B08_Attachment_07_GLCA_Hite_ARDR.pdf

National Park Service

Glen Canyon National Recreation Area Low Water Ramp at Hite District

Aquatic Resources Delineation Report

December 2024

Prepared by:

Jacobs Government Services Company

Greenwood Village, CO

Contract No. 140P2023D0006

Task Order No. 140P2024F0242

U.S. Department of the Interior

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Table of Contents Page i

Table of Contents

Acronyms and Abbreviations ............................................................................................ ii

Executive Summary

Chapter 1 – Introduction ............................................................................................... 1-1

1.01 Study Area Location................................................................................ 1-1

Chapter 2 – Regulatory Setting .................................................................................... 2-1

2.01 Clean Water Act (CWA) .......................................................................... 2-1

2.02 NPS Director’s Order #77-1: Wetland Protection .................................... 2-1

Chapter 3 – Methods .................................................................................................... 3-1

3.01 Pre-field Investigation ............................................................................. 3-1

3.02 Field Survey ............................................................................................ 3-1

Chapter 4 – Environmental Setting............................................................................... 4-1

4.01 Regional Setting ..................................................................................... 4-1

4.02 Study Area Setting .................................................................................. 4-1

Chapter 5 – Results...................................................................................................... 5-4

5.01 Other Waters .......................................................................................... 5-5

5.02 Other Areas Investigated ........................................................................ 5-7

Chapter 6 – References ............................................................................................... 6-1

List of Tables

Table 1-1. Location Information .................................................................................... 1-1

Table 4-1. Soil Series Mapped Within the Study Area.................................................. 4-2

Table 5-1. Summary of Aquatic Resources Investigated in the Study Area ................. 5-4

List of Appendices

Appendix A – Figures

Appendix B – Wetland Determination Data Forms

Appendix C – Rapid Ordinary High Water Mark (OHWM) Field Identification Data Sheets

Appendix D – Antecedent Precipitation Tool Results

Appendix E – Representative Photographs

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Acronyms and Abbreviations Page ii

Acronyms and Abbreviations

Acronym Definition

AMSL Above mean sea level

CFR Code of Federal Regulations

CWA Clean Water Act

D.O. Director’s Order

°F degree(s) Fahrenheit

FGDC Federal Geographic Data Committee

GLCA Glen Canyon National Recreation Area

HUC Hydrologic Unit Code

LF linear feet

NHD National Hydrography Dataset

No. Number

NPS National Park Service

NWI National Wetlands Inventory

OHWM Ordinary High Water Mark

TNW Traditional Navigable Waters

USACE United States Army Corps of Engineers

U.S.C. United States Code

USGS United States Geological Survey

WOTUS Waters of the United States

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Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Executive Summary Page 1

Executive Summary

The National Park Service (NPS) is proposing to construct a new ramp to provide river and lake access at lower water levels in the Hite District of Glen Canyon National Recreation Area (GLCA). This ramp will replace an existing ramp that is inaccessible at current and anticipated lake levels due to its alignment.

This report presents the methods and results of an aquatic resources delineation for a 107.33-acre study area that encompasses the footprint of the proposed new ramp at Hite District project (project). This delineation was conducted in accordance with the Corps of Engineers Wetland Delineation Manual (Environmental Laboratory 1987), the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Arid West Region (Version 2.0) (USACE 2008), the National Ordinary High Water Mark Field Delineation Manual for Rivers and Streams (Interim Version) (USACE 2022), and NPS Procedural Manual #77-1: Wetland Protection (referred to as

D.O. #77-1) (NPS 2016).

A total of 9.29 acres of aquatic resources were delineated within the study area, which includes 2.60-acres of riverine and 6.69-acres lacustrine waters. There are 6.21-acres of aquatic resources within the study area that are potentially subject to regulation by the NPS under D.O.

#77-1, which includes all aquatic resources except for open water that is 8.2 feet (2.5 meters) deep, or greater, below low water. There are 6.76-acres of aquatic resources within the study area that are potentially subject to regulation by the U.S. Army Corps of Engineers (USACE), which include all aquatic resources except for ephemeral watercourses.

The results and conclusions presented in this delineation report are considered preliminary, pending verification by the USACE, and are provided for the purpose of supporting planning, design, and permitting, if required, under the Clean Water Act.

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 1 – Introduction Page 1-1

Chapter 1 – Introduction

The National Park Service (NPS) is proposing to construct a ramp in the Hite District of Glen Canyon National Recreational Area (GLCA) to facilitate water access under lower water conditions.

Lake Powell is formed by the impounded waters of the Colorado River above the Glen Canyon Dam and is the second-largest reservoir in the nation. The lake is considered a premier watersports destination and recreation area. When Lake Powell is full (at a water elevation of 3,700 feet above mean sea level [AMSL]), it accounts for 13 percent of GLCA’s geographic area and is a major draw for the approximately 4 million visitors who visit annually. However, persistent droughts are contributing to unprecedented low-water conditions. Water levels fluctuate throughout the year, with recent levels in the lake dropping as low as 3,522 feet AMSL in April 2022. In October 2024 water levels were at 3,577 feet AMSL. The U.S. Bureau of Reclamation determined that under a Probable Minimum Scenario, Lake Powell’s physical elevation is projected to be 3,571.63 feet by December 31, 2024 (USBR 2022).

These lower water levels in Lake Powell have exposed reservoir sediments. In upper reaches of the river no longer influenced by the downstream control of Glen Canyon Dam, the transition from a reservoir to river conditions has caused dynamic changes in riverbed elevation and stability and associated riverbank stability.

In the Hite District, the Colorado River is actively adjusting to abundant sediment supply from the Dirty Devil tributary and change in base level (local control on elevation of the riverbed) resulting from reservoir declines. The alignment of the river has also changed compared to pre-dam conditions.

Currently, access to the river at the existing Hite Ramp on the river left (south/east) bank is no longer possible due to the presence of unconsolidated reservoir sediments, creating conditions causing trucks and trailers to get stuck. On the river right (north) bank, an unmaintained access road (North Wash Ramp) leads to the river located downstream of the Dirty Devil River confluence. Maintenance of the ramp is challenging, and river conditions are dynamic (these features are displayed on Figure 1 in Appendix A). Together, these factors create inconsistent and sometimes unsafe access to the water at this location. GLCA is initiating this project to provide ongoing water access at the Hite District.

1.01 Study Area Location

The study area is situated between the Hite Crossing Bridge and Hite Marina Campground, and is within San Juan County, Utah (Figure 1 in Appendix A). The study area can be accessed from Hite Marina Road off State Route 95. Table 1-1 includes location information for the study area.

Table 1-1. Location Information

Main Waterbodies Lake Powell (Colorado River) (TNW)

Tributary to and Downstream Waterbody

Gulf of California

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 1 – Introduction Page 1-2

Table 1-1. Location Information

Watershed HUC and Name

Upper Lake Powell (14070001)

Central Latitude and Longitude (DD)

37.886523, -110.380379

Township, Range, Section

Township 33S, Range 14E, Sections 21, 22, 27, 28

USGS Quadrangles Hite North and Sewing Machine

Directions From the USACE Albuquerque District office, take I-25 north and continue for 12 miles then take US-550 N. Continue on US-550 N to Bloomington, NM then take US-64 W.

Continue on US-64 W for 26 miles then take US-491 N, continue on US-491 N for 21 miles then turn left onto US-160 W. Continue on US-160 W for 13 miles then take CO- 41 N / UT-162 W to US-191 N in Bluff, UT. Take US-191 N and continue for approximately 20 miles then turn left onto UT-95 N. Continue on UT-95 N for 73 miles then turn left onto Hite Marina Road. Continue for 0.75-mile and the study area is on the right down a dirt access road.

CO = Colorado State Route HUC = Hydrologic Unit Code I = Interstate TNW = traditional navigable waters US = United States Highway USGS = U.S. Geological Survey UT = Utah State Route

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 2 – Methods Page 2-1

Chapter 2 – Regulatory Setting

This section describes the federal laws, regulations, and standards that apply to aquatic resource protection for the study area.

2.01 Clean Water Act (CWA)

Sections 401 and 404 of the Clean Water Act (CWA) prohibit the discharge of dredged or fill material into “waters of the United States,” (WOTUS) including wetlands, without a permit from USACE. The definition of WOTUS includes rivers, streams, estuaries, the territorial seas, ponds, lakes, and wetlands. Wetlands are defined as those areas “that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions” (33 CFR § 328.3(c)(1)). Under Section 10 of the Rivers and Harbors Act of 1899, USACE has the authority to regulate the navigable capacity of any of the WOTUS.

Under the Rivers and Harbors Act, it is not “lawful to excavate or fill, or in any manner alter or modify the course, location, condition, or capacity of…any navigable water of the United States…” (33 U.S.C. § 403).

All Section 404 CWA permit actions require water quality certification or a waiver pursuant to Section 401 of the CWA. This authority has been delegated by the U.S. Environmental Protection Agency (EPA) to the Utah Water Quality Board.

On May 25, 2023 the Supreme Court of the U.S. issued a decision in the Sackett v.

Environmental Protection Agency case that revised the definition of WOTUS. Per the decision, for a wetland to be considered a WOTUS it must, with limited exceptions, have a continuous surface connection to a relatively permanent body of water connected to traditionally navigable waters (TNW) or jurisdictional interstate waters. The EPA and USACE issued a final rule on August 29, 2023 to amend the definition of WOTUS to conform to the Sackett ruling and removed the significant nexus standard from the definition of WOTUS. By removing the significant nexus standard, only tributaries (i.e., streams that flow into TNWs, territorial seas, or interstate waters) that are "relatively permanent, standing or continuously flowing bodies of water" are WOTUS. This change excluded streams with an ephemeral flow regime as WOTUS.

2.02 NPS Director’s Order #77-1: Wetland Protection

The purpose of the Director's Order is to establish NPS policies, requirements, and standards for implementing Executive Order (E.O.) 11990: "Protection of Wetlands" (42 Fed. Reg. 26961).

E.O. 11990 was issued by President Carter in 1977 in order "…to avoid to the extent possible the long and short term adverse impacts associated with the destruction or modification of wetlands and to avoid direct or indirect support of new construction in wetlands wherever there is a practicable alternative...." (42 Fed. Reg. 26961).

Section 6 of E.O. 11990 directed federal agencies to issue procedures to implement the Executive Order. NPS wetland protection procedures were originally adopted together with E.O.

11988 (Floodplain Management) procedures in the 1980 "NPS Floodplain Management and Wetland Protection Guidelines" (45 Fed. Reg. 35916, minor revisions in 47 Fed. Reg. 36718).

Experience with implementing the wetland procedures, and changes in wetland management https://www.supremecourt.gov/opinions/22pdf/21-454_4g15.pdf https://www.supremecourt.gov/opinions/22pdf/21-454_4g15.pdf

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 2 – Methods Page 2-2 concepts since they were first published necessitated updating, streamlining, and clarifying NPS wetland policies and procedures in Director’s Order #77-1: Wetland Protection (issued October 22, 1998). The 1998 Director’s Order and the accompanying Procedural Manual #77-1 superseded and replaced the 1980 NPS wetland guidance. Director’s Order #77-1 included: 1) adoption of a “no net loss of wetlands” goal, which was first proclaimed in 1989 by President George Bush and has been sustained by subsequent Administrations; and 2) adoption of the Cowardin et al. (1979) wetland classification system as the NPS standard for defining, classifying, and inventorying wetlands.

In addition to the requirements of the Director’s Order, NPS activities that involve the discharge of dredged or fill material into wetlands or other “waters of the United States” must also comply with Section 404 of the Clean Water Act and Section 10 of the Rivers and Harbors Act (regulations and permit process are described in 33 CFR Parts 320-331).

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 3 – Methods Page 3-1

Chapter 3 – Methods

The following sections describe the field sampling procedures and methods used to determine and map aquatic resources.

3.01 Pre-field Investigation

Resources relevant to site conditions and aquatic resources were collected and reviewed as part of the delineation. The following materials were included in this data review:

• Bing satellite imagery (Bing 2024)

• Natural Resources Conservation Service (NRCS) soil maps and descriptions (NRCS 2024a)

• National Hydrography Dataset (NHD) maps (USGS 2024a)

• National Wetlands Inventory (NWI) (USFWS 2024)

• Lake Powell, Arizona and Utah Topographic Lidar Technical Data Report (NV5 Geospatial, Inc. 2022)

• Hite North and Sewing Machine USGS topographic maps (USGS 2024b)

3.02 Field Survey

Jacobs Government Services Company wetland scientists Greg Davis and Sabra McNeish conducted the aquatic resources field survey on October 2 and 3, 2024. The field survey was limited to the study area.

The delineation method was routine and conducted in accordance with the Corps of Engineers Wetland Delineation Manual (Environmental Laboratory 1987), the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Arid West Region (Version 2.0) (USACE 2008), the National Ordinary High Water Mark Field Delineation Manual for Rivers and Streams (Interim Version) (USACE 2022), and the NPS Procedural Manual #77-1: Wetland Protection (D.O. #77-1) (NPS 2016).

Aquatic resources within the survey area were mapped in ArcGIS Field Maps using an Apple iOS device paired with a Juniper Geode global navigation satellite system that provided submeter accuracy. Aerial imagery of the survey area was used to identify locations with potential wetland signature for field investigation and mapping (Bing 2024).

3.02.1 Method for Delineating Wetlands

Wetland determination sample points were established in locations where landforms indicated the potential for wetlands to occur (for example, closed depressions or other low areas). At these points, plant species within proximity of each sample point were identified by stratum and assigned a wetland indicator status to determine the presence of hydrophytic vegetation. The wetland indicator status of each plant species was taken from the National Wetland Plant List, Arid West Region (USACE 2020). The soil profile was examined to a depth of approximately 12 inches, where possible, and soil color was described using a Munsell Soil Color Chart (Munsell 2009). Each sampling location was also examined for indicators of wetland hydrology. Wetland determination data forms associated with this survey are provided in Appendix B.

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 3 – Methods Page 3-2

In addition to the USACE delineation methods above, the NPS Procedural Manual #77-1:

Wetland Protection (referred to as D.O. #77-1) provides methods on wetland identification using the Federal Geographic Data Committee (FGDC) Wetlands Classification Standard (NPS 2016).

The method utilizes the USACE delineation methods but allows for positive wetland identification based on two attributes (hydrophytic vegetation and wetland hydrology or hydric soil and wetland hydrology) or one attribute (wetland hydrology).

Under the FGDC Wetlands Classification Standard, a wetland must have one or more of the following three attributes:

1. at least periodically, the land supports predominantly hydrophytes (wetland vegetation).

2. the substrate is predominantly undrained hydric soil.

3. the substrate is non-soil and is saturated with water or covered by shallow water during the growing season of each year.

The FGDC Wetlands Classification Standard encompasses more aquatic habitat types than the USACE definition (33 CFR § 328.3) and delineation manual used by the USACE for identifying wetlands subject to Section 404 of the CWA. The following section provides guidance for delineating and mapping wetlands on NPS-managed lands so that both Section 404 wetlands and wetlands subject to these NPS procedures are included (NPS 2016). The method is provided below:

• For sites with vegetation and soils, use the most recent version (and any approved Regional Supplements) of the 1987 USACE Manual, including problem area and atypical situation procedures.

• If plants and soil are present (e.g., swamps, marshes or wet meadows), then all three attributes (wetland hydrology, hydrophytic vegetation and hydric soil) are required for positive wetland identification.

• If plants are present but soil is absent (e.g., vegetated rock substrates), then a predominance of hydrophytic vegetation and presence of wetland hydrology are required for positive wetland identification.

• If plants are absent but soil is present (e.g., playas or mudflats), then a predominance of undrained hydric soil and wetland hydrology are required for positive wetland identification.

• If neither plants nor soil are present (e.g., rocky shorelines or unvegetated shallow stream bottoms), then wetland identification must be made solely on the basis of hydrology.

• For naturally unvegetated or non-soil sites, such as many stream channels, tidal mudflats, playas, wave-active shorelines, and so on, use the "limits" of these systems as described in the FGDC Wetlands Classification Standard. In such cases, clear evidence of wetland hydrology is always required. However, the absence of vegetation or hydric soil characteristics due to natural physical or chemical conditions such as fluvial processes, wave action, or high salinity may make it appropriate to waive the hydrophytic vegetation and/or hydric soil requirements. Such modifications must be explained on data sheets and in wetland delineation/mapping reports.

• At drained sites that no longer meet wetland hydrology criteria, relic hydric soils or relic hydrophytic vegetation are not indicative of current wetlands. However, if such sites are

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 3 – Methods Page 3-3 encountered and the hydrologic alterations are likely human-induced, then they should be identified as potential wetland restoration opportunities.

• Additionally, the FGDC Wetlands Classification Standard defines the riverine wetland/deepwater habitat boundary as a depth of 8.2 feet (2.5 meters) at low water, or at the limits of emergent or woody vegetation extending beyond this depth.

3.02.2 Method for Delineating Nontidal Stream Boundaries (Rivers, Creeks, Lakes, Drains, Canals, and Ditches)

Within nontidal waters, in the absence of adjacent wetlands, the extent of USACE jurisdiction is defined by the ordinary high water mark (OHWM). In Code of Federal Regulations, Title 33 Part

328.3 (33 CFR § 328.3), the OHWM is defined as the “line on the shore established by the fluctuations of water and indicated by physical characteristics such as clear, natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, or the presence of litter and debris” (Environmental Laboratory 1987).

OHWM delineations were conducted using the appropriate OHWM characteristics, as defined in 33 CFR § 328.3(e) and 33 CFR § 329.11(a)(1). Any delineation of nontidal stream boundaries identified is consistent with OHWM Regulatory Guidance Letter Number (No.) 05‐05 (USACE 2005). Additionally, the National Ordinary High Water Mark Field Delineation Manual for Rivers and Streams, Interim Version (USACE 2022) was used to characterize OHWM conditions.

Rapid OHWM field identification data sheets associated with this survey are provided in Appendix C.

3.02.3 Limitations to Survey Accuracy

Hydrologic conditions within the study area were normal at the time of the delineation, as discussed in 3.02.3 and shown in Appendix D. Steep cliffs prohibited safe access and data collection at the lake shore. Additionally, persistent drought conditions have contributed to a lowered OHWM throughout Lake Powell. Perched locations on the terraces above Lake Powell were used as vantage points for observation of OHWM indicators. The OHWM was mapped using a combination of recent gage data, aerial imagery, and field observations.

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 4 – Exisisting Conditions Page 4-1

Chapter 4 – Environmental Setting

This section discusses the environmental setting of the aquatic resource study area.

4.01 Regional Setting

The study area is within the Colorado Plateau Level III Ecoregion and the Arid Canyonlands Level IV Ecoregion (Woods et al. 2001). The Arid Canyonlands Ecoregion consists of arid narrow chasms, cliffs, valley floors, floodplains, structural benches, mesas, and cuestas where the terrain has been deeply eroded by major rivers and their tributaries (Woods et al. 2001).

Elevations within this arid ecoregion range from approximately 3,200 to 5,000 feet.

4.02 Study Area Setting

The following sections describe the topography, climate, hydrology, soil, and habitat types associated with the study area.

4.02.1 Topography

Topography within the study area varies drastically and ranges from gently sloping terraces to vertical cliff faces with the natural gradient generally sloping downward from south to north.

Several watercourses flow through the site and eventually drain to Lake Powell, which is located in the northern portion of the study area. Elevations in the study area range from approximately 4,035 feet above mean sea level (ASML) near Hite Marina Road in the southern portion of the study area to approximately 3,550 feet ASML within Lake Powell in the northern portion of the study area.

4.02.2 Climate

Climate within the study area is characterized by mild winters and hot, dry summers, with average high temperatures of up to 100 degrees Fahrenheit (°F) in July to 48°F in January.

Annual precipitation in the Arid Canyonlands Ecoregion ranges between 5 and 8 inches, with precipitation values being lower in deeper canyons (Woods et al. 2001).

4.02.3 Hydrology

The study area is located within the Upper Lake Powell (14070001) watershed within the Colorado River basin. Persistent drought conditions within the Colorado River basin over the past two decades have resulted in reduced flows into Lake Powell as well as a significant decrease in water surface elevation.

Named surface water features in the study area include the Colorado River, which is discussed in this report primarily as Lake Powell, however the terms can be used interchangeably. It is important to note that due to persistent drought conditions, the site is in a dynamic period where fluctuating water elevation results in a free-flowing river during certain portions of the year and lake conditions in other portions of the year due to backwatering from the Glen Canyon dam.

For decades, the study area was significantly more influenced by backwater from Lake Powell, however in recent years the site has fluctuated between riverine and lacustrine conditions.

Given that gage data from the USGS indicates that the river at Hite still receives backwater from the Glen Canyon dam at certain times of the year, the term Lake Powell is used as part of this

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 4 – Exisisting Conditions Page 4-2 assessment. The study area also includes several watercourses that appear to only flow in response to wet season precipitation and runoff.

Fieldwork for the aquatic resource delineation was conducted on October 3 and 4, 2024.

USACE’s Antecedent Precipitation Tool (USACE 2024) was used to define precipitation conditions over the time period preceding the survey. The wetness condition in the months preceding the October 2024 survey was normal, however the Antecedent Precipitation Tool also indicated that the study area was in a moderate drought at the time of the survey. Appendix D contains the complete results of the Antecedent Precipitation Tool query.

4.02.4 National Wetlands Inventory and National Hydrography Dataset

Figure 2 in Appendix A shows aquatic resources in the study area identified by the National Wetlands Inventory (NWI) (USFWS 2024) and the National Hydrography Dataset (NHD) (USGS 2024a). The NWI identifies Lake Powell as lacustrine, limnetic, unconsolidated bottom, permanently flooded, diked/impounded (L1UBHh). One tributary to Lake Powell is identified as riverine, intermittent, streambed, seasonally flooded (R4SBC). These features were mapped using color infrared imagery from 1986, and since their mapping in the NWI, the extent and water level of Lake Powell has significantly reduced (USFWS 2024). The NHD also displays Lake Powell (Colorado River) and the same intermittent drainage as the NWI (USGS 2024a).

4.02.5 Soils

Soil in the study area has been mapped by the NRCS and are described in the Soil Survey of San Juan Area, Utah (NRCS 2024b and SCS 1962). Soil series mapped within the study area are summarized in Table 4-1 and shown on Figure 3 in Appendix A. In addition to the soil types mapped within the site, the northern portion of the study area associated with Lake Powell is mapped as water.

Table 4-1. Soil Series Mapped Within the Study Area

Type or Series Texture Landscape Position and Parent Material

Drainage and Permeability

NRCS

Hydric Rating

Myton Extremely boulder loam

Deep soils on steep to very steep hillslopes and mountain slopes.

Formed in colluvium derived from sandstone and shale.

Well drained; high runoff; moderately rapid permeability

No

Needle Fine sand Shallow to very shallow soils on hills with soil derived from eolian and alluvial deposits. Includes sand sheets on structural benches and rolling plateaus.

Excessively drained;

slow to medium runoff; rapid permeability

No

Sources: NRCS 2024a and 2024b.

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 4 – Exisisting Conditions Page 4-3

4.02.6 Land Cover and Vegetation Communities

Biotic communities in the study area mapped by the USGS Southwest Regional Gap Analysis Project (SWReGAP) consist of mostly unvegetated Colorado Plateau Mixed Bedrock Canyon and Tableland as well as Colorado Plateau Blackbrush-Mormon Tea Shrubland (USGS 2005).

Colorado Plateau Mixed Bedrock Canyon and Tableland consists of barren to sparsely vegetated landscapes over steep cliff faces, narrow canyons, and open tablelands that occur on substrates derived predominantly from sedimentary rocks, such as sandstone, shale, and limestone (USGS 2005). Colorado Plateau Blackbrush-Mormon Tea Shrubland occurs on benches, colluvial slopes, and bajadas that generally have shallow sandy or gravelly substrates derived from sedimentary rock. Blackbrush-Mormon Tea Shrubland can also occur in deeper soils on sandy plains and is characterized by extensive open shrublands with sparse herbaceous cover (USGS 2005). A lesser amount of Inter-Mountain Basins Mixed Salt Desert Scrub is present, along with small pockets of Invasive Annual Grassland and Inter-Mountain Basins Active and Stabilized Dune communities.

Dominant vegetation species observed throughout the study area include blackbrush (Coleogyne ramosissima), Mormon tea (Ephedra sp.), and shadscale saltbush (Atriplex confertifolia). Other plant species observed in the study area include broom snakeweed (Gutierrezia sarothrae), fragrant sumac (Rhus aromatica), singleleaf ash (Fraxinus anomala), Stansbury cliffrose (Purshia stansburiana), soaptree yucca (Yucca elata), plains prickly pear (Opuntia polyacantha), Mojave hedgehog cactus (Echinocereus mojavensis), and desert trumpet (Eriogonum inflatum). Invasive species detected included Russian thistle (Salsola tragus) and saltlover (Halogeton glomeratus).

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 5 – Results – Aquatic Resources Page 5-4

Chapter 5 – Results

Figure 4 in Appendix A shows the aquatic resources delineated in the study area and Appendix E contains representative photographs of features within the study area. Results of the aquatic resource delineation are summarized in Table 5-1 below.

Table 5-1. Summary of Aquatic Resources Investigated in the Study Area

Aquatic Resource

ID[a]

Cowardin Code[b]

Latitude Longitude Potential NPS or USACE

Jurisdiction[c]

OHWM

Width (Feet)

Area (Acres)

Length (Linear Feet)

Other Waters

Riverine Features

EDR-1 R6 37.8806006 -110.36902332 NPS 2 <0.01 78

EDR-2 R6 37.88059034 -110.3693721 NPS 2 – 15 0.04 286

EDR-3 R6 37.88094707 -110.36976242 NPS 2 – 10 0.02 221

EDR-4 R6 37.88084116 -110.37033376 NPS 2 – 30 0.17 580

EDR-5 R6 37.88142524 -110.37102082 NPS 2 – 45 0.29 638

EDR-6 R6 37.88229795 -110.37191981 NPS 2 – 25 0.12 400

EDR-7 R6 37.88196807 -110.37184328 NPS 2 – 25 0.22 680

EDR-8 R6 37.88312386 -110.37351531 NPS 2 – 60 0.63 1,906

EDR-9 R6 37.88370008 -110.37513084 NPS 2 0.01 180

EDR-10 R6 37.88457993 -110.37490243 NPS 2 – 35 0.22 400

EDR-11 R6 37.88560554 -110.37622342 NPS 2 – 4 0.01 213

EDR-12 R6 37.88592953 -110.37661102 NPS 2 – 35 0.10 579

EDR-13 R6 37.88611555 -110.37849447 NPS 3 – 22 0.11 420

EDR-14 R6 37.88485548 -110.38040274 NPS 2 – 4 0.06 460

EDR-15 R6 37.88484975 -110.37931432 NPS 2 – 5 0.18 1,532

EDR-16 R6 37.88714358 -110.37995296 NPS 2 – 30 0.32 1,236

EDR-17 R6 37.88920805 -110.37273018 NPS 3 – 5 0.03 261

IDR-1 R4SB 37.88985144 -110.37206943 NPS, USACE 5 – 20 0.07 306

Riverine Features Total 2.60 10,376

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 5 – Results – Aquatic Resources Page 5-5

Table 5-1. Summary of Aquatic Resources Investigated in the Study Area

Aquatic Resource

ID[a]

Cowardin Code[b]

Latitude Longitude Potential NPS or USACE

Jurisdiction[c]

OHWM

Width (Feet)

Area (Acres)

Length (Linear Feet)

Lacustrine Features

LP-1 L2US 37.89023702 -110.37564741 NPS, USACE N/A 3.61 N/A

OW-1 L1UB 37.89050757 -110.37425695 USACE N/A 3.08 N/A

Lacustrine Features Total 6.69 N/A

Total Other Waters 9.29 10,376

[a] EDR = ephemeral watercourse; IDR = intermittent watercourse; LP = Lake Powell; OW = open water

[b] Source: Cowardin et al. 1979. L1UB = lacustrine, limnetic, unconsolidated bottom; L2US = lacustrine, littoral, unconsolidated shore; R4SB = riverine, intermittent, streambed; R6 = riverine, ephemeral

[c] Potential NPS or USACE jurisdiction for aquatic resources are based on the definitions specified in the following sections of this report: Section 2.01, which discusses waters of the US subject to regulation by the USACE under Section 404 of the CWA under current regulations, as well as traditional navigable waters subject to regulation under Section 10 of the Rivers and Harbors Act; and Section 3.02.1, which discusses the FGDC Wetland Classification Standard and wetlands subject to regulation by the NPS under D.O. #77-1.

5.01 Other Waters

5.01.1 Riverine Features

Riverine features delineated within the study area include 17 ephemeral watercourses (2.53 acres, 10,070 linear feet) and one intermittent watercourse (0.07 acre, 306 linear feet). These features are further discussed below and are depicted on Figure 4 in Appendix A.

Representative photographs of these features are included in Appendix E.

Ephemeral Watercourses

Seventeen ephemeral watercourses, features EDR-1 through EDR-17, were delineated within the study area. These ephemeral features consisted of broad washes and incised drainages that were mostly barren to sparsely vegetated with upland herbaceous and shrub species.

Shrub species observed along the banks of the ephemeral watercourses varied but included species such as four-wing saltbush (Atriplex canescens), shadscale, Fremont barberry (Berberis fremontii), yellow rabbitbrush (Chrysothamnus viscidiflorus), rubber rabbitbrush (Ericameria nauseosa), Stansbury cliffrose, and single-leaf ash (Fraxinus anomala). Occasionally, scattered individuals of these shrubs were observed within the channels of the ephemeral watercourses.

These species are not listed in the Arid West Wetland Plant List and therefore are presumed to be upland plants (USACE 2020).

Five of these ephemeral watercourses, EDR-4, EDR-5, EDR-7, EDR-8, and EDR-12, cross the existing dirt access road. A slight berm is present along the outboard edge of the road surface in some areas and other sections of the road are sloped towards the inboard edge of the road.

This has caused several portions of these ephemeral features to divert seasonal flow down the road before exiting at a low point (Appendix E, Photos 5 and 10).

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 5 – Results – Aquatic Resources Page 5-6

Several watercourses within the study area, EDR-10 and EDR-13 through EDR-17, are partially conveyed over rock outcrops. These features convey seasonal flow via broad sheet flow over relatively flat rock outcrops (Photo 8, Map 2 of Figure 4) and by well-defined bedrock channels (Photo 11, Map 3 of Figure 4). One of these drainages, EDR-16, flows through a steep bedrock canyon and transitions into an incised channel on the bench above Lake Powell at the base of a cliff (Photo 15, Maps 4 and 5 of Figure 4). Another drainage, EDR-17, flows down to a cliff edge where the channel dissipates within the rock outcrops and infiltrates the ground on the terrace below (Photos 22 and 23, Map 6 of Figure 4).

Ephemeral watercourses within the study area are considered riverine wetlands under the FGDC Wetland Classification Standard and are likely subject to regulation by the NPS under D.O. #77-1. However, these ephemeral waters would not likely be considered waters of the US subject to regulation by the USACE under the CWA given that they would not be considered relatively permanent waters.

Intermittent Watercourse

One intermittent watercourse, feature IDR-1, was delineated within the study area. This intermittent watercourse flows through a bedrock canyon in the northeastern portion of the study area and drops down a steep cliff face to an inaccessible terrace above Lake Powell (Photo 23, Map 6 of Figure 4). IDR-1 is conveyed through an incised channel into Lake Powell, where hydrophytic shrubs such as mule fat (Baccharis salicifolia) and tamarisk (Tamarix sp.), as well as other emergent herbaceous species, are present along the channel and margins of the lake.

This feature is shown on USGS topographic maps as a blue line feature and is also documented by the NWI and NHD dataset as an intermittent drainage (refer to Section 3.02.04 and Figure 2).

The intermittent watercourse within the study area is considered a riverine wetland under the FGDC Wetland Classification Standard and is likely subject to regulation by the NPS under D.O.

#77-1. Additionally, this feature would likely be considered WOTUS subject to regulation by the USACE under the CWA given that it would be considered as a relatively permanent water with a continuous surface water connection to Lake Powell, which is a TNW.

5.01.2 Lacustrine Features

Lacustrine features delineated within the study area include Lake Powell (3.61 acres) and open water (3.08 acres). These features are further discussed below and are depicted on Figure 4 in Appendix A.

Lake Powell

Approximately 3.61 acres of Lake Powell, feature LP-1, were delineated within the study area.

The boundaries of LP-1 were mapped between the open water of Lake Powell up to the OHWM.

Within the study area, LP-1 consisted of vertical cliff faces and shoreline that has started to revegetate due to receding water elevation (Photos 18-21, Maps 5 and 6 of Figure 4). Observed field indicators of the OHWM of Lake Powell included break in slope, shelving, change in vegetation type and density, and water staining (Photos 18 and 21). Water staining was evident on the opposite side of Lake Powell (north bank) and is visible as a white band that corresponds with the delineated OHWM (Photos 18-21). Additionally, portions of the shoreline had incised rivulets extending from the OHWM to OW-1 are indicative of receding water. Supplemental data

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 5 – Results – Aquatic Resources Page 5-7 utilized to confirm field observations of the OHWM included data from the USGS Colorado River AB Dirty Devil NR Hite, UT stream gage (09328990), aerial imagery, and LiDAR. The extent of this lacustrine littoral wetland extends from the OHWM down to lacustrine limnetic wetland boundary, which is where the water depth reaches 8.2 feet (2.5 meters) at low water.

Lake Powell within the study area is considered a lacustrine littoral wetland under the FGDC Wetland Classification Standard and is likely subject to regulation by the NPS under D.O. #77-1.

Additionally, this feature would likely be considered waters of the US subject to regulation by the USACE under Section 404 the CWA and Section 10 of the Rivers and Harbors Act given that it is a TNW.

Open Water

Approximately 3.08 acres of open water (also referred to as deepwater habitat) associated with Lake Powell, feature OW-1, were delineated within the study area. The open water boundary delineated during the survey is represented by the current low-flow extent of Lake Powell where water is over 8.2 feet (2.5 meters) deep below low water. The low-flow water elevation at Lake Powell, as measured by the USGS Colorado River AB Dirty Devil NR Hite, UT stream gage (09328990), was approximately 3,571 feet AMSL in 2024.

Lake Powell within the study area is considered deepwater habitat under the FGDC Wetland Classification Standard and is not likely subject to regulation by the NPS under D.O. #77-1.

However, this feature would likely be considered waters of the US subject to regulation by the USACE under Section 404 the CWA and Section 10 of the Rivers and Harbors Act given that it is a Traditional Navigable Water.

5.02 Other Areas Investigated

Areas exhibiting primary wetland hydrology indicators and sparse to barren vegetation cover were investigated in several locations throughout the study area. These sampling points were generally taken within ephemeral washes where water appears to temporarily pool in small depressions or relatively flat areas. The first elevated terrace above Lake Powell in the northern portion of the study area was investigated due to NWI and NRCS soil maps indicating lacustrine features; however, this location was determined not to be a wetland or other water (SP-HT6, Photo 17). In addition to potential wetland features, flood deposits were observed throughout the northern portion of the study area at elevations near or just above the 3,700-foot full pool elevation of Lake Powell. These were likely deposited during extreme flood events in the 1980’s (Photo 24).

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 6 – References Page 6-1

Chapter 6 – References

Bing. 2024. Microsoft Bing Maps. Accessed September 2024.

Cowardin, L.M., V.C. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States/Riverine System. U.S. Fish and Wildlife Service Office of Biological Services. Jamestown, ND: Northern Prairie Wildlife Research Center Online.

Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical Report Y-87-1. U.S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, MS. NTIS No. AD A176 912.

Munsell Soil-Color Charts (Munsell). 2009. Munsell Soil Color Charts. Year 2009 Revised Edition. Grand Rapids, Michigan.

National Park Service (NPS). 2016. National Park Service Procedural Manual #77-1: Wetland Protection. June 16.

Natural Resources Conservation Service (NRCS). 2024a. Web Soil Survey 2.0 National Cooperative Soil Survey. Accessed September 2024.

http://websoilsurvey.nrcs.usda.gov/app/.

Natural Resources Conservation Service (NRCS). 2024b. State Soil Data Access (SDA) Hydric Soils List. Accessed September 2024.

https://geodata.geology.utah.gov/pages/download.php?direct=1&noattach=true&ref=246 97&ext=pdf&k=.

NV5 Geospatial, Inc. 2022. Lake Powell, Arizona and Utah Topographic Lidar Technical Data Report.

Soil Conservation Service (SCS). 1962. Soil Survey of San Juan Area, Utah. accessed September 2024.

https://geodata.geology.utah.gov/pages/view.php?ref=57455&search=&offset=4206&ord er_by=field51&sort=ASC&archive=0&k=&

U.S. Army Corps of Engineers (USACE). 2005. Regulatory Guidance Letter No. 05‐05. Ordinary High Water Mark Identification.

U.S. Army Corps of Engineers (USACE). 2008. Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Arid West Region, Version 2.0.

U.S. Army Corps of Engineers (USACE). 2020. Arid West Wetland Plant List. https://wetland-plants.sec.usace.army.mil/nwpl_static/data/DOC/lists_2020/Regions/pdf/reg_AW_2020v 1.pdf.

U.S. Army Corps of Engineers (USACE). 2022. National Ordinary High Water Mark Field Delineation Manual for Rivers and Streams, Interim Version. Wetlands Regulatory Assistance Program. USACE ERDC/CRREL TR-22-16. November.

U.S. Army Corps of Engineers (USACE). 2024. The Antecedent Precipitation Tool. Version 2.0.

https://github.com/erdc/Antecedent-Precipitation-Tool.

http://websoilsurvey.nrcs.usda.gov/app/ https://geodata.geology.utah.gov/pages/download.php?direct=1&noattach=true&ref=24697&ext=pdf&k= https://geodata.geology.utah.gov/pages/download.php?direct=1&noattach=true&ref=24697&ext=pdf&k= https://geodata.geology.utah.gov/pages/view.php?ref=57455&search=&offset=4206&order_by=field51&sort=ASC&archive=0&k=& https://geodata.geology.utah.gov/pages/view.php?ref=57455&search=&offset=4206&order_by=field51&sort=ASC&archive=0&k=& https://wetland-plants.sec.usace.army.mil/nwpl_static/data/DOC/lists_2020/Regions/pdf/reg_AW_2020v1.pdf https://wetland-plants.sec.usace.army.mil/nwpl_static/data/DOC/lists_2020/Regions/pdf/reg_AW_2020v1.pdf https://wetland-plants.sec.usace.army.mil/nwpl_static/data/DOC/lists_2020/Regions/pdf/reg_AW_2020v1.pdf https://github.com/erdc/Antecedent-Precipitation-Tool

Aquatic Resources Delineation Report, Low Water Ramp at Hite District – December 2024

Chapter 6 – References Page 6-2

U.S. Bureau of Reclamation (USBR). 2022. November 2022 24-Month Study Projections Lake Powell and Lake Mead: End of Month Elevation Charts. Available online at:

https://www.usbr.gov/uc/water/crsp/studies/images/PowellElevations.pdf. Accessed November 7, 2024.

U.S. Fish and Wildlife Service (USFWS). 2024. National Wetlands Inventory Data. Accessed September 2024. http://www.fws.gov/wetlands/data/datadownload.HTML.

U.S. Geological Survey (USGS) National Gap Analysis Program. 2005. Southwest Regional GAP Analysis Project – Land Cover Descriptions. RS/GIS Laboratory, College of Natural Resources, Utah State University.

U.S. Geological Survey (USGS). 2024a. National Hydrography Dataset. Accessed September 2024. https://www.usgs.gov/core-science-systems/ngp/national-hydrography.

U.S. Geological Survey (USGS). 2024b. Topoview. United States Department of the Interior.

Accessed September 2024. https://ngmdb.usgs.gov/topoview/viewer/#4/40.01/-100.06.

Woods, A.J., Lammers, D.A., Bryce, S.A., Omernik J.M., Denton, R.L., Domeier, M., and Comstock, J.A. 2001. Ecoregions of Utah (color poster with map, descriptive text, summary tables, and photographs): Reston, Virginia, U.S. Geological Survey (map scale 1:1,175,000).

http://www.fws.gov/wetlands/data/datadownload.HTML https://www.usgs.gov/core-science-systems/ngp/national-hydrography https://ngmdb.usgs.gov/topoview/viewer/#4/40.01/-100.06

Glen Canyon National Recreation Area Low Water Ramp at Hite District

Aquatic Resources Delineation Report, December 2024

Glen Canyon National Recreation Area Low Water Ramp at Hite District

Aquatic Resources Delineation Report, December 2024 Appendix B – Wetland Determination Data Forms

Appendix B – Wetland Determination Data Forms

Project/Site:

Applicant/Owner: State:

Investigator(s):

Landform (hillside, terrace, etc.): 5-10

Subregion (LRR):

Soil Map Unit Name: NWI classification:

x

Are Vegetation , Soil , or Hydrology Are “Normal Circumstances” present? Yes x No

Are Vegetation , Soil , or Hydrology x

SUMMARY OF FINDINGS – Attach site map showing sampling point locations, transects, important features, etc.

Yes X Yes X Yes X Yes X

1.

2. (A) 3.

4. (B)

Sapling/Shrub Stratum (A/B) 1.

2.

3.

4. OBL species x 1 =

5. FACW species x 2 =

FAC species x 3 = Herb Stratum FACU species x 4 =

1. UPL species x 5 =

2. Column Totals: (A) (B) 3.

4.

5.

6.

7.

8. Morphological Adaptations1 (Provide supporting

Woody Vine Stratum 1.

2.

% Bare Ground in Herb Stratum Yes X

Terrace Local relief (concave, convex, none):

U.S. Army Corps of Engineers WETLAND DETERMINATION DATA SHEET – Arid West Region

See ERDC/EL TR-08-28; the proponent agency is CECW-CO-R

OMB Control #: 0710-0024, Exp: 11/30/2024 Requirement Control Symbol EXEMPT:

(Authority: AR 335-15, paragraph 5-2a)

Sampling location is mostly barren within the ephemeral wash with some scattered shrubs and herbs present. Species with no indicator (NI) are treated as upland (UPL) species for this analysis.

Hydric Soil Present?

Wetland Hydrology Present?

30' x 30'

5' x 5'

100 % Cover of Biotic Crust

LRR D Lat: 37.88161 naturally problematic? (If needed, explain any answers in Remarks.)

Yes

NI

0.0%

Multiply by:

Percent of Dominant Species That Are OBL, FACW, or FAC:

Absolute % Cover

(Plot size:

Chrysothamnus viscidiflorus

(Plot size:

within a Wetland?

Total Number of Dominant Species Across All Strata:

Remarks:

1Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic.

data in Remarks or on a separate sheet) significantly disturbed?

Dominant Species?

No

Dominance Test worksheet:

15' x 15' )

Total % Cover of:

Prevalence Index worksheet:

No No

No

VEGETATION – Use scientific names of plants.

Tree Stratum

Is the Sampled Area

Prevalence Index = B/A = 5.00

Prevalence Index is ≤3.01

Hydrophytic Vegetation Indicators:

Are climatic / hydrologic conditions on the site typical for this time of year?

Problematic Hydrophytic Vegetation1 (Explain)

Hydrophytic Vegetation Present?

(Plot size:

Hydrophytic Vegetation Present?

Dominance Test is >50%

S27, T33S, R14E

Concave

16 - Myton very gravelly sandy loam, 5 to 18% slopes

Yes No (If no, explain in Remarks.)

GLCA - Hite Low-water Boat Ramp Project Sampling Date: 10/3/2024

National Park Service (NPS) Sampling Point:UT SP-HT1

City/County: Hite / San Juan County

WGS 84-110.370387 Datum:

Section, Township, Range:G. Davis, S. McNeish

Slope (%):

Long:

=Total Cover

Sampling location is within an ephemeral wash where surface cracks are present. While the site functions as an ephemeral wash and conveys seasonal flow downslope, it does not contain hydrophytic vegetation or hydric soils.

=Total Cover

Indicator Status

Remarks:

No

Number of Dominant Species That Are OBL, FACW, or FAC:

=Total Cover

(Plot size: 30' x 30' )

=Total Cover

ENG FORM 6116-1, FEB 2024 Arid West – Version 2.0

None

Sampling Point:

% % Type1 Loc2

Type:

Depth (inches): Hydric Soil Present? Yes No X

Primary Indicators (minimum of one is required; check all that apply)

X

X

Surface Water Present? Yes Water Table Present? Yes Saturation Present? Yes Wetland Hydrology Present? Yes X No

Sandy Gleyed Matrix (S4) 3Indicators of hydrophytic vegetation and wetland hydrology must be present, unless disturbed or problematic.

1 cm Muck (A9) (LRR C) 2 cm Muck (A10) (LRR B) Iron-Manganese Masses (F12) (LRR D) Reduced Vertic (F18) Red Parent Material (F21) Very Shallow Dark Surface (F22) Other (Explain in Remarks)

Sandy Mucky Mineral (S1) Redox Depressions (F8)

Loamy Mucky Mineral (F1) Loamy Gleyed Matrix (F2) Depleted Matrix (F3) Redox Dark Surface…