife (USFWS 2017a). This assessment is being used to determine whether implementing the Proposed Action will have a significant impact on the quality of the natural and human environments. The USFWS has conducted an analysis and evaluation of the environmental consequences of implementing the Proposed Action and the No Action Alternative on the PNWR. This impact evaluation has considered all aspects of the affected environment, including physical, biological, cultural, and socioeconomic resources that are relevant to the Proposed Action. It is part of the USFWS’ decision-making process in accordance with the National Environment Policy Act (NEPA) of 1969, as amended.

This EA will assist the USFWS in deciding as to whether any “significant” impacts could result from the Proposed Action or the No Action Alternative. “Significance” is determined by the consideration of context and intensity of the impacts. Should a determination be made that implementation of the Proposed or Alternative actions would not result in “significant environmental impacts” or “significant environmental impacts beyond those already disclosed in the existing NEPA documents,” a Finding of No Significant Impact (FONSI) will be prepared to document that determination.

Description of the Proposed Action The USFWS proposes improving approximately 4,400 feet of an earthen water delivery ditch;

rehabilitating approximately 1,200 feet of Upper Lake Dam; creating approximately 100 feet of new diversion channel into critical nesting habitat for the federally-endangered southwestern willow flycatcher (Empidonax traillii extimus); modernizing current water monitoring stations; and improving approximately 640 feet of the Pahranagat Ditch Drain (Figure 1).

Purpose and Need for Action The USFWS is requesting approval of funds to implement these enhancements to improve the integrity of the Upper Lake Dam, North Marsh Inlet, and Upper Supply Ditch. Since 1963, PNWR has provided habitat for migratory birds, especially waterfowl by managing water through a series of culverts, dikes, ditches, water control structures, and the Upper Lake Dam. Most of the infrastructure at the Pahranagat Drain, Upper Lake, and Upper Supply Ditch have been in place for 30-80 years. PNWR has been targeting and completing infrastructure improvements to address the inefficiencies of the water and wetland

Upper Lake Dam Modernization and Improvements 1 management systems through a variety of avenues, such as the USFWS deferred maintenance and Southern Nevada Public Land Management Act (SNPLMA) funding processes.

The purpose of the Proposed Action is to: modernize existing aged infrastructure; improve water delivery from the Upper Lake; and modernize the water monitoring system. The completion of the proposed action will: improve water delivery to each wetland unit; decrease water loss; eliminate water loss through permeable soils; reduce detrimental erosion; complete the PNWR water conservation plan and ensure that over 1,800 acres of rare wetland habitats in southern Nevada will persist for the next 50 years.

These improvements will result in significant habitat improvements for myriad bird species. Special attention will focus on providing optimal southwest willow flycatcher (SWFL) nesting habitat conditions;

open water habitat is available for migrating and nesting waterbirds such as grebes (Podicipedidae), loons (Gavia spp.), and white pelicans (Pelecanus erythrorhynchos); and ensure the management of 1,800 acres of marsh habitats for nesting, migrating, wintering marsh birds, waterfowl, shorebirds, raptors, and wading birds. In addition to providing critical wetland habitat for migratory birds, the improvements will enhance the flood control holding capabilities of the Upper Lake for the Pahranagat Valley, and provide secure flood protection for Highway 93.

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Figure 1: Pahranagat National Wildlife Refuge Study Region, Lincoln County, Nevada.

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The Decision to be Made As required by NEPA and its implementing regulations, preparation of an environmental document must precede final decisions regarding the proposed project and be available to inform decision-makers of the potential environmental impacts of selecting the action. The analysis in this EA evaluates the potential environmental consequences of the Proposed Action and the No Action Alternative. Upon completion of the EA process, the USFWS will then decide based on the analysis within this EA, which will conclude with a FONSI, a Notice of Intent (NOI) for an Environmental Impact Statement (EIS), or the No Action Alternative.

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II. ALTERNATIVES

Alternative A – No Action Alternative The No Action Alternative would maintain the status quo. Structures and improvements will not be installed and updated to modernize PNWR’s water-holding capabilities through the Upper Lake. The water delivery system and dam would remain in their current form and continue to provide inefficient delivery and deteriorate.

Alternative B – Proposed Action Modernize PNWR’s water-holding capabilities through the Upper Lake (Figure 2).

Under this Alternative, the following would be implemented:

• A construction design to determine appropriate improvements, materials, construction sequencing, and best management practices (BMPs).

• Complete improvements on approximately 640 feet of the Pahranagat Drain Inlet access and water monitoring system.

• Rehabilitate approximately 1,200 feet of Upper Lake Dam into Nevada Department of Environmental Protection compliance.

• Improve emergency water conveyance from the Upper Lake Dam into nearby wetland units by replacing two existing non-functioning 24-inch culverts with two 36-inch structures that will direct water directly into surrounding wetlands.

• Improve and modernize approximately 4,400 feet of water delivery system from Upper Lake Dam to the pipeline inlet structure to decrease water loss through filtration to insignificant levels.

• Improve the water routing system in the Upper Supply Ditch by modernizing approximately seven water control/culvert structures.

• Create approximately 100 feet of new SWFL diversion channel into North Marsh, to allow Pahranagat Drain spring and summer flows to directly enter critical SWFL nesting habitat.

• Modernize water monitoring stations by installing two digital flow meters with data loggers (Pahranagat Drain and Upper Supply Ditch) to eliminate flow estimations and improve water budgeting and reporting of water rights.

• Restoration of approximately three acres of grassland habitat on the Upper Lake Dam, approximately six acres of riparian habitat, and approximately 7 acres of invasive species management on disturbed sites within the nomination Area of Interest (AOI).

The equipment used for the proposed action will likely be excavators and trucks with trailers moving along the construction zone. The staging area has not been determined, but will likely consist of up to three possible locations. The width of the corridor will likely be approximately 40 feet; however, this value is unconfirmed as this will be a design-build project. Access points will be the existing access points for refuge equipment, including Dove Dike, Wildlife Habitat Improvement of Nevada (WHIN) Marsh Dike, and the closed portion of old Highway 93 south of Middle Marsh Park. The estimated timeline to complete the construction of the project is approximately four months.

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Figure 2: Pahranagat National Wildlife Refuge Study Area, Lincoln County, Nevada.

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III. AFFECTED ENVIRONMENT

The Affected Environment includes the existing environment (i.e., the physical, biological, social, and economic values and resources) potentially affected by changes that would occur due to implementing the Proposed Action. Federal regulations (40 Code of Federal Regulations [CFR] §1500 et seq.) require certain topics to be addressed as part of a NEPA analysis. Resource areas that could be affected by the Proposed Action have been selected to allow for a comprehensive analysis of potential impacts. The baseline conditions presented in this chapter are described to the level of detail necessary to support the analysis of potential impacts presented in Chapter 4, Environmental Consequences.

General Site Information The PNWR is managed by the USFWS under the Department of the Interior (DOI) and is a unit of the National Wildlife Refuge System (NWRS). The PNWR is part of the Desert National Wildlife Refuge (NWR) Complex, which consists of four refuges located in southern Nevada: Desert NWR, Pahranagat NWR, Ash Meadows NWR, and Moapa Valley NWR. The PNWR (“Refuge”) was established on August 16, 1963, to provide habitat for migratory birds, especially waterfowl (USFWS 2017a). It spans just over 5,380 acres and is surrounded by the Mojave Desert, acting as an ecological oasis of lakes, marshes, wet meadows, and desert uplands (USFWS 2017a). The PNWR is located approximately 10 miles south of the town of Alamo, or 90 miles north of Las Vegas (Figure 2) in Lincoln County, Nevada. The PNWR borders the Pahranagat Valley to the north, the Delamar Valley and the Delamar Mountains to the east, the Sheep Range to the south, and the East Pahranagat Range to the west (USFWS 2009a).

The White River, an ancient perennial river that was formerly a tributary of the Colorado River, flowed through the Pahranagat Valley from the north, forming a distinct but relatively narrow floodplain. The riverbed is dry for many miles north and south of Pahranagat Valley, but large, thermal springs along the flood plain cause the emergence of perennial water in the valley. Sitting at slightly less than 4,000 feet above sea level, the Refuge is comprised of a ten-mile stretch of Pahranagat Valley and associated desert uplands. Perennial water is stored in the Refuge's Upper Lake and North Marsh and is released to create conditions that enhance the presence of plants used as food by wildlife and to supplement lakes, marshes, and grasslands south of the Refuge Headquarters (USFWS 2012b). The diversity of habitats found at the PNWR ranges from Mojave/Great Basin Desertscrub to marsh and open water, and provides excellent habitat for a stunning variety of wildlife species. Pahranagat NWR lies within the Mojave Desert bioregion and is characterized by a semi-arid climate. Rainfall is seasonal, occurring mainly between January to March with a spike in summer rains in July, averaging 6.6 inches per year. Temperatures typically range from 24 °F to 58 °F from December through February and 57 °F to 99 °F from June through August.

Located on the Pacific Flyway, the variety of lakes and wetlands of the PNWR provide essential fish and wildlife habitat in the arid southern Nevada climate. Designated by The Nature Conservancy (TNC) as one of the nation's prime biological "hotspots" and by the Audubon Society as an Important Bird Area (IBA), the Refuge is a critical stopover for hundreds of different species of waterfowl, raptors, and songbirds, as well as home to multiple fish and mammal species, including federally-listed endangered and threatened species. The Refuge’s abundant water originates from large springs to the north and is managed to create

Upper Lake Dam Modernization and Improvements 7 the greatest value for wildlife. Various types of wetland habitats support many plants favored as food by over 230 species of migratory birds and other resident wildlife (Nevada State Parks 2018).

Management of the Refuge focuses on migration and wintering habitat for waterfowl and other migratory birds as a priority, providing habitat for endangered and sensitive animal and plant species, maintaining biodiversity, and providing wildlife-dependent recreation to the public. The purpose of the PNWR derives from the Migratory Bird Conservation Act (MBCA) of 1929, as amended:

“…for use as an inviolate sanctuary, or any other management purpose, for migratory birds…” (16 U.S. Code (U.S.C.) 715d).

The Refuge goals (USFWS 2009a) are as follows:

• Wetland Habitat (Goal 1): Restore and maintain wetland habitat for waterfowl and other migratory birds with an emphasis on spring and fall migration feeding and resting habitat requirements.

• Wildlife Diversity (Goal 2): Restore and maintain the ecological integrity of natural communities within Pahranagat NWR and contribute to the recovery of listed and other special-status species.

• Visitor Services (Goal 3): Provide visitors with compatible wildlife-dependent recreation, interpretation, and environmental education opportunities that foster an appreciation and understanding of Pahranagat NWR’s wildlife and plant communities.

• Cultural Resources (Goal 4): Manage cultural resources for their educational, scientific, and traditional cultural values for the benefit of present and future generations of refuge users, communities, and culturally affiliated tribes.

The PNWR area is also a very important cultural landscape to many tribal people as it contains a diversity of prehistoric and historic resources, including the Black Canyon National Register District. Furthermore, the word “Pahranagat” originates from the Southern Paiute language and includes the term “pah” meaning water (Kelly 1934). The PNWR is an important tourist attraction, receiving more than 50,000 visitors per year. Activities include wildlife observation, photography, fishing, hunting, hiking, environmental education, interpretation, camping, non-motorized boating, and picnicking.

Resource Topics Eliminated from Detailed Analysis The Proposed or Alternative Actions would not affect some resources. Resources that have been eliminated from further study in this document and the rationale for eliminating them are presented below.

• Land Use: The Proposed Action would be contained within the boundaries of PNWR. The land surrounding the PNWR consists of agricultural, open space, and Bureau of Land Management (BLM) property.

• Noise: Maintenance operations would involve automobile traffic to and from the site. The noise would be generated from the operation of heavy construction equipment; however, the Proposed Action area is not close to any sensitive noise receivers such as residential neighborhoods, schools, or parks.

Upper Lake Dam Modernization and Improvements 8

Because construction would occur during the daytime on weekdays and far from sensitive noise receivers, no noise impacts associated with construction activities would occur.

• Prime and Unique Agricultural Lands: The Farmland Protection Policy Act (FPPA) (7 U.S.C. 4201 et seq, implementing regulations 7 CFR Part 658, of the Agriculture and Food Act of 1981, as amended) minimizes the effect of federal programs on the unnecessary and irreversible conversion of farmland to nonagricultural uses. Prime agricultural land is defined (7 U.S.C. 4202(a)) as land that has the best combination of physical and chemical characteristics for producing food, feed, forage, fiber, and oilseed crops and is also available for these uses. No prime agricultural land occurs within the Proposed Action limits (NRCS 1997).

• Hazardous Materials: Hazardous material use and management at PNWR are regulated under the Toxic Substances Control Act (TSCA), the Occupational Safety and Health Administration (OSHA), and the Emergency Planning and Community Right-to-Know Act (EPCRA). Hazardous wastes are defined by the Solid Waste Disposal Act (SWDA) as amended by the Resource Conservation and Recovery Act (RCRA), which was further amended by the Hazardous and Solid Waste Amendments, RCRA Subtitle C (40 CFR, Parts 260 through 270). No known hazardous materials occur in the Proposed Action area.

Within the location of the Proposed Action, asbestos is not present at aboveground or belowground locations. Therefore, no impacts related to lead-based paint would be anticipated under the Proposed Action, and lead-based paint was not considered for detailed analysis.

• Visual Resources: No impacts to visual resources would be anticipated under the Proposed Action.

The Proposed Action would largely be in the existing dam and water delivery footprint. Therefore, the effects on visual resources would be similar to what currently exists and were not considered for detailed analysis.

Resource Topics Analyzed in Detail

Geology and Soils The Proposed Action area lies within the Mojave Desert region of the greater Basin and Range physiographic province characterized by numerous long, narrow, and parallel mountain ranges with a north-to-south orientation separated by deep valleys. Many Great Basin rivers do not reach the sea, but instead find base-level in large lakes and dry-lake playas when evaporation rates are high. The arid conditions characterizing the region are created by east- and west-flanking mountain ranges. The Sierra Nevada to the west captures moisture from Pacific storms and the Rocky Mountains to the east intercept storms from the Gulf of Mexico. Elevations of PNWR range from approximately 3,020 feet above mean sea level at Lower Pahranagat Lake to approximately 3,900 feet above mean sea level along the valley walls formed by the Sheep Range at the extreme southeast corner of the Refuge (Heitmeyer 2011).

The Pahranagat Range lies within the Mesozoic and early Tertiary Sevier Fold-and-Thrust Belt and the Cenozoic Basin and Range Province (Jayko 2007a). The majority of the soils in the region are older alluvial gravels (Quaternary), generally unconsolidated, boulder- to sand-sized deposits in alluvial fans. These alluvial silts and gravels, washed down from the surrounding mountains, reach a thickness of 1,000 feet in many locations within the valley (Stewart and Carlson 1978). Deposits are usually dissected by washes, Upper Lake Dam Modernization and Improvements 9 forming an irregular surface commonly cemented by caliche. Additionally, the area contains regions of surficial deposits (Quaternary), sedimentary deposits (Quaternary and/or Tertiary), and volcanic ash-flow tuffs (Jayko 2007b). The East Pahranagat and Hiko mountain ranges that surround Pahranagat NWR consist of silicic ash-flow tuffs (Miocene).

Soils at the Proposed Action area are classified as Seaman sandy loam and Maynard Lake complex (USDA 2011) (Figure 3). Seaman sandy loam is a well-drained soil, capable of forming slopes of 0–2%, with moderate available water capacity. Maynard Lake complex soil is excessively drained, capable of forming slopes of 4–12%, with a low available water capacity (ATC 2011).

Three soil mapping units exist within the watershed: Alko loamy coarse sand on 0-8% slopes; Adaven loam; and the Boxspring-Theriot-Rock outcrop association (USGS 2016). Prime Farmlands are soils that when treated and managed in particular ways, and using proper farming methods, can favor economic production of crops. No Unique Farmlands exist in the State of Nevada. Livestock management on adjacent lands could influence hydrologic function (e.g., overland flow, water quality, groundwater recharge).

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Figure 3: Pahranagat National Wildlife Refuge Soils, Lincoln County, Nevada.

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Water Resources The Refuge occurs within Pahranagat Valley in Lincoln County, Nevada; a fertile narrow river valley (approximately no more than 1 mile wide and 40 miles long) running north and south. The prehistoric (late Pleistocene-early Holocene wet periods) White River flowed south from its headwaters in the northern White River Valley, through the Pahranagat Valley into Kane Springs Wash, southeast through Arrow Canyon into Moapa Valley, where it joined the pluvial Carpenter River (now referred to as Meadow Valley Wash), and ultimately reached the Virgin River above the Colorado River confluence (Hubbs and Miller 1941; Williams and Wilde 1981; Courtenay et al. 1985; USFWS 1998; Wurster 2010; Heitmeyer 2011).

The Proposed Action area lies within the White Watershed (15010011) of the Pahranagat Valley Hydrophobic area of the Colorado River Basin (USFWS 1998). Currently, perennial flows are confined to the headwater tributaries of the White River; outflow streams from springs in White River, Pahranagat, and Moapa Valleys; and the Muddy (Moapa) River (Courtenay et al. 1985; USFWS 1998). Pahranagat Valley is principally watered by three large natural springs (Hiko Springs, Crystal Springs, and Ash Springs) and contains four lakes, two near the north end of the valley (Nesbitt Lake and Frenchie Lake) and two towards the south end (Upper Pahranagat Lake and Lower Pahranagat Lake at Pahranagat NWR) (Heitmeyer 2011); however, the low flow volumes, water chemistry, and seasonal fluctuations suggest refuge springs are supported by groundwater flow paths that are different from those supporting Ash and Crystal Springs (Wurster 2010). Additionally, water accumulates from precipitation and surface infiltration and discharges into several of the springs in the PNWR from a local alluvial aquifer (USFWS 2009a;

Heitmeyer 2011).

Surface Water The White River is the primary drainage for all runoff in the basin and ultimately flows into Upper Pahranagat Lake. This river is the only perennial stream that flows through the central portion of the Pahranagat Valley. Despite numerous tributaries, the remainder of the streams are intermittent or ephemeral systems, and flows into PNWR are now highly seasonal and intermittent (Heitmeyer 2011).

Several surface water sources exist within the region when referencing the United States Geological Survey (USGS) 7.5-minute Hiko, Ash Springs, and Alamo topographic quadrangle maps, including Ash Springs, Crystal Springs, Brownie Springs, Grove Springs, and several unnamed springs.

Within the PNWR, there are four main water reservoirs consisting of the North Marsh, the Upper and Lower Pahranagat Lakes, and the Middle Marsh (Middle Marsh and WHIN Marsh) (USFWS 2009a).

Approximately 1,970 acres of wetland habitat exist on the refuge (Wurster 2010). Upper Pahranagat Lake and North Marsh occupy approximately 450 acres and occur in the northern extent of the PNWR; Lower Pahranagat Lake occurs near the southern end of the Refuge and occupies approximately 365 acres (USFWS 2009a). Water management, control, and diversion have changed the hydrology within the Pahranagat NWR; spring-fed water flowing into Upper Pahranagat Lake begins later and ends sooner than in the 1960s (Wurster 2010; Heitmeyer 2011). Upper Pahranagat Lake and North Marsh only receive discharge from Pahranagat Creek in winter, when upstream irrigation is low (USFWS 2009a). Additionally, Upper Lake Dam Modernization and Improvements 12

PNWR contains several springs, including Cottonwood, Cottonwood Spring North, Lone Tree, “L”, and Maynard Lake Upper and Lower Springs, which discharge small amounts of surface water (Heitmeyer 2011). Access to Pahranagat Creek water rights is limited to these months, which results in a severe lack of water to the entire PNWR site, especially during the summer months. Water from Middle Marsh can be released into the alkali Lower Pahranagat Lake; however, most years, very little water occurs there.

Additionally, the PNWR is a closed system where no surface water flows out of it. Man-made ponds on Pahranagat NWR have increased by nine times since 1965, resulting in more open water areas and less wet meadows and seasonal wetland areas than historically present (Heitmeyer 2011). Since PNWR was established, water management has focused on maintaining a minimum pool in the Upper Lake, which has caused less water availability for wetlands south of the headquarters and likely contributed to drying conditions in the southern third of the refuge since 1965 (Wurster 2010).

Floodplains Executive Order (EO) 11988 regulates Floodplain Management and requires that federal agencies provide leadership and take action to reduce the risk of flood loss; minimize the impacts of floods on human safety, health, and welfare; and restore and preserve the natural and beneficial values of floodplains when acquiring, managing, or disposing of federal lands. The PNWR is located within a 100-year floodplain and is designated by the Federal Emergency Management Agency (FEMA) as Zone D. Zone D refers to areas where there are possible but undetermined flood hazards; no analysis of flood hazards has been conducted in these areas. Zone D areas are often undeveloped and sparsely populated. Correspondingly, flood insurance is available but not federally required by lenders for loans on properties in these zones.

Furthermore, on January 30, 2015, the President signed EO 13690 amending EO 11988, Establishing a Federal Flood Risk Management Standard and a Process for Further Soliciting and Considering Stakeholder Input. Under EO 13690 agencies are required to expand management from the base flood elevation (100-year flood) to a higher vertical flood elevation and corresponding horizontal floodplain for federally-funded projects. The most common approach to define the floodplain is an area that is 2 feet above the elevation of the 100-year flood.

Wetlands/Riparian Zones Wetlands are protected from development under EO 11990, Protection of Wetlands. Guidance from the EO requires federally-funded activities associated with wetlands to minimize the destruction, loss, or degradation of wetlands, and to preserve and enhance the natural beneficial values of wetlands. A site must display evidence of all three wetland indicators: hydric soils, hydrophytic vegetation, and hydrology to be considered a wetland, or, in the case of a problem area, such as arid regions, hydric soil indicators are considered a constant factor during the drier times of the growing season. The USFWS National Wetlands Inventory (NWI) shows expansive areas of freshwater emergent wetlands interspersed with freshwater forested/shrub wetlands along the White River (Figures 4-9; Table 1). These wetlands are restricted to the valley floor where the availability of surface water and higher groundwater is maximized.

Figures 4-9 depict the Proposed Action area intersecting through wetlands classified by the USFWS’s NWI, while Table 1 summarizes the type and length of wetland that is intersected by the Proposed Action.

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Table 1: Acreage of the Proposed Action area with respect to NWI wetland type.

NWI Code Wetland Type Acres PEM1A Freshwater Emergent Wetland 0.07 PEM1B Freshwater Emergent Wetland 2.10 PEM1C Freshwater Emergent Wetland 0.45 PEM1Fh Freshwater Emergent Wetland 0.10 Freshwater Emergent Wetland Total 2.72 PFOA Freshwater Forested/Shrub Wetland 0.06 PFOAh Freshwater Forested/Shrub Wetland 0.18 PFOB Freshwater Forested/Shrub Wetland 0.45 PFOC Freshwater Forested/Shrub Wetland 4.72 PFOCh Freshwater Forested/Shrub Wetland 0.03 PFOF Freshwater Forested/Shrub Wetland 0.04 PSSA Freshwater Forested/Shrub Wetland 0.04 PSSB Freshwater Forested/Shrub Wetland 0.00 PSSC Freshwater Forested/Shrub Wetland 0.16 Freshwater Forested/Shrub Wetland Total 5.67 L2UBHh Lake 0.59 R2UBHx Riverine 0.35 R4SBCx Riverine 0.56 R5UBH Riverine 0.97 Riverine Total 1.87 Grand Total 10.85

P = Palustrine, EM = Emergent, 1 = Persistent, AF = Temporary Flooded, B = Seasonally Saturated, C = Seasonally Flooded, H = Permanently Flooded, h = Diked/Impounded, F = Semi permanently Flooded, FO = Forested, UB = Unconsolidated Bottom, R = Riverine, 4 = Intermittent, SB = Streambed.

As this system is used recreationally and has a perennial surface water connection to the White River and Upper Pahranagat Lake, it would likely be considered jurisdictional under Section 404 of the Clean Water Act (CWA) by the U.S. Army Corps of Engineers (USACE). Section 404 of the CWA regulates the discharge of dredge and fill material into waters of the United States (WUS) (33 CFR 328). The USACE and United States Environmental Protection Agency (EPA) jointly determine the federal jurisdiction of WUS and permit activities that are subject to Section 404. According to the FEMA’s Mapping Information Platform, there are no special flood hazard areas present within the immediate area of the Proposed Action site.

The White River, and many of the intermittent streams in the area, likely maintain a narrow and contained hydrologic floodplain typically characteristic of the desert southwest. As this system has a perennial surface water connection to the White River and Upper Pahranagat Lake, it would likely be considered jurisdictional under Section 404 of the CWA by the USACE. The White River and many of the intermittent streams in the area likely maintain a narrow and contained hydrologic floodplain typically characteristic of the desert southwest. All of the potential locations of the Proposed Action may impact WUS.

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Figure 4: Pahranagat National Wildlife Refuge Study Area Wetlands, Lincoln County, Nevada.

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Figure 5: Northern extent of the proposed Upper Lake Dam with respect to wetlands.

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Figure 6: Southern extent of the proposed Upper Lake Dam with respect to wetlands.

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Water Quality Under Section 303(d) of the CWA, states are required to develop lists of impaired waters. These waters do not meet federal or state water quality standards. There are no 303(d)-listed waters in the immediate vicinity of the Proposed Action area (NDEP 2022).

According to the executive summary of the Hydrologic Analysis Report of the PNWR, generated by the

USFWS (2010):

“Water in spring pools tends to be cooler, fresher, and has a lower pH than water in irrigation ditches and lakes on the refuge. Water chemistry analyses confirm that springs on the refuge have a different source than springs fed by the regional carbonate rock aquifer. The source of the spring water is probably alluvial groundwater that is recharged locally by precipitation inside the boundaries of the Pahranagat Valley.

Surface water entering the refuge is a 70:20:10 mix of Crystal Springs, Ash Springs, and groundwater with a chemical signature similar to Cottonwood and Maynard Springs. Water collected from refuge wetlands is a mixture of surface water released from Upper Pahranagat Lake and groundwater with a chemical signature similar to Cottonwood and Maynard Springs. Spring pools have lower concentrations of dissolved oxygen than surface water in the ditch system, presumably due to high rates of biological activity, less surface area, and little oxygen-entraining turbulence.”

In summary, the state of water quality on the PNWR is good and stable, but current water distribution and detrimental erosion may negatively affect long term water quality.

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Ground Water The Pahranagat Valley basin covers approximately 790 square miles, beneath which exists a large regional carbonate aquifer and a local, basin-fill alluvial aquifer (Heitmeyer 2011; King 2014). Hiko, Crystal, and Ash Springs are the three main sources of groundwater discharge in the valley. The magnitude of the combined discharge of Hiko, Crystal, and Ash Springs in the valley is 25,000 acre-feet per year and greatly exceeds the volume expected by recharge from precipitation alone (estimated at 1,800 acre-feet per year); thus, much of the groundwater discharged by the springs is likely derived from outside of the valley (Eakin 1963).

Water Rights In Nevada, the first person or entity who uses water beneficially establishes priority for the ongoing legal use of that water resulting in the state doctrine of prior appropriation in granting water rights. Nevada water law limits the issuance of water rights in any given hydrographic basin to the amount of water available. The Pahranagat Valley Hydrographic Basin (Basin 209) is fully appropriated, as established under the Pahranagat Lake Decree of 1929 and reaffirmed by court decisions and by the Nevada State Engineer’s Office under the Nevada Division of Water Resources (NDWR).

Nevada State Engineer’s Ruling #5940 Nevada State Engineer’s Ruling #5940 (2009) was issued on February 10, 2009, in response to an application for a change of use for water rights held by the USFWS on the water in Pahranagat Lake. The lake is on property managed by the USFWS and is the terminus of flow from Ash and Crystal Springs. There is no surface outlet from the lake and there are no other holders of water rights from Pahranagat Lake.

The USFWS was granted its Application No. 20234 for 30.0 cubic feet per second, not to exceed 3,500 annual acre-feet on the condition that it be the most junior right in the basin; the right can only be exercised after all other users in the basin have exercised their rights. Streamflow data supporting the application showed a “positive inflow” to Upper Pahranagat Lake between October and March in 12 of 14 years between 1963 and 2003, and three of four years from 1991 to 1994.

The withdrawals for irrigation accounted for approximately 97.07% of water use in the county (Table 2).

Water use and water withdrawals are equivalent terms but are not the same as consumptive use and do not account for return flows. Domestic, commercial, industrial, and thermoelectric water withdrawals include both public and self-supplied water.

Table 2: Lincoln County Water Withdrawals, Estimated by Type in 1995. Source: Nevada Division of Water Planning 1997.

Water Use by Major Category

Domestic Commercial Industrial

1995 Water Use (Acre- Feet/Year)

1,355

Percent of 1995 Total Water Use

2.01% 0.54% 0.00%

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Water Use by Major Category

1995 Water Use (Acre- Feet/Year)

Percent of 1995 Total Water Use

Thermoelectric 0 0.00% Mining 0 0.00% Livestock 123 0.18% Irrigation 65,537 97.07% Public Use and Losses 138 0.20% Total Water Withdrawals/Use

67,516 n/a

Riparian System The Refuge is located in the northeastern Mojave Desert and is dominated by low-growing vegetation adapted to harsh environments. It is unique because it differs from the surrounding area in that it provides a perennial water source for wildlife and riparian habitat in the form of cover, breeding, and foraging habitat types. The National Vegetation Classification System (i.e., Warm Southwest Riparian Forest) classifies the riparian area as the Interior Warm and Cool Desert Riparian Forest Macro group. This macro group includes warm and cold climate riparian and wetland forested vegetation of the western interior U.S., including the southwestern deserts and the Tamaulipas area of southern Texas (USGS 2016). This is a lowland riparian forest association typically found within elevations ranging from 1,200 to 1,550 meters, and sites are typically rocky or sandy banks of low gradient (1.5%) stream systems that are frequently flooded (NatureServe 2016). Soils are typically coarse-loamy over fragmental Typic Torrifluvents and as cobbly riverwash (NatureServe 2016). Fremont’s cottonwood (Populus fremontii) and velvet ash (Fraxinus velutina) co-dominate moderate to dense canopies (>50% cover); undergrowth is moderately diverse with low cover (NatureServe 2016).

Air Quality Air Quality Standards and Regulations The EPA has established primary and secondary National Ambient Air Quality Standards (NAAQS) under the Clean Air Act Amendments (CAAA) of 1990. The CAAA also set emission limits for certain air pollutants from specific sources, set new source performance standards based on best demonstrated technologies, and established national emission standards for hazardous air pollutants.

The CAAA specifies two sets of standards – primary and secondary – for each regulated air pollutant.

Primary standards define levels of air quality necessary to protect public health, including the health of sensitive populations such as people with asthma, children, and the elderly. Secondary standards define levels of air quality necessary to protect against decreased visibility and damage to animals, crops, vegetation, and buildings. Federal air quality standards are currently established for six pollutants (known as criteria pollutants), including carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), sulfur oxides (SOx, commonly measured as sulfur dioxide – SO2), lead (Pb), particulate matter equal to or less than 10 micrometers in aerodynamic diameter (PM10) and particulate matter equal to or less than 2.5 micrometers

Upper Lake Dam Modernization and Improvements 20 in aerodynamic diameter (PM2.5). Although O3 is considered a criteria pollutant and is measurable in the atmosphere, it is often not considered as a pollutant when reporting emissions from specific sources, because O3 is not typically emitted directly from most emission sources. Ozone is formed in the atmosphere from its precursors – nitrogen oxides (NOx) and volatile organic compounds (VOC’s) – that are directly emitted from various sources. Thus, emissions of NOx and VOC’s are commonly reported instead of O3.

The NAAQS for the six criteria pollutants is shown in Table 3. Units of measure for the standards shown in this table are micrograms per cubic meter of air (µg/m3), except for ozone, SO2, and CO which are in parts per million (ppm), and NO2 which is in parts per billion (ppb).

The EPA classifies the air quality within an Air Quality Control Region (AQCR) according to whether the region meets federal primary and secondary air quality standards. An AQCR, or portion of an AQCR, may be classified as attainment, non-attainment, or unclassified concerning the air quality standards for each of the criteria pollutants. “Attainment” describes a condition in which standards for one or more of the six pollutants are being met in an area. The area is considered an attainment area for only those criteria pollutants for which the NAAQS are being met. “Non-attainment” describes a condition in which standards for one or more of the six pollutants are not being met in an area. “Unclassified” indicates that air quality in the area cannot be classified and the area is treated as attainment. An area may have all three classifications for different criteria pollutants. The Proposed Action area is situated in Lincoln County, which is classified as an “attainment area” (USEPA 2011) because it meets ambient air quality standards for pollutants according to the NAAQS.

Table 3: National Ambient Air Quality Standards (EPA 2021a).

Pollutant Primary/ Secondary

Averaging Time Level Form

Carbon Monoxide (CO) primary 8 hours 9 ppm Not to be exceeded more than once per year 1 hour 35 ppm

Lead (Pb) primary and

Rolling 3 month average

0.15 μg/m3 (1) Not to be exceeded secondary

Nitrogen Dioxide (NO2) primary 1 hour 100 ppb

98th percentile of 1-hour daily maximum concentrations averaged over 3 years primary and 1 year 53 ppb (2) Annual Mean secondary

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Pollutant Primary/ Secondary

Averaging Time Level Form

Ozone (O3) primary and 8 hours 0.070 ppm (3)

Annual fourth-highest daily maximum 8-hour concentration averaged over 3 years secondary

Particulate Matter (PM) Particle Pollution

PM2.5

primary 1 year 12.0 μg/m3 annual mean averaged over 3 years secondary 1 year 15.0 μg/m3 annual mean averaged over 3 years primary and secondary

24 hours 35 μg/m3 98th percentile averaged over 3 years

PM10

primary and secondary 24 hours 150 μg/m3

Not to be exceeded more than once per year on average over 3 years

Sulfur Dioxide (SO2) primary 1 hour 75 ppb (4)

99th percentile of 1-hour daily maximum concentrations averaged over 3 years secondary 3 hours 0.5 ppm Not to be exceeded more than once per year

(1) In areas designated non-attainment for the Pb standards before the promulgation of the current (2008) standards, and for which implementation plans to attain or maintain the current (2008) standards have not been submitted and approved, the previous standards (1.5 µg/m3 as a calendar quarter average) also remain in effect.

(2) The level of the annual NO2 standard is 0.053 ppm. It is shown here in terms of ppb for the purposes of clearer comparison to the 1-hour standard level.

(3) Final rule signed October 1, 2015, and effective December 28, 2015. The previous (2008) O3 standards additionally remain in effect in some areas. Revocation of the previous (2008) O3 standards and transitioning to the current (2015) standards will be addressed in the implementation rule for the current standards.

(4) The previous SO2 standards (0.14 ppm 24-hour and 0.03 ppm annual) would additionally remain in effect in certain areas: (1) any area for which it is not yet 1 year since the effective date of designation under the current (2010) standards, and (2) any area for which an implementation plan providing for attainment of the current (2010) standard has not been submitted and approved and which is designated non-attainment under the previous SO2 standards or is not meeting the requirements of a State Implementation Plan (SIP) call under the previous SO2 standards (40 CFR 50.4(3)). A SIP call is an

Upper Lake Dam Modernization and Improvements 22

Pollutant Primary/ Secondary

Averaging Time Level Form

EPA action requiring a state to resubmit all or part of its SIP to demonstrate attainment of the required

NAAQS.

Regional Air Quality The Proposed Action area is located within Lincoln County in the Nevada Intrastate Air Quality Control Region. Lincoln County is classified as an “attainment area” (USEPA 2011) because it meets ambient air quality standards for pollutants according to the NAAQS. Therefore, air quality within the Proposed Action area is of better quality than the NAAQS.

Greenhouse Gases There are six primary Greenhouse Gases (GHGs) of concern: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). The emissions of each GHG are measured based on their global warming potential (GWP); the universal unit of measurement to express how much a given mass of greenhouse gas is estimated to contribute to climate change. Table 4 lists the GWP (USEPA 2013) of the six primary GHGs.

Table 4: Global Warming Potential of GHGs.

Gas Chemical Formula GWP Carbon dioxide CO2 1 Methane CH4 25 Nitrous oxide N2O 298 Hydrofluorocarbons HFCs various Perfluorocarbons PFCs various Sulfur hexafluoride SF6 22,800

CH4 = methane CO2 = carbon dioxide GWP = global warming potential HFCs = hydrofluorocarbons N2O = nitrous oxide PFCs = perfluorocarbons SF6 = sulfur hexafluoride

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The three GHGs; CO2, CH4, and N2O, represent the majority of carbon dioxide equivalent (CO2eq) emitted to the atmosphere from typical stationary sources. The other GHGs are emitted by specific industries:

HFCs are most commonly used in refrigeration and air conditioning systems; PFCs and SF6 are predominantly emitted from various industrial processes including aluminum smelting, semiconductor manufacturing, and magnesium casting. Direct emissions of CO2, CH4, and N2O occur naturally in the atmosphere, but human activities have increased global GHG atmospheric concentrations. The largest source of GHG emissions from human activities in the U.S. is from burning fossil fuels for electricity, heat, and transportation. The EPA tracks total U.S. emissions by publishing the Inventory of U.S. GHG Emissions and Sinks and publishes an annual report that includes estimates of the total GHG emissions and removals associated with human activities across the U.S. The primary sources of GHG emissions in the U.S. are (EPA 2021c):

• Transportation (nearly 27% of 2020 GHG emissions) – Sources are from burning fossil fuel for cars, trucks, ships, trains, and planes.

• Electricity production (25% of 2020 GHG emissions) – Approximately 68% of U.S. electricity comes from burning fossil fuels; mostly coal and natural gas.

• Industry (24% of 2020 GHG emissions) – Sources are from burning fossil fuels for energy, as well as GHG emissions from certain chemical reactions to produce goods from raw materials.

• Commercial and Residential (13% of 2020 GHG emissions) – Sources from businesses and homes arise primarily from fossil fuels burned for heat, the use of certain products that contain GHGs, and the handling of waste.

• Agriculture (11% of 2020 GHG emissions) – Sources are from livestock such as cows, agricultural soils, and rice production.

• Land Use and Forestry (offset of 13% of 2020 GHG emissions) – Land areas can act as a sink (absorbing CO2 from the atmosphere) or a source of GHG emissions. In the U.S., since 1990, managed forests and other lands have absorbed more CO2 from the atmosphere than they emit.

Biological Resources Managed by the USFWS, the PNWR is “a living heritage, conserving wildlife and habitats for people today and generations to come” (USFWS 2012b). In 1999, the American Bird Conservancy designated the PNWR as a state Important Bird Area (IBA), and three sections of the western side of the Refuge have been designated as wilderness study areas (USFWS 2009a). Numerous wildlife and plant species occur in the refugee desert, lake, spring, wetland, meadow, and riparian habitats.

The Proposed Action area is mostly comprised of former agricultural fields and levees/ponds, saltbush (Atriplex spp.) upland, cottonwood (Populus fremontii) woodland, creosote (Larrea tridentata) upland and bare/playa areas, and contains a non-linear irrigation channel. The former agricultural fields contain a mixture of plants from the adjacent vegetation areas but also contain a high concentration of noxious and invasive weed species (SWCA 2011). The saltbush upland consists of mainly fourwing saltbush (Atriplex canescens). Riparian areas within the Refuge consist of approximately 100 acres and contain a mixture of multi-aged stands of riparian tree species, such as Goodding’s willow (Salix gooddingii), Fremont cottonwood (Populus fremontii), red willow (Salix laevigata) and coyote willow (Salix exigua) (USFWS 2009a). Non-native shrubs, such as tamarisk (Tamarix spp.) and Russian olive (Elaeagnus angustifolia), are

Upper Lake Dam Modernization and Improvements 24 also present (Otis Bay 2012). Pockets of both mature and early seral cottonwood woodlands, containing cottonwood over-stories and a mixed shrub and grass understory, are present within the site. Pockets of both barren playa and creosote uplands are also present within the eastern extent of the Proposed Action area.