V-EIS-98-03-D
300D05903
>ver Dam
ass Project
•rative Draft
mental Impact Statement
ighway Administration
iral Lands Highway Division
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Contents
Chapter Page
Executive Summary , ES-1
1 Purpose and Need 1-1
1.1 Introduction 1-1
1.2History , 1-2
1.3 Need for the Project 1-7
1.4 Purpose of Project - 1-11
1.5 Relationship of the Proposed Project to the Statewide Plan or Urban
Transportation Plan - • • 1-11
1.6 Legislation Regarding the Proposed Project 1-13
1.7 Relationship of the Proposed Project to Other Modes of Transportation 1-13
2 Alternatives 2-1
2.1 Introduction 2-1
2.2 Previous Studies Conducted 2-1
2.3 Initial Identification of Alternatives 2-4
2.4 Criteria for Screening Alternatives 2-9
2.5 Public Input 2-10
2.6 Alternatives Considered but Eliminated from Detailed Evaluation 2-11
2.7 Alternatives Studied in Detail 2-14
2.8 No Build Alternative 2-28
2.9 Logical Termini 2-28
3 Affected Environment, Environmental Consequences, and Measures
to Minimize Harm 3-1
3.1 Air Quality 3-1
3.2Noise 3-7
3.3 Biology 3-16
3.4 Water Resources 3-34
3.5 Cultural Resources 3-40
3.6 Land Use 3-51
3.7 Visual Resources 3-55
3.8 Recreation Resources 3-78
3.9 Socioeconomics - 3-86
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Contents, Continued
Chapter, Continued Page
3.10 Hazardous Materials 3-93
3.11 Construction Activities and Impacts 3-98
3.12Energy 3-101
3.13 Local Short-term Uses versus Long-term Productivity 3-102
3.14 Irreversible and Irretrievable Commitment of Resources 3-103
4 Unavoidable Adverse Impacts .." 4-1
4.1 Introduction 4-1
4.2 Air 4-1
4.3 Noise 4-1
4.4 Biological Resources 4-1
4.5 Water Resources 4-1
4.6 Archaeological Resources 4-2
4.7 Land Use 4-2
4.8 Visual Resources 4-3
4.9 Recreation 4-3
4.10 Socioeconomics , 4-3
4.11 Hazardous Materials * 4-3
5 Cumulative Impacts 5-1
5.1 Nevada STIP 5-1
5.2 Boulder City Bypass , 5-2
5.3 Arizona STEP • 5-2
6 Coordination and Consultation 6-1
6.1 Introduction 6-1
6.2 Public Scoping 6-2
6.3 Public Comment Meetings 6-3
6.4 Public Agency Partnering Session Held October 29,1997 6-3
6.5 Project Management Team Meetings 6-4
6.6 Public Outreach 6-4
6.7 PDEIS Public Review and Comment 6-4
6.8 Permits 6-4
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Contents, Continued
Chapter, Continued Page
7 List of Report Preparers • 7'1
Federal Highway Administration - 7-1
Arizona Department of Transportation 7-1
Nevada Department of Transportation 7-1
U.S. Bureau of Reclamation 7-1
U.S. National Park Service 7-1
CH2MHILL - 7"2
8 References - 8"1
9 Index 9-1
Appendices
A Traffic Analysis
B Laughlin-Bullhead City Alternative
C Section 4(f) Evaluation
D Correspondence
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Contents, Continued
Tables Page
ES-1 Summary of Environmental Impacts ES-3
ES-2 Permits and Approvals Anticipated for the Hoover Dam Bypass Project ES-6
ES-3 Summary of Mitigation Measures ES-7
1-1 Historic and Projected Traffic Volumes and Level of Service at Hoover Dam 1-8
1-2 Accident Data for 1994 to 1997 1_10
2-1 Previous U.S. Highway 93 and Hoover Dam Studies 2-1
2-2 Comparison of Alternatives Considered " 2-13
3-1 Attainment Status 3.3
3-2 Existing Traffic Conditions 3,3
3-3 Estimated 1997 Vehicle Emission Rates 3.4
3-4 Existing Project Burden 3.5
3-5 Daily Emissions by Alternative 3.5
3-6 Federal Highway Administration Design Noise Level/Activity Relationships 3-8
3-7 Measured Noise Levels (dBA-Leq) 3-8
3-8 Existing Peak-Hour Noise Levels (dBA-L,,q) 3.9
3-9 Estimated Peak Construction Noise Levels (dBA) 3-10
3-10 Future Peak-Hour Noise Levels (dBA-L^) 3-13
3-11 Gold Strike Canyon Alternative Future Peak-Hour Noise Levels (dBA-L^) 3-15
3-12 Special-status Vegetation and Wildlife Species Potentially Occurring in the
Proposed Project Area and Likelihood of Occurrence 3-22
3-13 Comparison of Impacts to General Terrestrial Communities from All
Alternatives (Colorado River Bridge - Hoover Dam) 3-25
3-14 Comparison of Impacts of All Alternatives to Special-status Species., 3-27
3-15 Comparison of Impacts of Build Alternatives on Desert Bighorn Sheep 3-29
3-16 Acreage of Permanent and Temporary Fill in Waters of the United States for Each
Alignment , 3.3!
3-17 Estimated Number of Wildlife Crossing Structures for Each Alternative 3-32
3-18 Acreage to be Developed for Each Build Alternative 3-54
3-19 1990 Census Data by Locality Near the Proposed Project Area 3-88
3-20 Average Annual Daily Traffic and Level of Service at Hoover Dam 3-90
3-21 Forecasted Average Annual Daily Traffic and Level of Service at Hoover Dam Under
No Build Alternative 3.93
3-22 Estimated Construction Period for Proposed Alternatives 3-99
6-1 Permits and Approvals Anticipated for the Hoover Dam Bypass Project 6-5
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Contents, Continued
Figures
Page
1-1 U.S. 93 Transportation Corridor 1-3
1-2 Existing Alternate Routes to U.S. 93 and Hoover Dam Crossing 1-5
2-1 Alternatives Considered 2-5
2-2 Typical Roadway Section • • • • 2-15
2-3 Alternatives Being Evaluated in Detail 2-17
2-4 Promontory Point Project Features • 2"19
2-5 Sugarloaf Mountain Project Features 2-23
2-6 Gold Strike Canyon Project Features - 2-25
3-1 Noise Receptor Sites and Recommended Mitigation 3-11
3-2 Location of Sensitive Biological Resources 3-19
3-3 Viewpoints for Visual Simulations 3-61
3-4 Promontory Point Alternative Visual Simulations 3-63
3-5 Promontory Point Alternative Visual Simulation 3-65
3-6 Sugarloaf Mountain Alternative Visual Simulations 3-67
3-7 Gold Strike Canyon Alternative Visual Simulations 3-69
3-8 Representative View from the Road Visual Simulation - 3-71
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Acronyms and Abbreviations
AADT average annual daily traffic
ACHP Advisory Council on Historic Preservation
ADEQ Arizona Department of Environmental Quality
ADOT Arizona Department of Transportation
AGFD Arizona Game and Fish Department
APE area of potential effects
AQRV air quality-related value
ARPA Archaeological Resources Protection Act of 1979
ASTIP Arizona State Transportation Improvement Plan
BMP Best Management Practice
B.P. Before Present (before 1950)
CAA Clean Air Act
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
CFLHD Central Federal Lands Highway Division
CFR Code of Federal Regulations
CO carbon monoxide
CFR Code of Federal Regulations
dBA decibels on the A-scale
DEIS Draft Environmental Impact Statement
DOI U.S Department of the Interior
EIS Environmental Impact Statement
EO Executive Order
EPA U.S. Environmental Protection Agency
FEMA Federal Emergency Management Agency
FHWA Federal Highway Administration
FIA Federal Insurance Administration
GCVTC Grand Canyon Visibility Transport Commission
GMP General Management Plan
HDNHL Hoover Dam National Historic Landmark
HDR Hoover Dam Reservation
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IX
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EXECUTIVE SUMMARY
The project would be located on lands under the jurisdiction of the U.S. Department of the
Interior, U.S. Bureau of Reclamation, and National Park Service. No other major federal actions
are currently proposed for the proposed project area.
Summary of Alternatives Considered
Three build alternatives and the No Build Alternative are being considered.
Promontory Point Alternative
The Promontory Point Alternative crosses Lake Mead about 1,000 feet upstream of Hoover
Dam. This alternative requires constructing approximately 2.7 miles of highway approach in
Nevada; a 2,200-foot-long bridge; and an approximately 0.9-mile highway approach in Arizona.
Sugarloaf Mountain Alternative
The Sugarloaf Mountain Alternative crosses the Colorado River about 1,500 feet downstream of
Hoover Dam. This alternative requires constructing approximately 2.2 miles of highway
approach in Nevada, a 1,900-foot-long bridge, and an approximately 1.1-mile highway
approach in Arizona.
Gold Strike Canyon Alternative
The Gold Strike Canyon Alternative crosses the Colorado River about 1 mile downstream of
Hoover Dam. This alternative requires constructing approximately 2.2 miles of highway
approach in Nevada, a 1,700-foot-long bridge, and a 1.1-mile highway approach in Arizona.
No Build Alternative
The No Build Alternative is no action being taken. No Hoover Dam Bypass is developed; no
change in the current highway configuration occurs; and no other structural or nonstructural
improvements are developed on U.S. 93 near Hoover Dam. Existing hairpin curves, inadequate
sight distances, narjow dam crest roadway, and steep grades on U.S. 93 in the Hoover Dam
vicinity remain unchanged. No direct construction costs result from this alternative. However,
an increase in operations and maintenance costs is foreseeable because of increased traffic and
congestion. The public also incurs added cost because of more frequent traffic delays and
accidents.
The No Build Alternative does not meet the project purpose and need (see Chapter 1) because
it does not decrease travel times and increase travel speeds in the vicinity of the dam. The
increased traffic, which will continue to travel at slower speeds, contributes to decreased air
quality in the Hoover Dam vicinity and increases accidents and congestion for tourists at
Hoover Dam and the Lake Mead National Recreation Area. The potential for a catastrophe
involving vehicles containing hazardous materials reasonably may be expected to increase with
increasing traffic volume. Risks to innocent bystanders, property damage to the dam and its
facilities, contamination of Lake Mead or the Colorado River, and interruption of the power
and water supplies to Southwest residents remains or increases.
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EXECUTIVE SUMMARY
Table ES-3
Summary of Mitigation Measures
Environmental
Issue
Promontory Point
Alternative
Sugarloaf Mountain
Alternative
Gold Strike Canyon
Alternative
No Build
Alternative
Biological Resource Effects
Mitigation
Measures
Construction
Revegetate disturbed
land; protect desert
washes with barriers;
construct offsite watering
facilities; build wildlife
overpasses and
underpasses; place
fencing along corridor to
guide bighorn sheep and
other wildlife to crossing
structures; implement
monitoring plan to assess
effectiveness of bighorn
sheep mitigation;
contribute project funds to
desert tortoise habitat
compensation program;
conduct preconstruction
tortoise surveys; relocate
tortoises from
construction areas; initiate
construction worker
desert tortoise education
program; conduct
monitoring program of
peregrine falcon breeding
pairs before/during/after
construction; restrict
blasting operations during
peregrine falcon breeding
season; monitor bald
eagle use of bridge sites
prior to construction;
protect bald eagle perch
sites
Operation
No mitigation required
Construction
Revegetate disturbed
land; protect desert
washes with barriers;
construct offsite
watering facilities; build
wildlife overpasses and
underpasses; place
fencing along corridor
to guide bighorn sheep
and other wildlife to
crossing structures;
implement monitoring
plan to assess
effectiveness of
bighorn sheep
mitigation; contribute
project funds to desert
tortoise habitat
compensation
program; conduct
preconstruction tortoise
surveys; relocate
tortoises from
construction areas;
initiate construction
worker desert tortoise
education program;
conduct monitoring
program of peregrine
falcon breeding pairs
before/during/after
construction; restrict
blasting operations
during peregrine falcon
breeding season;
monitor bald eagle use
of bridge sites prior to
construction; protect
bald eagle perch sites
Operation
No mitigation required
Construction
Revegetate disturbed
land; protect desert
washes with barriers;
construct offsite
watering facilities;
build wildlife
overpasses and
underpasses; place
fencing along corridor
to guide bighorn
sheep and other
wildlife to crossing
structures; implement
monitoring plan to
assess effectiveness
of bighorn sheep
mitigation; contribute
project funds to
desert tortoise habitat
compensation
program; conduct
preconstruction
tortoise surveys;
relocate tortoises
from construction
areas; initiate
construction worker
desert tortoise
education program;
conduct monitoring
program of peregrine
falcon breeding pairs
before/during/after
construction; restrict
blasting operations
during peregrine
falcon breeding
season; monitor bald
eagle use of bridge
sites prior to
construction; protect
bald eagle perch sites
Operation
No mitigation required
N/A
ES-8
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CHAPTER 1 PURPOSE AND NEED
may not specifically remedy these conditions, but reducing the number of vehicles carrying
these materials over this point will result in a corresponding reduction in potential spill risks.
1.3.7 Quality of Visitors' Experience at Hoover Dam
Hoover Dam is a popular national and international tourist destination. Tourists enter the
visitor center, take the tour, patronize the snack bar, and walk across the dam crest to
photograph the facilities from various upstream and downstream vantage points. These
activities contribute to traffic congestion and can result in vehicle and pedestrian conflicts.
Through-vehicle and truck traffic also emit noise and vehicle exhaust, which impacts conditions
for tourists.
1.4 Purpose of Project
The purpose of the project is to reduce or eliminate through traffic over Hoover Dam to
accomplish the following objectives:
• Remove a major bottleneck to interstate and international commerce and travel in the west
by reducing traffic congestion and accidents in this segment of the major commercial route
between Phoenix and Las Vegas
* Replace an inadequate federally owned highway river crossing with a new crossing that
meets current roadway design criteria, and improves through-vehicle and truck traffic
capacity on U.S. 93 at the dam
• Reduce travel time and increase travel speed in the dam vicinity
• Protect Hoover Dam employees, visitors, equipment, power generation capabilities, and
Colorado River waters while enhancing the visitors' experience at Hoover Dam by:
- Minimizing the potential for pedestrian-vehicle accidents on the dam crest and on the
Nevada and Arizona approaches to the dam
- Safeguarding dam and power plant facilities and the waters of Lake Mead and the
Colorado River from hazardous spills or explosions
- Protecting the dam and power plant facilities from interruptions in electricity and water
delivery
- Providing improved conditions for operating and maintaining Hoover Dam facilities
1.5 Relationship of the Proposed Project to the Statewide Plan or
Urban Transportation Plan
This section describes travel demand in relation to the Nevada and Arizona plans and pertinent
legislation.
1.5,1 Nevada
The NDOT's Statewide Transportation Improvement Program (STEP) was developed through
coordinated efforts of the NDOT; federal, state, local, and tribal governments; and with agencies,
planning organizations, transportation providers, and the general public (NDOT, 1997).
Evaluating a Hoover Dam bypass is included in the STEP (1998). Constructing a bypass at
Hoover Dam is one of six projects listed in NDOT's billion dollar Highway Superproject
Program and is shown in NDOT's Work Program—Long Range Element (1998 through 2007).
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CHAPTER 2
Alternatives
2.1 Introduction
This chapter describes project alternatives to be evaluated, previous studies of those alter-
natives, screening criteria developed to aid in selecting alternatives to be evaluated, and
alternatives eliminated from detailed impact evaluation.
2.2 Previous Studies Conducted
As discussed in Chapter 1, U.S. 93 deficiencies in the Hoover Dam vicinity were identified as
long ago as 1965. Recognition of these roadway deficiencies resulted in a series of studies that
evaluated alternative methods to alleviate deficiencies. Table 2-1 lists the studies conducted to
date and provides a brief description of study purposes and findings.
Table 2-1
Previous U.S. Highway 93 and Hoover Dam Studies
Study Name, Author, and Year Prepared
Summary of Study
U.S. 93 - 466 Hoover Dam Origin and Destination
Study, prepared by State of Nevada Department of
Highways and U.S. Department of Commerce, Bureau
of Public Roads, November 1966.
Study determined the characteristics of traffic
congestion at Hoover Dam. Determined that traffic
near Hoover Dam can be divided into two
categories: through traffic (defined as vehicles
using the dam as a bridge to complete their trip),
and Hoover Dam dead-end trips (defined as
vehicles whose destination is Hoover Dam).
Suggested four methods to alleviate traffic
problems: (1) develop more parking areas and
modify the dam to add two traffic lanes, (2)
construct an upstream crossing, (3) construct a
downstream crossing, and (4) construct a
downstream crossing near Willow Beach {not
considered economically justified in 1966 because
of Davis Dam crossing downstream).
A Study and Recommendations for Handling Traffic
and Conducting Visitors at Hoover Dam, prepared by
Perkins & Will Corporation, April 1971.
Study determined methods and facilities to handle
vehicle traffic and conduct visitors on dam tour.
Study assumed that through traffic would bypass
the dam by relocating U.S. 93 to a new downstream
bridge, and that all other traffic would continue to
travel across the dam. Recommended a highway
bypass, parking structures, and minor highway
improvements.
Resume of Studies on Colorado River Crossing Below
Hoover Dam, prepared by Reclamation, January 1972.
Study requested Congressional authorization to
construct an alternative Colorado River crossing
near Hoover Dam.
Facilitating Traffic Flow, Alleviating Safety Hazards,
and Expediting Access - Hoover Dam, prepared by
Reclamation, September 1977.
Study requested Congressional authorization to
increase the cost ceiling of the Boulder Canyon
Project Act (authorized in 1928). Additional funds
would have provided new facilities to improve traffic
flow, alleviated safety hazards, and provided a safe
experience for Hoover Dam visitors.
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CHAPTER 2 ALTERNATIVES
Table 2-1
Previous U.S. Highway 93 and Hoover Dam Studies
Study Name, Author, and Year Prepared
Summary of Study
Desert Bighorn Movements and Habitat Use in Relation
to the Proposed Black Canyon Bridge Project: Nevada,
University of Nevada, May 1993.
Hazardous Material Truck Safety Study • U.S. Highway
93 at Hoover Dam, prepared by CH2M HILL, November
1993.
U.S. 93 Colorado River Crossing Corridor Study,
prepared by NDOT, December 1994.
This study characterized bighorn sheep habrtat
quality and information on movements of radio-
collared bighorn to estimate home range size and
patterns ofmovement. Total home range size was
determined. It was found that bighorn sheep heavily
use the area of the proposed alignments on a year
round (ewes) and seasonal basis (rams in fall). The
Sugarioaf Mountain Alternative was found to intrude
the least on high use areas and that habitat loss will
be greatest for the Gold Strike Canyon Alternative.
Big game fencing is recommended along the new
highway to reduce bighorn sheep/motor vehicle
collisions.
This study was to determine traffic accident
projections, identify potential impacts o1 hazardous
material spills, and prepare a program to reduce the
accident exposure of trucks hauling hazardous
materials on U.S. 93 in the area of Hoover Dam.
Based on historic accident information and traffic
volume forecasts, approximately five hazardous
material truck overturns are expected to result in
approximately two hazardous spills over the next
20 years. The material most likely to be involved (70
percent chance) will be flammable, either gasoline or
diesel fuel. The next most likely material to be
involved in a spill (6 percent chance) is corrosive.
Based on data from 1981 through 1991, the overall
accident rate in the study area is 3.66 per million
vehicle miles traveled; the truck accident rate is 7.07
per million truck miles traveled.
A continuation of Reclamation studies, this report
analyzed two longer alternatives: Willow Beach
South (26 miles) and Hoover Dam/Boulder City
Bypass (31 miles). Study purpose was to determine
the relative feasibility of these corridors. Feasibility
was determined by relative cost, technical
engineering difficulty, major impacts, and user
benefits.
2.3 Initial Identification of Alternatives
Study summaries in Table 2-1 include descriptions of potential build alternatives that were
identified during the public meetings conducted for this EIS. Figure 2-1 shows alignments of
these alternatives. In addition, a No Build Alternative is considered. The following sections
briefly describe these alternatives.
2-4
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CHAPTER 2 ALTERNATIVES
the site (the integrity and setting of the dam and its status as a National Historic Landmark);
and limited space available for separating traffic, vehicle turning movements, and parking
maneuvers.
Table 2-2 summarizes the results of applying screening criteria and rationale for eliminating
certain alternatives.
Table 2-2
Comparison of Alternatives Considered
4{f) Lands
Potentially
Alternative Name Disturbed (acres)
Promontory Point
Sugarloaf Mountain
Gold Strike Canyon
Boulder City North
Boulder City South
Boulder City South Option
Willow Beach North
Willow Beach South
Nelson
Cottonwood
Laughiin-Bullhead City
U.S. 95/1-40
Temple Bar
Modifications to Hoover Dam
Restricting Motorized Traffic
to Hoover Dam
Traffic Systems
Management
360
60
87
145
165
135
405
575
491
436
36
0
818
n/a
n/a
n/a
Distance from the
U.S. 93/95
Interchange NV to Results of Applying
Kingman, AZ (miles) Screening Criteria
88
88
88
84
87
85
83
82
84
94
111
158
149
n/a
n/a
n/a
Meets criteria
Meets criteria
Meets criteria
Reason for Elimination
2,3,4
2,3,4
2,3,4
2, 3, 4, 5, 6
2, 3, 4, 5, 6
2, 3, 4, 5, 6
2,3,4,5,6
1,4,5
1,5
2, 3. 4, 5, 6
1,9
1,7,8
1,7,8
Screening Criteria
1. Does not meet Purpose and Need.
2. Substantial Section 4(f) Impacts.
3. Severe impacts to pristine habitat.
4. Severe impacts to wildlife.
5. Excessive costs.
6. Requires operation and maintenance of duplicate parallel roadways.
7. Conflicts with NDOT criteria.
8. No reduction in congestion.
9. Does not solve public safety problem or protect power and water supplies; impacts to historic
appearance of dam.
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CHAPTER 3 AFFECTED ENVIRONMENT. ENVIRONMENTAL CONSEQUENCES. AND MEASURES TO MINIMIZE HARM
Under noise abatement policies of the Federal Highway Administration, noise barriers will
only be constructed if they are determined to be reasonable and feasible (FHWA, Highway
Traffic Noise Analysis and Abatement - Policy and Guidance, June 1995). A 5 dBA noise reduction
must be achieved for the noise barriers to be considered feasible, which can be accomplished
for the Gold Strike Canyon Trail (as shown in Table 3-11). One reasonableness factor that can
be analyzed for recommended barriers is benefit-cost. To achieve the minimum noise reduction
of 5 dBA and break the line-of-sight along the portion of the hiking trail impacted by the Gold
Strike Alternative would require construction of approximately 5,170 feet of noise barriers
located along approximately 7,000 feet (13 miles) of the roadway. The barriers would begin
near the trailhead off U.S. 93 (engineering station 45+50) and end at a major side-canyon/sheep
crossing bridge (station 115+50), where the roadway diverges from the main canyon/trail and
heads northeasterly (see Figure 3-1).
To construct 5,170 feet of noise barriers at a height of 10 feet would cost approximately
$l,048,000-subject to adjustment during final design. The barriers would be placed only on the
outside shoulder of the roadways and bridges facing the trail, but not in locations where the
trail lies under the elevated roadway. This mitigation cost would benefit the hikers and
rock-climbers using this hiking trail to the hot springs. The NFS estimates that approximately
500 hikers currently use the Gold Strike Canyon Trail on an annual basis (Jim Holland, personal
communication, July 2,1998). Thus, the cost of the noise barriers would equate to
approximately $2,096 per hiker annually, or about $105 per hiker over a 20-year period.
Although the FHWA noise abatement policy does not have a specific guideline for the number
of people to be protected, as compared against the total cost of noise abatement, this is a critical
factor in making a determination on the reasonableness of the cost of noise mitigation, and it
needs to be considered during selection and design of the preferred project alternative. This
cost may not be reasonable, considering that the total number of hikers using the Gold Strike
Canyon Trail is very small compared to the total number of visitors to the Lake Mead National
Recreation Area (9.3 million in 1992) and the barriers will not reduce the projected noise levels
in the canyon below the 57 dBA federal noise criterion. Even with mitigation, the projected
traffic noise level from U.S. 93 through the canyon would be 20 dBA greater than existing
ambient conditions. The final decision on installing noise abatement barriers will be made after
public comments are received on the Draft EIS, an alternative has been selected, and project
design has been completed.
3.3 Biology
3.3.1 Affected Environment
The proposed project area consists of the Black Canyon of the Colorado River where it crosses
the eastern Mojave Desert. The Black Mountains to the east and the El Dorado Mountains to
the west dominate the area's topography. These ranges are part of the Basin and Range
Geologic Province, with numerous isolated mountain ranges running north to south
throughout the Great Basin.
The Black Canyon has winter habitat for bald eagles. Portions of the proposed project area,
including U.S. 93 and Hoover Dam, have been previously disturbed by hurnanmade
developments, including electric transmission line towers, construction spoil sites, maintenance
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
facilities, and access roads. Figure 3-2 shows the locations of sensitive biological resources in
the proposed project area.
3.3,1.1 Terrestrial Vegetation and Wildlife Communities
Plant communities and associated wildlife in the proposed project area are typical of the
Eastern Mojave Desert. Within areas adjacent to the Lake Mead National Recreation Area
(LMNRA), about 384 plant species and 463 vertebrate animals are known to occur (Niles et aL,
1977). Vegetation-type classifications (Brown, 1982) and typical landscapes, plant communities,
and wildlife habitats found in the proposed project area are described below.
Creosote-Bursage Plant Community. Creosote-bursage is the dominant vegetation found in the
proposed project area, comprising about 70 percent of the LMNRA (NFS, 1986) and most of the
Mojave Desert below the 3,000-foot elevation. Dominant plant species include creosote bush,
white bursage, sweetbush, white ratany, brittlebush, indigo bush, and Mojave yucca.
Associated cacti include single barrel cactus, silver cholla, and beavertail. Common perennial
plant species include globemallow and desert trumpet.
Desert Wash Community. Desert washes that support the desert wash community provide
relatively higher soil moisture than the creosote-bursage plant community. Within the
proposed project area, this community is limited to the bottom of a few narrow drainages
found in Gold Strike Canyon. Species composition is similar to the creosote-bursage plant com-
munity, with the addition of catclaw acacia, and less occasionally, honey mesquite and desert
willow. This plant community has a more complex vegetative structure than the surrounding
creosote-bursage plant community, which contributes to more abundant and diverse wildlife.
More bird species are found in desert washes than in the surrounding creosote-bursage plant
community.
Seep Wetlands and Riparian Areas. A concentration of active springs and seeps occurs on both
sides of the Colorado River between Hoover Dam and Willow Beach and in some side canyons
including Gold Strike Canyon. Many of these springs and seeps are geothermal, highly
mineralized, and support specialized aquatic plants and invertebrates. Riparian and wetland
plant species associated with these areas include maidenhair fern, bushy beardgrass, sedges,
cattails, salt grass, arrowweed, and salt cedar. Much of the natural riparian vegetation in Gold
Strike Canyon has been disturbed by heavy recreational use. The large wash in Arizona
immediately south of the Gold Strike Canyon Alternative supports a dense stand of saltcedar
and other riparian vegetation. Riverbanks along the Colorado River immediately downstream
of Hoover Dam support only widely scattered stands of sparse riparian plants, of which
saltcedar is the predominant shrub species.
Waters of the United States. Well-defined drainage paths generally exist throughout most of the
proposed project area (see Figure 3-2). Approximately 27 small, natural intermittent washes
occur along the proposed alignments that drain relatively small watersheds. These are narrow
washes (1 to 3 feet wide) that drain a local watershed of approximately 2 acres. Two larger,
intermittent desert washes also occur in the study area. These washes are broader (from a few
feet to over 20 feet wide) and drain watersheds that cover more than 50 acres. One of the larger
washes (Gold Strike Canyon Wash) runs along the Gold Strike Canyon Alternative (GS on
Figure 3-2). The lower end of the wash has perennial flow. Hot springs occur before the
terminus at the Colorado River (lake Mohave), producing year-round runoff into the Colorado
River. A medium-sized, unnamed drainage runs in a north-south direction west of U.S. 93 in
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CHAPTEH 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES. AND MEASURES TO MINIMIZE HARM
Arizona, intersecting each of the build alternatives (PP on Figure 3-2). The major perennial
water source in the area is the Colorado River. As shown on Figure 3-2, the river (Lake Mead)
is approximately 1,000 feet wide upstream of Hoover Dam and approximately 400 feet wide
downstream of Hoover Darn. The width of the river varies both daily and seasonally
depending on the amount of rainfall and the amount of water released by Hoover Dam to Lake
Mohave.
A field delineation was performed in March 1998 (see Appendix 3, Wetlands Delineation
Report) to determine the extent of waters of the United States under the jurisdiction of the U.S.
Army Corps of Engineers. All of the desert washes shown on Figure 3-2 and the Colorado
River are considered waters of the United States. No jurisdictional wetlands were identified in
the proposed project area.
Cliff Habitat. Extensive cliff habitat exists immediately adjacent to the Colorado River and in
Gold Strike Canyon. Many of these areas are composed of basalt and andesite, which have the
necessary cracks, ledges, and caverns to provide cover for many wildlife species. These
volcanic rocks resist erosion, thus providing relatively stable habitat. Plants adapted for steep
cliffs in Black Canyon include cloak fern, pungent brickellia, desert tobacco, pygmy cedar, and
desert rock nettle. Cliffs in Black Canyon support reptiles, birds, and mammals. Various raptor
species use upward-flowing warm air currents associated with the higher cliffs. Cliff habitat in
arid landscapes within 0.25 mile of water has an especially high wildlife value (Maser et al
1979).
Examples of wildlife species found in the cliff habitat of Black Canyon include collared lizard,
chuckwalla, peregrine falcon, bald and golden eagle, great horned owl, white-throated swift,
common raven, canyon wren, several bat species, and desert bighorn sheep. A colony of
double-crested cormorants has nested recently on the cliffs on the Nevada side of the canyon
about 100 yards downstream of Hoover Dam.
3.3.1.2 Aquatic Communities
Colorado River. After Hoover Dam was built, the portion of the Colorado River downstream of
the dam changed from a warm, silt-laden river to a cold-water river system. Thus, native
warm-water fish, such as the Colorado River squawfish, humpback and bonytail chub, and
razorback sucker have been affected by introduced cold-water species. The area downstream
of Hoover Dam has subsequently become a popular trout fishery. The Colorado River has been
stocked with rainbow trout to maintain the fishery because natural reproduction rates are low
or nonexistent.
The Colorado River supports birds during migration and in winter. Year-long resident
waterbird species include the pied-billed grebe, double-crested cormorant, ruddy duck,
common gallinule, and American coot (Blake, 1978).
Lake Mead. The LMNRA, although seemingly barren, contains a surprising variety of plants
and animals, some of which are found nowhere else in the world. This reservoir, described as a
deep, subtropical, moderately productive desert impoundment, supports a valuable sport
fishery (Baker et al., 1977). Fish species occurring in Lake Mead are striped and largemouth
bass, channel catfish, bluegill, and black crappie (listen and Grabowski, 1988).
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
3.3,1.3 Wildlife Resources
The proposed project area supports wildlife characteristic of the eastern Mojave Desert.
Biological diversity varies according to topography, plant community, proximity to water, soil
type, and season, A literature search and field survey revealed 64 mammal species, 313 bird
species, and 46 amphibian and reptile species occurring in the LMNRA.
The most abundant mammals in the proposed project area are cactus mice and Merriam
kangaroo rats. Desert kangaroo rats and desert pocket mice are relatively uncommon and are
restricted to areas with sandy soil, such as desert washes. Species associated with rocky
habitats include the wood rat, rock pocket mouse, and rock squirrel. Species such as the
black-tailed hare, desert cottontail, and southern grasshopper mouse also have widespread
distribution in the proposed project area.
The most widespread and numerous predators in the proposed project area are the coyote, gray
fox, and several species of raptors (birds of prey). Kit fox, mountain lion, and bobcat are less
common and are associated with cliff habitat, such as cliffs and availability of prey.
The proposed project area supports diverse and abundant reptile populations. Common
species include zebra-tailed, long-tailed brush, desert spiny, and western whiptail lizards, and
western diamondback and speckled rattlesnakes. More reptiles are found in desert washes
than in other habitats.
Birds are the most diverse and abundant dass of vertebrate animals found in the proposed
project area. The greatest number of birds are associated with major desert washes. Typical
breeding birds found in the desert washes include Gambel's quail, mourning dove,
ash-throated flycatcher, verdin, and black-tailed gnatcatcher. Breeding birds found in the
creosote-bursage plant community include black-throated sparrow and cactus wren.
Numerous migratory birds (including Brewer's sparrow, western flycatcher, and species of
warblers) move through the proposed project area. Wintering birds include phainopepla,
homed lark, and ruby-crowned kinglet.
Special-status species are protected pursuant to federal and state laws. These include those
species listed as threatened and endangered and those proposed for listing as threatened and
endangered. Although candidate species (federal) and species of concern (federal and state) are
not currently protected under federal or state laws, they are also considered special-status
species in this analysis, since during the project these species may be upgraded to threatened or
endangered status. These special-status species include:
• Wildlife and plant species listed or proposed for listing as threatened or endangered
pursuant to the federal Endangered Species Ad (50 CFR 17.11 for wildlife, 50 CFR 17.12 for
plants; and various notices in the Federal Register for proposed species)
• Wildlife and plant species that are candidates for listing as threatened or endangered
pursuant to the federal Endangered Species Act (50 CFR 17, February 28,1996) (USFWS
1997a,b)
• Species listed by the State of Arizona as threatened or endangered
• Wildlife species identified by the Arizona Game and Fish Department (AGFD) as a species
of concern (wildlife species that do not have state or federal status but may still be
threatened with extinction)
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
A large prehistoric archaeological site was discovered in November 1997. An archaeological
survey of the three build alternatives was conducted in March 1998. Following FHWA
standards, an Area of Potential Effects (APE) was established for the three build alternatives.
The APE, defined as all ground surface 200 feet to each side of the staked centerline, was
intensively surveyed by a team of archaeologists walking transects parallel to the centerline,
spaced a maximum of 20 meters. When cultural materials were found, the location was
flagged, and the archaeological sites were formally recorded. The survey resulted in the
discovery and recordation of five prehistoric archaeological sites (including the site found in
1997):
NV:DD:14:21
Sugarloaf Mountain (in the APE)
NV;DD:14:22
Sugarloaf Mountain (in the APE)
NV:DD:14:23
Promontory Point (in the APE)
NV:DD:14:24
Promontory Point (outside APE)
NV:DD:14:25
Promontory Point (in the APE)
Gypsum Period (5000-2000 B.P.) or Late
Prehistoric (750 B.P-Contact)
Unknown prehistoric time period
Unknown prehistoric time period
Unknown prehistoric time period
Unknown prehistoric time period
No additional historic archaeological sites or historic buildings or structures were detected.
3.5.1.2 Interpretive Context
The prehistory of the proposed project area covers the time period from about 12,000 years
before present (B.P.) (B.P. being before 1950) to the time of initial European contact in
A.D. 1600, and is divided into five periods: Lake Mohave (12,000-7000 B.P.), Pinto
(7000-5000 B.P.), Gypsum (5000-2000 B.P.), Saratoga Springs (2000-800 B.P.), and Late
Prehistoric (750 BJP.-Contact) (Ezzo et al., 1995).
Lake Mohave Period (12,000-7000 B.P.). Evidence of Paleo-Indian occupation in the vicinity of
the proposed project is lacking. Either the material remains were quickly covered over, or they
were rapidly scattered about or washed away from their original location, effectively
destroying the site. The Paleo-Indian culture gave rise to a series of more localized cultural
manifestations known as the Archaic, represented in the proposed project area by the Pinto and
Gypsum periods.
In general, the Archaic represents a period of hunting and gathering characterized by reduced
mobility, more localized adaptations, and greater diversity of tool kits. Most recorded sites
from this time period are surface finds.
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
Pinto Period (7000-5000 B.P.). The Pinto period is defined by the presence of the Pinto
complex— an assemblage characterized by leaf-shaped knives, scrapers, and projectile points.
Pinto settlement in the proposed project vicinity was centered around water sources,
particularly drainages and remnant pluvial lakes. Settlement focused on valley floors, favoring
lowland, well-watered habitats. Hunting continued to be an important dietary component, but
milling implements appeared for the first time, indicating a greater reliance on, and orientation
toward, plant food resources than during the preceding Lake Mohave period (Ezzo et al., 1995).
Gypsum Period (5000-2000 B.P.). The Gypsum period represents a continuation of the pre-
agricultural Pinto foraging lifestyle. Gypsum sites evidence greater use of milling implements,
resource diversification, and greater emphasis on plant and seed processing. Gypsum period
assemblages are characterized by a variety of projectile points. Other tools include leaf-shaped
points, flake scrapers, choppers, hammerstones, rectangular-based knives, manos, mortars, and
pestles.
The Gypsum period appears to have been a time of increased human activity in the proposed
project area. Groups moved through a range of diverse ecological zones that included
mountains, riverine habitats, and other lowland areas, to hunt, collect, and process seeds and
wild plants (Ezzo et al., 1995). Compared to previous periods, there are a greater variety of site
types: rockshelters and caves were utilized, and open-air sites included camps and specialized
activity areas. Bighorn sheep became a significant food source, and small game, which were
abundant in the riparian communities or well-watered areas, were also hunted (Ezzo et al.,
Saratoga Springs Period (2000-800 B.P.). The Saratoga Springs period exemplifies the influence
of the Anasazi in the proposed project area. It can be divided into four phases: Moapa phase
(1650-1450 B.P.), Muddy River phase (1450-1250 B.P.), Lost City phase (1250-850 B.P.), and Mesa
House phase (850-800 B.P.), The Moapa phase corresponds to the Basketmaker U period of the
Colorado Plateau, a time when pithouse villages made their first appearance. The Moapa phase
represents the beginning of the transition from a foraging to a sedentary, agricultural way of
life in the northern Southwest (Ezzo et al., 1995).
The Muddy River phase corresponds to the Basketmaker m period on the Colorado Plateau
and is characterized by the introduction of ceramics and the bow and arrow. Settlements
consisted of small numbers of randomly arranged pithouses and food storage cists. The
introduction of ceramics and the bow and arrow had significant effects on hunting and storage
capabilities. This introduction reduced the use of food storage cists in caves for storing seeds
and plant materials for extended periods of time; it also reduced the need for woven baskets for
use in cooking, storage, and water transport (Ezzo, et al. 1995).
The Lost City phase corresponds to the Pueblo I and the early and middle stages of the
Pueblo II period on the Colorado Plateau. There was a shift from subterranean or semi-
subterranean structures to surface structures, generally with associated storage facilities.
The Mesa House phase corresponds to the late Pueblo H period on the Colorado Plateau, and
represents the final period of Anasazi settlement in the Las Vegas Valley and neighboring
areas. The primary distinguishing characteristic of the Mesa House phase is the new types of
decorated ceramics. Agriculture continued to be an important component of subsistence, but
wild foods continued to be significant (Ezzo et al., 1995).
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES. AND MEASURES TO MINIMIZE HARM
Late Prehistoric Period {750 B.P.-Contact). Late prehistoric occupation in the proposed project
area is characterized by artifact assemblages that include Owens Valley Brownware ceramics, a
variety of projectile points, large triangular knives, incised stones, steatite beads, slate
pendants, shell beads, unshaped manos and metates, and mortars and pestles. These artifacts
describe the basic lifestyle of a foraging people who may have practiced horticulture on a small
scale, and lived in small, mobile groups that exploited well-watered and upland environments.
These assemblages provide good evidence for the abandonment of the region by the Anasazi
and the arrival of the Southern Paiute (Ezzo, et al. 1995),
Historic Period (Contact - Hoover Dam Construction). The earliest Euro-American exploration of
the Colorado River dates from the mid-1500s. The Colorado River was discovered and
explored in 1540 by the Alarcon, Diaz, and Cardenas expeditions. In 1604-05, Ornate led
another Spanish expedition to the mouth of the Little Colorado River, then followed the river to
the Gulf of California. Throughout the 1700s, the Spanish conducted several expeditions into
the area including explorations by Father Sedelmeyer (1744), Father Garces (1771 and 1775-76),
Father Anza (1774), and Father Escalate (1776).
Trappers began to explore the area in the mid-1800s. In 1826, James Puttie became five first
white to ascend the Colorado River from its mouth to the Rocky Mountains and in the same
year, Jedediah Smith also explored the Colorado River, beginning at its confluence with the
Virgin River to the area around Needles, California, From 1846 to 1860, War Department
survey parties explored and mapped the Lower Colorado River. In 1857-58, Lt. J.C. Ives
completed the first detailed exploration of the Colorado River as he traveled by steamboat from
the mouth of the river to a point in the vicinity of Las Vegas Wash. When the Civil War ended,
survey and exploration resumed in the Colorado River basin.
Regulation of the Colorado River demanded federal involvement because the river had
navigable status (the government had jurisdiction over its control and use) and the river was
international (actions affecting water supply required agreement with Mexico). In addition, the
Colorado flowed through several states with different and sometimes contradictory water
needs and interests. To reach agreement on the disposition of water rights to the Colorado
River, the states of Colorado, California, Nevada, Arizona, Utah, Wyoming, and New Mexico
formed the League of the Southwest in 1919. The league urged the federal government to help
develop the water resources of the Colorado River basin. In 1921, Congress authorized the
states to form a compact to achieve agreement on equitable water distribution. Not all states
agreed to the terms, however, and the compact was never ratified.
The states did not reconcile their differences until Congress enacted the Boulder Canyon Project
Act in 1928. Six of the seven states had to ratify the compact in order for the Act to take effect;
it was ratified in 1929 with only Arizona abstaining. The compact provided for equitable water
distribution and ensured Mexico's rights to use the waters of the Colorado River system. It also
acknowledged that domestic, agricultural, and hydropower uses should take precedence over
navigation.
The Boulder Canyon Project Act authorized construction of a 20,000,000 acre-foot capacity
reservoir and dam in Boulder Canyon and a high-line canal from Laguna Dam to the Imperial
Valley. By 1920, all alternative potential dam sites had been eliminated except for those in
Boulder Canyon and Black Canyon, near Las Vegas. Site D in lower Black Canyon was
eventually selected as the dam site. Designs for a dam had been developed during the 1920s
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CHAPTER 3 AFFECTED ENVIRONMENT. ENVIRONMENTAL CONSEQUENCES. AND MEASURES TO MINIMIZE HARM
and final designs for a massive arch-gravity dam were approved by the Colorado River Board
on November 19,1932.
The design called for the dam to have a base thickness of 660 feet, a crest width of 45 feet, and a
crest length of 1,282 feet. The dam would create the largest reservoir in the world at that time,
approximately 115 miles long, with a maximum depth of 590 feet, covering 227 square miles, '
with a capacity of 32,000,000-acre feet. Construction began in November 1932 and the first
concrete was poured in June 1933. By February 1935, enough of the dam was completed to
begin controlling the flow of the Colorado River and creating the reservoir. Secretary of the
Interior Harold Ickes officially accepted the dam and power plant as complete in March 1936,
almost 2 years ahead of schedule. President Franklin Roosevelt dedicated the dam on
September 30,1935 and the reservoir was named Lake Mead in February 1936 in honor of Dr.
Elwood Mead, former Commissioner of Reclamation.
3.5.1.3 Traditional Cultural Properties
Both sides of the Colorado River were traditionally occupied by American Indian ethnic
groups, the western side by Southern Paiutes, and the eastern side by Walapai people. The
Mojave occupied the Colorado River banks from below the study area to about Blythe,
California. No evidence suggests that Hopi or Zuni peoples occupied the study area during the
aboriginal period. Nevertheless, preliminary consultation was offered with several tribes and
tribal organizations including the Hopi Tribe, the Navaho, Zuni Pueblo, the Hualapai Tribe, the
Colorado River Indian Tribes Museum, the Kaibab Paiute Tribe, the San Juan Paiute Tribe, the
Las Vegas Indian Center, the Pahrump Paiute Tribe, the Las Vegas Paiute Tribe, the Moapa
Paiute Tribe, the Paiute Indian Tribes of Utah, the Chemehuevi Tribe, and the Fort Mojave
Indian Tribe. Three tribal entities responded in writing: the Las Vegas Indian Center, the
Pahrump Paiute Tribe, and the Kaibab Paiute Tribe.
3.5.2 Environmental Consequences
3.5.2.1 Historical
Eleven previously identified historic sites or features would be affected or potentially affected
by the three alternatives.
Promontory Point Alternative. Hoover Dam is a National Historic Landmark (NHL) and is also
listed in the NRHP. Applying the criteria of effect and adverse effect (36 CFR 800.9), in
prelirninary opinions of the Nevada and Arizona State Historic Preservation Officers (SHPOs)
construction of the Promontory Point Alternative would have an adverse effect on the Hoover
Dam National Historic Landmark - a historic property. The Hoover Dam Bypass Project, a
federal undertaking, would therefore have an adverse effect on this historic property because
the bypass project may diminish the integrity of the property's location, design, setting,
materials, workmanship, feeling, or association. Adverse effects on historic properties include,
but are not limited to, introduction of visual, audible, or atmospheric elements that are out of
character with the historic property or alter its setting. Section 110(f) of the National Historic
Preservation Act requires an Agency Official, to the maximum extent possible, undertake such
planning and actions as may be necessary to minimize harm to any National Historic
Landmark that may be directly or adversely affected by an undertaking (36 CFR 800.10),
The old government railroad grade (within Reclamation jurisdiction) is ineligible for listing in
the NRHP; it would be partially affected by the Promontory Point Alternative. The diversion
channel and retaining wall are not individually eligible for listing in the NRHP but are eligible
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MIMMIZE HARM
as contributing elements to a potential Hoover Dam historic district under NRHP criterion "C."
Both may suffer possible direct impact as a result of Promontory Point Alternative construction.
The trash scatter is ineligible for listing in the NRHP; it would suffer direct impact from
Promontory Point Alternative construction.
The electric power transmission switchyard is not individually eligible, but is eligible as a
contributing element to a potential district under NRHP criterion "C." The Promontory Point
Alternative construction could produce both direct and indirect impacts, and partial demolition
may be required.
Sugarloaf Mountain Alternative. Hoover Dam, the electric transmission tower and platform, the
old government railroad grade within Reclamation jurisdiction, and the electric power
transmission switchyard may be affected by construction of the Sugarloaf Mountain
Alternative.
Hoover Dam is an NHL and is also listed in the NRHP, The historic and visual setting of
Hoover Dam would be affected by construction of the Sugarloaf Mountain Alternative, but the
physical integrity of the dam would not be affected. Preliminary opinions of the Nevada and
Arizona SHPOs are that construction of a bridge at the Sugarloaf crossing location would
result in an adverse affect on the historic visual setting of the landmark [36 CFR 800.9(b)].
However, their preliminary opinion was that this adverse affect could be mitigated through
measures which would include a bridge designed and constructed so that it would be
compatible with the setting. The Sugarloaf Alternative would enhance protection of the
physical features of the dam by virtually eliminating the potential for vehicle collisions with
dam facilities.
The electric transmission tower and platform is not individually eligible, but it is eligible as a
contributing element to a potential district. Sugarloaf construction could produce indirect
affects on its visual and historic setting. The old government railroad grade (within
Reclamation jurisdiction) is ineligible for listing in the NRHP; it would be partially affected by
Promontory Point Alternative construction. The electric power transmission switchyard is not
individually eligible, but is eligible as a contributing element to a potential district under NRHP
criterion "C". Sugarloaf construction could produce both direct and indirect impacts, and
partial demolition may be required.
Gold Strike Canyon Alternative. The following properties may be affected by construction of the
Gold Strike Canyon Alternative: Hoover Dam, waste tailings on the Arizona side, the
cantilevered walkway, the tunnel, and tailings on the Nevada side.
Hoover Dam is an NHL and is also listed in the NRHP. The historic and visual setting of
Hoover Dam could be affected by the construction of the Gold Strike Canyon Alternative, but
the physical integrity of the dam would not be affected. Implementation of the Gold Strike
Alternative would only indirectly affect Hoover Dam through a slight change to the visual
historic setting. Preliminary opinions of the Nevada and Arizona SHPOs were that
construction of a bridge at the Gold Strike crossing location would have no adverse effect on
the historic visual setting of the landmark, under 36 CFR 800.9. No other cultural resource sites
would be affected by this alternative. As with the other two alternatives, the Gold Strike
Alternative would enhance protection of the physical features of the dam by virtually
eliminating the potential for vehicle collisions with dam facilities.
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES. AND MEASURES TO MINIMIZE HARM
The waste tailings, cantilevered walkway, tunnel, and tailings on the Nevada side are not
individually eligible, but are eligible as contributing elements to a potential district. These
Nevada side tailings would suffer direct impact of Gold Strike Canyon construction, while the
walkway could suffer partial or direct impact. The tunnel could provide construction access to
the Gold Strike Canyon work site if it were enlarged to accommodate heavy equipment. The
Arizona site tailings could also suffer partial impact from Gold Strike Canyon construction.
3.5.2.2 Archaeological
Five prehistoric archaeological sites were recorded during investigation of the proposed project
alternatives. Four of the five sites are within the APE while one appears to be outside the APE.
All four sites within the APE would likely be adversely affected while the site outside the APE
might be adversely affected,
Promontory Point Alternative. Two prehistoric archaeological sites were recorded within the
APE of the Promontory Point Alternative, and one site was recorded just outside the APE.
These three sites are probably ineligible for NRHP listing,
Sugarloaf Mountain Alternative. Two prehistoric archaeological sites lie within the APE of the
Sugarloaf Mountain Alternative. One site is probably eligible for NRHP listing, and the other is
not.
Gold Strike Canyon Alternative. No archaeological sites were detected in those portions of the
Gold Strike Canyon Alternative APE that were surveyed in March 1998.
3.5.2.3 Traditional Cultural Properties
Promontory Point Alternative. A prehistoric rock alignment is located within the Promontory
Point Alternative. Pending the outcome of tribal consultations, this site (and perhaps nearby
lithic scatters) could be identified as a culturally important feature(s) and as a possible TCP
related to Native American spirit and vision quest activities.
Sugarloaf Mountain Alternative. Mr. Ben Pikyavik of the Kaibab Paiute Tribe participated in the
March 1998 survey of the three alternatives. Mr. Pikyavik recommended that Paiute elders be
interviewed to determine whether Sugarloaf Mountain has cultural importance to the Paiute
people. In response to this request, tribal elders and project ethnographers visited the proposed
project area on May 26 through June 4,1998.
Gold Strike Canyon Alternative. While the Gold Strike Canyon Alternative would not physically
affect hot spring features within the canyon itself, such hot springs are often culturally
important places to tribes along the Colorado River. Elder interviews should clarify the
possible presence of TCPs within this alternative.
3.5.2.4 Construction Impacts
Promontory Point Alternative. In a preliminary opinion of the Arizona and Nevada SHPOs and
an NPS historian, construction of the Promontory Point Alternative would produce an adverse
affect on the historic visual setting of Hoover Dam. These visual impacts are considered to be
nonmitigatable. Segments of the old government railroad grade within Reclamation
jurisdiction would be destroyed. A part of the diversion tunnel and a small segment of the
retaining wall would be destroyed by construction. The trash scatter would be completely
destroyed, and the northernmost electrical power transmission switchyard would be partially
or totally destroyed.
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
The two prehistoric archaeological sites within the APE would likely be destroyed during
construction. The prehistoric archaeological site found just outside the APE might be destroyed
during construction.
Sugarloaf Mountain Alternative. In a preliminary opinion of the Arizona and Nevada SHPOs
and an NFS historian, construction of the Sugarloaf Mountain Alternative would produce an
adverse effect to the historic visual setting of Hoover Dam; however, this effect could be
mitigated. Visual impacts are also expected to affect the electrical transmission tower and
platform. Segments of the old government railroad grade within Reclamation jurisdiction
would be destroyed. The southernmost electrical power transmission switchyard would be
indirectly affected.
Two prehistoric archaeological sites are located in the APE. One site would be partially
destroyed during construction, and the other site would be completely destroyed during
construction.
Gold Strike Canyon Alternative. In a preliminary opinion of the Arizona and Nevada SHPOs
and an NFS historian, construction of the Gold Strike Canyon Alternative would have no
adverse affect on the historic visual setting of Hoover Dam. The waste tailings on the Arizona
site would be partially destroyed by project construction. The cantilevered walkway and
tailings on the Nevada side would be partially destroyed. The tunnel could be substantially
altered if it is enlarged to accommodate access by large, heavy equipment needed for
construction.
3.5.2.5 Operational Impacts
Promontory Point Alternative. Construction of the Promontory Point Alternative would produce
an adverse affect on the historic visual setting of Hoover Dam. Therefore, once constructed, the
Promontory Point Alternative would continue to produce an adverse impact to the visual
setting of Hoover Dam. Because segments of the old government railroad grade within
Reclamation jurisdiction would be destroyed, there would be no operational impacts to this
feature. Similarly, those portions of the diversion tunnel and retaining wall that would be
destroyed by construction would likely not experience further impact resulting from project
operation. The trash scatter, which would be completely destroyed, and the northernmost
electric power transmission switchyard, which would also be partially or totally destroyed,
would not likely experience further impact from project operations.
Since construction would probably destroy one prehistoric archaeological site and may likely
destroy another, the potential effects of project operation would be moot. If one of the sites
escape destruction or damage from road construction, it could still be subject to operational
impacts from the new roadway. A third prehistoric archaeological site located just outside the
APE is still located sufficiently close to the construction zone that it too could be subject to
indirect impacts associated with increased access afforded by the presence of a new roadway.
Destructive impacts during operation could take the form of off-road-vehide use adjacent to
the roadway, or illegal collection of artifacts facilitated by easy road access to the site.
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CHAPTER 3 AFFECTED ENVIRONMENT. ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
Sugarloaf Mountain Alternative. Construction of the Sugarloaf Mountain Alternative would
produce an adverse effect on the historic visual setting of Hoover Dam. Project operation
would not produce further visual impacts if mitigation or treatment measures approved by the
Arizona and Nevada SHPOs are implemented. Unless the anticipated visual impacts expected
to affect the electric transmission tower and platform can be mitigated, project operation is
likely to produce continuing visual impact. Segments of the old government railroad grade
within Reclamation jurisdiction that would be destroyed, and the southernmost electric power
transmission switchyard that would be indirectly affected, would not likely experience further
impact from project operations,
Operation of this alternative would produce impacts to a prehistoric archaeological site in
addition to its partial destruction resulting from construction. Destructive impacts during
operation could take the form of off-road-vehicle use adjacent to the roadway or illegal
collection of artifacts facilitated by easy road access to the site.'
Gold Strike Canyon Alternative. Construction of the Gold Strike Canyon Alternative would have
no adverse affect on the historic visual setting of Hoover Dam, Project operation would also
have no adverse affect on the historic visual setting of Hoover Dam. The waste tailings on the
Arizona site that would be partially destroyed by project construction, and the cantilevered
walkway and tailings on the Nevada side that would also be partially destroyed, would not
likely experience any further impact resulting from project operation. The tunnel, which might
be substantially altered if it is enlarged to accommodate access by large, heavy equipment
needed for construction, would not likely experience further impact from project operations.
Because no archaeological sites were identified in or adjacent to this alternative, no operational
impacts are expected.
Since no archaeological sites were identified in or adjacent to this alternative, no operational
impacts are expected.
3.5.3 Measures to Minimize Harm
For the 11 historic features affected or potentially affected by the project alternatives, formal
consultations with Arizona and Nevada SHPOs and applicable federal land-managing agencies
(NFS and Reclamation) will be initiated after a preferred alternative is selected for the
determination of specific measures to irartimize harm to these cultural resource sites. Similarly,
for the 5 prehistoric archaeological sites, formal consultations with the Arizona SHPO,
Reclamation staff archaeologists, and appropriate tribal representatives have yet to be
undertaken by FHWA. Again, the following discussion proposes measures to minimize harm
that might be required; these being subject to change after completion of the formal
consultation process.
3.5.3.1 Construction Mitigation
Promontory Point Alternative. In a preliminary opinion of Arizona and Nevada SHPOs and an
NPS Historian, construction of the Promontory Point Alternative would produce non-mitigable
adverse effects to the historic visual setting of Hoover Dam. Measures to minimize harm may
not be required for segments of the old government railroad grade within Reclamation
jurisdiction because this feature is ineligible for NRHP listing. Measures may be required for a
portion of the diversion tunnel and a small segment of the retaining wall because these features
are eligible as contributing elements to a potential historic district. The trash scatter is ineligible
for NRHP listing, and no measures would likely be required. Because the electric power
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CHAPTERS AFFECTED ENVIRONMENT, ENVIRONMENTAL CONS EQUEMCES, AND MEASURES TO MINIMIZE HARM
transmission switchyard is eligible as a contributing element to a potential historic district,
measures to minimize harm would likely be required. Consultation with the Nevada SHPO
would be required to determine the nature and magnitude of the measures.
Mitigation for construction impacts to prehistoric archaeological site NV:DD:14:23 would
probably be conducted in the form of data recovery. Consultation with the Arizona SHPO
would be required to develop a mitigation plan. No mitigation measures are likely to be
required for the two other prehistoric archaeological sites: NV:DD:14:24 and NV:DD:14:25.
Sugarloaf Mountain Alternative. In a preliminary opinion of the Arizona and Nevada SHPOs
and an NFS Historian, construction of the Sugarloaf Mountain Alternative would produce
adverse effects to the historic visual setting of Hoover Dam. These visual impacts could be
mitigated by minimizing contrast by using building materials that are of compatible color and
texture and by a simple bridge geometry.
Measures to minimize harm may be required for the electric transmission tower and platform
because this feature is eligible as a contributing element to a potential historic district.
Measures to minimize harm may not be required for segments of the old government railroad
grade within Reclamation jurisdiction because this feature is ineligible for NRHP listing.
Because the electric power transmission switchyard (26-CK-4765) is eligible as a contributing
element to a potential historic district, measures to minimize harm would likely be required.
Consultation with the Nevada SHPO would be required to determine the nature and
magnitude of the measures.
Archaeological site NV:DD:14:21 appears to be eligible for NRHP listing. As an eligible site,
adverse impacts would be mitigated through a formal mitigation plan developed in
consultation with the Arizona SHPO, Reclamation archaeologists, and appropriate tribes.
Mitigation measures for site NV:DD:14:22 may not be required if the site is found to be
ineligible for NRHP listing.
Gold Strike Canyon Alternative. In a preliminary opinion of the Arizona and Nevada SHPOs
and an NPS Historian, construction of the Gold Strike Alternative would have no adverse affect
to the historic visual setting of Hoover Dam, suggesting that measures to minimize harm would
not be required. Because the waste tailings on the Arizona site (NV:DD:14:15) are eligible for
NRHP listing as contributing elements to a potential historic district, measures to minimize
harm could be required. The same situation would apply to the cantilevered walkway (26-CK-
4742) and tailings on the Nevada side (26-CK-4750). The tunnel (26-CK-4748), if substantially
altered to accommodate passage of large construction equipment, might also be subject to
measures because it is also eligible for NRHP listing as a contributing element to a potential
historic district.
No prehistoric archaeological sites were detected in those portions of the Gold Strike Canyon
Alternative surveyed in March 1998 or examined by Reclamation's archaeological staff in 1991
to 1992. Because no archeological sites were identified along this alternative, no specific
mitigation measures would be required; although some standard precautionary measures
might be added as conditions to the final EIS (e.g., implementation of an archaeological
contingency plan).
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
3.5.3.2 Operational Mitigation
Promontory Point Alternative. As noted above, construction of the Promontory Point Alternative
would produce adverse effects to the historic visual setting of Hoover Dam. These visual
impacts are considered to be unmitigable. Therefore, no available measures exist to minimize
harm during project operation.
Because measures to minimize harm during construction may not be required for segments of
the old government railroad grade within Reclamation jurisdiction (26-CK-4751)—a feature that
is ineligible for NRHP listing—measures to minimize harm during project operation may not
be required.
Measures to minimize harm may be required during construction for the portion of the
diversion tunnel (26-CK-4753) and small segment of the retaining wall (26-CK-4754) because
these features are eligible as contributing elements to a potential historic district. Once
constructed, it is unlikely that harm minimization measures would be required for these two
features during project operation.
The trash scatter (26-CK-4763), which is ineligible for NRHP listing, would probably be
destroyed during construction; thus, no measures to minimize harm during project operation
would be required. Because the electric power transmission switchyard (26-CK-4765) is eligible
as a contributing element to a potential historic district, measures to minimize harm would
likely be required during construction; but once constructed, such measures are not likely to be
required during project operation. Consultation with the Nevada SHPO would be required to
determine the nature and magnitude of the measures.
Site NV:DD:14:23 would probably be destroyed by construction; therefore, operational impacts
would be irrelevant Sites NV:DD:14:24 and NV:DD:14:25 are probably not eligible for NRHP
listing, and mitigation would not be required.
Sugarloaf Mountain Alternative. As noted above, construction of the Sugarloaf Mountain
Alternative would produce adverse effects to the historic visual setting of Hoover Dam. If
these visual impacts can be mitigated during construction, further harm minimization
measures would probably not be required during project operation.
Measures to rninimize harm during construction may be required for the electric transmission
tower and platform (NV:DD:14:1) because this feature is eligible as a contributing element to a
potential historic district. If suitable measures are implemented during construction, it is
unlikely that further measures to minimize harm would be required during project operation.
Measures to minimize harm during construction or operation may not be required for segments
of the old government railroad grade within Reclamation jurisdiction (26-CK-4751) because this
feature is ineligible for NRHP listing. Because the electric power transmission switchyard (26-
CK-4765) is eligible as a contributing element to a potential historic district, measures to
minimize harm during construction would likely be required. Once implemented, no further
measures are likely to be required during project operation. Consultation with the Nevada
SHPO would be required to determine the nature and magnitude of the measures.
Construction impacts would require mitigation of NV:DD:14:21 to the degree that operational
impacts would probably be irrelevant, and no additional mitigation would be required. Site
NV:DD:14:22 does not appear to be an eligible site and therefore mitigation would not be
required.
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CHAPTER 3 AFFECTCD ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
Gold Strike Canyon Alternative. As noted above, construction of the Gold Strike Canyon
Alternative would have no adverse effect to the historic visual setting of Hoover Dam,
suggesting that measures to minimize harm would not be required, either during construction
or operation. Because the waste tailings on the Arizona site (NV:DD:14:15) are eligible for
NKHP listing as a contributing element to a potential historic district, measures to minimize
harm during construction could be required. Once implemented, however, it is unlikely that
further measures to minimize harm would be required during operation. The same situation
would apply to the cantilevered walkway and tailings on the Nevada side. The tunnel, if
substantially altered to accommodate passage of large construction equipment, might also be
subject to measures because it too is eligible for NRHP listing as a contributing element to a
potential historic district. Once implemented, however, it is unlikely that further measures to
minimize harm to the tunnel would be required.
No archaeological sites were identified in this alternative; therefore, no impacts are expected
and no mitigation required.
3.6 Land Use
3.6.1 Affected Environment
This section discusses existing land uses in the vicinity of the three build alternatives. Three
types of federal land are in the proposed project area: LMNRA, administered by the NFS;
Hoover Dam Reservation (HDR), administered by Reclamation; and the Hoover Dam National
Historic Landmark (HDNHL), also administered by Reclamation (see Figure 2-3). Current land
uses are described below. A Section 4(f) report pertaining to federally protected parklands and
historic sites was prepared and is included as Appendix C Although the proposed project area
includes land under the jurisdictions of Clark County and Mohave County, these local
jurisdictions are superceded by federal designations. However, for comparative purposes, brief
descriptions of applicable land use policies are given below.
The Promontory Point and Sugarloaf Mountain alternatives would traverse LMNRA, HDR, and
HDNHL lands; the Gold Strike Canyon Alternative would traverse only LMNRA and HDR
lands. The portions of the three alternatives on the Nevada side of the Colorado River are in
Clark County, and the portions on the Arizona side of the Colorado River are in Mohave
County.
3.6.1.1 Existing Land Uses in the Project Area and Vicinity
To characterize existing land uses along the three build alternative alignments and in the
vicinity, on-the-ground and drive-by area surveys were performed March 9 and 10,1998.
Outside the proposed project area, immediately west of the western terminus of the three build
alternatives is the Gold Strike Inn. Outside the proposed project area, immediately east of the
eastern terminus of the three build alternatives is undeveloped open space. Immediately north
and south are lands dedicated to open space and recreational uses. To the north is Lake Mead;
to the south is the Colorado River. Hoover Dam separates the two water features. Most of the
proposed project area is undeveloped open space, portions of which are used for recreational
purposes.
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES. AND MEASURES TO MINIMIZE HARM
Existing land uses along the Promontory Point Alternative and in its vicinity include
undeveloped recreation land (36 acres minimum, Mohave County General Plan) and electric
transmission and distribution facilities and other facilities associated with Hoover Dam.
Existing land uses along the Sugarloaf Mountain Alternative and in its vicinity include
undeveloped recreation land, a water tank, sewage evaporation ponds, and electric
transmission facilities associated with Hoover Dam. About 400 feet downstream of this
alternative is a rafting concessionaire's put-in on the Colorado River. Access to this put-in is
provided by Reclamation's restricted access Lower Portal Road. Reclamation operates a
warehouse associated with the dam operations approximately midway between the
western terminus and Hoover Dam.
Existing land uses along the Gold Strike Canyon Alternative and in its vicinity include
undeveloped recreation land and an undesignated trail used to hike through Gold Strike
Canyon down to the river. Near the mouth of the canyon are the drainages of geothermal seeps
and hot springs, some of which have humanmade blockages to form ponds of warm water.
These ponds are used for recreational purposes.
Farmlands. As previously noted, most land within the vicinity of the proposed project is
undeveloped, with a large portion dedicated to recreational uses. Agricultural land uses
typically are not excluded from these areas.
As a result of a substantial decrease in the amount of open farmland, Congress passed the
Farmland Protection Policy Act (PL 97-98; 7 U.S.C. 4201 et seq.). The purpose of the Act is to
minimize the unnecessary and irreversible conversion of farmland to nonagricultural uses by
federal programs/actions. The Act further requires that federal programs/actions be
administered in a manner that will be compatible with state and local government and private
programs and policies to protect farmland. The Act specifies three categories of farmlands:
• Prime farmland—land that has the best combination of physical and chemical
characteristics for producing food, feed, fiber, forage, oilseed, and other agricultural crops
with minimum inputs of fuel, fertilizer, pesticides, and labor, and without intolerable soil
erosion [7 U.S.C. 4201(c)(l)(A)J.
• Unique farmland—land other than prime farmland that is used for the production of
specific high-value food and fiber crops such as citrus, tree nuts, olives, cranberries, fruits,
and vegetables [7 U.S.C. 4201(c)(l)(B)j.
» Additional farmland of statewide or local importance—land identified by state or local
agencies for agricultural use, but not of national significance [7 U.S.C 4201(c)(l)(C)].
No present agricultural land uses have been identified within the project vicinity which fall
within these farmland categories.
3.6.1.2 Land Use Planning
The Clark County General Plan, Mohave County General Plan, the LMNRA General
Management Plan (GMP), Reclamation's Hoover Dam Reservation, and the National Historic
Landmark are the development guides in the proposed project area.
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AMD MEASURES TO MINIMIZE HARM
Clark County General Plan. The proposed project area within Nevada is located within Clark
County. The Clark County General Plan lists several general planning goais applicable to the
proposed project. These goals are provided below.
• Goal 1: To promote public health, safety and welfare
• Goal 2: To promote efficient use of public services
• Goal 3: To promote development compatible with the natural environment
Mohave County General Plan. The proposed project area within Arizona is located within
Mohave County, The Mohave County General Plan lists several major planning concepts that
define its vision for year 2010. Among these are three concepts applicable to the project:
promote beneficial economic growth, development, and renewal; protect the environment; and
preserve and enhance historic, cultural, open space, and recreational lands and structures.
Transportation is addressed as part of the General Plan's Public Infrastructure Element. The
County recognizes the relationship between land uses and transportation facilities. In addition,
the County acknowledges the importance of compatibility of the County's roadway system
with city, state, and federal roads. General Plan transportation policies apply to streets within
the County's jurisdiction, namely arterial roads and collectors within the County's street
system. No specific General Plan transportation policies apply to the proposed project area;
however, the following three goals generally apply to the proposed project area:
• Goal 51: To plan, construct, and maintain an efficient transportation system that is
adequate to meet the mobility needs of County residents and businesses
* Goal 52: To promote compatibility between roadway improvements, land use patterns, and
natural features
• Goal 53: To minimize the impacts of automobile travel on the County's air quality, natural
environment, and developed communities (Freilich, Leitner & Carlisle, 1995)
Lake Mead National Recreation Area General Management Plan. The LMNRA GMP, prepared by
the NPS, provides a management strategy for the two reservoirs (Lake Mead and Lake Mohave)
and surrounding lands within the National Recreation Area (NRA). The NRA contains
1,482,476 acres of federal land and 28,212 acres of nonfederal land (see Figure C-2).
The NPS management strategy focuses on accommodating increasing visitor use at the NRA
while protecting the area's most outstanding natural and cultural values. The NPS seeks to
provide a quality visitor experience in a manner that will ensure visitor safety and will protect
the area's significant resources. The GMP's planning horizon is approximately 25 years beyond
the 1986 publication date.
Hoover Dam Reservation. The Hoover Dam Reservation (Reservation) delineates lands
managed by Reclamation for security purposes and for operating and maintaining Hoover
Dam, its buildings and structures, electric transmission lines, towers, switchyards, and spoil
disposal sites. No specific management plan has been prepared for guiding development
within the Reservation; however, public access to certain areas within the Reservation is
restricted, and portions of the area are fenced. As such, Reservation lands do not fall under
federal parkland protective provisions (see Appendix C). Controlled access to the Colorado
River about 1 mile west of Hoover Dam is provided by a locked gate at the Lower Portal Road
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
and U.S. 93 intersection. Access is allowed to a rafting concessionaire, a tour group operator,
and individuals having permits issued by Reclamation.
Hoover Dam National Historic Landmark. Hoover Dam is a designated National Historic
Landmark and is listed in the National Register of Historic Places. It is under the jurisdiction of
Reclamation. National Historic Landmarks identify, designate, recognize, and protect
buildings, structures, sites, and objects of national significance. The NFS, in cooperation with
other government agencies, professionals, and independent organizations, administers the
landmark program. Once a site is designated a National Historic Landmark, the owner
maintains all rights and privileges of ownership. However, the designation requires that
federal transportation projects affecting a landmark take steps to minimize harm to the affected
property, under Section 4(f) of the Department of Transportation Act The dam also falls under
the protective provisions of Section 106 of the National Historic Preservation Act.
3,6.2 Environmental Consequences
3.6.2.1 Construction Impacts
Consequences associated with development of the proposed alternatives were based on the
compatibility of the alternatives with both existing land uses and applicable planning
documents governing the use of project lands. Changes in land use and patterns resulting from
the three build alternatives evaluated are generally consistent with federal and local land use
plans. Impacts from the three build alternatives are separated into those associated with
construction, and those resulting from operation of the alternatives.
Potential effects on land use are associated with project construction rather than operation
because once the right-of-way easement has been granted and construction begins, no further
changes to land use patterns are expected. Existing land uses surrounding the proposed project
area would not be precluded during the construction period. Access to most existing land uses
would be maintained; the exception is the trail in Gold Strike Canyon, which would be closed
to public access during construction of the Gold Strike Canyon Alternative.
The primary land use change associated with the build alternatives is the development of
currently undeveloped recreation land in the proposed project area. Table 3-18 shows the total
acreage that would be developed in each jurisdiction.
Table 3-18
Acreage to be Developed for Each Bufld Alternative
Jurisdiction Promontory Point Sugarloaf Mountain Gold Strike Canyon
Lake Mead National 94.5 95.9 97,1
Recreation Area
National Historic Landmark 40.6 25.7 0.0
Boundary
Hoover Dam Reservation
Total Acreage
73.9
209.0
70.7
192.3
81.2
178.3
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
3,6.2.2 Operational Impacts
Existing land uses surrounding the proposed project area would not be affected following
project completion. The change from recreation land to highway would constitute a small
change when compared to the expansive amount of open space area in the surrounding region.
Access to existing land uses would be maintained during project operation. Implementing
measures outlined in the Air Quality and Noise sections would mitigate noise and dust
emissions during project operation. Therefore, neither of these emissions is expected to impact
land use.
3.6.2.3 No Build Alternative
Because the No Build Alternative would result in no construction, no land use changes would
occur.
3.6.3 Measures to Minimize Harm
No adverse impacts during construction or operation were identified; therefore, no mitigation
is warranted.
3.7 Visual Resources
3.7,1 Affected Environment
3.7.1.1 Visual Environment
Landscape Description. The proposed project area is within the LMNRA, which retains an
undisturbed character throughout much of its area, but also includes some developed facilities.
The desert in the proposed project area is at elevations ranging from about 650 feet to about
2,000 feet. Soils in the proposed project area are pink, red, and brownish-gray. Landforms are
mountains, valleys, and beaches, and include the deeply incised Black Canyon, Gold Strike
Canyon, and Sugarloaf Mountain. Landcover in the proposed project area includes Lake Mead,
the Colorado River, low-lying and sparse desert vegetation, rock formations, and humanmade
development such as Hoover Dam facilities, electric transmission towers and lines, access
roads, and U.S. 93.
Visual Character. Primary forms in the proposed project area are Lake Mead, Hoover Dam,
Colorado River, and Black Canyon, Hoover Dam, viewed either from U.S. 93 or from the air, is
a large mass. Views from the dam, lake, river, or canyon also show the area's variety of forms.
Aerial views and views from the river and dam all exhibit strong lines. For example, Hoover
Dam provides both horizontal and vertical lines in the landscape. Electric transmission towers
and lines provide angled, vertical, and horizontal lines. U.S. 93 introduces a horizontal line
across the landscape. The walls of Black Canyon exhibit vertical lines, and viewed from the air,
the river exhibits a meandering line.
Color variety in the proposed project area is evidenced by the Canyon's pinkish-brown rock
formations and soils; lightness is introduced by the concrete of the dam structure; and
brightness is provided by the sun's reflection off the dam, lake, and river. Additional color is
added by the blues and greens of the lake and river. Area texture includes rock formations,
topography, water surfaces, and low-lying vegetation.
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CHAPTER 3 AFTECTEO ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES. AND MEASURES TO MINIMIZE HARM
Hoover Dam is the most dominant humanmade feature within the proposed project area. Its
position in the canyon relative to overlooks, viewpoints, and the visitor center clearly make it
the visual focus. Its size makes it an impressive structure, and its placement within the deep
canyon makes it compatible with the area. Visual diversity is provided by the mixture of
natural and humanmade environment such as the variety of forms; straight and curved lines-
lightness, darkness, and color variety; and texrural variety offered by ground surface relief and
vegetation. The area's landscape forms, lines, color combinations, and textures all contribute to
visual continuity.
Visual Quality. Three criteria were used to evaluate the proposed project area's visual quality:
vividness, intactness, and unity. Determining vividness of the proposed project area includes
assessing the area's landforms, landcover, and humanmade development. The proposed
project area's vividness rating is high. The area's landforms (steep canyon walls and
mountains) contribute to the memorable view. Water bodies (both lake and river) provide a
vivid landscape because of their color, reflection of sunlight, motion, and shoreline.
Humanmade development in the area contributes to the view's vividness by its contrast with
the natural landscape (the dam and its facilities, angled design of electric transmission line
towers, and roads).
Intactness of the proposed project area is demonstrated by the integrity of the features.
Humanmade features add to the area's complexity and visual variety. The area appears very
ordered; a view of the dam from downstream exhibits symmetry and strong lines.
Landscape unity is achieved by the mixture of natural elements and humanmade alterations.
Compatibility exists between the natural landscape (canyon, lake, and river) and the
humanmade facilities (dam, electric transmission line, and road).
The IMPS considers many natural features within the LMNRA to be outstanding. Uniqueness,
critical habitat protection, and aesthetic and recreational value are criteria used by the NFS to'
consider natural features outstanding. Features include warm springs, unique geologic
formations and plant communities, scenic vistas, desert bighorn lambing grounds, and coves
popular for their sandy beaches or scenic beauty.
Black Canyon is the only site near the proposed project area afforded special protection by the
NFS because of its geologic and scenic values, numerous hot and warm springs, and winter
habitat for bald eagles. The NFS-protected area begins about 1 mile south of the Gold Strike
Canyon Alternative and extends south for about 9 miles. In addition to protecting the integrity
of the natural feature, the NFS indicates that the views provided by this feature must also be
considered. Therefore, the NFS indicates that if development around Black Canyon is made
visible from U.S. 93 on the Arizona side of Hoover Dam, the canyon's scenic integrity would be
compromised. In addition, the NFS recognizes that the view corridor from the Colorado River
through Black Canyon is an outstanding view that should be protected (NFS, 1986).
National Scenic Byways possess outstanding qualities that exemplify a region's characteristics.
No National Scenic Byways are in Nevada or Arizona near the proposed project area. U.S. 93 is
a Nevada Scenic Byway; however, it is not designated as such in or near the proposed project
area. No Arizona Scenic Byways are in or near the proposed project area.
No rivers in Nevada or Arizona near the proposed project area are designated pursuant to the
Wild and Scenic Rivers Act.
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3.7.1.2 Viewer Characteristics
Viewer Groups, Exposure, and Sensitivity. For ail three build alternatives, viewer groups can be
classified as one of two types:
• Recreationists visiting the Hoover Dam area (including Hoover Dam itself, Lake Mead,
Colorado River, and Black Canyon)
• Drivers and passengers traveling in vehicles through the Hoover Dam area
Recreationists are considered a sensitive viewer group because their viewing of the dam, the
lake, the river, and the canyon is expected to last up to several hours. Recreationists generally
value, and are more aware of, the aesthetic quality of their surroundings than commuters or
when at work, because their focus is usually on their surroundings while they are relaxing; or
the recreation activity they are engaging in, which is usually enhanced by their surroundings.
Because Hoover Dam is a National Historic Landmark visited by more than 1 million tourists
annually, is so well known both nationally and internationally, and provides spectacular
photograph opportunities, recreationists visiting the Hoover Dam area are considered
particularly sensitive to the surrounding views.
Drivers and passengers traveling over Hoover Dam (through traffic) are considered a less
sensitive viewer group than recreationists because of their relatively short view time while
traveling across the dam and the obstructed views offered from within vehicles; and because
their focus is to negotiate a vehicle in traffic congestion and reach a final destination. Scenic
driving for pleasure is a valid recreational activity, and the sensitivity of such viewers should
not be ignored. However, because of the short view time, the driver distraction occurring from
traveling in heavy traffic, and the obstructed views within vehicles while crossing the dam,
these travelers are considered less sensitive viewers than recreationists.
Recreationists1 Existing Views. Recreational boaters on Lake Mead experience unobstructed
views of Black Canyon and Hoover Dam from up to 1.2 miles upstream. Recreationists on Lake
Mead or its shores do not have views of the downstream side of the dam, Black Canyon
downstream of the dam, or the Colorado River.
Recreationists visiting Lakeview Point Overlook in Nevada have a view of Lake Mead. Viewer
groups at the Arizona Lookout have a view of the dam and lake. Recreationists on the dam
crest looking upstream have an unobstructed view of Lake Mead and Black Canyon for 1.2
miles. Looking downstream from the dam crest, recreationists have an unobstructed view of
the Colorado River and Black Canyon for 0.5 mile.
Recreationists on the Colorado River at the rafting and canoeing put-ins about 0.5 mile
downstream of Hoover Dam have an unobstructed view of the dam and Black Canyon when
looking upstream. From the put-ins, looking downstream, recreationists have unobstructed
views of the Colorado River and Black Canyon for about 0.6 mile.
Recreationists hiking the Gold Strike Canyon trail have limited views. Because Gold Strike
Canyon is narrow, winding, and steeply sloped, views of Hoover Dam from the trail are
precluded. From the trail, views of the Colorado River and Black Canyon are completely
obstructed until the last 0,1 mile of the trail.
Recreationists at the hot springs in Gold Strike Canyon have views of the Colorado River and
Black Canyon from the pool closest to the river; views of the river and the canyon from the
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_CHAPTEB 3 AFF£CTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
other pools are obstructed. Views of Hoover Dam (upstream) from the hot springs are
completely obstructed.
Drivers' and Passengers' Existing Views. Drivers and passengers traveling over existing U.S. 93
and Hoover Dam have limited views. At a speed of 10 mph, a vehicle crosses the dam in
1.5 minutes, which is considered a short view time. In addition, from passenger vehicles
traveling east, Lake Mead and the Colorado River cannot be seen at all, and views of Black
Canyon are limited. Views from passenger vehicles traveling west are obstructed in a similar
manner. The viewshed from within higher vehicles, such as commercial trucks, is greater than
from passenger vehicles, but is still of short duration and is partially obstructed by the vehicle
itself.
3.7.2 Environmental Consequences
3.7.2.1 Construction Impacts
Impacts on visual resources during construction that are common to all three build alternatives
include the following:
• Dust would be emitted from earthmoving activities, construction vehicles and equipment,
construction worker vehicles, materials delivery vehicles, and from areas within the
construction zone that have been disturbed or where excavated material is stockpiled.
Fugitive dust, if emitted in sufficient quantities, and if adverse weather conditions persist,
could impair or degrade existing views (either from the ground or from the air).
• Depending on their values, interests, and preconceived expectations, for some recreationists
viewing the area (either from the ground or from the air), the presence of construction
equipment and its associated activities would detract from the views currently experienced.
For other recreationists, the presence of equipment and construction activities would be
interesting and would add visual variety to the landscape, creating additional photographic
opportunities.
• Hoover Dam is currently lit at night and provides interesting nighttime views. For some
recreationists, the additional light that would be emitted during nighttime construction (if it
occurs) would detract from the nighttime views experienced during the dam visit.
Depending on their values and expectations, for other recreationists, the additional light
and associated construction activities would add visual interest to the setting. This issue is
expected to be of less concern to recreationists if the Gold Strike Canyon Alternative is
constructed because that alternative is not visible from Hoover Dam. However, it is
possible that the canyon downstream may appear brighter during nighttime construction if
that alternative is selected.
Promontory Point Alternative. Construction of the Promontory Point Alternative is expected to
last approximately 4 years, 9 months. During construction of this alternative, the view of Lake
Mead from Hoover Dam (regardless of bridge design) would be altered from its existing,
primarily undisturbed, state to one exhibiting a highly disturbed character. Construction
vehicles, equipment, and personnel would alter the slopes on both sides of the lake. The waste
disposal area would not be visible from the dam, river, or lake, but would be seen from U.S. 93
in Arizona.
Changes to the visual environment in the area of this alternative would be noticeable to visitors
to the dam, the lake (when near the dam), and from the air. As discussed previously, changes
to the landscape are expected to be offensive to some viewers, and interesting to others. The
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
impact on visual resources from construction activities would not be permanent, but because of
the length of the construction period, they are not short-term. Other existing views, such as
from the rafting put-ins on the Colorado River and the hiking trail and hot springs, would not
be affected.
Sugarloaf Mountain Alternative, Construction of the Sugarloaf Mountain Alternative is expected
to last approximately 4 years, 7 months. During construction of this alternative, the view of
Black Canyon from Hoover Dam and Lake Mead would be affected. Although the view area is
already largely disturbed, construction vehicles, equipment, and personnel would alter the
slopes on both sides of the canyon.
Changes to the visual environment in the area of this alternative would also be noticeable from
the dam, the river (when near the dam), and from the air. Construction vehicles, equipment,
and personnel would alter the canyon slopes on both sides of the river. As discussed
previously, changes to the landscape are expected to be offensive to some viewers and
interesting to others. The impact on visual resources from construction activities would not be
considered permanent, but because of the length of the construction period, they are not
considered short-term. Other existing views, such as from the hiking trail and hot springs,
would not be affected.
Gold Strike Canyon Alternative. Construction of the Gold Strike Canyon Alternative is expected
to last approximately 5 years, 3 months. During construction of this alternative, views from the
lake or dam toward the Gold Strike Canyon Alternative (regardless of bridge design) would not
be affected because that alternative cannot be seen from the lake or dam.
Changes to the visual environment in the area of this alternative would be noticeable from the
river and the air. Construction vehicles, equipment, and personnel would alter the canyon
slopes on both sides of the river. One waste disposal area would be visible from the trail, and
another disposal area would be visible from U.S. 93 in Arizona. No waste disposal areas would
be visible from the dam, lake, or river. In addition, areas for cut and fill and materials laydown
would be visible from the put-in area on the Colorado River. As discussed previously, changes
to the landscape are expected to be offensive to some viewers, and interesting to others. The
impact on visual resources from construction activities would not be considered permanent,
but because of the length of the construction period, they are not considered short-term.
Much of the Gold Strike Canyon Alternative would either parallel or cross the hiking trail. Use
of the trail would be precluded during construction of this alternative; therefore, existing views
from the hiking trail would be eliminated. Because the trail would be closed to the public,
access to the hot springs would only be available from the river. The view from the hot springs
looking directly north toward the Gold Strike Canyon Alternative would be obstructed by
topography and, therefore, would not be affected. The view from the hot springs looking to the
northwest would be affected by construction equipment and activities.
No Build. Because the No Build Alternative would result in no construction, no
construction-related impacts on existing visual resources are expected at Hoover Dam, Lake
Mead, the Colorado River, Black Canyon, or the Gold Strike Canyon hiking trail and hot
springs. In addition, no construction-related impacts on aerial views would occur.
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3.7.2.2 Operational Impacts
Visible structural features of the three build alternatives have been assessed and compared with
the area's pattern elements and character, and its vividness, intactness, and unity to determine
the compatibility of the proposed features with the existing landscape.
Figure 3-3 shows the five viewpoints selected for visual simulations. To show what is currently
visible from five viewpoints in the proposed project area, photographs were taken at each
location. These photographs serve as existing condition views and provide the basis for
comparing various bridge designs and alternatives being considered. Alternative bridge
designs have been superimposed onto the photographs in visual simulations. The following
viewpoints were selected:
• From aboard the Desert Princess on Lake Mead looking toward Hoover Dam (Figure 3-4)
* . From the Arizona Overlook toward Lake Mead (Figure 3-5)
• From atop Hoover Dam on the Arizona side looking downstream (Figure 3-6)
• From the rafting put-in on the Colorado River about 0.5 mile downstream of Hoover Dam
looking south (Figure 3-7)
• From a location on the Gold Strike Canyon Alternative on the west side of Black Canyon
looking east across the canyon (Figure 3-8)
Figure 3-3 shows the locations of each of the five viewpoints and the alignments of the three
build alternatives. As shown in Figure 3-3, the direction of each view is toward one of the three
alternatives. The viewpoints chosen are popular photograph opportunity locations.
Viewpoints 1 through 3 were selected because they represent views that recreationists would
experience while visiting the Hoover Dam area. Many locations exist at the dam, lake, and
scenic lookouts where photographs could be taken, and many views from each location could
be generated. The location and direction of each photograph taken are considered
representative of the views provided while at the Hoover Dam area.
Viewpoint 4 was chosen to show the view seen by the 18,500 recreationists who put-in annually
to raft or canoe the Colorado River. Because the Gold Strike Canyon Alternative is not visible
from Hoover Dam but is visible from the put-in location, the river put-in provides the best view
of that alternative by recreationists. Although a view looking upstream toward Hoover Dam
could also have been provided from Viewpoint 4, (which would have shown the Sugarloaf
Mountain Alternative), it was determined that the Sugarloaf Mountain Alternative could be
adequately assessed from Viewpoint 3, a location visited by more tourists than Viewpoint 4.
Viewpoint 5 was selected because it provides the existing view eastward across Black Canyon
where the Gold Strike Canyon Alternative would cross the canyon. Access to the location
where the Viewpoint 5 photograph was taken is not currently available to the public; therefore,
the public cannot see this view. However, this viewpoint was considered important to provide
the base for a simulation of a driver's or passenger's view from the road while crossing Black
Canyon, and it is considered representative of the landscape view from the road regardless of
die alternative ultimately selected
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
Impacts Common to All Build Alternatives. Adding a bridge and its associated facilities to the
landscape in the Hoover Dam area would alter the landscape. Regardless of the alternative
implemented, these facilities would be visible from at least one viewpoint. For some viewers,
these features would add visual variety and interest to the landscape. For other viewers, the
addition of such features would detract and possibly even degrade the landscape. If the
proposed project is implemented, regardless of the alternative selected, a new view of the
surrounding landscape from the bridge and its roadway approaches would be created. This
view would be limited to those from moving vehicles traveling about 60 mph; bicyclists,
pedestrians, and stopped vehicles would not be allowed on the new bridge.
Promontory Point Alternative. Views of the Promontory Point Alternative would be
unobstructed from locations on Lake Mead up to 1.2 miles upstream of the dam. The new
bridge would be visible from Hoover Dam and by aerial sightseers, thus changing the
landscape setting of Lake Mead from the dam and the air. For some viewers, this change
would detract from the lake's view. This viewer group expects the views to be unchanged from
existing conditions, or expects the changes to be unnoticeable or unobtrusive. For others, the
bridge design would add variety to the lake view. This viewer group would notice the visual
change, but would not be offended by the change to the view.
Steel Truss Rib Through Arch Bridge. Figure 3-4 shows Hoover Dam from aboard the Desert
Princess on Lake Mead (Viewpoint 1). The top photograph shows the existing view from the
boat toward Hoover Dam. The middle photograph simulates what the steel truss rib through
arch bridge crossing Lake Mead would look like from aboard the Desert Princess. This bridge
design would add a large form, contrasting lines, unobtrusive color, and texture changes (from
the appearance of lattice steelwork on the arch) to the view.
From this viewpoint, the Hoover Dam facilities and electric transmission line towers are
subordinate features and do not detract from the existing view. The position, size, and shape of
the steel truss rib through arch bridge make it a feature that would dominate the view from the
boat. This bridge design would add to visual diversity by intermixing horizontal, vertical, and
curved lines to a predominantly undisturbed view of the landscape. Although adding
diversity, the bridge would not add visual interest to the landscape. In addition, it would
interrupt the visual continuity of the mountains in the background because of the presence of
the arch and vertical bridge lines near the center of the photograph.
The visual quality shown in Figure 3-4 would be affected by this bridge design. Vividness
would be compromised by the introduction of the bridge structure. In addition, the landscape
intactness and unity would be affected by the size and prominence of the form, contrasting
lines, and textural differences between the proposed bridge and the existing landscape.
Hoover Dam would be visible to motorists traveling over the new bridge. Because stopped
vehicles, bicyclists, and pedestrians would be precluded from the new bridge, the bridge would
not provide the benefits of additional viewing opportunities of Hoover Dam.
Concrete Cable-Stayed Bridge. Also shown in Figure 3-4 from aboard the Desert Princess on
Lake Mead (Viewpoint 1) is a simulation (lower photograph) of how the concrete cable stayed
bridge crossing Lake Mead would look. This bridge would add a large form that exhibits little
texture; contrasting diagonal, vertical, and horizontal lines; and a color contrast from the
concrete pillars.
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From this viewpoint, the position, size, and presence of the concrete pillars make the bridge a
dominant feature within the photograph. Their presence is the most obvious structural feature
that would affect the view of the landscape. This bridge design is less dominant than the steel
truss nb through arch design discussed above. This bridge design would add little diversity to
the view because the diagonal cables, although visible, are not prominent. The cables,
therefore, would not detract from the view, but would maintain the view's contmuity'by
minimizing obstructions to the existing view of the mountains in the background.
Impacts on the visual quality of the view shown in Figure 3-4 would not be adverse because of
this bridge design. As shown in the simulation, the vividness (memorability of the existing
landscape components) would remain, and the landscape view would remain intact. The unity
(visual harmony between landscape elements) would be affected by the structure's size and
prominence, its contrasting lines, and textural differences; however, this impact is not
considered adverse.
Hoover Dam would be visible to motorists traveling over the new bridge. Because stopped
vehicles, bicyclists, and pedestrians would be precluded from the new bridge, the bridge would
not provide the benefits of additional viewing opportunities of Hoover Dam.
Suspension Bridge. Figure 3-5 is the view from the Arizona Overlook (Viewpoint 2) looking
across Lake Mead. The top photograph shows the existing view from the overlook. The lower
photograph shows how the suspension bridge across Lake Mead would look. This bridge
would add a large form that exhibits little texture, strong horizontal and vertical lines, and a
color contrast from the concrete pillars.
From this viewpoint, the bridge is not a dominant feature that detracts from the existing view.
Although the bridge's concrete pillars are prominent features, because of the hillside in the
right foreground the other pillar and remainder of the span are not visible from this viewpoint.
Similar to the concrete cable stayed bridge design, this bridge design is less dominant than the
steel truss rib through arch design. This bridge design would add little diversity to the view
because the vertical cables, although noticeable, would not detract from the view at the
overlook, thus maintaining the view's continuity. The height of the pillar (below the mountain
slope in the background) would also aid in maintaining the view's continuity. Therefore, this
bridge design would not adversely affect Viewpoint 2 visual resources.
If this bridge design were viewed from aboard the Desert Princess (similar to Viewpoint 1
shown in Figure 3-4), the pillars would appear shorter than the concrete cable stayed bridge,
but would appear to be similar. The vertical cables would be visible, but would add little
diversity to the view, and would not detract from it. As such, the view's continuity would be
maintained. The landscape's vividness and intactness would remain. The landscape's unity
would be affected by the structure's size and prominence, its contrasting lines, and textural
differences. Therefore, the impacts on the visual quality of Viewpoint 1 from the suspension
bridge design would be similar to that of the concrete cable stayed bridge (not adverse).
Hoover Dam would be visible to motorists traveling over the new bridge. Because stopped
vehicles, bicyclists, and pedestrians would be precluded from the new bridge, the bridge would
not provide the benefits of significant additional viewing opportunities of Hoover Dam.
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Sugarloaf Mountain Alternative. Views of the Sugarloaf Mountain Alternative would be
unobstructed from Hoover Dam and from the put-in 0.5 mile downstream of the dam. In
addition, the new bridge would be visible by aerial sightseers, thus changing the aerial view of
the dam and canyon. For some viewers, this change would detract from the lake view. This
viewer group expects views to be unchanged from existing conditions, or expects changes to be
unnoticeable or unobtrusive. For others, the bridge design would add variety to the lake view.
This viewer group would notice the visual change, but would not be offended by the change to
the view.
Concrete Cable-Stayed Bridge. Figure 3-6 is a view of Black Canyon looking downstream from
the eastern side of Hoover Dam (Viewpoint 3). As shown in the top photograph, the view is
dominated by humanmade development such as the electric transmission line towers in the
foreground, and to a lesser degree, U.S. 93 and the vehicles on the right side of the photograph.
The middle photograph simulates how the concrete cable stayed bridge crossing Black Canyon
would look when standing atop the dam. This bridge design would drastically alter the view
by adding a large form, a variety of lines, contrasting color, and little texture.
From this viewpoint, the bridge pillars, bridge deck, and diagonal lines dominate the view.
The bridge design would add to the visual diversity of the landscape because of the contrasting
lines and colors; however, it would not add to the visual interest of the view. The presence of
the bridge would interrupt the visual continuity of the view of the one mountain in the
middleground (center of photograph) and the mountains in the background.
The visual quality of the view shown in Figure 3-6 would be affected by this bridge design.
The vividness of the view would be degraded by the presence and closeness of the bridge
structure. In addition, the intacmess and unit)' of the view would be affected by the size and
prominence of the bridge form; the vertical, horizontal, and diagonal lines; and the textural
differences between the proposed bridge and the existing landscape.
Hoover Dam would be visible to motorists traveling over the new bridge. Because stopped
vehicles, bicyclists, and pedestrians would be precluded from the new bridge, the bridge would
not provide the benefits of additional viewing opportunities of Hoover Dam.
Steel Deck Arch Bridge. Figure 3-6 simulates how the steel deck arch bridge crossing Black
Canyon would look. This bridge would add a large form that exhibits little texture; vertical,
horizontal, and curve lines; and minimal color difference.
From mis viewpoint, the position, size, and strong horizontal line created by the bridge deck
makes the bridge a dominant feature within the photograph and detracts from the view. Visual
diversity of the view would not be notably improved or degraded, and the visual continuity of
the mountain in the middleground (center of photograph) and the mountains in the
background would be decreased. The height of the bridge deck (along the top of the mountain
in the middleground) also adversely affects the view.
The visual quality shown in Figure 3-6 would be affected by this bridge design, although the
visual impact is considered less than that was discussed for the concrete cable stayed bridge
design. Similar to that discussed for the concrete cable stayed bridge/ the vividness of the view
would be degraded by the presence and closeness of the bridge structure, In addition, the
view's intactness and unity would be affected by the size and prominence of the bridge form;
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the vertical and horizontal lines; and the textural differences between the proposed bridge and
the existing landscape.
Hoover Dam would also be visible to motorists traveling over the new bridge. Because stopped
vehicles, bicyclists, and pedestrians would be precluded from the new bridge, the bridge would
not provide the benefits of additional viewing opportunities of Hoover Dam.
Gold Strike Canyon Alternative. Views of the Gold Strike Canyon Alternative would be
completely obstructed from Hoover Dam, the Arizona Overlook, and Lake Mead. The new
bridge would be visible from the put-in 0.5 mile downstream of Hoover Dam and by aerial
sightseers. The bridge at this location would also change the landscape setting of Gold Strike
Canyon as seen from the hiking trail and hot springs. For some viewers at the river put-in and
those seeing the area by air, this change would detract from the view. For other viewers, the
bridge design would add variety to the view. It should be noted that tine view of the bridge
from rafts floating down river from the rafting put-in would increase as the rafters float toward
the bridge. Once downstream of the bridge, views of the bridge would again decrease. Views
by recreationists using the hiking trail or hot springs would be adversely affected by this
alternative, regardless of the bridge design selected.
Steel Deck Arch Bridge. Figure 3-7 shows a view of Black Canyon looking downstream from the
rafting put-in located 0.5 mile south of Hoover Dam. The top photograph is the existing view
from the put-in. The middle photograph simulates how the steel deck arch bridge would look
from the put-in. This bridge design would add a large form; contrasting horizontal, vertical,
and curved lines; unobtrusive color; and texture changes to the view.
From this viewpoint, the existing landscape appears largely undisturbed. The only noticeable
humanmade feature is the retaining wall in the upper right corner of the photograph. The
position, size, and shape of the bridge structure make it a feature that would dominate the view
from a raft. The structure would add to the visual diversity of the view, but would not add
visual interest. The bridge structure would not interrupt the visual continuity of the mountains
in the background, and it would not affect the view of the slopes in the middleground.
The visual quality shown in Figure 3-7 would be affected by this bridge design; although, of the
two bridge designs being considered for this alternative, it is the less obtrusive design. The
vividness of the landscape components would not be adversely affected by the bridge structure;
however, the view's intactness and unity would be compromised by the size and prominence
of the form and contrasting lines.
Concrete Deck Arch Bridge. Figure 3-7 simulates how the concrete deck arch bridge would look.
Similar to that discussed for the steel deck arch bridge, this bridge design would add a large
form; contrasting horizontal, vertical, and curved lines; unobtrusive color, and texture changes
to the view. As the simulation shows, these affects would be more pronounced with this bridge
design than that for the steel deck arch bridge.
This design would have the same effect on the visual dominance, diversity, and continuity of
the view as was described for the steel deck arch bridge. In addition, this bridge design would
affect the view's vividness, intactness, and unity in the same manner; however, these effects
would be more pronounced with this bridge design.
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This bridge design would affect the quality of the view shown in Figure 3-7 in the same manner
as that described for the steel deck arch bridge. Because the concrete forms on this bridge are
larger than the steel shown in the steel deck arch bridge, the visual impact from this bridge
design is greater than that for the steel deck arch bridge.
Figure 3-8 is a view looking across Black Canyon while standing on the Gold Strike Canyon
Alternative alignment. Figure 3-8 also shows a view from the road traveling east across Black
Canyon atop a simulated bridge deck. This view is from a location not currently accessible to
the public, and therefore not currently seen. Regardless of the alternative or bridge design
selected, because vehicles would be traveling 60 mph and would not be able to stop on the new
bridge, visual acuity and view duration would be limited; therefore, no visual benefit would
occur. Although the Gold Strike Canyon Alternative was selected to show the view from the
road, the simulation is considered representative of the type of landscape that would be seen
from the road, regardless of the alternative selected.
No Build Alternative, Implementing the No Build Alternative would result in no additional
roadway or bridge being constructed, and would therefore result in no physical changes to the
existing roadway and Hoover Dam crossing. No change to the views currently experienced by
recreationists visiting the Hoover Dam area (including the dam, Lake Mead, Colorado River,
Black Canyon, Gold Strike Canyon hiking trail and hot springs) is expected. Aerial views
would also be unaffected by this alternative.
As traffic levels continue to increase, vehicle speeds on the dam are expected to decrease,
resulting in longer views for through-traffic drivers and passengers. Although the view
duration would be increased for this viewer group, the quality of the view would remain
obstructed (either by vehicle height or by the vehicle itself). In addition, as noted previously,
the focus of this viewer group is not its surroundings but primarily its concentration on
negotiating through traffic and reaching its final destination. Therefore, this is not considered a
benefit to this viewer group.
3.7.3 Measures to Minimize Harm
Visual simulations were created to illustrate the impacts to visual resources from each of the
three build alternatives. Figure 3-3 shows the viewpoints for the visual simulations.
Figures 3-5 through 3-7 are visual simulations for each alternative. Figure 3-8 is a
representative view from the road.
3.7.3.1 Construction Mitigation
Regardless of the alternative selected, certain views during the construction period would be
altered by the presence of construction vehicles, equipment, personnel, and activities. This
impact is expected to be considered adverse by some viewers and is an unavoidable
consequence of project construction.
The following mitigation measure should be implemented to reduce impacts on visual
resources: implement a public information program that could include an Internet website, and
provide data sheets to Hoover Dam visitors. Information that should be provided would
include a description of the proposed project, the purpose and need, a construction schedule,
and an explanation of what viewers are seeing and what can be expected to be seen in the
future. A visual simulation could be included so that the viewer could see what the
constructed project would look like when complete. Providing project information may
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES , AND MEAS URES TO MINIMIZE HARM
alleviate viewers' concerns about construction-related view obstruction by explaining that the
project is intended to improve traffic continuity and visitor safety.
3,7.3.2 Operational Mitigation
Regardless of the alternative selected, the proposed bridge would alter the view, either from
Hoover Dam, Lake Mead, the river put-ins, or the Gold Strike Canyon hiking trail and hot
springs. For all the alternatives, the rock cuts adjacent to the proposed bridge should be
engineered to rninimize impacts on visual resources. This could include special blasting
techniques to avoid pre-split shear rock faces. Resulting ledges should be topsoiled and
revegetated to the extent possible. Rock slopes and slope protection in the vicinity of the bridge
should be stained with a desert varnish to reduce the visual impact from the proposed
construction adjacent to the bridge.
Promontory Point Alternative. Impacts on visual resources from the steel truss rib through arch
bridge are considered unmitigable.
To reduce impacts on visual resources from the concrete cable stayed bridge and the
suspension bridge, the concrete should be tinted to blend with the surrounding environment
which would reduce the visibility of the pillars on the bridge.
Sugarloaf Mountain Alternative. Impacts on visual resources from the concrete cable stayed
bridge would be reduced by tinting the concrete with a non-glare color that blends with the
surrounding environment. However, the dominance and closeness of the bridge to the dam
results in the impact on visual resources remaining after mitigation is implemented.
Although the computer simulation is conceptual in Figure 3-6, impacts on visual resources from
the steel deck arch bridge could be lessened by setting the bridge deck elevation so that the
mountain in the center of the photograph could be visible from Hoover Dam. However, this
may not be feasible from an engineering design, earthwork, or economic standpoint. If not, the
impact on visual resources from this bridge design would be considered unmitigable.
Gold Strike Canyon Alternative. Impacts on visual resources from either the concrete deck arch
bridge or the steel deck arch bridge are considered adverse and unmitigable for hikers, hot
spring users, rafters, and other river users near the proposed alignment.
3.8 Recreation Resources
3.8.1 Affected Environment
Hoover Dam, about 1,244 feet long and 726 feet tall, is situated in Black Canyon and is one of
the most spectacular structures in the world. It is a National Historic Landmark and a popular
tourist attraction in southern Nevada and northern Arizona, Reclamation operates a visitor
center at the dam, offers daily guided tours, provides parking for 851 personal vehicles and 22
buses (a multi-story parking garage and outdoor parking are adjacent to and on the dam), and
has several scenic overlooks providing photograph opportunities (pers. comm. with Dan
Jensen/Reclamation, 1998). Photography is a very popular activity at the dam because of the
dam's historic significance and its massive size. In addition, souvenir shops and restrooms are
available.
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Three food and beverage concessionaires were located at the dam until a fire destroyed the one
located at the Arizona Lookout. Current plans are to relocate the two remaining concessions
(one in Nevada and the other in Arizona) to the lower level of the multi-story parking garage
by late 1999, and to rebuild the third concession at the Arizona Lookout. The existing
concession building on the Nevada side of the dam will be converted into a museum, and the
existing Arizona-side concession trailer will be removed from the site (pers. comm. with Dan
Jensen/Reclamation, 1998).
About 33.2 million visitors have toured Hoover Dam since 1937. There were about 1.03 million
visitors in 1997 and an average of 2,823 persons daily in 1997 (pers. comm. with Kris
Mills/Reclamation, 1998). Public access to the downstream side of the dam and Colorado River
for 0.5 mile is precluded for safety reasons. The area is fenced in certain locations, and warning
signs are posted. This area is accessible only to dam personnel and those having Reclamation
permits.
The LMNRA had 9.7 million visitors in 1997 (pers. comm. with Bill Burke/NFS, 1998). Six
developed recreation areas are on Lake Mead, with day use areas, boating facilities,
campgrounds, and lodging. In addition, Lake Mead Cruises operates a boat tour aboard the
Desert Princess, a paddle wheel boat with a capacity of several hundred people. Sightseeing is
the most popular activity; other activities include fishing, boating, houseboating, parasailing,
scuba diving, jet skiing, swimming, canoeing, kayaking, hiking, and nature study.
The developed recreation area on Lake Mead nearest to the proposed project is Boulder Beach,
located on the western arm of Lake Mead. Boulder Beach can be accessed from U.S. 93/95 in
Henderson via Lake Mead Drive and from Nevada SR166 (Lakeshore Drive). Facilities at
Boulder Beach include a marina, camping areas, picnic areas, a swimming beach, lodging, 2
launch ramps, store and restaurant, boat gasoline station, restrooms, and parking areas (pers.
comm. with Bill Burke/NFS, 1998).
The Gold Strike Inn, located on U.S. 93 about 3 miles west of Hoover Dam, provides gaming,
lodging, and eating facilities. About 0.5 mile downstream from Hoover Dam, a rafting
concessionaire (Black Canyon Raft Tours) operates a dock with a fleet of 11 rafts that
accommodate from 18 to 42 people each and are used to float customers down the Colorado
River. About 18,500 customers floated the river in 1997. The rafting concession operates from
February 1 to November 30, and by special arrangement in December and January (pers. comm.
with Ron Opfer/Black Canyon Raft Tours, 1998). It has a permit to use Reclamation's restricted
access road (the Lower Portal Road) from U.S. 93 down to the river (pers. comm. with Dan
Jensen/Reclamation, 1998).
Reclamation also issues permits to individuals to launch canoes at a put-in about 20 yards
downstream of the rafting put-in. Groups of up to 15 people are escorted twice daily from
Reclamation's warehouse to the river put-in via Lower Portal Road. Demand for this service
exceeds capacity; the service is currently sold out until mid-summer 1999. In 1997,7,212
individual permits were issued for this service (pers, cornrn. with Dan Jensen/ Reclamation,
1998).
In addition, in February 1998 a tour group was issued an annual permit by Reclamation to
escort groups from Las Vegas to tour Hoover Dam and provide access to Lower Portal Road to
photograph the dam from the helicopter pad and canoe put-in. To date, the average number of
users has been 10 per week (pers. comm. with Dan Jensen/Reclamation, 1998).
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An undesignated 2.5-miIe-long trail is used by visitors to hike down through Gold Strike
Canyon to the Colorado River. Drainages of hot springs near the canyon mouth have been
blocked to form ponds of warm water. The trail is used for nature study, photography,
technical rock climbing, and accessing the hot springs. An estimated 5,000 hikers use the trail
and hot springs annually, mostly in the cooler months {pers. comm. with Bill Burke/NPS,
1998). To accommodate the needs of hot springs users, the NFS provides a portable toilet at the
canyon mouth. In addition, historic railroad grades and runnels near Hoover Dam are
currently used for hiking and mountain biking.
Commercial airplane and helicopter sightseeing flights originating in Las Vegas and nearby
small airports and helipads also are available to recreationists wanting aerial views of Hoover
Dam, Lake Mead, and the Colorado River.
3.8.2 Environmental Consequences
3.8.2.1 Construction Impacts
Impacts during construction of the proposed project common to all three build alternatives
include the following:
• Dust would be emitted from earthmoving activities, construction vehicles and equipment,
construction worker vehicles, material delivery vehicles, and from areas within the
construction zone that have been disturbed or where excavated material is stockpiled. The
magnitude of the impact on recreationists visiting Hoover Dam, Lake Mead, the Colorado
River, and Gold Strike Canyon hot springs and hiking trail would vary by alternative.
• Noise would be emitted during all construction phases. Noise sources include construction
vehicles and equipment, construction worker vehicles, and materials delivery vehicles.
Noise levels associated with construction activities are typically 88 dBA to 92 dBA at a
distance of 50 feet, which would be a noticeable change from ambient noise levels (see
Appendix 2). Magnitude of the impact on recreationists visiting Hoover Dam, Lake Mead,
Colorado River, hot springs, and the hiking trail would vary by alternative.
• Effects on water-dependent recreation activities would occur at Lake Mead near Hoover
Dam and at the Colorado River rafting and canoeing put-ins from construction activities
because of the temporary impacts on access and water quality (this would apply only to the
Promontory Point and Sugarloaf Mountain Alternatives).
• Effects on access to Hoover Dam, Lake Mead, the Colorado River, and the hiking trail in
Gold Strike Canyon would occur because of proposed project construction activities..
Roadway access and the access to Hoover Dam from Lake Mead may be restricted at times
during construction to ensure the public's safety. The canyon trail would be closed during
construction of the Gold Strike Canyon Alternative.
• Effects of the presence of construction equipment would occur. For some recreationists, the
presence of construction equipment and its associated activities would detract from the
recreation experience. For others, the presence of equipment and construction activities
would be interesting, creating additional photograph opportunities.
• Increased light emitted from the construction area would occur if nighttime construction is
conducted. Hoover Dam is currently lit at night and provides interesting nighttime views
for tourists. For some recreationists, the additional light that would be emitted during
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
nighttime construction, if it occurs, would detract from the nighttime views experienced
during the dam visit. Again, depending on their values and expectations, for other
recreationists, the additional light and associated construction activities would add interest
to the setting. This issue is expected to be less of a concern to recreationists if the Gold
Strike Canyon Alternative is constructed because that alternative is not visible from Hoover
Dam. However, it is possible that the canyon downstream may appear brighter during
nighttime construction, if that alternative is selected.
Impacts specific to the three build alternatives and the No Build Alternative are described
below.
Promontory Point Alternative. Construction of the Promontory Point Alternative is expected to
last approximately 4 years, 9 months. During construction of this alternative, an area of Lake
Mead upstream of Hoover Dam would be designated as a construction safety zone. This
designation would preclude public use of that area of the lake for recreation activities by
eliminating access to Hoover Dam on its upstream side (from Lake Mead). No other effects on
activities at Lake Mead are expected.
Existing recreation activities at Hoover Dam, the Colorado River, hiking trail and hot springs,
and the Gold Strike Inn would not be affected by construction of the proposed project. In
addition, the ground and aerial tour groups would not be affected by construction of this
alternative.
In areas where blasting, earthmoving, other construction activities, and spoil disposal areas are
located, construction safety zones would also be established. These zones would preclude
using the area for hiking or other dispersed recreation activities currently occurring along the
alignment.
Sugarloaf Mountain Alternative. Construction of the Sugarloaf Mountain Alternative is expected
to last approximately 4 years, 7 months. Certain areas along the Colorado River and along U.S.
93 would be designated as construction safety zones. These designations would preclude
public use of those areas for recreation activities. The rafting concession and the canoeing put-
in should be able to continue to operate with minor interruptions in service by coordinating
launching to avoid conflicts with construction activities.
Existing recreation activities at Lake Mead, Hoover Dam, hiking trail and hot springs, and die
Gold Strike Inn would not be affected by construction of the proposed project. In addition,
ground and aerial tour groups would not be affected by construction of this alternative.
In areas where blasting, earthmoving, other construction activities, and spoil disposal areas are
located, construction safety zones would be established. These zones would preclude using the
area for biking or other dispersed recreation activities currently occurring along the proposed
alternative.
Gold Strike Canyon Alternative. Construction of the Gold Strike Canyon Alternative is expected
to last approximately 5 years, 3 months. Certain areas along the Colorado River and U.S. 93
would be designated as construction safety zones. These designations would preclude public
use of those areas for recreation activities. The Gold Strike Canyon trail would be closed
during construction. The rafting concession and the canoeing put-in should be able to continue
to operate with minor interruptions in service by coordinating launching and passage through
the construction zone to avoid conflicts with construction activities.
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CHAPTERS AFFECTED ENVIRONMENT. ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
Existing recreation activities at Lake Mead, Hoover Dam, and the Gold Strike Inn would not be
affected by construction of the proposed project. In addition, aerial tour groups would not be
affected by construction of this alternative. Access to the river put-in and helipad by ground
tours may be interrupted by construction activities; coordination should occur to avoid conflicts
with such activities.
In areas where blasting, earthmoving, other construction activities, and spoil disposal areas are
located, construction safety zones would be established. These zones would preclude using the
area for hiking or other dispersed recreation activities currently occurring along the proposed
alternative.
No Build Alternative. Because the No Build Alternative would result in the proposed project not
being constructed, no construction-related impacts on existing recreation activities are expected
at Hoover Dam, Lake Mead, Colorado River put-ins, Gold Strike Canyon hiking trail and hot
springs, Gold Strike Inn, and ground or aerial tours.
3.8.2.2 Operational impacts
Impacts during the operational phase of the proposed project common to all three build
alternatives include the following:
• The new bridge, regardless of the alternative chosen, would likely become a tourist
attraction because of its association with and proximity to Hoover Dam, its design, and the
setting in which it would be located. This would result in recreationists in the area making
it a travel destination. This is considered a benefit to recreationists desiring the experience.
Views of the dam and new bridge and its environs from atop the bridge would be limited to
those from moving vehicles; bicyclists, pedestrians, and stopped vehicles would not be
allowed.
• For some recreationists, the presence of the new bridge would detract from the recreation
experience offered at Hoover Dam by changing the view from the dam. For other
recreationists, the presence of the new bridge would add to the variety of the view from the
dam, which they would consider to be interesting, thus creating additional photographic
opportunities. (The view from the dam would change with either the Promontory Point
Alternative or Sugarloaf Mountain alternative).
• Because traffic congestion would be alleviated at Hoover Dam, CO and VOC daily
emissions are expected to be reduced by approximately 50 percent and 80 percent,
respectively, and pedestrian safety would be improved. This is considered a benefit to
recreationists atop the dam.
Impacts specific to the three build alternatives and the No Build Alternative are described
below.
Promontory Point Alternative. The new bridge would be visible from Hoover Dam and from
aerial sightseeing recreationists, thus changing the recreational setting of Lake Mead from the
dam and the air. For some recreationists, this change would detract from tine lake view. For
other recreationists, the bridge design would add variety to the lake view. The presence of the
new bridge would not preclude recreational opportunities currently offered at Hoover Dam
and by aerial sightseeing.
The bridge would also be visible to recreationists on Lake Mead (those in motorized and non-
motorized water craft, anglers, and swimmers), and along adjacent shores (e.g., hikers and
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
picnickers) in the dam vicinity. Similar to that discussed for views from Hoover Dam and the
air, the quality of the recreation experience of some recreationists on and around Lake Mead
would be degraded/ and the experience of other recreationists would be enhanced by the
presence of the new bridge. The new bridge would not preclude recreational opportunities
currently offered by Lake Mead and its shores. No significant changes to existing noise levels
are expected.
Because traffic would be diverted from atop Hoover Dam to the new bridge, traffic congestion
would be reduced, thereby reducing the potential for vehicle collisions with pedestrian tourists
on the dam. The reduction in traffic would also reduce the amount of traffic noise and volume
of air pollutants emitted from vehicles on the dam. These three reductions are considered
benefits to recreationists visiting Hoover Dam.
Unless it is screened from view, Hoover Dam would also be visible to motorists traveling over
the new bridge. Because stopped vehicles, bicyclists, and pedestrians would be precluded from
the new bridge, additional opportunities to photograph Hoover Dam would not be provided.
Implementation of the Promontory Point Alternative would riot affect recreation activities at
the Colorado River, the biking trail and hot springs, or the Gold Strike Inn.
Sugarloaf Mountain Alternative. The new bridge would be visible from Hoover Dam and from
aerial sightseeing tours, thus changing the recreational setting of the Colorado River
immediately downstream of the dam from both the dam and the air. For some recreationists,
this change would degrade the river view. For other recreationists, the bridge design would
add variety to the river view. The presence of the new bridge would not preclude the
recreational opportunities currently offered by Hoover Dam and aerial sightseeing.
The bridge would be visible to recreationists on the Colorado River at the rafting and canoeing
put-in locations, located about 0.5 mile downstream of Hoover Dam. Similar to that discussed
for views from Hoover Dam and the air, the quality of the recreation experience of some
recreationists on the Colorado River and at the hot springs would be degraded, and the
experience of other recreationists would be enhanced by the presence of the new bridge. The
new bridge would not preclude recreational opportunities currently offered at the rafting and
canoeing put-ins or at tine hot springs and hiking trail. As rafters and canoeists float
downstream away from the proposed bridge, the view of the bridge would diminish, until
approximately 0.4 mile downstream from the put-in, at which point, the bridge would not be
visible. No significant changes from existing noise levels are expected.
Because traffic would be diverted from atop Hoover Dam to the new bridge, traffic congestion
would be reduced, thereby reducing the potential for vehicle collisions with pedestrian tourists
on the dam. The reduction in traffic would also reduce the amount of traffic noise and volume
of air pollutants emitted from vehicles on the dam. These three reductions are considered
benefits to recreationists visiting Hoover Dam.
Unless it is screened from view, Hoover Dam would also be visible to motorists traveling over
the new bridge. Because stopped vehicles, bicyclists, and pedestrians would be precluded from
the new bridge, additional opportunities to photograph Hoover Dam would not be provided.
Implementation of the Sugarloaf Mountain Alternative would not affect recreation activities at
Lake Mead and the Gold Strike Inn.
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
Gold Strike Canyon Alternative, The new bridge would not be visible from Hoover Dam or by
the ground tours; therefore, those activities would not be affected. It would be visible to aerial
sightseeing recreationists, thus changing the recreational setting of the Colorado River in the
vicinity of the construction zone from the air. For some recreationists, this change would
degrade the river view. For other recreationists, the bridge design would add variety to the
river view. The presence of the new bridge would not preclude aerial sightseeing
opportunities.
The location where the bridge would cross the river would be visible to recreationists at the
rafting and canoeing put-in locations, located about 0.5 mile downstream of Hoover Dam. It
would be visible to recreationists using the hot springs and hiking trail. For some
recreationists, the quality of the recreation experience on the Colorado River and at the hiking
trail and hot springs would be degraded, and the experience of other recreationists would be
enhanced by the new bridge's presence. The presence of the new bridge would not preclude
recreational opportunities currently offered at the rafting and canoeing put-ins or at the hot
springs and hiking trail. After put-in, rafters and canoeists would float downstream toward the
proposed bridge, resulting in the bridge becoming increasingly large. Once downstream of the
bridge, it would remain visible for approximately 0.8 mile.
Because traffic would be diverted from atop Hoover Dam to the new bridge, traffic congestion
on the dam would be reduced, thereby reducing the potential for vehicle collisions with
pedestrian tourists on the dam. The reduction in traffic would also reduce the amount of traffic
noise and volume of air pollutants emitted from vehicles on the dam. These three reductions
are considered benefits to recreationists visiting Hoover Dam.
The addition of vehicle traffic to the currently undeveloped Gold Strike Canyon would increase
existing ambient noise levels by 26 dBA. With construction of noise barriers on the roadway,
noise levels along the canyon trail would still exceed federal standards by 3 dBA, which would
be an adverse impact. This increase in noise levels would affect the quality of the recreation
experience of users of the hiking trail in that area (see Appendix C - Section 4(f) Evaluation).
Implementation of the Gold Strike Canyon Alternative would not affect recreation activities at
Lake Mead and the Gold Strike Inn.
No Build Alternative. Implementation of the No Build Alternative would result in no additional
roadway or bridge being constructed, and would result in no physical changes to the existing
roadway and Hoover Dam crossing. Traffic levels on U.S. 93 are projected to continue to
increase, and the number of recreationists visiting Hoover Dam, Lake Mead, and the Colorado
River and its environs is also expected to continue to increase. The continued increase in
vehicles along US. 93 near Hoover Dam and atop the dam is expected to further increase traffic
congestion.
Increased traffic would result in increased travel times for both through-vehicles and vehicles
whose final destination is the dam, and would also result in additional noise and vehicle fumes
on the roadway and atop the dam. Increased travel times may affect the enjoyment of the
travelers' recreation experience, and the visit to Hoover Dam would likely be degraded by
associated additional noise and vehicle fumes.
Additional traffic would increase the potential for a vehicle and pedestrian collision on the
dam, resulting in an increased public safety hazard. Continuing to allow commercial trucks to
cross the dam, in combination with the expected increased traffic levels, would also increase
the public safety hazard. The increase in recreationists visiting the dam would compound this
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AMD MEASURES TO MINIMIZE HARM
public safety hazard. This increased hazard potential would adversely affect the recreation
experience at the dam.
Implementation of the No Build Alternative would not adversely affect Lake Mead recreational
activities. However, if traffic congestion increases to intolerable levels to motorists, they may
elect to drive to their destination using an alternate route, even if it is longer. Motorists who
chose an alternate route would forego the recreational opportunities offered at Hoover Dam,
the Colorado River, the Gold Strike Canyon hiking trail and hot springs, and the Gold Strike
Inn.
3.8,3 Measures to Minimize Harm
3.8.3.1 Construction Mitigation
Regardless of the alternative selected, certain areas would be designated for construction
activities, which would preclude using those areas for dispersed recreation activities. In most
cases, this impact on recreation activities is not considered adverse. Designated construction
safety zones and construction areas would have signs posted, and public access to those areas
would be precluded, thus reducing the potential for recreationists to be injured in the
construction zone or by construction activities. The hiking trail in Gold Strike Canyon would
be closed during construction of the Gold Strike Canyon Alternative, which would be an
adverse impact on the recreationists using this area.
Promontory Point Alternative. The following mitigation measures should be implemented:
* Construction activities should be coordinated with Lake Mead Cruises to avoid conflicts.
• The construction zone within Lake Mead should be marked with buoys, or other devices, to
preclude access by private and commercial boats.
Sugarloaf Mountain Alternative. Raft and canoe launchings at the put-ins on the Colorado River
should be scheduled to avoid conflicts between construction activities and put-ins.
Gold Strike Canyon Alternative. The following mitigation measures should be implemented:
• Raft and canoe launchings at the put-ins on the Colorado River, and floating through the
construction zone, should be scheduled to avoid conflicts between construction activities
and river floating.
* A net or other device should be used to prevent construction materials or equipment from
failing from the bridge into the river.
• The loss of trail access from U.S. 93 to the hot springs during the construction period is
considered unmitigable.
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CHAPTERS AFFECTED ENVIRONMENT. ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
3.8.3.2 Operational Mitigation
Recreation activities at Hoover Dam, Lake Mead, and the Colorado River would not be
precluded by implementation of any of the three build alternatives. If either the Promontory
Point or Sugarloaf Mountain Alternative is selected, the proposed bridge would alter the view,
either from Hoover Dam, Lake Mead, or the river put-ins. If the Gold Strike Canyon
Alternative is selected, the proposed bridge would alter the view from the river put-ins only.
To reduce visibility of the bridge from recreation viewpoints, the bridge should be painted or
tinted with non-glare colors that blend with the surrounding environment.
Promontory Point Alternative. No additional mitigation for this alternative is required or
recommended.
Sugarloaf Mountain Alternative. No additional mitigation for this alternative is required or
recommended.
Gold Strike Canyon Alternative. Noise levels resulting from operation of this alternative were
calculated to be 65 dBA-L^ at the top of the hiking trail. The federal/state noise criterion or
standard to be achieved is 56 dBA-L^. It would be possible to reduce the noise levels by
constructing noise barriers, located at the outside edge of the roadway adjacent to the trail
(shown on Figure 3-7). However, only a 6 dBA-L^ reduction could be achieved; therefore, this
impact could not be completely mitigated, and noise impacts on recreation remain significant
along the hiking trail. Reduced access for hikers and esthetic impacts from the elevated
roadway in the canyon also cannot be mitigated.
3.9 Socioeconomics
3.9.1 Affected Environment
This section describes the population, employment, and income levels in Clark County and
Boulder City, Nevada and Mohave County, Arizona. Boulder City is the nearest town to the
proposed project area and is, therefore, the focus of the discussion. This section also discusses
social conditions, environmental justice, and transportation and circulation.
3.9.1.1 Population
The Hoover Dam area is located within Clark County, Nevada, and Mohave County, Arizona.
Clark County, in southern Nevada, is 7,911 square miles and has a countywide population
density of 125 people per square mile. The 1996 population was 992,593, an increase of
34 percent over 1990. the Las Vegas and Henderson population of 560,359 represents
approximately 48 percent of Clark County's total population.
Mohave County, in western Arizona, is 13,312 square miles with a countywide population
density of 9 people per square mile. Between 1990 and 1996, population increased by
30 percent, to 121,602.
Boulder City is situated along the eastern border of Clark County, about 24 miles southeast of
Las Vegas and 6 miles southwest of Hoover Dam. Boulder City's population has grown more
slowly than the rest of the county because of its controlled growth ordinance. Current
population is approximately 14,500.
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
3.9,1.2 Employment
Tourism is a primary economic force in Clark County. Boulder City offers a full range of
services to the increasing numbers of tourists, with motels, restaurants, and an airport.
Although gambling is not permitted within the city, Gold Strike Inn (located on U.S. 93
between Boulder City and Hoover Dam) is a major employer in the area. Federal and local
government agencies are the most significant employers in the local labor force. In addition to
tourism and government, a light industrial area in the city provides commercial and
manufacturing jobs to the local economy.
Construction, trade, finance, real estate, and services provide the majority of employment in
Mohave County. Employment opportunities at Hoover Dam consist of federal jobs and
privately operated food and gift concessionaires.
In 1989, average personal per capita income in Boulder City was $17,231; Clark County was
$15,109; and the State of Nevada was $15,214. The national personal per capita income was
$14,420.
3.9.1.3 Social Conditions
The proposed project is located entirely on federal land about 6 miles northeast of the nearest
residential area in Boulder City. Boulder City is the only city in Nevada where gambling is
prohibited. The city has also instituted a controlled growth policy to prevent rapid growth and
to preserve the utility systems and social infrastructure. Boulder City offers a quiet small town
atmosphere.
3.9.1.4 Environmental Justice
Environmental justice refers to social inequity in bearing the burdens of adverse environmental
impacts. Certain U.S. socioeconomic groups, including ethnic minorities, the elderly, rural
residents, and others, have historically experienced a disproportionate share of undesirable side
effects from locally undesirable land uses such as toxic waste dumps, landfills, and freeway
projects.
Consistent with Title VI of the 1964 CM Rights Act and Executive Order 12898, Federal Actions
to Address Environmental Justice in Minority Populations and Low Income Populations, dated
February 11,1994, all proposed projects and decisions must ensure that minority and low-
income populations are not disproportionately adversely affected by transportation programs
or projects.
The FHWA policy toward environmental justice is to address whether any social group is
disproportionately impacted by a proposed project, and identify possible mitigation measures
to avoid or minimize adverse social impacts. Specifically, the FHWA intends that no person in
the U.S. shall, on the grounds of race, color, or national origin, be excluded from participation
in, be denied the benefits of, or be subjected to discrimination under any program or activity
receiving federal financial assistance.
Table 3-19 presents 1990 census data for Las Vegas, Henderson, and Boulder City, Nevada; and
for Kingman, Arizona.
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CHAPTER 3 AFFECTED ENVIRONMENT. ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
Table 3-1 9
1990 Census Data by Locality Near the Proposed Project Area
Las Vegas
Total Population
258,295
Race (%)
White: 78.4
Black: 11. 5
A!a: 0.9
Ab: 3.6
Other0: 5.6
Total Households
99,954
Race (%)
White: 82
Black:. 10.1
Al: 0.9
A: 2.8
Other: 4.2
Households by Age Group
<25: 5,904
25-34: 24,401
35-44: 22,469
45-54: 16,431
55-64: 13,510
65-74: 11,903
>75: 5,336
Henderson
64,942
White: 91.5
Black: 2.7
Al: 1.0
A: 2.1
Other: 2.7
23,353
White: 92.7
Black: 2.7
Al: 1.0
A: 1.4
Other 2.2
<25: 1,288
25-34: 6,019
35-44: 6,059
45-54: 3,846
55-64: 2,876
65-74: 2,422
>75: 843
Boulder City
12,567
White: 97
Black: 0.4
Al: 1.0
A: 1.2
Other: 0.4
5,116
White: 98
Black: 0
Al:1.0
A: 0.7
Other: 0.3
<25: 104
25-34: 616
35-44: 874
45-54: 880
55-64: 888
65-74:1,092
>75: 662
Kingman
12,722
White: 94.5
Black: 0.1
Al: 1.3
A: 1.5
Other: 2.6
4,961
White: 95
Black: 0.2
Al: 1.1
A: 1.2
Other 2.5
<25: 210
25-34: 849
35-44: 967
45-54: 800
55-64: 772
65-74: 807
>75: 556
Households {all races) Age 55 and Over and
Percentage Below the Poverty Level
30,749
(52%)
Households Age 55 and Over Below
the Poverty Level" by Race6 (%)
White: 50.5
Black: 63.8
Al: 65.1
A: 60.1
Other: 51.4
Families Above the Poverty Level in
White: 76.3
Black: 7.9
Al: 0.9
A: 2.8
Other: 4.0
6,141
(46%l
White: 45.7
Black: 48.4
Al: 24.5
A: 32.4
Other: 71.7
1989 by Race (%}
White: 88.2
Black: 2.1
Al: 0.8
A: 1.3
Other: 2.5
2,642
(45%)
White: 23.5
Black: 0
Al: 12.8
A: 21 .4
Other 0
White: 93.5
Black: 0
Al: 1.3
A: 0.4
Other 0.3
2,135
(65%)
White: 64.3
Black: 100
Al:41.1
' A: 100
Other 100
White: 89.2
Black: 0.2
Al: 1.4
A: 1.2
Other: 2.5
Families Below the Poverty Level in 1989 by Race (%)
White: 4.6
Black: 2.4
Al: 0.1
A: 0.2
Other: 0.8
White: 4.4
Black: 0.4
Al: 0.1
A: 0.1
Other 0.1
White: 4.5
Black: 0
A!: 0
A: 0
Other 0
White: 5.2
Biack: 0
A!: 0
A: 0.2
Other: 0.1
3-88
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
Table 3-19
1990 Census Data by Locality Near the Proposed Project Area
Las Vegas
Per Capita Income by Race in 1989 ($)
White: 16,121
Black: 9,252
Al: 12,140
A: 12,465
Other: 8,436
Henderson
White: 16,951
Black: 11,691
Al: 11,008
A: 10,846
Other 9,773
Boulder City
White: 17,254
Black: 1,096
Al: 13,788
A: 26,219
Other 9,712
Kingman
White: 12,370
Black: 10,400
Al: 10,480
A: 37,571
Other: 12,523
* Al American Indian, Eskimo, or Aleut
" A Asian or Pacific Islander
6 Other Other Race
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE Hum
Hoover Dam is the only Colorado River crossing near Las Vegas. The next closest crossings are
at Davis Dam, 67 miles downstream, or at Laughlin, 70 miles downstream. Because shorter
travel times and distances reduce accident exposure and transit costs, the shorter Hoover Dam
crossing is preferred by the commercial trucking industry for travel in the Las Vegas to Phoenix
corridor.
Other routes that cross the Colorado River are U.S. 95 and SR163 in Nevada to Arizona SR 68
(see Figure 2-1), which would add 23 miles to the trip from Kingman to Las Vegas. Another
route from Kingman to Las Vegas, 1-40 to Needles, California, and then north on U.S. 95 to Las
Vegas, adds 75 miles to the trip.
As the shortest route, U.S. 93 across Hoover Dam would offer a time savings for through traffic
between Arizona and Nevada if the existing bottleneck is eliminated at the dam. Traffic flow is
generally at speeds near posted limits except at roadway approaches to Hoover Dam. Average
speeds recorded on the approaches to the dam and across the dam crest were as low as 8 mph
(Traffic Study: Colorado River Bridge, December 1991).
The Hoover Dam section of U.S. 93 has reached capacity during peak periods and cannot
provide additional capacity with the current roadway alignment. In 1991, average travel
speeds for the 2 miles of roadway on either side of Hoover Dam were 8 to 18 mph. Table 3-20
presents 1997 average annual daily traffic (AADT) and LOS at Hoover Dam (see Traffic
Analysis - Appendix A).
Table 3-20
Average Annual Daily Traffic and Level of Service at Hoover Dam
Measurement 1997
AADT 11,500
LOS F
The LOS compares projected traffic with the theoretical capacity of a roadway segment. LOS is
designated A to F, with A representing unconstrained and free-flowing traffic, and F
representing unstable flow with near gridlock conditions. As shown in Table 3-20, traffic
congestion at Hoover Dam is nearing gridlock.
3.9.2 Environmental Consequences
3.9.2.1 Buiid Alternatives
Population. No change in regional (Clark and Mohave counties) population is expected from
implementation of any of the build alternatives. Recent trends in population growth are not
expected to be altered. Because Boulder City has a growth ordinance, population increases
within the city are expected to continue at the same rate as in the past 10 years.
Employment Construction of any of the build alternatives would create both direct and indirect
employment opportunities in the region. Direct employment would be provided for project
construction workers. Indirect employment would be provided for those in construction
material manufacturing and delivery, project goods and services, and project operation and
maintenance.
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AMD MEASURES TO MINIMIZE HARM
The number of direct and indirect jobs that would be created during the construction period is
based on the relationship between construction costs and the multipliers for construction
employment. It is expected that Las Vegas, Henderson, Boulder City, and Kingman would
provide the labor pool. During the construction period, between 2,900 to 3,440 new jobs would
be created in the region.
The Gold Strike Inn, located about 3 miles west of Hoover Dam, employs about 450 people,
many of whom live in Boulder City. Implementation of the build alternatives is not expected to
affect the number of employees at this establishment.
Income. Few permanent jobs would be created by construction of any of the build alternatives;
therefore, the personal per capita income is not expected to change in Clark or Mohave
counties.
In both Arizona and Nevada, minor adverse impacts may occur to the dam concessionaires as a
result of through-traffic reduction over the dam. However, these impacts would be offset by
the expected continued increase in dam visitors. Reduced traffic congestion on the dam would
make it a more desirable attraction to visit. The raffing concession would continue operation
with only minor interruptions by coordinating its scheduled raft launching to avoid conflicts
with construction activities; therefore, it is not expected to be adversely affected.
Economic impacts to the local economy would be most notable during the construction period.
Based on the cost range for the alternatives, for every dollar spent in bridge construction and
highway approaches, $1.75 would be generated in the regional economy. An estimated range
of economic activity from construction expenditures would be from $233 to $257 million.
During operation of the proposed project, traffic would continue to pass through Boulder City
as it currently does. Therefore, changes in spending within the City (and resultant economic
impacts) are expected to be negligible when compared to existing levels.
Social Conditions. Because the proposed project's western terminus is located about 4 miles
east of the Boulder City limits, the city's existing social infrastructure (including schools,
recreation areas, churches, businesses, and emergency services) is not expected to be adversely
affected. In fact the reduction in traffic congestion and potential safety hazards at and near the
dam are likely to reduce the demand upon Boulder City emergency response personnel. In
addition, no businesses or households would need to be relocated, and Boulder City's
community cohesion and property values would not be affected.
If the proposed project is implemented, perceived social impacts, such as noise, pollution, and
associated decreases in quality of life, would occur in Boulder City at the current same rate.
Therefore, no impact on the city's social conditions is expected from any of the build
alternatives.
Environmental Justice. E.0.12898 requires identification and avoidance of disproportionately
high and adverse human health or environmental affects on minority and low-income
populations.
Because the area where the build alternatives would be constructed and operated is currently
unpopulated, no minority or low-income groups live in that area. Therefore,
disproportionately high and adverse human health or environmental affects on minority and
low-income groups are not anticipated.
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Transportation and Circulation, U.S. 93 traffic forecasts were completed using historic traffic
data obtained from ADOT and NDOT and applying expected annual traffic growth rates of
between 4 and 5 percent for 1997. The AADT volumes and associated LOS at Hoover Dam for
years 2017 and 2027 under the No Build Alternative presented in Table 3-21.
The LOS at Hoover Dam is expected to improve from F to E with implementation of any of the
build alternatives. The primary reason the LOS would not improve more than level E is the
mountainous terrain, steep grades, and sharp curves. Speeds are expected to be low; however,
the roadway capacity would be well above the anticipated demand, and traffic delays on the
dam are not expected.
If any of the build alternatives are implemented, the AADT and associated LOS in year 2017 for
the new bridge crossing are 16,400 and A, respectively. In year 2027, the AADT and LOS
would be 19,900 and B, respectively.
3.9.2.2 No Build Alternative
Implementation of the No Build Alternative would result in no change to existing population
trends and growth in Clark and Mohave counties. In addition, this alternative would result in
the creation of no direct or indirect jobs (and, therefore, no change to the local economy), and
no change to the existing personal per capita income level in the region.
Similar to that for the build alternatives, no impacts to the city's existing social infrastructure
(including schools, recreation areas, churches, and businesses) are expected. However, the
expected increase in traffic congestion and associated potential safety hazards at and near the
dam may affect the demand upon Boulder City emergency response personnel during
emergencies. No businesses or households would need to be relocated, and Boulder City's
community cohesion and property values would not be affected by this alternative.
If the No Build Alternative is implemented, perceived social impacts (such as noise, pollution,
and associated decreases in quality of life) would occur in Boulder City at the current rate.
Because the No Build Alternative would result in no project being constructed, no adverse
effects on minority or low-income populations are expected.
With implementation of the No Build Alternative, LOS is expected to remain F at Hoover Dam.
The AADT and associated LOS in year 2017 at the dam if the No Build Alternative is
implemented are 21,100 and F, respectively. In year 2027, the AADT and LOS would be 26,000
and F, respectively. Although LOS at the dam would continue to be F when compared to
existing conditions, the increase in AADT (83.5 and 126 percent in years 2017 and 2027,
respectively) would result in significant transportation and circulation impacts on U.S. 93 at
and near the dam (see Table 3-20).
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Table 3-21
Forecasted Average Annual Daily Traffic and Level of Service at Hoover Dam
Under No Build Alternative
Year
Measurement 2017 2027
AADT 21,100 26,000
LOS F F
Source: Appendix A, Traffic Analysis
3.9.3 Measures to Minimize Harm
Because no adverse Impacts on population, employment, income, social conditions, minority or
low-income populations, or transportation and circulation are expected as a result of
implementing any of the build alternatives or the No Build Alternative, no mitigation is
required.
3,10 Hazardous Materials
3.10.1 Affected Environment
Sites with known or suspected hazardous waste that may be affected by the proposed project
were evaluated to assess environmental concerns at each site. These sites are known or
suspected to be contaminated with hazardous wastes because of historical use, storage, or
release of hazardous materials at the site. This evaluation is based on Level I Contaminant
Surveys that were conducted for the Promontory Point, Sugarloaf Mountain, and Gold Strike
Canyon alternatives in May 1992 {Reclamation, 1992a, b, c) as well as a subsequent survey in
May 1998.
3.10.1.1 Promontory Point Alternative
Seven potential hazardous waste sites exist on or adjacent to the Promontory Point Alternative
corridor: the Reclamation warehouse storage yard; two staging areas used by contractors
during construction of the new visitor center; two disposal areas used during construction of
the new visitor center and during rehabilitation of U.S. 93 in the vicinity of the dam; a dump
pile; and an abandoned switchyard.
Reclamation Warehouse Storage Yard. The Promontory Point Alternative would pass through
the Reclamation warehouse storage yard. Environmental concerns at this site include past and
present chemical use and storage, stained soils, and drains and other pathways for potential
contamination. Another concern at this site is potential residual petroleum hydrocarbons in
soil resulting from two leaking underground fuel storage tanks that were removed in 1991. An
estimated 500 gallons of unleaded fuel were released to the soil and subsequently remediated
in accordance with Nevada Division of Environmental Protection regulations.
Contractor Staging and Disposal Areas. The two contractor staging areas are of concern because
chemicals including motor oil, antifreeze, and diesel fuel were used and stored at these sites.
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Several noticeable oil stains were observed on the ground (Reclamation, 1992a). If it is
determined that chemicals were released to the soil, contaminated soil may be encountered
during construction activities.
The two disposal areas consist primarily of excavated rock, soil, and milled pavement;
however, some old pipe, rebar, scrap metal, and other construction debris are evident. One of
the disposal areas has been flattened and is used for equipment storage.
Dump Pile. An original dump pile used during construction of Hoover Dam is located along the
Promontory Point Alternative alignment (Reclamation, 1992a), the area is scattered with metal
shavings, numerous rusted 5-gallon and 55-gallon containers, concrete blocks, scrap metal, and
sheet metal. Some ground discoloration was observed, possibly indicating that hazardous
materials were released to the soil. Because the dump pile is located upgradient from the
proposed alignment, a potential pathway for contamination exists from the dump to the subject
alignment through surface runoff or a subsurface plume of contamination.
Abandoned Switchyard. An out-of-service switchyard exists along the Promontory Point
Alternative. Environmental concerns at this site include oil stains on the ground. If the oil is
the result of a transformer leak, the oil could potentially contain polychlorinated biphenyls
(PCBs).
PCBs are a subset of the synthetic organic chemicals known as chlorinated hydrocarbons.
Between 1926 and 1977, PCB-containing products were manufactured for use in applications
such as electrical transformers, where stable, fire-resistant, heat-transfer properties were
demanded. The most extensive use of PCBs occurred in dielectric fluids. Such fluids typically
have the following characteristics: a heavy oil appearance, high boiling point, high chemical
stability, high flash point, low electrical conductivity, and low water solubility. PCBs are
known to cause chronic reproductive effects, gastric disorders, and skin lesions in laboratory
animals. In addition, the U.S. EPA suspects that PCBs are probable human carcinogens.
During the 1970s, in an effort to minimize the potential for adverse health effects caused by
PCBs and other substances, Congress passed the Toxic Substances Control Act (TSCA), which
strictly regulates all aspects of PCB use. TSCA prohibits the manufacture, processing, and
distributing in commerce of PCBs, except as exempted by the EPA. TSCA also prescribes that
the use, marking, and disposal of PCBs be strictly regulated by the EPA. Regulations issued
pursuant to TSCA require generator identification numbers and the manifesting of PCB wastes.
Also, some state Resource Conservation and Recovery Act of 1976 (RCRA) programs,
particularly in the area of disposal, place additional restrictions on the handling of PCBs.
In July 1992, the Tennessee Valley Authority (TVA), under a Western Area Power Authority
(WAPA) contract (Contract No. DE-A165-91WA 09429), conducted a preliminary
environmental assessment of the potential for PCB contamination of this and other Nevada
Power Company switchyards at this location. The report of this assessment, which included
sampling and analysis of transformer oils, noted that approximately 6,600 gallons of oil
containing PCBs were present onsite in seven circuit breakers, ranging in capacity from 600 to
2,200 gallons. Blue PCB labels on these circuit breakers indicated that PCBs were present in the
oil at concentrations under 50 ppm. An exception was one circuit breaker bushing which had a
yellow label, indicating PCB concentrations greater than 50 ppm. The Hazardous Material
Coordinator for Hoover Dam has indicated that these units have not been drained, and that
jurisdiction and responsibility for proper closure of the transformers/circuit breakers would lie
with WAPA (personal communication, Weaver, 1998).
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The TVA preliminary assessment also noted that one minor spill involving PCB-containing oil
occurred in 1990 at this location. The spill was remediated under the supervision of the
Phoenix office of WAPA. The assessment further evaluated the potential for PCBs at this
location to migrate into the environment. It was determined that the greatest threat to the
environment would come from storm-induced drainage through the site's lower switchyards
and culverts to the river. The potential hazards to the public and worker exposures via the soil
and air pathways was judged to be minimal (personal communication, Weaver, 1998).
3.10.1.2 Sugarloaf Mountain Alternative
Six potential hazardous waste sites exist on or adjacent to the Sugarloaf Mountain Alternative
corridor: the Reclamation warehouse storage yard; two staging areas used by contractors
during construction of the new visitor center; two disposal areas used during construction of
the new visitor center and during rehabilitation of U.S. 93 in the vicinity of the dam; an active
switchyard; and sewage evaporation ponds. Because the Sugarloaf Mountain and Promontory
Point alternatives both impact the Reclamation warehouse storage yard, the two contractor
staging areas, and one of me contractor disposal areas, environmental concerns are the same as
those discussed previously. The following sections address environmental concerns regarding
the active switchyard and the sewage evaporation ponds.
Active Switchyard. An active switchyard is located downgradient of the Sugarloaf Mountain
Alternative. Surface soils may have been affected by leaking transformers possibly containing
PCBs.
Sewage Evaporation Ponds. The Sugarloaf Mountain Alternative would cross two sewage
evaporation ponds. The two sewage evaporation ponds would need to be excavated, closed,
and relocated if the Sugarloaf Mountain Alternative is implemented. These ponds receive
sewage from the visitor center. No evidence exists to suggest that industrial wastewater has
been discharged to the ponds.
3.10.1.3 Gold Strike Canyon Alternative
One hazardous waste site, a spoil pile located in Nevada near the Colorado River, would be
impacted by the Gold Strike Canyon Alternative. The spoil pile is littered with metal shavings,
numerous 5-gallon and 55-gallon containers, concrete pillars, scrap metal, wood timbers, and
roofing material (that may contain asbestos). The spoil site is used as a practice range for the
police personnel working at the dam. Surface soils at this waste site could potentially be
contaminated from historical chemical releases. Because the spoil site is located downgradient
of this proposed alignment, roadway runoff could potentially carry and spread surface soil
contamination further downgradient of the waste site.
3,10.1.4 No Build Alternative
Should the No Build Alternative be selected, hazardous materials sites described above would
not be affected. No further testing or remediation would occur.
3.10.2 Environmental Consequences
3.10.2.1 Promontory Point Alternative
Reclamation Warehouse Storage Yard. To address environmental concerns at this site, it is
recommended that chemical usage, storage, and releases be investigated and documented.
Interviews of onsite personnel and internal record reviews, should be performed to determine
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locations and quantities of hazardous materials used and released in the storage yard. This
information can then be used to implement an investigation of soils that would be affected by
roadway construction. Soil samples should be taken in areas where discoloration, odors, or
known releases have occurred or are suspected. Soil should be monitored during excavation
activities to segregate contaminated soils.
Records documenting underground fuel tank removal should be reviewed to determine the
vertical and horizontal extent of contamination, location and quantity of contaminated soil
excavated, whether in situ remediation was implemented, and the cleanup standard attained.
This review will help determine where residual petroleum hydrocarbons could be encountered
during excavation and at what concentrations. Soil in the tank area should be monitored
during excavation to segregate contaminated soils.
If it is determined that chemicals used and stored at the warehouse were released to the
environment, or that residual petroleum hydrocarbons are present, contaminated soil may be
encountered during excavation and construction activities. Contaminated soils may pose
health and safety risks to construction workers and may require special handling, storage, and
disposal procedures according to applicable state and federal environmental regulations.
Contractor Staging and Disposal Areas. According to the Level I Contaminant Survey
(Reclamation, 1992a), contractors were responsible for cleaning staging areas. Documentation
reviews and personnel interviews should be conducted to determine whether releases had
occurred, the extent of contamination, and how the contamination was addressed. An
assessment will be conducted at the site to ensure that cleanup was conducted properly. Soil
sampling may be required if evidence (e.g., discolored soil, odors, stressed vegetation) suggests
that contamination may still be present. If contaminated soil is encountered before or during
construction activities, worker health and safety, as well as soil storage and disposal
procedures, may be affected.
During construction operations, some of the material in the two disposal areas may be
excavated and either recompacted or moved to another location. Prior to excavation, additional
sampling and testing may be required to confirm that no hazardous materials were disposed of
at these sites.
Dump Pile. To determine whether dump pile contamination has affected the proposed
alternative site, soil sampling should be conducted. Subsurface soil samples will determine
whether a plume of subsurface contamination has migrated from the dump pile to the
proposed alternative site. Excavation or remediation of affected soils may be required,
depending on contaminant types and concentrations. At a minimum, soil should be monitored
during excavation activities to segregate suspected contaminated soils. In addition, surface soil
samples will determine whether surface runoff has carried contaminants to the proposed
roadway site. Roadway runoff should be controlled by barrier use or by being diverted to
prevent future runoff from impacting the roadway site.
Abandoned Switchyard. To address environmental concerns at this site, surface soil samples
should be conducted before construction begins to determine whether oil or PCBs are present.
Affected soil should be removed and disposed of in accordance with applicable environmental
regulations. PCB-contaminated soil requires special cleanup and disposal procedures and may
pose health and safety risks to construction workers.
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Any PCBs remaining in the transformers at the abandoned switchyard would require proper
disposal prior to demolition or dismantling. In addition, per EPA Region DC PCB Spill Cleanup
Policy, any PCB-contaminated soil would need to be remediated to background levels (i.e.,
detection limits), where practicably attainable, for any PCB spill from a source greater than
50 ppm PCBs. In certain cases, the EPA, Region IX, will consider alternative cleanup levels.
Cleanup under the CERCLA of 1980 allows deviation from the Regional Policy when the reason
for deviation is included in the ROD.
3.10.2.2 Sugarloaf Mountain Alternative
Because the Sugarloaf Mountain and Promontory Point alternatives both impact the
Reclamation warehouse storage yard, the two contractor staging areas, and one of the
contractor disposal areas, measures to address environmental concerns at these sites are the
same as those discussed previously. The following sections discuss suggested measures to
address environmental concerns at the active switchyard and the sewage evaporation ponds.
Active Switchyard. Surface soil samples should be taken in areas where oil stains are observed
or leaks are suspected. These samples should be analyzed for PCBs. PCB-contaminated soil
requires special cleanup and disposal procedures and may pose health and safety risks to
construction workers. If PCB-contaminated soil is discovered in the switchyard, affected soil
should be removed and disposed of in accordance with applicable environmental regulations.
Alternately, if contaminated soils remain in place, roadway runoff should be controlled by
barrier use or by being diverted to prevent future runoff from spreading the contamination
downgradient of the yard.
Sewage Evaporation Ponds. It is expected that no industrial wastewater has been discharged to
the ponds; however, this should be verified through sludge and soil sampling. The two sewage
evaporation ponds would need to be excavated, dosed, and relocated if the Sugarloaf Mountain
Alternative is implemented. If industrial wastewater is discovered in the pond, contaminated
sludge or soils could impact worker health and safety as well as soil and sludge storage and
disposal procedures. The ADEQ should be contacted before pond excavation to determine
whether specific closure or material handling and disposal requirements apply.
3.10.2.3 Gold Strike Canyon Alternative
Because the Nevada Spoil Pile is located downgradient of the proposed alternative, roadway
runoff could potentially affect this waste site. Roadway runoff should be controlled through
barriers or diverted to prevent future runoff from spreading potential surface soil
contamination downgradient of the waste site.
3.10.2.4 No Build Alternative
Because there would be no effect, no mitigation is warranted.
3.10.3 Measures to Minimize Harm
To construct the proposed project, fuel must be used to power construction vehicles and
equipment and workers' vehicles. No state or local energy plans are in effect in the proposed
project area.
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Mitigation measures to reduce the amount of fuel used for construction and to maximize
efficiency are described below.
• A regular inspection and maintenance program for all vehicles and equipment should be
implemented. Inspection and maintenance are two distinct components, but they are
interrelated. Inspection would allow the construction contractor to identify potential
problems with vehicles or equipment, potentially reducing down time. Maintenance
should be performed during regular inspections to keep construction contractor's vehicles
and equipment in optimum condition.
• The construction contractor should plan construction vehicle and equipment staging
locations in proximity to usage areas to reduce the number and length of vehicle and
equipment trips.
• Vehicle and equipment use should be scheduled to maximize work efficiency.
« Equipment idling times should be minimized.
Any PCBs remaining in the transformers at the abandoned switchyard would require proper
disposal prior to demolition or dismantling. In addition, per EPA Region DC PCB Spill Cleanup
Policy, any PCB-contaminated soil would need to be remediated to background levels (i.e.,
detection limits), where practicably attainable, for any PCB spill from a source greater than
50 ppm PCBs. In certain cases, the EPA, Region DC, will consider alternative cleanup levels.
Cleanup under the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) of 1980 allows deviation from the Regional Policy when the reason for deviation is
included in the Record of Decision (ROD).
3.11 Construction Activities and impacts
This section presents activities and associated impacts that would occur during construction of
the build alternatives.
3.11.1 Construction Activities
Project construction activities would include the following:
• Earthwork (including clearing, grading, grubbing, embankment construction, batch plant
accommodation, fill, and erosion control activities)
* Removal or relocation of existing facilities
* Roadway approach construction (both Nevada and Arizona)
• Structure construction (bridges, tunnels, ramps, and walls)
* Roadway surfacing and barriers
• Existing traffic maintenance during construction
• Dust abatement
* Wildlife fencing, security fencing, and gates
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• Cross drainage culverts
• Signing and lighting
• Pavement marking and paint striping
• Landscaping and seeding
• Abandoned roadway obliteration
3.11.2 Construction Duration
Four separate construction contracts are expected for the proposed project: the Nevada
approach, the Arizona approach, the bridge, and completion activities. Table 3-22 shows
estimated construction times for the Promontory Point, Sugarloaf Mountain, and Gold Strike
Canyon Alternatives.
It is anticipated that Nevada and Arizona highway approach construction would occur
concurrently. Regardless of the alternative selected, the Arizona highway approach would be
completed before the Nevada highway approach.
Bridge construction would not begin until significant portions of the approach highways are
completed. Paving would not begin until the bridge and both highway approaches are
completed.
Table 3-22
Estimated Construction Period for Proposed Alternatives ,
Contract Promontory Point Sugarloaf Mountain Gold Strike Canyon
Nevada Approach
Arizona Approach
Bridge
Completion Activities
Total Construction Time
28 months
15 months
38 months
4 months
4 years, 9 months
34 months
23 months
36 months
4 months
4 years, 7 months
42 months
30 months
33 months
4 months
5 years, 3 months
Source: Reclamation, 1992. Colorado River Bridge—Hoover Dam, Arizona-Nevada.
Phase B—Corridor Studies. August.
Completion activities include paving the roadway and bridge, installing barriers and signs, and
finishing the tie-ins to the existing highway. Table 3-22 shows that these activities are
anticipated to require about 4 months, regardless of the alternative selected.
3.11.2.1 Promontory Point Alternative
This alternative would be located just south of existing U.S. 93 until it reaches the Reclamation
warehouse. Improvements to the existing highway to provide access to the project alternative
would occur. Project construction would not affect traffic operations on the existing highway,
except at the beginning of the alternative where the two roads cross near the warehouse.
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On the Nevada approach, it appears that a balance between cut and fill quantities can be
attained, and a waste disposal area would not be required. On the Arizona approach, one
waste disposal area would be required.
An electric transmission tower and an abandoned Western Area Power Administration
switchyard on the Nevada approach would need to be relocated. Relocation of any one
transmission tower may require additional work on adjoining towers of that particular line.
The highway and Nevada interchange affects the Reclamation warehouse storage yards and
possibly the warehouse.
No major detours, closures, or traffic delays are expected during construction of the highway
approaches. The existing highway could remain open with little interference except during the
tie-in activity at the beginning and end of the project. Completion of the frontage road in
Arizona is required before the existing highway could be dosed to the public. Hauling across
the existing Arizona highway would be necessary. Some delays could occur during blasting
operations associated with excavation above the existing highway.
3.11.2.2 Sugarloaf Mountain Alternative
This alternative follows the same corridor as the Promontory Point Alternative except at the
Reclamation warehouse area, where the alternative turns to the southeast. A new frontage road
would be constructed on the south side of the highway in Nevada. The frontage road would
provide dam access by passing beneath the new highway.
On the Nevada approach, it appears that a balance between cut and fill quantities can be
attained, and a waste disposal area would not be required. Hauling material for embankments
would be required. On the Arizona approach, all material excavated from Sugarloaf Mountain
is expected to be used to build roadway embankments-
Four electric transmission towers (three in Nevada and one in Arizona) would need to be
relocated. Two circuits spanning the Colorado River would need to be removed before bridge
construction. The highway and Nevada interchange affects the Reclamation warehouse storage
yards and possibly the warehouse.
The sewage evaporation ponds would be removed, and new ponds would need to be
reconstructed downhill to the east of the existing ponds.
No major detours, closures, or traffic delays are expected to occur during highway approach
construction. The existing highway could remain open with little interference except during
the tie-in activity at the beginning and end of the project. Hauling across the existing highway
in two locations would be necessary. Construction of the Nevada frontage road would
accommodate existing highway traffic during construction.
3.11.2.3 Gold Strike Canyon Alternative
This alternative would begin about 1,000 feet east of the Gold Strike Inn. The proposed
alternative would turn to follow Gold Strike Canyon toward the Colorado River.
Three waste disposal areas would be required on the Nevada approach to accommodate excess
waste material. One waste disposal area on the Arizona approach would be required.
No significant relocation of existing features has been identified for this alternative. The
proposed alternative would cross under several existing transmission lines; no existing
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transmission towers would be affected. Two existing wood pole electric lines (one in Nevada
and one in Arizona) cross the alternative, and some minor pole relocation may be necessary.
No major detours, closures, or traffic delays are expected during construction of the highway
approaches. The existing highway could remain open with little interference except during the
tie-in activity at the beginning and end of the project. Some improvements to the existing
Reclamation access road, including enlarging the old haul road tunnel, would be required. All
other Nevada construction access would be along the alternative from the beginning of U.S. 93.
The Gold Strike Canyon hiking trail would be dosed during construction, as the canyon bottom
would be graded and used as an access road. On the Arizona approach, construction access is
expected to be primarily along the alternative from U.S. 93 back toward the river.
3.11.3 Construction Impacts
Construction impacts are short-term and temporary, and cease when a project is operational.
Project construction impacts include affects on local air quality and ambient noise levels;
increased erosion; potential fuels or chemical spills; potential transportation and circulation
impacts; affects on vegetation, wildlife habitat, recreation, and cultural resources; disturbance
of special-status species; and affects on the area's visual resources. These impacts are discussed
in more detail in this chapter.
3.12 Energy
3.12.1 Construction Energy Usage
This section discusses the energy used to construct and operate the proposed project.
Construction and operation of the three build alternatives would require similar fuel
commitments. The No Build Alternative would not require fuel for construction.
The energy consumed to construct the proposed project can be estimated by making
assumptions about the following variables:
Construction cost of the alternative
Construction duration of the alternative
Number of construction workers traveling to and from the construction site
Number of trucks and pieces of equipment used
Efficiency of trucks and equipment (e.g., mpg)
Length of time trucks and equipment would be used
For this analysis, the energy consumed would be the fuel used for project trucks, construction
equipment, and workers' personal vehicles. Based on construction cost and duration, the
estimated number is 70 full-time-equivalent workers throughout each of the build alternative's
construction duration.
For the Promontory Point Alternative, fuel usage over the 4-year, 9-month construction period
is estimated at 500,000 to 800,000 gallons, or 400 to 640 gallons per day.
For the Sugarloaf Mountain Alternative, fuel usage over the 4-year, 7-month construction
period is estimated at 520,000 to 835,000 gallons, or 430 to 690 gallons per day.
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For the Gold Strike Canyon Alternative, fuel usage over the 5-year, 3-month construction
period is estimated at 560,000 to 900,000 gallons, or 400 to 650 gallons per day.
3.12.2 Operation Energy Usage
Primary energy usage during operation of the proposed highway and bridge would be fuel for
vehicles traveling over the roadway and structure. Because roadway and bridge inspection and
maintenance would require regular, but infrequent, trips to the area, energy usage for this
phase would be lower than for the construction phase, and is not considered significant.
Post-construction operational energy requirements are expected to be less per vehicle for the
three build alternatives than for the No Build Alternative because the existing traffic congestion
on U.S. 93 near Hoover Dam and atop the dam is expected to worsen as traffic volumes
increase. This condition would result in increasingly lower fuel efficiency of vehicles traveling
across Hoover Dam.
3.13 Local Short-term Uses versus Long-term Productivity
This section discusses the proposed project's short-term impacts resource use, and maintenance
and enhancement of long-term productivity. Construction and operation of the three build
alternatives would result in similar short- and long-term impacts and benefits. The following
sections discuss these impacts and benefits.
3.13.1 Short-term Uses of Man's Environment
Short-term project costs include the commitment of substantial financial and material resources.
Short-term uses of man's environment include project impacts considered significant and
temporary, including construction affects on local air quality; ambient noise levels; increased
erosion; potential fuel or chemical spills; potential transportation and circulation impacts;
affects on vegetation, wildlife habitat, recreation, and cultural resources; disturbance of
special-status species; and affects on the area's visual resources. Many of these impacts are
mitigated to less than significant levels.
Project construction impacts are discussed in more detail in this chapter. A benefit during the
construction phase would be the creation of construction-related employment.
3.13.2 Long-term Effects of the Proposed Project
Dedication for the proposed project would preclude opportunities for alternate land uses.
Long-term effects of the proposed project include changes in landforms, visual quality,
recreational opportunities, and localized hydrology; an increase in localized ambient noise
levels; reduction of open space; and a loss of vegetation and wildlife habitat.
Long-term benefits would include increased public safety at Hoover Dam resulting from traffic
reduction and commercial truck elimination, and improved travel speeds on U.S. 95 resulting in
time savings for personal vehicles. An additional benefit in U.S. 93 would become part of the
international trade route proposed by NAFTA.
U.S. 93 on the Arizona and Nevada approaches to Hoover Dam currently operates at LOS E.
The LOS at the dam is currently E If the No Build Alternative is implemented, both
3-102 RDD-SFQ/981890072.WPD(vh-ch3,wpd)
-------
CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
approaches and Hoover Dam will be at LOS F by year 2017. Constructing and operating the
proposed project would result in LOS E at Hoover Dam, LOS B at the Nevada approach in year
2017 and C for year 2027, and LOS A at the Arizona approach in year 2017 and B for year 2027.
3.13.3 Conclusion
The proposed transportation improvements would meet long-term needs identified in the
Nevada and Arizona state transportation plans. These plans consider present and future traffic
requirements based on existing and future intended land use patterns. The local short-term
project construction impacts, after mitigation is implemented, are acceptable in view of the
maintenance and enhancement of long-term productivity that would be provided for the local
area; for Nevada, Arizona, and Utah; and for international trade pursuant to NAFTA. In
addition, long-term benefits provided by the proposed bridge and roadway alternative are
anticipated to outweigh the long-term impacts of operating the facility.
3.14 Irreversible and Irretrievable Commitment of Resources
This section discusses the proposed project's irreversible and irretrievable commitment of
resources. Implementation of any of the build alternatives would require a commitment of
natural, physical, human, and fiscal resources. Construction and operation of any of the three
build alternatives would require a similar commitment of these resources. This discussion
focuses on the following issues:
• The project's use of non-renewable resources during the construction and operation of the
project. Included in this discussion are fossil fuels, highway construction materials,
electricity, water, and labor.
• The changes expected to occur as a result of the proposed project. These changes include
the commitment of land for the proposed project, physical changes in the environment,
effects on human populations, and fiscal changes.
3.14.1 Use of Non-Renewable Resources
As discussed in Section 3.12, construction of the proposed project would require the use of
fossil fuels for construction vehicles and equipment and construction worker vehicles.
Relatively minor amounts of electricity may also be used at construction trailers or by portable
generators during project construction. In addition, operation of the proposed project would
require the use of fossil fuels by vehicles traveling along the constructed alternative.
Both labor and highway construction materials, such as concrete, sand, aggregate, and steel,
would be expended during construction. Labor and natural resources would also be used in
the fabrication of construction materials. These materials generally are not retrievable. The use
of these materials and labor during project construction would not have an adverse effect on
the continued availability of these resources. Operation of the proposed project would result in
greater fuel efficiency of vehicles traveling on the newly constructed alternative when
compared to those vehicles traveling at slower speeds on the existing highway across Hoover
Dam.
RDD-SFO/981890Q72.WPD (vh-ch3.wpd) 3-103
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CHAPTER 3 AFFECTED ENVIRONMENT, ENVIRONMENTAL CONSEQUENCES, AND MEASURES TO MINIMIZE HARM
3.14.2 Expected Changes as a Result of the Proposed Project
Nevada and Arizona have committed land for use as a transportation corridor along U.S. 93.
The new Nevada and Arizona approaches would require the commitment of additional land to
construct and implement the proposed project. This additional commitment would result in
the loss of vegetation and wildlife habitat and foraging areas, and would affect special-status
species, wetlands, and wildlife dispersion opportunities.
Land used for the proposed project is considered an irreversible commitment during the period
land is used for the highway facility. If, in the future, a greater need arises for use of the land,
or if the highway facility is no longer needed, the land could be converted to another use.
However, it is not likely that once the proposed project is constructed such a conversion would
ever be necessary or desirable.
As discussed in Section 3.7, Visual Resources, the alteration of the landscape where the
proposed project is constructed would be considered an irreversible environmental change.
Although the proposed bridge and new alternative could be removed and the land converted
to another use in the future, it is neither likely that such conversion would occur, nor is it likely
that the landscape would return to its pre-project condition.
Construction of the proposed project would generate jobs for the approximately 4- to 5-year
construction period. During construction, labor would be needed to build the proposed bridge
and roadway and to fabricate construction materials. Long-term maintenance of the proposed
project would also generate jobs.
Construction of the proposed project would require a substantial one-time expenditure of
federal and possibly state funds, which are not considered retrievable. Long-term facility
maintenance costs are also not retrievable. A slight decrease in the amount of expenditures at
the two concession stands on die dam may result from fewer vehicles traveling across the dam
after the new roadway and bridge are constructed. No change in expenditures in Phoenix or
Kingman, Arizona, or Las Vegas, Boulder City, or Henderson, Nevada, are expected from
implementation of the proposed project. No change in highway taxes are expected from the
proposed project.
3.14.3 Conclusion
Tourists, residents, and die commercial trucking industry of Clark County, Mohave County,
and throughout Nevada, Arizona, and Utah would benefit by die proposed improvements to
die transportation system. These benefits consist of increased public safety at Hoover Dam by
reducing die amount of traffic on tine dam and eliminating commercial trucks from it; and
improved travel speeds on US. 93, resulting in a time savings and reduction in transit costs for
commercial trucks and a time savings for personal vehicles traveling between Phoenix and Las
Vegas. In addition, roadway improvements would allow die U.S. 93 corridor to be part of die
international trade route proposed by NAFTA. These benefits are anticipated to outweigh die
commitment of die above-listed natural and fiscal resources.
RDD-SFO/98t890072.WPD(vh-ch3.wpd)
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CHAPTER 4
Unavoidable Adverse Impacts
4.1 introduction
Some impacts to specific resources were evaluated for each build alternative and the No Build
Alternative, while others were evaluated regionally. Where data were available for each
alternative and affects differed, individual alternative analyses were performed.
Constructing and operating any build alternative would irreversibly and irretrievably commit
environmental resources to the project. An irreversible commitment is the permanent loss of the
resource.
4.2 Air
After implementing construction mitigation measures, no further adverse impacts were
identified. As a result of implementing one of the proposed alternatives, a beneficial impact
would occur because air quality is expected to improve in the proposed project area during
operations. Because of increased traffic, air quality in the Hoover Dam vicinity would decrease
if the No Build Alternative were selected.
4.3 Noise
Even with mitigation measures, the Gold Strike Canyon Alternative will still exceed standards at
the upper end of the canyon on the hiking trail. Noise is higher for the No Build Alternative
than for any of the build alternatives at the dam crossing.
4.4 Biological Resources
Implementing any build alternative could result in the loss of 122 to 143 acres of wildlife habitat
(see Table 3-13), including associated vegetation and either the displacement of, or direct loss of,
associated wildlife. Partial recovery of some of these losses may be attained through the
mitigation measures described in Chapter 3, Measures to Minimize Harm. Implementation of
the build alternatives will result in 0.66 to 2.77 acres of temporary fill and 0.08 to 0,67 acres of
permanent fill in waters of the United States.
4.5 Water Resources
For the proposed alternatives, constructing the roadway will increase both short-term and long-
term sediment yield over existing conditions. Removing existing vegetative and rock cover will
disturb existing conditions, increasing the sediment yield and impacting local, and to a lesser
extent, regional water quality. Using BMPs will reduce this impact but will not eliminate it
totally.
RDD-SFO/981410008.WPD (chap4.wpd) 4-1
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CHAPTER 4 UNAVOIDABLE ADVERSE IMPACTS
4.6 Archaeological Resources
4.6.1 Promontory Point Impacts
Unavoidable adverse impacts would occur from the introduction of visual elements that would
be out of character with the historic setting of Hoover Dam. Earlier consultations among the
Nevada and Arizona SHPOs, the NPS, and the Advisory Council on Historic Preservation
suggest that these impacts cannot be mitigated. Based on the preliminary design, the
Promontory Point Alternative may result in unavoidable adverse impacts to sites 26-CK-4751 -
4753, -4754, -4763, and -4765.
Unavoidable adverse impacts would occur to prehistoric archaeological site NV:DD:14:23, and
probably to site NV:DD:14:25. These impacts would occur during construction for the former
and operations for the latter.
4.6.2 Sugarloaf Mountain Impacts
Unavoidable adverse impacts would occur from the introduction of visual elements that would
be out of character with the historic setting of Hoover Dam. Earlier consultations among the
Nevada and Arizona SHPOs, the NFS, and the Advisory Council on Historic Preservation
suggest that these impacts can be mitigated through project design. Based on the preliminary
design, the Sugarloaf Mountain Alternative may result in unavoidable adverse impacts to sites
AZ:NV:DD:14:1,26-CK-4751, and -4765.
Unavoidable adverse impacts would occur to prehistoric archaeological sites NV:DD;14:21 and
NV:DD:14:22 from construction of this alternative.
4.6.3 Gold Strike Canyon Impacts
Based on the preliminary design, the Gold Strike Canyon Alternative may result in unavoidable
adverse impacts to sites NV:DD:14:15,26-CK-4742, -4748, and -4750.
Since no archaeological sites were identified along this alternative, no unavoidable adverse
impacts are expected.
4.7 Land Use
No unavoidable adverse impacts are identified for any of the three build alternatives. If the No
Build Alternative is selected, changes in land use would not occur.
4-2 RDD-SFO/981410008.WPD(chap4.wpd)
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CHAPTER 5
Cumulative Impacts
Cumulative impacts associated with the proposed project would be those which, in
conjunction with impacts due to other projects either in the immediate vicinity or with
similar characteristics, would have the potential to collectively result in adverse effects to the
environment that are of greater significance than those generated individually by the
proposed project. Cumulative impacts could include those effects which may be considered
to be less than significant individually, but which could become significant when evaluated
in relation to impacts from other projects.
The Council on Environmental Quality (CEQ) defines cumulative impact as "the impact on
the environment which results from the incremental impact of the action when added to
other past, present, and reasonably foreseeable future actions regardless of what agency
(Federal or non-Federal) or person undertakes such other actions. Cumulative impacts can
result from individually minor but collectively significant actions taking place over a period
of time" (40 CFR 1508.7).
Following is a list and discussions of the reasonably foreseeable actions that have been
evaluated for their potential to contribute to the cumulative effects associated with the
proposed project:
• Nevada Department of Transportation (NDOT) Statewide Transportation Improvement
Program (STIP)
• Boulder City Bypass Project
• Arizona State Transportation Improvement Program (ASTIP)
5.1 Nevada STIP
Studies for a Hoover Dam bypass project have been included in the NDOT's 1998-STTP. In
addition, construction of a bypass has been listed as one of six projects in NDOT's Highway
Superproject Program and is shown in NDOT's Work Program - Long Range Element (1998
through 2007). Although certain elements of the construction of the identified STTP projects
(e.g., the Boulder City Bypass) may overlap with those of the Hoover Dam Bypass project,
resulting in temporary localized impacts (e.g. air quality, traffic, noise, etc.), these impacts
will be individually mitigated on a project-by-project basis. Consequently, they are not
anticipated to result in a regionally significant cumulative impact in conjunction with those
associated with the Hoover Dam Bypass project. Operation of STIP projects and the Hoover
Bypass project will work together to ease such regional impacts as traffic congestion and
traffic-related air emissions.
RDD-SFO/98141Q012.WPD (crchapS.wpd) 5-1
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Appendix A
Traffic Analysis
RDD/SFO-981420008.WPD (cr-cov,wpd)
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-------
APPENDIX A
Traffic Analysis
Introduction
The purpose of this report is to summarize traffic forecast updates and operational analysis
for the Hoover Dam Bypass EIS. The work is being administered by the Central Federal
Lands Highway Division (CFLHD) of the Federal Highway Administration (FHWA).
The study includes two traffic elements. The first element is an update of current forecasts
and development of more comprehensive traffic operational data for the three relatively
close new Colorado River Crossings. The updated information is used for impact definition
and mitigation planning. The second element is the evaluation of a Laughlin Crossing
Alignment (LCA) {see DEIS Appendix B).
Traffic Forecast Update
Traffic forecast updates have been completed using historic traffic count information
available from ADOT and NDOT. Additional traffic counts or surveys were not included in
the scope of this work. Key assumptions for traffic forecast updates are:
• AADT data from NDOT and ADOT are the most current references to update traffic
forecasts.
• The two sets of data showing different growth rates and forecasts on the east
(NDOT Sta 03-222 and ADOT MP 20.50) and west side (NDOT Sta 03-221) of the
Colorado River should be used to develop different traffic growth rates for those
locations. This is consistent with the fact that traffic west of the Colorado River is
influenced by regional development in Las Vegas and associated tourism, and traffic
east of the Colorado River is influenced more by interstate trade and tourism.
• Long-range traffic forecasts will have the strongest correlation to the last 15 years of
growth. Using this long of a study period will help identify and average out high and
low years. It will also allow us to evaluate long-term and interim conditions that help
prevent a "radical" forecast.
• Traffic on Hoover Dam should reflect a volume that is between the western and eastern
forecasts.
Further details, calculations, and graphs showing traffic growth and traffic diversion for the
LCA Alternative are attached to the end of this report.
No Build Traffic Forecasts
Based on the above scope and assumptions, Average Annual Daily Traffic (AADT) draft
forecasts for no build conditions have been developed as follows.
RDD-SFO/981410Q12.WPD (CLR234.WPD) A-1
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APPENDIX A TRAFFIC ANALYSIS
AADT West of Colorado River. Traffic growth is forecasted at an uncompounded (straight
line) rate of 5.0 percent per year.
The last 15 years of traffic data at NDOT Station 3-0222, VS. 93,0.6 miles south of Lake
Shore Road show a 5.79 percent average annual rate (straight line) of traffic growth as
compared to our '92 forecasted average annual rate of 4.14 percent. While 5.79 percent
average growth per year might seem high, it has been sustained over a significant period
of time. Based on this more current data, the previous '92 forecasted growth is low. For
the purposes of this study, the approximate average, or 5.0 percent from the year 1996 is
used to forecast future traffic growth.
Traffic forecasts west of the Colorado River reflect a location prior to eastbound traffic
having a choice of using a the existing Dam crossing or a new Bridge. It can be assumed
that title majority of this traffic is originating from locations near or northwest of Las
Vegas and is destined for the Hoover Dam or locations east of Kingman. As shown in
Figure A-l, forecasts are:
• Year 1997 forecast = 12,600 (1+0.05) = 13,230, use 13,200
• Year 2017 forecast = 12,600 (1+0.05*21) = 25,830, use 25,800
• Year 2027 forecast = 12,600 (1+0.05*31) = 32,130, use 32,100
AADT East Of Colorado River. Traffic growth is forecasted at an uncompounded (straight
line) rate of 4.0 percent per year.
The last 15 years show a 7.46 percent average annual (straight line) rate of traffic growth
as compared to our '92 forecasted average annual rate of 3.6 percent. This rate is high
due to a recent five year traffic growth explosion over 9.4 percent average per year.
During this period the highest single year was 36 percent. The last 5 years also included
a reduction of traffic by 27.9 percent from 1995 to 1996. Using NDOT data that exclude
the last 5 years, growth is 4.35 percent.
Given the volatile nature of traffic growth over the last 5 years at this location, counts
from ADOT east of the dam were reviewed. These data show traffic growth of 3.7
percent for the last 10 years. Data from 1981 through 1986 were not included because the
total volume was too low to reflect sustainable growth rates.
Based on both NDOT and ADOT data, a 4 percent average annual growth rate for
growth east of the Colorado River is projected.
Traffic forecasts east of the Colorado River reflect a location prior to westbound traffic
having a choice of using a the existing Dam crossing or a new Bridge. It can be assumed
that the majority of this traffic is originating from locations in east of Kingman and
destined for locations near or northwest of Las Vegas. As shown in Figure A-2, forecasts
for this location are:
• Year 1997 forecast = 8,900(1+0.04) = 9,256, use- 9,300.
• Year 2017 forecast = 8,900(1+0.04*21) = 16,376, use- 16,400.
• Year 2027 forecast = 8,900(1+0.04*31) = 19,936, use-19,900.
A-2 RDD-SFO/981410012.WPD(CLR234.WPD)
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APPENDIX A TRAFFIC ANALYSIS
AADT on Hoover Dam. Traffic on Hoover Dam is more directly proportional to traffic
west of the Dam than traffic east of the Dam. Traffic east will be lower than the total
traffic west of the Dam because all Hoover Dam destined trips are not expected to drive
over the Dam itself. The reason for this change from previous conditions is that the new
visitor center parking garage is located west of the Dam.
It is assumed that half the current traffic parks at the new parking garage. This is a
reasonable estimate because the new garage represents over half the parking available in
the area. Given this assumption, traffic (AADT volumes) on the Dam would be
(13,200-9,300)72+9300=11,450. Forecasts for the years 2017 and 2027 are 21,100 and
26,000, respectively. NDOTs most recent AADT projections southeast of the Dam are
17,800 and 22,100 for the years 2017 and 2027, respectively. Since the NDOT forecasts
are consistent with our forecasts east of the river and on the Dam, so the following
volumes are used as AADT forecasts at Hoover Dam:
• Year 1997 forecast = 11,500
• Year 2017 forecast = 21,100
• Year 2027 forecast = 26,000
Build Alternative Traffic Forecasts
Starting with the No Build forecasts, traffic forecasts for build alternatives have been
developed on the following assumptions.
• Truck traffic will be prohibited from using the Dam crossing.
• Since they are relatively close to each other, the three new crossings closest to Hoover
Dam should not have significant differences in traffic demands. Therefore, forecasts for
those alternatives are the same.
• The Laughlin Alternative will not significantly attract private auto trips from Hoover
Dam until traffic congestion on the existing U.S. 93 Colorado River crossing on the Dam
consistently creates delays that are equal to the additional driving time. This delay time
due to traffic congestion on the Dam is estimated at 30 minutes. Operating conditions
will need to be at LOS F for at least one-half hour for the delay to approach 30 minutes.
• Traffic Origins and Destinations have not changed significantly since the Traffic Study at
Hoover Dam, 1991, or since the update for the Traffic and Revenue Study, 1992. Key
items from those studies show that all trips using the Dam are to and from the Las Vegas
area and to and from southeast and east of Kingman.
• The crossings closest to Hoover Dam will provide an opportunity for trips from Las
Vegas to Hoover Dam to circulate locally on a new Colorado River bridge. This could
reduce the total number of tourist trips on the Dam originating during times of traffic
congestion.
Given these assumptions, AADT draft forecasts for build alternatives have been developed
as follows.
RDD-SFO/98141Q012.WPD (CLR234.WPD) A-3
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APPENDIX A TRAFFIC ANALYSIS
Key Locations. Key locations for AADT forecasts of these alternatives include the three
for the No Build conditions and a new Colorado River crossing. The approach for
making these forecasts is to distribute all traffic east of the river to the new crossing, and
to distribute the remaining traffic to the existing Dam crossing. This approach may seem
simplistic because it assumes all traffic currently east of the Dam is through traffic that
does not stop at tihe Dam, but is the most accurate given available data. It is noted that
this approach is also consistent with current Hoover Dam visitor travel characteristics.
AADT West of Colorado River
• Year 1997 forecast = 13,200
• Year 2017 forecast = 25,800
• Year 2027 forecast = 32,100
AADT on Hoover Dam
• Year 1997 forecast = 3,900
• Year 2017 forecast = 9,400
• Year 2027 forecast = 12,200
AADT East of Colorado River
• Year 1997 forecast = 9,300
• Year 2017 forecast = 16,400
• Year 2027 forecast = 19,900
AADT on New Bridge
• Year 1997 forecast = 9,300
• Year 2017 forecast = 16,400
• Year 2027 forecast = 19,900
Traffic Analysis
Analysis of traffic operations for existing conditions, build alternatives based on HCS
methods and procedures. Key factors for the analysis include:
Peak Hour of AADT = 9%
Percentage of Trucks = 18%
Percentage of Buses = 2%
Percentage of RVs = 4%
Peak Hour Factor = 95%
Directional Distribution = 95%
All new alignments will have four lanes.
Further details and HCS calculations forms are attached to the end of this report.
A-4 RDD-SFO/981410012.WPD(CLR234.WPD)
-------
-------
-------
1985 HCM:TWO-LANE HIGHWAYS
FACILITY LOCATION US 93 on Dam
ANALYST TKR
TIME OF ANALYSIS..... All
DATE OF ANALYSIS..... 05-21-1998
OTHER INFORMATION.... Build
A) ADJUSTMENT FACTORS
PERCENTAGE OF TRUCKS 0
PERCENTAGE OF BUSES 2
PERCENTAGE OF RECREATIONAL VEHICLES 4
DESIGN SPEED (MPH) 50
PEAK HOUR FACTOR 95
DIRECTIONAL DISTRIBUTION (UP/DOWN) . 53/47
LANE WIDTH (FT) 11
USABLE SHOULDER WIDTH (AVG. WIDTH IN FT.)... 2
PERCENT NO PASSING ZONES 100
B) CORRECTION FACTORS
MOUNTAINOUS TERRAIN
E E E f . f
LOS T B R w d
A
B
C
D
E
C) LEVEL OF
7
10
10
12
12
SERVICE
5.7 5 .75 .98
6 5.2 .75 .98
6 5.2 .75 .98
6.5 5.2 .75 .98
6-5 5.2 .88 .98
RESULTS
f
HV
.8
.79
.79
.78
.78
INPUT VOLUME(vph): 1000
ACTUAL FLOW RATE: 1053
SERVICE
LOS FLOW RATE V/C
A
B
C
D
E
16
163
260
532
1477
.01
.1
.16
.33
.78
LOS FOR GIVEN CONDITIONS: E
-------
1985 HCM:TWO-LANE HIGHWAYS
FACILITY LOCATION US 93 on Dam
ANALYST TKR
TIME OF ANALYSIS All
DATE OF ANALYSIS 05-19-1998
OTHER INFORMATION No Build
A) ADJUSTMENT FACTORS
PERCENTAGE OF TRUCKS , 18
PERCENTAGE OF BUSES » 2
PERCENTAGE OF RECREATIONAL VEHICLES 4
DESIGN SPEED (MPH) 50
PEAK HOUR FACTOR 95
DIRECTIONAL DISTRIBUTION (UP/DOWN) 53/47
LANE WIDTH (FT) 12
USABLE SHOULDER WIDTH (AVG. WIDTH IN FT.)... 2
PERCENT NO PASSING ZONES 100
B) CORRECTION FACTORS
MOUNTAINOUS TERRAIN
E E E f f
LOS T B R w d
A
B
C
D
E
C) LEVEL OF
7
10
10
12
12
SERVICE
5.7 5 .81 .98
6 5.2 .81 .98
6 5.2 .81 .98
6.5 5.2 .81 .98
6.5 5.2 .93 .98
RESULTS
f
HV
.43
.35
.35
.31
.31
INPUT VOLUME(vph): 1000
ACTUAL FLOW RATE: 1053
SERVICE
LOS FLOW RATE V/C
A
B
C
D
E
LOS FOR GIVEN CONDITIONS: F
10
77
123
226
612
.01
.1
.16
.33
.78
-------
1985 HCM;TWQ-LANE HIGHWAYS
FACILITY LOCATION.... S 93 East and west of Dam
ANALYST TKR
TIME OF ANALYSIS..... All
DATE OF ANALYSIS 05-19-1998
OTHER INFORMATION.... NO Build
A) ADJUSTMENT FACTORS
PERCENTAGE OF TRUCKS 18
PERCENTAGE OF BUSES 2
PERCENTAGE OF RECREATIONAL VEHICLES '. '. '. 4
DESIGN SPEED (MPH) 60
PEAK HOUR FACTOR 95
DIRECTIONAL DISTRIBUTION (UP/DOWN) 53/47
LANE WIDTH (FT) 12
USABLE SHOULDER WIDTH (AVG. WIDTH IN FT.)... 6
PERCENT NO PASSING ZONES 50
B) CORRECTION FACTORS
ROLLING
LOS
A
B
C
D
E
C) LEVEL OF
TERRAIN
E
T
4
5
S
5
5
SERVICE
E
B
2
3.4
3.4
2.9
2.9
RESU
E
R
3.2
3.9
3.9
3.3
3.3
LTS
f f f
w d HV
1 .98 .5
1 .98 .53
1 -98 .53
1 ,98 .54
1 .98 .54
INPUT VOLUME(vph): 1000
ACTUAL FLOW RATE: 1053
SERVICE
LOS FLOW RATE V/C
A
B
C
D
E
115
277
511
773
1367
.07
.19
.35
.52
.92
LOS FOR GIVEN CONDITIONS: E
-------
1985 HCM:TWO-LANE HIGHWAYS
FACILITY LOCATION S 93 East and West of Dam
ANALYST TKR
TIME OF ANALYSIS All
DATE OF ANALYSIS..... 05-19-1998
OTHER INFORMATION LCA Alt
A) ADJUSTMENT FACTORS
PERCENTAGE OF TRUCKS 0
PERCENTAGE OF BUSES 2
PERCENTAGE OF RECREATIONAL VEHICLES 4
DESIGN SPEED (MPH} 60
PEAK HOUR FACTOR 95
DIRECTIONAL DISTRIBUTION (UP/DOWN) 53/47
LANE WIDTH (FT) , 12
USABLE SHOULDER WIDTH (AVG. WIDTH IN FT.) ... 6
PERCENT NO PASSING ZONES 50
B) CORRECTION FACTORS
ROLLING TERRAIN
E
LOS T
A
B
C
D
E
C) LEVEL
4
5
5
5
5
OF SERVICE
E
B
3
3.4
3.4
2.9
2.9
E
R
3.2
3.9
3.9
3.3
3.3
f f f
w d HV
1 .98 .89
1 .98 .86
1 .98 .86
1 .98 '.88
1 .98 .88
RESULTS
INPUT VOLUME(vph): 1000
ACTUAL FLOW RATE: 1053
SERVICE
LOS FLOW RATE V/C
A
B
C
D
E
171
449
827
1265
2239
.07
.19
.35
.52
.92
LOS FOR GIVEN CONDITIONS: D
-------
HCS: Multilane Highways Release 2.1
File Name
Facility Section
US 93 West of Dam
From/To
Analyst
TKR
Time of Analysis
2017
Date of Analysis
05/19/98
Other Information.... Build close in
A. Adjustment Data
Direction 1 Direction 2
Volume
Percentage of Trucks and Buses
Percentage of Recreational Vehicles
Ideal Free-Flow Speed
Peak-Hour Factor or Peak 15 Minutes
Lane Width
Access Points per Mile
Distance from Roadway Edge
Type of Median
B. Adjustment Factors
E E F
Terrain Type T R HV
ROLLING 3.00 2.00 0.69
3.00 2.00 0.69
C. Level of Service Results
Service Flow Rate (Vp)
Average Passenger Car Speed (mph)
Free Flow Speed (mph)
Density {pcpmpl)
Level of Service (LOS)
1230
20.0
4.0
60.0
0.95
12.0
4.0
6.0
U
F F
M LW
1.60 0.00
1.60 0.00
Direction 1
932
57
57
16
B
1090
20.0
4.0
60.0
0.95
12.0
4.0
6.0
U
F F
LC A
0.00 1.00
0.00 1.00
Direction 2
826
57
57
14
B
-------
HCS: Multilane Highways Release 2.1
File Name
Facility Section
. US 93 West of Dam
From/To
Analyst
TKR
Time, of Analysis
2027
Date of Analysis
05/19/98
Other Information.... Build close in
r**************
A. Adjustment Data
Direction l Direction 2
Volume
Percentage of Trucks and Buses
Percentage of Recreational Vehicles
Ideal Free-Flow Speed
Peak -Hour Factor or Peak 15 Minutes
Lane Width
Access Points per Mile
Distance from Roadway Edge
Type of Median
B. Adjustment Factors
E E F
Terrain Type T R HV
ROLLING 3.00 2.00 0.69
3.00 2.00 0.69
C. Level of Service Results
Service Flow Rate (Vp)
Average Passenger Car Speed (mph)
Free Flow Speed (mph}
Density (pcpmpl)
Level of Service (LOS)
1530
20.0
4.0
60.0
0.95
12.0
4.0
6.0
U
F F
M LW
1.60 0.00
1.60 0.00
Direction 1
1160
57
57
20
C
1360
20.0
4.0
60.0
0.95
12.0
4 . Q
6.0
U
F F
LC A
0.00 1.00
0.00 1.00
Direction 2
1031
57
57
18
B
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HCS: Multilane Highways Release 2.1
File Name
Facility Section
US 93 East of Dam
From/To
Analyst
TKR
Time of Analysis
2017
Date of Analysis
05/19/98
Other Information.... Build close in
A. Adjustment Data
Direction 1 Direction 2
Volume
Percentage of Trucks and Buses
Percentage of Recreational Vehicles
Ideal Free -Flow Speed
Peak-Hour Factor or Peak 15 Minutes
Lane Width
Access Points per Mile
Distance from Roadway Edge
Type of Median
B. Adjustment Factors
E E F
Terrain Type T R HV
ROLLING 3-00 2.00 0.69
3.00 2.00 0.69
2, Level of Service Results
Service Flow Rate (Vp)
Average Passenger Car Speed {mph)
Free Flow Speed {mph)
Density (pcptnpl)
Level of Service (LOS)
780
20.0
4.0
60.0
0.95
12.0
4.0
6.0
U
F F
M LW
1.60 0.00
1.60 0.00
Direction 1
591
57
57
10
A
695
20.0
4.0
60.0
.
0.95
12.0
4.0
6.0
U
F F
LC A
0.00 1.00
0.00 1.00
Direction 2
527
57
57
9
A
-------
HCS: Multilane Highways Release 2.1
File Name
Facility Section
US 93 East of Dam
From/To. ..
Analyst
TKR
Time of Analysis
2027
Date of Analysis
05/19/98
Other Information.... Build close in
A. Adjustment Data
Direction 1 Direction 2
Volume
Percentage of Trucks and Buses
Percentage of Recreational Vehicles
Ideal Free -Flow Speed
Peak-Hour Factor or Peak 15 Minutes
Lane Width
Access Points per Mile
Distance from Roadway Edge
Type of Median
B. Adjustment Factors
E E F
Terrain Type T R HV
ROLLING 3.00 2.00 0.69
3.00 2.00 0.69
C. Level of Service Results
Service Flow Rate (Vp)
Average Passenger Car Speed (mph)
Free Flow Speed (mph)
Density (pcpmpl)
Level of Service (LOS)
950
20.0
4.0
60.0
0.95
12.0
4.0
6.0
U
F F
M LW
1.60 0.00
1.60 0.00
Direction 1
720
57
57
13
B
840
20.0
4.0
60.0
0.95
12.0
4.0
6.0
U
F F
LC A
0.00 1.00
0.00 1.00
Direction 2
637
57
57
11
A
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Laughlin-Bullhead City Alternative
1, Introduction
The project management team (PMT) was requested, through the public outreach process
and by the Laughlin Town Advisory Board, to address the feasibility of the
Laughlin-Bullhead City Alternative (LBA) as an alternative route for the proposed Hoover
Dam Bypass project. This report defines the segment designations along the corridor and
presents a preliminary cost estimate, engineering and traffic considerations, operational
costs, and environmental issues associated with the proposed LBA corridor. This report,
along with other documentation included in the Hoover Dam Environmental Impact
Statement (EB) document, will be used to evaluate the overall feasibility of the LBA
alignment.
2. Description of Alternative
This alternative uses existing U.S. Highway 95 (U.S. 95), Nevada State Route 163 (SR163),
and Arizona State Route 68 (SR 68) (Figure B-l). Portions of these facilities would be
widened to create a four-lane highway, and a new multispan bridge would be constructed
across the Colorado River between Davis Dam to the norm and the existing Laughlin Bridge.
Existing roads along the LBA corridor would be overlaid with additional pavement to
accommodate the additional traffic diverted from U.S. 93.
The length of the facility from the U.S. 93/U.S. 95 Interchange (1C) near Boulder City,
Nevada, to Laughlin, Nevada, is approximately 75 miles, of which approximately 20 miles
are existing four-lane divided highway. For the 55 miles of two-lane section along U.S. 95, a
parallel set of lanes would be built adjacent to the existing lanes. A typical section has been
prepared to depict this proposed roadway section (Figure B-2). The length of the facility
between Bullhead City and SR 68/U.S. 931C in Arizona is approximately 28 miles, of which
approximately 13.5 miles are existing four-lane divided highway. Arizona Department of
Transportation (ADOT) has plans to widen the remaining 14.5 miles on SR 68 to four lanes,
so this study will not address the widening required on SR 68.
The project has been divided into segments for this study for the purposes of estimating
costs. These segments are described in Table B-l.
RDD-SFO/{Appb.wpd)
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1. Introduction
Purpose of Section 4(f) Evaluation
Section 4(f) of the U.S. Department of Transportation Act of 1966, codified in Federal law at
49 U.S.C. § 303, declares that, "it is the policy of the United States government that special
effort should be made to preserve the natural beauty of the countryside and public park and
recreation land, wildlife and waterfowl refuges, and historic sites." Section 4(f) specifies that,
"the Secretary [of Transportation] may approve a transportation program or project...
requiring the use of publicly owned land of a public park, recreation area, or wildlife and
waterfowl refuge of national, State, or local significance (as determined by the Federal, State,
or local officials having jurisdiction dver the park, area, refuge, or site) only if—
"1. There is no prudent and feasible alternative to using that land; and
2. The program or project includes all possible planning to minimize harm
to the park, recreation area, wildlife and waterfowl refuge, or historic
site resulting from the use."
The use of Section 4(f) resources occurs when: (1) land from Section 4(f) site is permanently
acquired for a transportation project, (2) when there is a temporary occupancy of land that is
adverse in terms of the statute's preservation purpose, or (3) when the proximity impacts of
the transportation project on the Section 4(f) site, without acquisition of land, are so great
that the purpose for which the Section 4(f) site exists are substantially impaired. The latter
type of use is also known as a "constructive use." Constructive use occurs when the
transportation project does not incorporate land from a Section 4(f) resource, but the project's
proximity impacts are so severe that the protected activities, features, or attributes that
qualify a resource for protection under Section 4(f) are substantially impaired. Constructive
use has been determined to occur under the following cases potentially applicable to this
project [23 CFR 771.135(p)J:
1. The projected noise level increase attributable to the project substantially interferes with
the use and enjoyment of a noise-sensitive facility of a resource protected by Section 4(f).
2. The proximity of the proposed project substantially impairs aesthetic features or
attributes of a resource protected by Section 4(f), where such features or attributes are
considered important contributing elements to the value of the resource.
3. The project results in a restriction on access which substantially diminishes the utility of a
significant publicly owned park, recreation area, or historic site.
4. The ecological intrusion of the project substantially diminishes the value of wildlife
habitat in a wildlife or waterfowl refuge adjacent to the project or substantially interferes
with the access to a wildlife or waterfowl refuge, when such access is necessary for
established wildlife migration or critical life cycle processes.
Section 4(f) is applicable to historic sites and archaeological resources when the resource is
included on, or eligible for, the National Register of Historic Places (NRHP) [23 CFR
771.135(e)]. Section 4(f) does not apply to archaeological sites where it is determined after
consultation with the State Historic Preservation Officer and the Advisory Council on
RDD-SFO/981180002.WPD (InbApE-1.wpd) 1-1
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EXPUNARN
0
— ApprwidBicteowtiyRc*!
— UWWBoundry
FIGURE C-2
LAKE MEAD NATIONAL
RECREATION AREA
HOOVER DAM BYPASS PflOIECT
ENVIROIiMALIMPACTSTATEMEM
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4. Impacts on the Section 4(f) Properties
As defined in the introduction, the use of a Section 4(f) resource occurs either when land from a
Section 4(f) site is permanently acquired for a transportation project, when temporary occupancy
has adverse effects, or when the proximity impacts of the project on the Section 4(f) site are so
great that the purposes for which the Section 4(f) site exists are substantially impaired. The
Hoover Dam Bypass project alternatives would impact two Section 4(f) properties: the Lake
Mead National Recreation Area, which is a federal public park and recreation land, and the
Hoover Dam National Historic Landmark, which is listed in the National Register of Historic
Places. No wildlife or waterfowl refuges are located in the vicinity of the proposed project.
Furthermore, no archaeological or cultural sites requiring preservation in place have been
identified to date within the project's area of potential effects. Impacts on Section 4(f) lands are
shown graphically in Figure C-l. The permanent and constructive uses of Section 4(f) lands are
summarized in the table on Figure C-l.
Sugarloaf Alternative
The Section 4(f) properties and/or resource values were identified and assessed for potential
impact by the Sugarloaf Alternative. The following summarizes the results of that effort. (A
more detailed description of these analyses and conclusions can be found in Chapter 4 of the
Park Land and Recreation
As stated previously, the Sugarloaf Alternative would permanently use 59.7 acres of Section 4(f)
land (47.3 acres within the LMNRA and 12.4 acres within the HDNHL) (see Figure G-l). The
Sugarloaf Alternative would not directly impact any recreational facility or resource located
within Section 4(f) land. During construction, the noise of construction and presence of heavy
equipment would temporarily lower the aesthetic experience for some visitors at the dam and in
the area; however, others would find the construction operation interesting. Undesignated trail
use regulations within the LMNRA might need to be adjusted to accommodate construction
activities, but these inconveniences would be minor and relatively short term. Following
construction and the subsequent diversion of traffic off the dam to the new bridge,
vehicle-derived noise and exhaust fumes would be removed from the dam, thereby improving
conditions for dam visitors. The new bridge could become a tourist attraction in itself because
of its proximity to Hoover Dam.
In summary, the Sugarloaf Alternative will not significantly change the remaining portions of
Section 4(f) lands in relation to noise or recreation qualities (see Chapter 3 of the DEB for
details). Construction activities will disrupt traffic flow and have some adverse effects on noise,
visual and aesthetics qualities, but these effects will be relatively short term. These activities
will be closely monitored by and coordinated with the Bureau of Reclamation and the National
Park Service to minimize and to prevent adverse impacts and activities.
The long-term effects of this alternative will be to improve the recreationists' access to Hoover
Dam by reducing traffic congestion and to make U.S. 93 a safer transportation facility.
RDD-SFQ/981180008.WPD (lnbApE-4.wpd)
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APPENDIX C: 4. IMPACTS ON THE SECTION 4(ri PROPERTIES
Cultural and Historic Resources
Implementation of the Sugarloaf Alternative would affect two historic sites (see DEIS,
Figure 3-9). These resources are the Hoover Dam National Historic Landmark (NHL) and one
power transmission switchyard (a contributing element to the NHL). The historic setting of the
transformer site would be visually altered. The alternative crosses the Colorado River gorge
1,500 feet downstream from the dam and takes approximately 12.4 acres of right-of-way from
the 330-acre National Historic Landmark property in its southwest comer. This constitutes a
permanent use of a portion of the historic property under Section 4(f). (See Table C-2.)
Preliminary opinions of the Nevada and Arizona State Historic Preservation Officers and the
NFS are that construction of a bridge at the Sugarloaf crossing location would result in an
adverse effect on the historic visual setting of the landmark.1 However, their preliminary
opinion was that this adverse effect could be mitigated through measures which would include a
bridge designed and constructed so that it would be compatible with the setting (see Mitigation
Measures Section). The Sugarloaf Alternative would enhance protection of the physical features
of the dam by virtually eliminating the potential for vehicle collisions with dam facilities.
The portion of the old railroad grade and tunnels leading to Hoover Dam affected by this
alternative is all within Reclamation-reserved land and is not considered to be eligible for listing.
A prehistoric archaeological site (designated NV:DD:14:21) is located near Sugarloaf Mountain.
The proposed Sugarloaf Mountain alignment bisects the site in an east/west direction. Cultural
materials observed on the site include extensive stone tool fragments. Preliminary analysis
suggests that the site was a raw material procurement site with natural rock suitable for stone
tool manufacturing. The presence of metate fragments indicates that seed or plant processing
also occurred on the site. This site appears to be eligible for the National Register on the basis of
its research value and therefore it does not fall under Section 4(f) provisions.
Noise
Five receptor sites were selected in human-use areas to determine current and predicted noise
impacts for this project: the Lakeview Point Overlook, the Nevada Intake Tower at the dam, a
raft launch concession below the dam, the hot springs located at the mouth of Gold Strike
Canyon, and a point along the Gold Strike Canyon Trail where maximum noise impacts might
occur (see DEIS, Figure 5-1). The closest noise receptor site to the Sugarloaf Alternative is the raft
launch site (receptor R2/M2) where the noise generated by traffic on the new bridge would be 57
decibels. The Nevada Intake Tower (R3/M3), which is about 2,030 feet from the proposed
Sugarloaf bridge, would experience a predicted future noise level of about 74 decibels; noise
sources consist of the new bridge, the existing dam crossing, and the Visitor's Center. Although
this exceeds the federal criteria, it represents a noise level decrease of approximately 3 dBA from
the future no build predicted level of 77 dBA and an increase above the existing noise level of
only 1 dBA. The future reduction is due to traffic being diverted to the new crossing
(approximately 1,500 feet downstream from the dam).
The predicted 56 dBA noise level at the Lakeview Point Overlook (Rl /Ml) would be the same as
the Promontory Alternative, given that these bypass alternatives are on essentially the same
Bureau of Reclamation October 2,1991 Colorado River Crossing - Hoover Dam Meeting vrith Arizona SHPO, Nevada
SHPO, and NPS Representatives notes; Arizona SHPO October 22,1991 comments on BOR meeting notes; Nevada
SHPO November 6,1991 comments on BOR meeting notes; and December 11,1991 Advisory Council on Historic
Preservation comments on BOR meeting notes.
4-2 RDD-SFO/981180008.WPD (lnbApE-4.wpd}
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APPENDIX C: 4, IMPACTS ON TOE SaecnoN 4(p) PROPERTIES
alignment near the overlook. Most of the proposed Sugarloaf Alternative falls within 2,000 feet of
the existing Highway 93 alignment; therefore, no significant increases in noise pollution would
result along the entire length of the proposed highway.
Aesthetics
Views of the Sugarloaf Mountain Alternative would be unobstructed from Hoover Dam and from
the raft put-in site 0.5 mile downstream of the dam. In addition, the new bridge would be visible
by aerial sightseers, thus changing the aerial view of the dam and canyon. As discussed in the
Draft EIS (Chapter 3), the visual quality of the view looking downstream from the eastern side of
Hoover Dam would be most affected by the concrete cable stayed bridge design. The vividness
(memorability of the existing landscape components) of the view would be degraded by the
presence and closeness of the bridge structure. In addition, the intacrness and unity (visual
harmony between landscape elements) of the view would be affected by the size and prominence
of the bridge form; the vertical, horizontal, and diagonal lines; and the textural differences
between the proposed bridge and the existing landscape.
As discussed in the introduction, constructive use is defined as not occurring when compliance
with the requirements of Section 106 of the National Historic Preservation Act (16 U.S.C. § 470)
and related regulations for proximity impacts of a proposed project on a NRHP site results in a
finding of "no effect" or "no adverse effect" (36 CFR 800.9). However, pursuant to the Advisory
Council on Historic Preservation (ACHP) regulations implementing Section 106, an undertaking
is considered to have an adverse effect when the effect on a historic property may diminish the
integrity of the property's location, design, setting, materials, workmanship, feeling, or
association. Adverse effects on historic properties include, but are not limited to: (1) physical
destruction, damage, or alteration of all or part of the property; (2) isolation of the property from
or alteration of the character of the property's setting when that character contributes to the
property's qualification for the National Register; and (3) introduction of visual, audible, or
atmospheric elements that are out of character with the property or alter its setting (36 CFR800.9
[b]).
Based on the preliminary opinions of the Nevada and Arizona State Historic Preservation Officers
and the NFS that the adverse effect on the historic visual setting of the landmark could be
mitigated, there would not be a constructive use of the Hoover Dam National Historic Landmark
property. A determination of no constructive use is consistent with the federal regulations
implementing Section 4(f), which stipulate that any proximity impacts which will be mitigated are
not considered a constructive use of the protected property (23 CFR 771.135(p)(6)(ii)). A formal
finding of effect under Section 106 by the FHWA and the Arizona and Nevada SHPOs, including
concurrence with the mitigation plan, will be required before a final Section 4(f) determination on
applicability of constructive use of the National Register property can be made.
Access
The Sugarloaf Alternative would improve access to the Hoover Dam National Historic Landmark
interpretive facilities by diverting all but visitor traffic off the existing, highly congested, two-lane
dam crossing and approaches and onto a new four-lane U.S. 93 bridge located 1,500 feet
downstream from the dam.
RDD-SFO/9811S0008.WPD(lnbApE-4.wpd) 4-3
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APPENDK C: 4 IMPACTS ON THE SECTION 4(f) PROPERTIES
Promontory Point Alternative
The Section 4(f) properties and/or resource values were identified and assessed for potential
impact by the Promontory Point Alternative. The following summarizes the results of that effort.
(A more detailed description of these analyses and conclusions can be found in Chapter 3 of the
DEIS.)
Park Land and Recreation
The Promontory Point Alternative would permanently use a total of 49.7 acres of Section 4(f) land
(29.4 acres within the LMNRA and 20.3 acres within the NHL; see Figure C-l). This alternative
would not directly impact any recreational facility or resource located with Section 4{f) land.
During construction, the noise of construction and presence of heavy equipment would
temporarily lower the aesthetics experience for some visitors at the dam and in the area;
however, others would find the construction operation interesting. Following construction and
subsequent diversion of traffic off the dam to the new bridge, vehicle-derived noise and exhaust
fumes would significantly decrease, thereby improving conditions for dam visitors. The new
bridge could become a tourist attraction in itself because of its proximity to Hoover Dam.
Cultural and Historic Resources
Implementation of the Promontory Alternative would affect a total of five historic resource sites
subject to protection under Section 4{f). These consist of Hoover Dam (listed as a National
Historic Landmark and in the National Register of Historic Places), an anti-aircraft bunker (a
contributing element to the NHL), a concrete diversion channel (a contributing element to the
NHL), a concrete retaining wall (a contributing element to the NHL), and a power transmission
switchyard (a contributing element to the NHL). The alternative crosses Lake Mead approx-
imately 1,000 feet upstream from the dam and takes 20.3 acres of right-of-way from the northern
portion of the 330-acre National Historic Landmark property. This constitutes a permanent use
of a portion of the historic property under Section 4(f). (See Table C-2.)
Preliminary opinions of the Nevada and Arizona State Historic Preservation Officers and the NPS
are that construction of a bridge at the Promontory Point crossing location would result in
Hoover Dam being adversely affected by the visual alteration of the historic setting and that these
visual impacts cannot be mitigated. The anti-aircraft bunker and the concrete retaining wall may
be indirectly affected by visually altering their historic qualities through the construction of a new
highway. The diversion dam and the transmission switchyard may be directly (physically)
affected by construction activities associated with the new highway.
As with the other two build alternatives, this alternative would enhance protection of the physical
features associated with Hoover Dam by eliminating the existing potential for vehicle collisions
with dam facilities.
Noise
The closest receptor sites for Promontory Point Alternative are the Lakeview Point Overlook and
the Nevada Intake Tower. The Lakeview Point Overlook and Nevada Intake Tower receptor
sites would experience the same noise impacts as described in the Sugarloaf Alternative. The
new bridge would be located approximately 1,000 feet upstream of the dam. Most recreational
activity in this area is associated with Hoover Dam visitation. As with Sugarloaf Alternative,
4-4 RDD-SFO/981180008. WPD (lnbApE-4.wpd)
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APPENDKC: 4. IMPACTS ON THE SELECTION 4(p) PROSES-TIES
most of the proposed alignment for Promontory falls within 2,000 feet of existing U.S. 93. Hence,
constructing Promontory Alternative would not result in significant increases in noise.
Aesthetics
Views of the Promontory Point Alternative would be unobstructed from locations on Lake Mead
up to 1.2 miles upstream of the dam. The new bridge would be visible from Hoover Dam (which
receives over one million visitors per year) and by aerial sightseers, thus changing the landscape
setting of Lake Mead from the dam and the air. As discussed in the Draft EIS (Chapter 4), the
visual quality of the view looking toward the dam from a boat on the lake would be most
affected by the steel truss rib through arch bridge design on this alignment. The vividness
(memorability of the existing landscape components) would be compromised by the introduction
of the bridge structure. In addition, the intactness of the landscape and the unity (visual harmony
between landscape elements) would be affected by the size and prominence of the form,
contrasting lines, and textural differences between the proposed bridge and the existing
landscape.
Based on the preliminary opinions of the Nevada and Arizona SHPOs and the NPS that there is
an adverse, unmitigable effect on Hoover Dam by visual alteration of the historic setting, it can
only be concluded that the Promontory Point Alternative would have an adverse effect on the
entire National Historic Landmark property, including the dam structure and other contributing
elements of the landmark, encompassing approximately 330 acres. This would result in a
constructive use of approximately 310 acres (330 acres, less the 20 acres permanently used) under
Section 4(f). (See Table C-2.)
This form of constructive use is defined in the federal regulations implementing Section 4(f) as
when the proximity of the proposed project substantially impairs aesthetics features or attributes
of a protected resource, where such features or attributes are considered important contributing
elements to the value of the resource.(23 CFR 771.135(p)(2). A formal finding of effect under
Section 106 of the National Historic Preservation Act by the FHWA and the Arizona and Nevada
SHPOs will be required before a final determination can be made on the degree of Section 4(f)
constructive use of the National Register property (i.e., all or a portion of the affected property).
Access
The Promontory Alternative would improve access to the Hoover Dam National Historic
Landmark interpretive facilities by diverting all but visitor traffic off the existing, highly
congested, 2-lane dam crossing and approaches and onto a new 4-lane U.S. 93 bridge located
approximately 1,000 feet upstream from the dam.
Gold Strike Alternative
The Section 4(f) properties and/or resource values were identified and assessed for potential
impact by the Gold Strike Alternative. The following summarizes the results of this effort. (A
more detailed description of these analyses and conclusions can be found in Chapter 3 of the
DEIS.)
Park Land and Recreation
The Gold Strike Alternative would permanently use a total of 72.7 acres of Section 4(f) recreation
land, all within the LMNRA (see Figure C-1). This alternative would result in negative impacts to
Gold Strike Canyon hikers. Although the Gold Strike Canyon trail is not an official
RDD-SFO/9811800Q8.WPD (lnbApE-4.wpd) 4-5
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APPENDIX C: 4. IMPACTS ON THESECTON4(F) PROPERTIES
NFS-designated trail, numerous hikers use it as a trail leading to the hot springs located at the
lower end of Gold Strike Canyon. The trail would be closed during construction. The proposed
highway for this alternative would over-pass the trail at several locations, and traffic from the
new highway would create new noise pollution along nearly the whole length of the trail. (See
the following discussion of noise, aesthetics and access impacts on the Gold Strike Canyon Trail.)
Within Gold Strike Canyon, the roadway would be constructed primarily on elevated structures
where it would overlay and cross the popular Gold Strike Canyon Trail from near the trail head
located just south of U.S. 93 (approximately one-half mile south of the Lakeview Point turnoff) to
within about one-half mile of the river, a total distance of approximately one mile. The length of
the trail from the trail head to the Hoover Dam Reservation Area Boundary (HDRA),
approximately three-quarters of a mile along the proposed highway, is within the Lake Mead
National Recreation Area (LMNRA) and is under Section 4(f) protection. The HDRA is excluded
from the LMNRA for the protection and security of the dam powerplant and associated facilities.
Cultural and Historic Resources
Implementation of the Gold Strike Alternative would only indirectly affect Hoover Dam through
a slight change to the visual historic setting. Preliminary opinions of the Nevada and Arizona
State Historic Preservation Officers and the National Park Service were that construction of a
bridge at the Gold Strike crossing location would have no adverse effect on the historic visual
setting of the landmark.2 No other cultural resource sites would be affected by this alternative.
As with the other two alternatives, the Gold Strike Alternative would enhance protection of the
physical features of the dam by virtually eliminating the potential for vehicle collisions with dam
facilities.
Noise
The Gold Strike Alternative is the farthest from existing traffic-generated noise pollution
associated with U.S. 93. Implementing this alternative would result in a permanent increase of
approximately 26 decibels (dBA) at the Gold Strike Canyon Trail site from traffic on the new U.S.
93 alignment, for a total of 65 dBA (the present ambient noise level is approximately 39 dBA).
This would exceed the 57 dBA-L^ federal noise abatement criterion for Category A3 land uses,
and it would constitute a substantial increase (>15 dBA) under NDOT and ADOT noise
abatement policies. Therefore, the projected noise level increase attributable to the project would
substantially interfere with the use and enjoyment of the Gold Strike Canyon Trail by hikers. This
impact would constitute a constructive use of a protected public recreation area under Section
4(f). With mitigation (see below), the projected noise level increase can be reduced to 20 dBA
above existing conditions, for a total of 59 dBA, which would still constitute a constructive use
under Section 4(f).
The Advisory Council on Historic Preservation concurred with these preliminary opinions in a December 11,1991
letter stating "we agree that the construction of the bridge at Gold Shrike Canyon appears to be the alternative which
is least likely to have an adverse effect on the Hoover Dam National Historic Landmark."
Category A land uses are tracts of land which serenity and quiet are of extraordinary significance and serve an
important public need and where the preservation of those qualities is essential if they are to continue to serve their
intended purpose. Such areas could include amphitheaters, particular parks or portions of parks, open spaces, or
historic districts which are dedicated or recognized by appropriate local officials for activities requiring special
qualities of serenity and quiet. {Source: Federal Highway Administration, Procedures for Abatement of Highway Traffic
Noise and Construction Noise, 23 CFR 772, April 1997.)
4-6 RDD-SFO/981180008.WPD (lnbApE-4.wpd)
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APPENDIX C: 4. IMPACTS ON TOE SELECTION 4(F) PROPERTIES
There is no predicted increase in the existing ambient noise level of 60 dBA a the Gold Strike
Canyon Hot Springs from this alternative realignment of U.S. 93. Although noise levels at the hot
springs are higher than the 57 dBA-l^ federal impact criterion, this is not an impact because the
noise level is caused from the sound of rushing water around the hot springs. The hot springs
site would be shielded from future traffic-associated noise from the Gold Strike Alternative by
intervening cliffs. Both locations are considered to be Category A sites according to Federal
Highway Administration criteria. Due to the serene and quiet nature of the previously
undisturbed area, mitigation would be required in those areas that would be affected by
excessive noise levels (increases greater than 15 dBA above the existing ambient levels). Noise
level decreases of approximately 3 dBA are predicted at both the Nevada Intake Tower and at
Lakeview Point (from predicted future no build levels of 77 dBA and 54 dBA, respectively) due
to traffic being diverted to the new crossing location approximately 1 mile downstream.
Aesthetics
Views of the Gold Strike Canyon Alternative would be completely obstructed from Hoover Dam,
the Arizona Overlook, and Lake Mead. The new bridge would be visible from the raft put-in 0.5
mile downstream of Hoover Dam and by aerial sightseers. As discussed in the Draft EIS
(Chapter 3), the new Colorado River bridge would substantially change the landscape setting of
Gold Strike Canyon as seen from the hiking trail and hot springs. From the view of Black Canyon
looking downstream from the raft put-in location, the concrete deck arch bridge design would
have the most pronounced visual affect. Because the concrete forms on this bridge are larger
than in the steel deck arch bridge, the visual impact from this bridge design is greater than for the
steel deck arch bridge. With either bridge design, the vividness of the landscape components
would not be adversely affected by the bridge structure; however, the intactness and unity of the
view would be compromised by the size and prominence of the form and contrasting lines.
The Gold Strike Canyon Trail is used by visitors to hike down through the canyon to the river.
The drainages of the hot springs near the mouth of the canyon have been blocked to form ponds
for bathing. Because of the heavy use of the hot springs area, the NFS has provided a portable
toilet and trash receptacles at the mouth of the canyon.
At several locations in the canyon the highway alignment would cross over or lay directly above
the canyon bottom and hiking trail. Construction of primarily highway bridges and retaining
walls is required in lieu of fills through Gold Strike Canyon because fill slopes would interfere
with drainage flows and drastically alter the canyon bottom for hiking. Views by recreationists
using the hiking trail or hot springs would be adversely affected by this alternative, regardless of
the bridge design that is selected.
Access
The Gold Strike Canyon Alternative would improve access to the Hoover Dam National Historic
Landmark interpretive facilities by diverting all but visitor traffic off the existing, highly
congested, 2-lane dam crossing and approaches and onto a new 4-lane U.S. 93 bridge located
about 1 mile downstream from Hoover Dam.
During the construction period for this alternative (5 to 6 years), the Gold Strike Canyon trail
would be closed from U.S. 93. Recreation activities within this area would be prohibited.
Consequently, hiking access along this popular public parkland trail through Gold Strike Canyon
to the river and hot spring pools would be blocked for years during construction of this highway
alternative. Furthermore, the natural views and rugged appeal of this pristine canyon setting
would be permanently replaced with concrete columns and overhead bridges crisscrossing the
canyon trail for most of its length. This condition would substantially diminish the utility of this
RDD-SFO/981180008.WPD (lnbApE-4.Wpd> 4-7
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APPENDIX C: 4. IMPACTS ON THE SECTION 4(F) PROPERTIES
natural trail access to the river and, in addition to the 5- to 6-year occupancy during construction,
may be considered a constructive use under Section 4(f). It is estimated that approximately
6,000 feet of canyon bottom trail within the LMNRA would be directly impacted, which is
calculated to be about 14 acres (at an average width of 100 feet).
Appendix Table C-2
Summary of Section 4(f) Use
Constructive Use
Alternatives
Sugarloaf Mountain
Promontory Point
Gold Strike
Permanent
Use
60 ac.
50 ac.
73 ac.
Noise
NA
NA
YES
Aesthetic
NA
YES
YES
Access
NA
NA
YES
Acres
Affected
0
310
14
Total Use
60 ac.
360 ac.
87 ac.
4-8 RDD-SFO/9811800Q8.WPD (InbApE-4.wpd)
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5. Avoidance Alternatives
Because of the unique situation of Section 4(f) lands being continuous from 50 miles north to
60 miles south of the existing corridor, it is not possible to avoid these lands and still maintain
the service that existing U.S. Highway 93 provides for this area of the Southwest (see Figure
C-2). Consequently, there are no reasonable alternative routes that meet the project purpose
and need, and avoid the use of Section 4(f) lands. The following avoidance alternatives are fully
described and compared in Chapter 2 of the DEIS.
A total of four alternatives would avoid the use of Section 4(f) lands;
• No Build Alternative
• Restricting motorized traffic from crossing Hoover Dam
- Option for restricting truck traffic only
- Option for restricting all traffic
• Traffic Systems Management
• U.S. Highway 95/1-40
No Build Alternative
The No Build Alternative would consist of no action being taken. No bypass of Hoover Dam
would be developed, no change in the current highway configuration would occur, and no other
structural or nonstructural improvements would be developed on U.S. 93 near Hoover Dam.
Existing hairpin curves, inadequate sight distance, narrow dam crest roadway, and steep grades
on U.S. 93 in the vicinity of Hoover Dam would remain unchanged. No direct construction costs
would result from this alternative.
However, an increase in operations and maintenance costs is foreseeable because of the
increased traffic and congestion on and near the dam. The public would also incur added costs
because of more frequent traffic delays and accidents.
The No Build Alternative would not meet the purpose and need of the project as it would not
remove a major bottleneck to regional commerce by increasing the capacity of U.S. 93 near the
dam to improve through-vehicle and truck traffic and substantially reduce traffic congestion and
accidents at the dam and approaches. It would not minimize out-of- direction travel during
periods of significant delays at the dam crossing or reduce vehicle hours of travel and improve
travel speeds. It may increase the potential for a catastrophic spill of hazardous materials with
increasing automobile and truck traffic volumes on the dam and approaches. The risks to
innocent bystanders, property damage to the dam and its facilities, contamination of the waters
of Lake Mead or the Colorado River, and interruption of the power and water supply for people
in the Southwest would remain or increase.
This alternative would not minimize impacts on recreation resources and tourists. It would not
reduce the potential for pedestrian-vehicular accidents on the crest of the dam and on the
Nevada and Arizona approaches to the dam. The increased traffic volumes, ranging from a
forecasted 21,100 AADT in 2017 to 26,000 AADT in 2027 on Hoover Dam under no build vs.
9,400 AADT in 2017 to 12,200 AADT in 2027 under the bypass alternatives, traveling at slower
speeds, would contribute to decreased air quality in the vicinity of Hoover Dam (see Traffic
RDD-SFQ/981180007.WPD (InbApE-S.wpd) 5-1
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APPENDIX C: 5. AVOIDANCE ALTERNATIVES
Analysis, Appendix A). There would also be increased congestion for tourists at Hoover Dam
and parts of the Lake Mead Recreational Area.
Restricting Motorized Traffic from Crossing Hoover Dam
The possibility of restricting traffic from using Hoover Dam to cross the Colorado River was
examined with two options:
• Restricting truck traffic (through restriction on specific classifications of vehicles), which
results in diversion to alternate routes, but leaves Hoover Dam open to automobile traffic;
and
• Restricting all traffic, which results in diversion of all traffic to alternate routes and thus
closes Hoover Dam to all motorized vehicles.
At the present time, Hoover Dam is the only Colorado River crossing in the general vicinity of
Las Vegas, Nevada. The closest alternate crossings are at Lee's Ferry, 250 miles upstream of
Hoover Dam; and at Davis Dam or Laughlin Bridge, 67 and 70 miles downstream, respectively.
As a result, the river crossing on Hoover Dam is very important to both the commercial
trucking industry and other travelers on U.S. 93.
In 1994, the annual average daily volume of traffic (AADT) to Hoover Dam was 13,000 vehicles.
Excluding commercial busses, approximately 18 percent of these daily vehicles were
commercial trucks. Closure of the dam to traffic would likely result in a diversion of these
vehicles to State Route (SR) 163 and U.S. 95 in Nevada and Arizona SR 68 (the Laughlin-
Bullhead City Alternative). These routes would add 23 miles to the trip from Kingman,
Arizona, to Las Vegas, Nevada. Another possible route from Kingman to Las Vegas would be
Interstate 40 to Needles, California, and then north on U.S. 95 to Las Vegas. However, vehicles
using these routes would travel 50 more miles than if they used SR 163 in Nevada as the
alternate route. In either instance, U.S. 95 south of Las Vegas would experience a dramatic
increase in traffic.
This alternative (with two options) for traffic restriction was eliminated because:
1. It does not fulfill the designated functional requirements of U.S. 93 as a principal arterial
highway.
2. It would eliminate a major segment of a primary north-south U.S. highway.
3. The traffic congestion and safety considerations would merely be shifted from Hoover Dam
to other locations.
4. While repair and replacement costs for U.S. 93 would decrease by eliminating all traffic,
these same costs would increase proportionately on other highways and there would be
additional costs to upgrade portions of the other highways to current highway standards.
U.S. 95 is only two lanes and could not handle the additional traffic volumes that would
result from the rerouting. Additionally, Arizona SR 68, between milepost 0 to 14, is a 2-lane
facility with 6 percent grades for 12 miles. The roadway deck (see DEIS glossary) of the
Davis Dam spillway bridge would require immediate replacement if subjected to heavy
truck traffic.
5-2 RDD-SFO/981180007.WPD (InbApiE-S.wpd)
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APPENDIX C: 5. AVOIDANCE ALTERNATIVES
5. Major sections of the alternate routes were not designed and built to sustain the heavy loads
and volume of vehicles that would be diverted from Hoover Dam, resulting in a shortened
life for those highways.
6. In addition to the extra travel distance, alternative transportation routes have greater
elevation changes, resulting in both increased travel time and operating cost for commercial
carriers and the general traveling public.
Traffic Systems Management
A Traffic Systems Management (TSM) Study was completed in January 1992 to determine
whether or not a low cost solution exists for the current and projected traffic congestion,
pedestrians, and vehicle safety problems at the present crossing. Typically, TSM addresses
signing and signalization, turn lanes and traffic channelization, vehicle turn-outs, vehicular
access and parking controls, and pedestrian channelization and barriers.
The TSM Study concluded that some minor improvements in traffic flow could result from low
cost changes in operational conditions; specifically: (1) existing crosswalks should be widened
and supplemental signing added to better concentrate pedestrian crossings, which would
minimize accident potential and improve overall traffic flow on the dam crest; and (2) the
immediate approaches to Hoover Dam should be signed to indicate the location of visitor
parking lots, which was done with construction of the Visitor's Center. The study concluded this
would alleviate some of the traffic congestion that results from visitor confusion regarding
parking lot locations.
However, because of the existing horizontal curves, roadway width on the dam, and pedestrian
volumes, no significant improvements could be realized without provision of an alternate route.
The existing traffic conditions will only deteriorate with future growth of the traffic volumes.
The existing geometry of the highway approaching and over Hoover Dam is a source of
difficulty for semitrailer trucks in making the necessary maneuvers around the hairpin curves
and the 90-degree curve. This condition will continue to result in accidents and extensive delays
to through traffic. The study recommended that a new four-lane route should be provided.
Therefore, this alternative was eliminated from further consideration because it could not meet
the purpose and need of the project Since this alternative would only involve modifications to
the existing route, it would not use additional Section 4(f) resources; however, the TSM Study
concluded that only minor improvements in traffic flow could result from changes in operational
conditions. This alternative was eliminated because:
1. No significant improvements to traffic flow would be realized due to the existing geometry
of the highway approaching and crossing Hoover Dam, including the inadequate horizontal
curves and highway width on the dam, and due to the high traffic and pedestrian volumes.
2. It does not fulfill the designated functional requirements of U.S. 93 as a principal arterial
highway.
3. The vehicle-pedestrian, vehicle-vehicle, and vehicle-sheep conflicts would not be changed.
RDD-SFO/981180007.WPD (InbApE-S.wpd) 5-3
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APPENDIX C: 5. AVOIDANCE ALTERNATIVES
U.S. 95/1-40
This alternative to U.S. 93 improves the existing route between Boulder City and Kingman via
Needles, California. Approximately 56 miles of U.S. 95 in Nevada and 13 miles of U.S. 95 in
California would be widened to four lanes. No improvements to existing 1-40 and its crossing of
the Colorado River south of Needles are necessary.
The U.S. 95/1-40 Alternative does not meet the project purpose and need because it would not
substantially eliminate roadway deficiencies and reduce traffic congestion on U.S. 93 at Hoover
Dam and dam approaches, eliminate through traffic from the dam/ enhance public safety, or
protect Hoover Dam and its visitors. The U.S- 94/1-40 Alternative was eliminated because
motorists would avoid driving the additional 70 miles by continuing to use the Hoover Dam
crossing. Therefore, meeting the objectives of enhanced safety and reduced congestion on
U.S. 93 at the dam would not be achieved.
5-4 RDD-SFO/981180007.WPD 0nbApE-5.wpd)
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6. Measures to Minimize Harm
Following is a description of the measures that will be implemented in an effort to minimize
harm to Section 4(f) resources.
Recreation Resources
During the 5- to 6-year construction period for this project, certain recreation activity areas
would be designated as construction safety zones and recreation would be limited, or in other
places it would be eliminated entirely. Specifically during blasting operations, short periods will
occur when recreation access to affected areas must be prohibited for protection of the public.
Trail use regulations within the LJMNRA may need to be adjusted to accommodate construction
activities and to assure the safety of trail users. Scheduling of these activities will'be closely
coordinated with the NFS and Bureau of Reclamation, and there will be ongoing public
information provided.
Bicyclists and pedestrians will be prohibited from using the new bridge on any of the bypass
alignments. However, the existing crossing will be maintained on the roadway across Hoover
Dam.
Construction safety practices will require that nets be used under the work area during
construction to protect areas below the bridges from falling debris, tools, equipment, or building
materials.
Aesthetics
Cuts, fills, and other construction activities will be performed so as to minimize impact to scenic
values, especially in undeveloped areas like Gold Strike Canyon. Mitigation techniques will
include rough cuts, feathering cut/natural environmental interfaces, use of artificial desert
varnish on rock cuts to match adjacent natural colors, colored concrete, and other state-of-the-art
methods. Care will be taken to remove all construction debris and other trash from the site after
construction is completed.
Excavated topsoil will be stored during construction and replaced on appropriate disturbed
areas outside the highway shoulders during construction to aid in reestablishing desert
vegetation. Cactus, yucca, and candidate plant species will be removed and replanted, or
reseeded in consultation with the NFS.
Specific mitigation measures for the three bypass alternatives, as developed in the Draft EIS, are
as follows:1
Sugarloaf Mountain Alternative
The preliminary opinions of the Nevada and Arizona SHPOs and the NFS are that the Sugarloaf
Mountain Alternative would have an adverse effect on the Hoover Dam National Historic
'CH2M HILL, Visual Impact Assessment Technical Report far the Hoover Dam Bypass EIS, May 1998.
RDD-SFO/981180012,WPD{lnbApE-6.wpd) 6-1
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APPENDIX C: 6. MEASURES TO MINIMIZE HARM
Landmark, but that this effect can be mitigated through design features. Specific mitigation
measures will be determined in consultation with the responsible agencies during review of the
Draft EIS and Section 106 determination of effect documentation. These measures to imnimize
harm will be described in the final Section 4(f) evaluation and the Final EIS. However, in lieu of
a formal finding of effect and from the standpoint of the visual impact assessment prepared for
the Draft EIS, the following information is useful for consideration.
Impacts on visual resources from the concrete cable stayed bridge for the Sugarloaf Mountain
Alternative would be reduced by using colored concrete or painting the bridge using a non-glare
color that blends with the surrounding environment. However, the dominance and closeness of
the bridge to the dam results in the impact on visual resources remaining after mitigation is
implemented.
Promontory Point Alternative
The preliminary opinions of the Nevada and Arizona SHPOs and the NFS are that the
Promontory Point Alternative would have an adverse, unmitigable effect on the Hoover Dam
National Historic Landmark. That opinion will be either reconfirmed or modified after review of
the Draft EIS and a formal Section 106 determination of effect by the responsible agencies.
However, in lieu of a formal finding of effect and from the standpoint of the visual impact
assessment prepared for the Draft EIS, the following information is useful for consideration.
As documented in the Visual Resources Analysis (DEIS, Appendix H), impacts on visual
resources from the steel truss rib through arch bridge are considered adverse and unmitigable.
Impacts on visual resources from the concrete cable stayed and suspension bridge designs can
be mitigated.
For the concrete cable stayed bridge, to reduce the visibility of the pillars on the bridge, the
concrete should be tinted with nonglare colors that blend with the surrounding environment. In
addition, the cuts for the roadway approaches should be engineered to minimize impacts on
visual resources. Any slope protection should be tinted to blend with the surrounding
landscape.
For the suspension bridge, to reduce the impacts on visual resources from the bridge, the
concrete pillars should be tinted with nonglare colors that blend with the surrounding
environment. In addition, the roadway cuts for the roadway approaches should be engineered
to minimize impacts on visual resources. Any slope protection should be tinted to blend with
the surrounding landscape.
Gold Strike Canyon Alternative
Impacts on visual resources from either the concrete deck arch bridge or the steel deck arch
bridge are adverse and unrnitigable for the hikers, hot spring users, rafters, and other river users
near the proposed alignment No impact on views from either Lake Mead or Hoover Dam is
expected from this alternative.
6-2 RDD-SFO/981180012.WPD (InbApE-S.wpd)
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APPENDIX C: 6. MEASURES TO MMMJZE HARM
Cultural and Historic Resources
Specific mitigation measures will be determined through consultation between the Federal
Highway Administration, the Nevada and Arizona SHPOs, and the Advisory Council on
Historic Preservation, as required under Section 106 of the National Historic Preservation Act
and related regulations (36 CFR 800). Mitigation will include a bridge designed and constructed
so that it will be compatible with the historic setting of the Hoover Dam National Historic
Landmark. Preliminarily, and subject to revision in the final Section 106 determination of effect,
the design will strive to meet the overall mitigation goals of:
• Using materials compatible with the NHL land in both color and material, including paint
color that blends in rather than contrasts with the environment. The bridge structure will be
made less imposing through using color that matches the canyon walls (i.e., darker colors
. will make the bridge recede into the surrounding landscape).
• Being compatible to the dam through some matching of material and massing.
• Reproducing the basic design elements of the dam area, as appropriate (e.g., open steel
frames of the compression arch of the steel bridge will share common elements with the
transmission towers).
Additionally, before construction, an extensive photographic recordation to Historic American
Engineering Record (HAER) standards will be initiated to document the historic view of the
landmark and its environs and also to document other cultural sites associated with the
proposed approach roads. This recordation will be done in consultation with the Advisory
Council on Historic Preservation and the Nevada and Arizona State Historic Preservation Offices
(SHPOs).
Noise
The Gold Strike Alternative will require mitigation measures in the upper reaches of Hie Gold
Strike Canyon Trail along the alignment where the predicted noise levels will be increased by 26
decibels above the ambient noise levels (39 dBA). A modeling/monitoring receptor site
(R4/M4) located on the Gold Strike Canyon Trail was used in the analysis of projected noise
from the Gold Strike Canyon Alternative. Appendix Table C-3 shows the effects of a noise
barrier constructed along the southern side of the U.S. 93 Bypass in the vicinity of location
receptor R4/M4,
Appendix Table C-3
Gold Strike Canyon Alternative
Mitiqated Future Peak-Hour Noise Levels (dBA-LM)
Receptor
Location
R4/M4
Build, No
Mitigation
65
8-Foot
Barrier1
59
10-Foot
Barrier
59
12-Foot
Barrier
59
14-Foot
Barrier
59
16-Foot
Barrier
59
^Minimum barrier height required to break the line-of-sight from an 11.5-fooi truck exhaust stack and the noise
receiver
Table C-3 shows that noise barriers located on the outside shoulder of the elevated roadway
could reduce noise levels in the affected portion of the hiking trail to 59 dBA-L^ (hourly
equivalent sound pressure levels). However, the mitigated noise levels would exceed the
RDD-SFO/981180012.WPD(lnbApE-6.wpd) 6-3
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APPENDIX C: 6. MEASURES TO MINIMIZE HARM
federal criteria of 57 dBA-Leq for Category A land uses, and would still result in a substantial
increase over existing ambient levels (> 15 dBA) under NDOT and ADOT noise abatement
policies.
Although the noise impact would not be mitigated below federal and state criteria, an insertion
loss of up to 6 dBA would be feasible with the addition of noise barriers. Under noise
abatement policies of the Federal Highway Administration, noise barriers will only be
constructed if they are determined to be reasonable and feasible (FHWA, Highway Traffic Noise
Analysis and Abatement - Policy and Guidance, June 1995). A 5 dBA noise reduction must be
achieved for the noise barriers to be considered feasible, which can be accomplished for the Gold
Strike Canyon Trail (as shown in Table 3-11). One reasonableness factor that can be analyzed for
recommended barriers is benefit-cost. To achieve the minimum noise reduction of 5 dBA and
break the line-of-sight along the portion of the hiking trail impacted by the Gold Strike
Alternative would require construction of approximately 5,170 feet of noise barriers located
along about 7,000 feet (1.3 miles) of the roadway. The barriers would begin near the trailhead
off U.S. 93 (engineering station 45+50) and end at a major side-canyon/sheep crossing bridge
(station 115+50), where the roadway diverges from the main canyon/trail and heads
northeasterly (see Figure 3-1).
To construct 5,170 feet of noise barriers, at a height of 10 feet would cost approximately
$1,048,000 (subject to adjustment during final design). The barriers would be placed only on the
outside shoulder of the roadways and bridges facing the trail, but not in locations where the trail
lies under the elevated roadway. This mitigation cost would benefit the hikers and
rock-climbers using this hiking trail to the hot springs. The NFS estimates that approximately
500 hikers currently use the Gold Strike Canyon Trail on an annual basis (Jim Holland, personal
communication, July 2,1998). Thus, the cost of the noise barriers would equate to approxim-
ately $2,096 per hiker annually, or about $105 per hiker over a 20-year period.
Although, the FHWA noise abatement policy does not have a specific guideline for the number
of people to be protected, as compared against the total cost of noise abatement, this is a critical
factor in making a determination on the reasonableness Of the cost of noise mitigation and it
needs to be considered during selection and design of the preferred project alternative. This cost
may not be reasonable considering that the total number of hikers using the Gold Strike Canyon
Trail is very small compared to the total number of visitors to the Lake Mead National
Recreation Area (9.3 million in 1992) and since the barriers will not reduce the projected noise
levels in the canyon below the 57 dBA federal noise criterion. Even with mitigation, the
projected traffic noise level from U.S. 93 through the canyon would be 20 dBA greater than
existing ambient conditions. The final decision on installing noise abatement barriers will be
made after public comments are received on the Draft EIS, an alternative has been selected, and
project design has been completed.
Recreation Resources
Construction safety practices will require that nets be used under the work area during bridge
construction to protect areas below from falling debris, tools, equipment, or building materials.
Since the location of the Sugarloaf bridge would be within the restricted access safety zone for
the Sugarloaf Alternatives, recreational uses would be restricted or prohibited during some
phases of construction. Some seasonal and daily blasting restrictions may be imposed
throughout the construction period. Restrictions and schedules for blasting will be determined
before construction. Access to the Gold Strike Canyon Trail would be prohibited during all
phases of construction.
6-4 RDD-SFQ/981180012.WPD(InbApE-6.wpd)
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07/15/98 WED 09:29 FAX FHWA CFLHD •*->-> CH2M HILL Santa 1^)002
MOHAVE COUNTY BOARD of SUPERVISORS
1130 Hancock Road Phone (520) 758-0713
Bullhead City, AZ 86442 FAX: (520) 758-0729
Public Access: 888-735-37] 1 e-mail:zmanl@ctaz,com
JIMZABORSKY
CHAIRMAN OF THE BOARD
DISTRICT 2 SUPERVISOR
July 1,1998
Terry Haussler
Federal Highway Administration
555ZangSt.,#259
Lakewood, CO 80228
Dear Mr. Haussler:
This letter is written to assure the Federal Highway Administration of Mohave County's support
of the effort to obtain a new bridge near Hoover Dam. Many years of effort have gone into this
endeavor and nothing should be done to alter, distract or delay that effort.
First and foremost is the need to complete the Federal Highway Administration's Environmental
Impact Study of the now three preferred sites for a through traffic bridge over the Colorado River
in the vicinity of the Hoover Dam. We are encouraging the administration to complete their
study as soon as possible.
Second, there is need of another Route 68 study because by the time the present Route 68
improvement project is completed, this study will be outdated. Because of the extensive road
improvements through Golden Valley and on through Mohave Valley Route 95, we will find the
traffic will continue to increase on Route 68 and this will very soon cause such congestion at the
present Bullhead City/Laughlin Bridge to be so great that it will necessitate a new through traffic
Colorado River Bridge north of the present bridge and south of the County Park. Your
consideration of a second Route 68 study will be appreciated.
Sincerely,
Moiiavetowitymo&d ofSupervisors
District I Carol Anderson - 809 E. Beale, Kingnaan, AZ 86401 - (520) 753-0722
District HI Buster Johnson-2001 ColleceDr TalceHavasnCttv
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United States Department of the Interior
HSH AND WILDLIFE SERVICE
RENO FISH AND WILDLIFE OFFICE
1340 FINANCIAL BOULEVARD, SUITE 234
RENO, NEVADA 89502 MAY "
File No. 1-5-98-1-167
Mr, Terry KHaussler
Federal Highway Administration
Post Office Box 25246
Lakewood, Colorado 80225-0246
DearMr. Haussler:
Subject: Hoover Dam Bypass Project, Clark County, Nevada and Mohave County,
Arizona
This is in response to your March 6,1998, letter requesting comments on the purpose and
need and alternatives sections of the environmental impact statement (ELS) prepared for the
Hoover Dam Bypass Project. The Fish and Wildlife Service (Service) has reviewed these
sections of the EIS and offers the following comments pursuant to your request and the
1993 memorandum of understanding (MOU) for surface transportation projects in Arizona,
California, and Nevada.
On September 4,1997, the Service provided you a list of federally listed species and species of
concern that potentially occur in the proposed project area. On November 21, 1997, we provided
scoping comments to you by letter for the proposed construction of the Hoover Dam Bypass
Project (File No. 1-5-98-TA-027). Please refer to these comments during the selection of the
environmentally preferable alternative and development of mitigation measures for the project.
The purpose and need chapter of the EIS provides an adequate description of deficiencies that
exist on U.S. Highway 93 in the vicinity of the Hoover Dam that result in traffic delays and safety
hazards. We suggest that Federal Highway Administration (FHWA) identify references for data
that supports the statement of need. Following review of this chapter, the Service believes that
the purpose and need section of the EIS is appropriate for the proposed project.
In the alternatives chapter of the EIS, FHWA identified 3 alternatives for the Hoover Dam Bypass
Project that have been chosen for further evaluation, and 11 alternatives that were eliminated from
further evaluation based on screening criteria. In your comparison of alternatives, the Laughlin/
Davis Dam Crossing alternative was eliminated because it did not meet the purpose and need of
the project. We suggest that you include screening criterion 4 (Table 2-2) to your evaluation of
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Mr. Terry K. Haussler File No. 1-5-98-1-167
the Laughlin/Davis Dam Crossing alternative. The Service is concerned that the LaughUn/
Davis Dam Crossing alternative would divert traffic onto U.S. Highway 95 (US 95) which bisects
the Piute-Eldorado Critical Habitat Unit for the desert tortoise (Gophents agassizii), a species
federally listed as threatened. Although installation of tortoise-proof barriers are proposed for
US 95, the direct and indirect effects of increased traffic on this highway may result in substantial
impacts to critical habitat. Such impacts may include road kills that result from breaches in the
barrier, increased risk of human-caused fires, vandalism, and poaching. Also, we recommend that
FHWA consider an additional screening criterion that addresses the issue of grades that vehicles
may encounter along each route.
We further suggest that you include impacts to wetlands in your discussion on screening
alternatives, As you are aware, each alternative potentially impacts wetlands to varying levels
(e.g., the Goldstrike Alternative has the greatest potential impact to wetlands). An analysis
pursuant to the Environmental Protection Agency's section 404 (b)(l) guidelines will need to be
completed as part of the U.S. Army Corps of Engineers' permitting process under section 404 of
the Clean Water Act to determine the least environmentally damaging practicable alternative. In
addition, FWHA should quantify, in acres, the extent of impact the alternatives will have on
wetlands, as suggested during the March 17,1998, meeting in Las Vegas, Nevada.
Upon incorporation of Service comments above, we concur with the basic and overall purpose
and need, section 404 coverage, alternatives, and criteria for alternative selection. We look
forward to reviewing the final document and results of field studies planned by CH2M Hill
Consultants in the proposed project area this spring and summer.
We appreciate the opportunity to participate in the planning process for this project. If you have
any questions, please contact Michael Burroughs at (702) 646-3499.
Sincerely,
Robert D. Williams
Field Supervisor
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USDepartment Central Federal Lands 555 Zang Street
of Transportation Highway Division P.O. Box 25246
_.,..., Denver, Colorado 80225-0246
Federal Highway
Administration
OCT 0 b 1997
In Reply Refer To:
HPD-16
Mr. Robert Williams
State Supervisor
U.S. Fish and Wildlife Service
4600 Kietzke Lane, Suite 125-C
Reno, NV 89502
Dear Mr. Williams:
Subject: Hoover Darn Bypass, U.S. 93, Interagency Coordination Meeting/Workshop
This letter is to confirm arrangements for an interagency coordination meeting/workshop on the
subject project. The meeting is set for Wednesday, October 29, from 8:00 a.m. to 4:00 p.m. in
the Pueblo Room (Room #1119) of the Clark County Government Center, 500 South Grand
Central Parkway, Las Vegas, Nevada.
The environmental process for this project was begun by the Bureau of Reclamation
(Reclamation) in 1989. Prior to the release of the Draft Environmental Impact Statement for
public review in 1993, Reclamation withdrew from the project "as the lead agency.
Reclamation's emphasis changed from construction of major public works projects to more
water resource management. With no lead agency or funding to continue the environmental
process for a new crossing, the project was officially put on hold in 1995. In May 1997, the
Federal Highway Administration, Central Federal Lands Highway Division, was named as the
lead agency to resume the Hoover Dam Bypass project.
This meeting is to formally commence the interagency-coordination aspect of that process. This
early coordination will help to facilitate an efficient Environmental Impact Statement (EIS)
preparation process and ensure that the draft EIS adequately addresses relevant issues. The goals
of the meeting are:
1, To identify the affected agency concerns,
2. To inform all agencies of the process for preparing the EIS,
3. To develop project goals and objectives, and
4. To identify the issues and concerns that will be examined in detail in the EIS.
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United States Department of the Interior
BUREAU OF RECLAMATION
Lower Colorado Regional Office
. P.O. Box 61470
LC-2318 Boulder City, NV 89006-1470
PRJ-1.10
2 9 1997
Mr, Terry K. Haussler, P.E.
Federal Highway Administration
Project Development (HPD-16)
555 Zang Street, Room 259
Lakewood CO 80228
Subject: Cooperating Partner in the Development of the Environmental Impact
Statement for the Hoover Dam Bypass (Bridge)
Dear Mr. Haussler:
This is in response to your September 11, 1997 letter requesting cooperating
agency status from the Bureau of Reclamation for the development of an
Environmental Impact Statement for the purpose of providing a Hoover Dam Bypass
near Hoover Dam across the Colorado River between the states of Arizona and
Nevada.
We appreciate being requested to participate in the project early in the process
and agree to participate as a cooperating agency. The Reclamation primary
representatives for this cooperative effort will be Mr. Kris Mills and Mr. Tom
Shrader will be the alternate representative.
Please call Mr. Mills at 702-293-8620 for any questions that you may have
regarding this cooperative effort.
Sincerely,
Laura Herbranson
Director, Resource Management
cc: Brian O'Halloran
2030 East Flamingo Road, Suite 160
Las Vegas NV 89119
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U.S. Department JMHIV Commander (Row) Bldg. 50-6
Of Transportation /Kp%^W Eleventh Coast Guard District Coast Guard Island
im^Sjfm • Alameda.CA 94501-5100
United States /Kgjijr Phone: <510) 437-3514
Coast Guard /JHBBf FAX; (510)437-5836
16590
Colorado River (330.0)
Sen 619-97
December 4. 1997
Larry C. Smith. P,E.
Division Engineer
Federal Highway Administration
555 Zang St.
P.O. Box 25246
Denver, CO 80225-0246
Dear Mr. Smith:
We received your letter of September 11,1997 (HPD-16), concerning the proposed construction
of a bridge over the Colorado River near Hoover Dam. We accept your request of us to become
a cooperating agency in the development of this project.
Your point of contact for our office is Susan Worden, Bridge Administrator. She can be reached
at the above address or contacted at (510) 437-3461, She was at the interagency scoping
meeting of October 29 in Las Vegas, and visited the site at Hoover Dam.
Thank you for including the Coast Guard at this stage of your planning.
Sincerely,
W. R. TILL
Chief, Bridge Section
U. S. Coast Guard
By direction of the District Commander
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STATE OF NEVADA
DEPARTMENT OF TRANSPORTATION
1263 S. Stewart Street
Carson City, Nevada 89712
BOB MILLER. Governor November 20, 1997 TOM STEPHENS, P.E., Director
In Reply Refer to:
Cooperating Agency
Hoover Dam Bypass
Mr. Larry C. Smith, P.E.
Division Engineer
FHWA, Central Federal Lands Highway Division
555 Zang Street
P.O. Box 25246
Denver, Colorado 80225-0246
Dear Mr. Smith:
I am writing in response to your letter requesting
cooperating agency status from the Nevada Department of
Transportation for the development of an EIS to construct a
bypass of US 93 in the vicinity of Hoover Dam.
The Nevada Department of Transportation is already part of
the Project Management Team and agrees to also be a cooperating
agency for the development of this EIS. Bill Crawford is a
member of the Project Management Team and will be the cooperating
agency representative. He is familiar with the past studies and
will keep me informed on the progress of this project.
Sincerely,
Tom
Director
TESrWCC
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United States Department of the Interior
FISH AND WILDLIFE SERVICE
NEVADA STATE OFFICE
4600 KIETZKE LANE, SUITE 125C
RENO, NEVADA 89502-5055
September 26,1997
File No. FHWA 1
Mr. Larry C. Smith
Division Engineer
Federal Highway Administration
Post Office Box 25246
Denver, Colorado 80225-0246
Dear Mr. Smith:
Thank you for your September 11, 1997, request to be a cooperating agency for preparation of
the environmental impact statement for the Hoover Dam Bypass/U.S. 93. We are interested in
providing input on this project. However, we have reviewed your "Guidance on Cooperating
Agencies" and, due to other program commitments and limitations on time and staff, we are
precluded from fulfilling the responsibilities outlined in this guidance without transfer funding
from your agency. If transfer of funds is not possible, we are willing to be a cooperating agency
and provide input on issues for which we have special expertise as time and funding allows.
Thank you for this opportunity to be a cooperating agency under the National Environmental
Policy Act. If you have any questions, please contact Mary Jo Eipers at (702) 784-5227.
Sincerely,
i. Chester C. Buchanan
0 Acting State Supervisor
-------
Mr. Larry C. Smith File No FHWA
cc;
Office Supervisor, Las Vegas Fish and Wildlife Service Suboffice, Las Vegas, Nevada
Assistant Regional Director, Fish and Wildlife Service, Interior Basin Ecoregion, Portland,
Oregon
Assistant Regional Director, Fish and Wildlife Service, Klamath and California Ecoregions,
Portland, Oregon
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IN REPLY REFER TU'
United States Department of the Interior
NATIONAL PARK SERVICE
LAKE MEAD NATIONAL RECREATION AREA
601 Nevada Highw>y
BOULDER CITY, NEVADA 89005
DIS(LAME-M)
September 24, 1997
Mr. Larry C. Smith, P.E., Division Engineer
Central Federal Lands Highway Division
Federal Highways Administration
P.O. Box 25246
Denver, Colorado 80225-0246
Dear Mr. Smith:
In reference to your letter dated September 11,1997, we are requesting cooperating
agency status for the preparation of the Environmental Impact Statement (EIS) for the
construction of a bridge over the Colorado River near Hoover Dam. We will do so in
accordance with the Council on Environmental Quality's Regulations for Implementing
the Procedural Provisions of the National Environmental. Policy Act for the preparation of
the EIS.
The National Park Service is a member of the Project Management Team and has been an
active participant in this process, along with the Bureau of Reclamation, for the last ten
years. We feel that our continued participation is important.
If there are any questions concerning this request, please contact Resource Management
Specialist Bill Burke at (702) 293-8935 or Park Planner Jim Holland at (702) 293~ 8986.
Sincerely,
Alan O'Neill
Superintendent
-------
US.Department Centra! Federal Lands 555 Zang Street
Of Transportation Highway Division P.O. Box 25246
Federal Highway Denver, Colorado 80225-0246
Administration
qpp * 4 4007
<3ti B I 533*
In Reply Refer To:
l-IPD-16
Mr. diet Buchanen
Acting Project Leader
U.S. Fish and Wildlife Service
4600 Kietzke Lane, Suite 125-C
Reno, NV 89502
Dear Mr. Buchanen:
The Federal Highway Administration (FHWA), Central Federal Lands Highway Division, in
cooperation with the Bureau of Reclamation (Reclamation), National Park Service, Arizona
Department of Transportation, and Nevada Department of Transportation, is proposing to
construct a bridge over the Colorado River near Hoover Dam. Environmental and engineering
studies for this proposal were initiated fay Reclamation in 1989, but were terminated in 1993 for
funding reasons.
The proposed improvement, along US 93 in Arizona and Nevada, consists of a bridge across the
Colorado River and approximately three miles of associated new roadway construction. The
entire project is on Federally-owned lands. See attached map showing project location and
alternatives currently being considered.
The purpose of this proposal is to remove through-traffic and trucks from the crest of Hoover
Dam, which will reduce the potential for pedestrian-vehicular conflicts; safeguard the dam and
power plant facilities and the waters of Lake Mead and the Colorado River from potential spills
or explosions involving transportation of hazardous cargo; protect the dam and power plant
facilities in the interest of national security; provide improved conditions for operation and
maintenance of the dam facilities; reduce traffic accidents and congestion near Hoover Dam; and
enhance the visitors' experience in the Hoover Dam area. Reclamation's environmental and
engineering studies will be used to the extent possible. The studies will be updated as necessary
to assess social, economic, and environmental (SEE) impacts and any other potential impacts of
the proposed improvement.
The FHWA, as the lead agency, will prepare an Environmental Impact Statement (EIS) for the
proposed project following the Council on Environmental Quality's (CEQ) "Regulations for
Implementing the Procedural Provisions of the National Environmental Policy Act (NEPA)" of
November 29, 1978,40 CFR, Parts 1500-1508. In accordance with CEQ REG 1501.6 and 23
CFR 771, the FHWA is requesting that your agency become a cooperating agency in the
development of this project.
-------
We are requesting cooperating agency status from the following agencies: U.S. Fish and Wildlife
Service (Reno office), U.S. Army Corps of Engineers (Reno office), Environmental Protection
Agency, U.S. Coast Guard, Bureau of Reclamation, National Park Service, Arizona Department
of Transportation, Nevada Department of Transportation, Arizona Game and Fish Department,
and Nevada Division of Wildlife.
The views of cooperating agencies will be sought throughout all stages of the development of the
EIS. This coordination is intended to preclude any subsequent and duplicative reviews by
cooperating agencies. This coordination will also aid in identifying all reasonable alternatives;
social, economic, and environmental impacts; and measures to minimize adverse impacts that
may result from this improvement.
Enclosed is a copy of the FHWA's "Guidance on Cooperating Agencies," which outlines the
responsibilities of the FHWA (as lead agency) and of cooperating agencies. More project-
specific responsibilities may be worked out during the scoping process.
An interagency Project Management Team (PMT) was formed in May of this year to guide our
project development process. Agencies already represented on the Project Management Team
(PMT) may want to designate one or both of their PMT members as our point of contact.
Cooperating agencies not represented on the PMT are asked to designate a single point of
contact for their agency. Regardless of your decision to participate as a cooperating agency,
your agency is invited to an interagency scoping meeting in Las Vegas that is tentatively
scheduled for Wednesday, October 29. Evening public scoping meetings are scheduled for
Kingman, Boulder City, and Las Vegas on October 27, 28, and 29, respectively. Meeting
locations and times will be announced prior to the meetings.
We look forward to your response for participating as a cooperating agency and for participating
in the interagency meeting. We ask that you please respond by September 26. If you have any
questions or need additional information, you may call Mr. Terry Haussler, Project Manager, at
303-969-5916, or write to the above address (Attention: Terry Haussler, HPD-16).
Sincerely yours,
'Larry C. Smith, P.E.
Division Engineer
Enclosures
cc (w/map encl): 23Z/
Mr. SamF. Spiller, Field Supervisor, US F&W Service, 3616 W. Thomaa Road, Suite 6,
Phoenix, AZ 85019
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be (w/ encl):
PMT members (Crawford, James, Wallace, Duarte, Mills, Shrader, Burke, Holland, Rud,
Thomas)
Brian O'Halloran, CH2M HILL
Rick Gushing
Terry Haussler
yc: reading fiie
Central file - Hoover Dam Road ~ftf
THAUSSLER:jm:9/ll/97:L:\des\ad2\wp\hoover\coopagy.wpd
Identical letter (w/ enclosure) to:
Mr. Kevin Roukey, Chief, Nevada Office
U.S. Army Corps of Engineers
C. Clifton Young Federal Building
300 Booth Street, Room 2103
Reno, NV 89509
cc (w/map encl): Chief, Phoenix Regulatory Branch, U.S. Army Corps of Engineers,
3636 N. Central, Suite 760, Phoenix, AZ 85012-1936
Ms. Felicia Marcus
Regional Administrator
Environmental Protection Agency
Region 9
75 Hawthorn Street
San Francisco, CA 94105
Commander (POW-2)
U.S. Coast Guard
Building 50-6
Alameda, CA 94501-5100
Mr. Robert W. Johnson
Regional Director
Bureau of Reclamation
P.O. Box 61470
Boulder City, NV 89006-1470
Mr. Alan O'Neill, Superintendent
Lake Mead National Recreation Area
601 Nevada Highway
Boulder City, NV 89005
Mr. John Louis, Assistant State Engineer
Arizona Department of Transportation
205 South 17th Avenue, Mail Drop 61 IE
Phoenix, AZ 85007
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Mr. Tom Stephens, Director
Nevada Department of Transportation
1263 South Stewart Street
Carson City, NV 89712
Mr. Bob Posey, Habitat Program Manager
Arizona Game and Fish Department
5325 N. Stockton Hill Road
Kingman, AZ 86401
Mr. Butch Padilla, Habitat Specialist
Nevada Division of Wildlife
4747 Vegas Drive
Las Vegas, NV 89108
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USDeparlment Central Federal lands 555 2ang Street
Of Transportation Highway Division P.O. Box 25246
Federal Highway Denver, Colorado 80225-0246
Administration
MAY 11 1998
In Reply Refer To:
HPD-16
Mr. David W. Brickey
Chair
Southern Nevada Group, Sierra Club
PO Box 19777
Las Vegas, NV 89132
Dear Mr, Brickey:
Thank you for your letter dated February 3, regarding the Hoover Dam Bypass project The
Laughlm route that the Sierra Club supports is one of several additional alternatives suggested
by the public since the project resumed last spring.
We have been in contact with Fred Dexter, who is your Hoover Dam Bypass Sub-Committee
Chairperson. We met briefly with Fred, as well as with Randy Harness, your Conservation
Committee Chairperson, at the Laughiin Town Advisory Board meeting on April 14. As we
discussed at the meeting, the Project Management Team (PMT) has agreed to do additional
studies to evaluate the feasibility of the Laughiin alternative.
The study will address the improvements that would be required for U.S. 95, NV 163, and
AZ 68. Assuming that the Arizona Department of Transportation completes their proposed
upgrades on AZ 68, the additional improvements needed are likely to include the following:
1) Widening U.S. 95 to four lanes (55 miles)
2) Constructing a new Colorado River crossing in the Laughiin vicinity
3) Adding substantial pavement overlays to 105 miles of existing highways to
accommodate the additional truck traffic
4) Constructing truck escape ramps, controlled access interchanges, and possibly adding
climbing lanes on NV 163 and AZ 68
In addition, the study will assess the following:
1) Effects of 23 additional miles on productivity, fuel consumption, air quality, and
number of accidents and fatalities
2) Potential effects of lower design speeds, sharper curvature, and steeper grades on
commercial trucking
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3) The amount of through-traffic expected to continue using U.S. 93 between Las Vegas
and Kingman and its effect on the traffic and safety issues at Hoover Dam. Origin and
destination surveys done on U.S. 93 and U.S. 95 will be used to help make this
evaluation.
The results of this evaluation will help us determine whether the Laughlin alternative sufficiently
meets the purpose and need for the project and whether it should be studied in detail as a viable
alternative. The evaluation will be completed sometime in June.
We would be happy to get together to discuss these studies in more detail, prior to the formal
distribution of the draft EIS. We are also looking forward to hearing more about your specific
concerns with the alternatives closer to Hoover Dam. If you have any questions or comments,
feel free to contact Terry Haussler, Project Manager, at 303-716-2116,
Sincerely yours,
Larry C. Smith, P.E.
Division Engineer
cc: Bruce O'Halloran, CH2M HILL, 2f 07 No. 1st St., Ste. 210, San Jose, CA 95131-2026
Ken MacDonald, CH2M fflLL, 2000 E. Flamingo Rd., Ste. A, Las Vegas, NV 89119-5163
be: T. Haussler
yc: reading file
Central file - NV Hoover Dam Bypass Road
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SIERRA CLUB - Toiyabe Chapter
Southern Nevada Group /rW
P.O. Box 19777, Las Vegas,, Nevada 89132
Mr. Terry Hausler (HPD-16) February 3, 1998
Federal Highway Administration
555 Zang Street, Room 259
Lakewood, CO 80228
Dear Mr. Hausler:
The Southern Nevada Group of the Sierra Club has been participating in the Hoover Dam
Bypass National Environmental Policy Act (NEPA) process since the scoping meeting
held on June 7, 1990. On behalf of the 1700 members of the Southern Nevada Group,
this letter and attachments constitute its position on this project.
The Southern Nevada Group approved the first attachment, "Hoover Dam Bypass
Resolution," on January 6, 1998. The second attachment, "Hoover Dam Bypass Laughlin
- Bullhead City Proposed Route," presents our analysis of a fifth alternative.
The Southern Nevada Group recognizes the need for a new Colorado River bridge to
provide a bypass for heavy trucks crossing the Hoover Dam.
However, it is the position of the Sierra Club, Southern Nevada Group that this proposed
southern crossing should be immediately added to the Hoover Dam bypass study Draft
Environmental Impact Statement for consideration as one of the formally proposed
alternatives. Failure to do so will render the Draft Environmental Impact Statement
fatally flawed. Such an omission will waste a great amount of precious time and money
that has already been dedicated to finding a solution to this hazardous truck congestion
problem.
Thank you for your consideration of our proposal. The Sierra Club anxiously awaits the
Draft Environmental Impact Statement for this proposed project.
If you have any questions please contact me at the address above or contact Fred Dexter
(Hoover Dam Bypass Sub-Committee Chair) at 702-293-7736.
Sincerely,
David W. Brickey
Chair
Southem Nevada Group
Sierra Club
To explore, enjoy, and protect the wild places of the earth .. .
-------
SIERRA CLUB - Tolyabe Chapter
Southern Nevada Group
P.O. Box 19777, Las Vegas,, Nevada 89132
March 6, 1998
Mr. Terry Haussler (HPD-16)
Project Manager
Hoover Dam Bypass
Federal Highway Administration
555 Zang Street, Room 259
Lakewocd, CO 80228
Dear Mr. Haussler,
Enclosed is the list of recipients of copies of the Southern Nevada Group of
the Sierra Club position documents on the proposed Hoover Dam Bypass. My regrets
for the delay in providing this information to you, but additional names were
being added until only a few days ago.
Sincerel
Dexter, Jr. (S
Chairman
Hoover Dam Bypass Sub-Conmittee
Southern Nevada Group
Sierra Club
To explore, enjoy, and protect the wild places of the earth . . .
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cc: Governor Jane Dee Hull of Arizona
Governor Bob Miller of Nevada
U.S. Senator Richard Bryan of Nevada
U.S. Senator Jon Kyi of Arizona
U.S. Senator John McCain of Arizona
U.S. Senator Harry Reid of Nevada
U.S. Congressman John Ensign, Nevada First District
U.S. Congressman Jim Gibbons, Nevada Second District
U.S. Congressman Bob Stump, Arizona Third District
Nevada State Senator Bob Coffin
Nevada State Senator Jon Porter
Arizona State Senator Carol Springer
Nevada State Senator Dina Titus
Arizona State Senator John Wettaw
Boulder City Mayor Bob Ferraro
Bullhead City Mayor Norm Hicks
( Laughlin Town Manager Jackie Brady
' Bullhead City Manager's Office
Kingman City Manager's Office
Mohave County Manager's Office
Needles City Manager's Office
U.S. Bureau of Reclamation Director Robert Johnson
Hoover Dam Project Manager Tim Ulrich
LMNRA Superintendent Alan O'Neill
Arizona DOT Director Larry Bonine
Nevada DOT Director Thomas Stephens
Mr. Don Laughlin, Owner Laughlin Riverside casino
Boulder City Chamber of Commerce
Bullhead City Chamber of Commerce
Laughlin Chamber of Commerce
Boulder City News
Bullhead City Bee
Kingman Daily Miner
Las Vegas Review Journal
Las Vegas Sun
Mohave Daily News/New West Publishing
-------
-------
US Department Central Federal Lands 555 Zang Street
Of Transportation Highway Division P.O. Box 25246 MmKmM
Denver, Colorado 80225-0246
Federal Highway
Administration
March 6, 1998
In Reply Refer To:
HPD-16
See addressee list below
Subject: Hoover Dam Bypass, U.S. 93
We are enclosing a draft copy of the "Purpose & Need" and "Alternatives" for the
Environmental Impact Statement on the Hoover Dam Bypass project. This transmittal
initiates the NEPA-404 Integration Process, Per the Memorandum of Understanding between
our agencies, you have up to 45 days to concur or nonconcur on NEPA purpose and need,
section 404 basic and overall project purpose, criteria for alternative selection, and project
alternatives to be evaluated in the draft EIS. A preferred alternative has not been identified at
this time.
We are looking forward to your attendance at a field review on Monday, March 16, at 1:00
p.m. We will meet at the east end of the Goldstrike Casino parking lot. On Tuesday, March
17, we will meet at McCarran Airport in Meeting Room #2 (near Gate B-17) at 8:00 a.m.
We will make a short presentation and the remainder of the morning will be spent discussing
the "Purpose & Need" and "Alternatives."
We appreciate your early input on this important project. We hope to answer any questions
you may have as well. Please contact me at (303) 716-2116 if you have any questions or
comments.
Sincerely yours,
Terry Haussler, P.E.
Project Manager
Enclosure
cc: Rick Gushing, FHWA
Brian O'Halloran, CH2M HILL
-------
STATE OF ARIZONA
STATE OF NEVADA
Fife Symington
Governor
Bob Miller
Governor
April 23, 1997
The Honorable Rodney Slater
Secretary
United States Department of Transportation
Washington, DC 20590
Dear Secretary Slater:
Sincerely,
Fife Symington
Governor of Arizona
ob Miller
Governor of Nevada
1700 West Washington
Phoenix. Arizona 85007
Capitol Complex
Canon
SQ7in
-------
,tID
NCVAOA
WASHINGTON, DC 20510-2803
April 9, 1997
The Honorable Rodney Slater
Secretary of Transportation
400 Seventh Street, SW
Washington, DC 20590
Dear Mr. Secretary:
We are writing both to express our concern about a federal transportation infrastructure project
that needs attention, and to seek your input regarding this project.
As you know, in 1984, the Secretary of the Interior was directed to build a bridge over the
Colorado River at Hoover Dam. This bridge was authorized under the Hoover Plant Act (Public Law
98-381), "to alleviate traffic congestion and reduce safety hazards" on the two-lane highway bridge
linking Arizona and Nevada atop the federally-owned and operated Hoover Dam. More than twelve
years have passed, however, and the federal government has not moved on the project. The current
Hoover Dam bridge is deteriorating to a point of critical risk. It is in extremely poor condition and
has been the source of numerous accidents, particularly accidents involving large trucks. Moreover,
something must be done to alleviate the extremely heavy traffic on the bridge, as well as the resulting
safety and congestion problems.
Hoover Dam is federal property and the federal government has the chief responsibility to
address this critical problem. Consequently, we would like to have your views on which federal
programs and funding sources would be most appropriate to utilize in advancing this project. We
firmly believe this bridge merits prompt attention and advancement.
Thank you for your kind attention to this request. We look forward to working with you on
this and other transportation projects in the future.
Sincerely,
HARRY REID
United States Senator
.RICHARD
United States Senator
PRINTED ON RECYCLED CAPER
-------
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COMMITTEE ON COMMERCE, SCIENCE
AND TRANSPORTATION
WASHINGTON, DC 20510-6125
March 10, 1997
The Honorable Rodney slater
Secretary
U.S. Department of Transportation
Washington, D.C. 20590
Dear Rodney:
We are writing to seek your input regarding a safety-
sensitive transportation infrastructure project which, we are
informed, is under the jurisdiction of the federal government
H-V K Se^re^arv of the Department of Interior was
directed to build a bridge crossing over the Colorado River at
the Hoover Dam. Specifically, the Hoover Plant Act, p L 98-381
authorized this crossing "to alleviate traffic congestion and
reduce safety hazards" on the two-lane highway bridge atop the
federally-owned and operated Hoover Dam which links Arizona and
Nevada. Yet more than 12 years have passed and the federal
government has not been able to fulfill its obligation to move
the authorized project forward. In the meantime, the current
crossing continues to deteriorate to the point where critical
transportation safety problems will multiply. Without a remedy
these risks will escalate even further on this designated hiqh
priority transportation corridor.
Because the Dam is federal property, we believe the federal
government has the prime responsibility for the problem.
Therefore, we would appreciate receiving your views regarding
what existing federal program or programs may be best suited to
advance this federal project and what funding resources may be
available. From what we have learned about this federal project
it could compete well with other proposals and merits fair
consideration for advancement.
-------
-------
United States Department of the Interior
FISH AND WILDLIFE SERVICE
RENO FISH AND WILDLIFE OFFICE
4600 KIETZKE LANE, SUITE 125C
RENO, NEVADA 89502 NQV 2 1 1997
• File No. 1-5-98-TA-027
Mr. Teny K. Haussler
Federal Highway Administration
Post Office Box 25246
Lakewood, Colorado 80225-0246
Dear Mr. Haussler:
- Subject:' Notice to Prepare an Environmental Impact Statement for Construction
of a Bridge Across the Colorado River to Bypass Hoover Dam,
Clark County, Nevada, and Mohave County, Arizona
We have reviewed your request for scoping comments for the preparation of an environmental
impact statement (EIS) for the construction of the proposed bridge across the Colorado River,
Clark County, Nevada, and Mohave County, Arizona. The purpose of the proposal is to remove
through-traffic from the Hoover Dam crossing by one of three proposed alternatives. Alternatives
for bridge construction include approximately 4 miles of associated new roadway construction.
On October 29, 1997, Fish and Wildlife Service (Service) staff attended the interagency
coordination workshop held in Las Vegas to discuss the proposed construction of a Hoover Dam
bypass. Our comments and recommendations regarding issues to be addressed in the EIS are
provided below, many of which were previously provided at the workshop.
Threatened. Endangered, and Candidate Species, and Species of Concern
A number of bat, plant, and other bird species of concern may occur in the project area, which are
identified on the species list provided to Federal Highway Administration (FHWA) (File No. 1-5-
97-SP-346) on September 4, 1997. Direct, indirect, and cumulative impacts on federally listed
species and species of concern to the Service should be evaluated. Species of concern have no
protection under the Endangered Species Act of 1973, as amended (Act). However, one
potential benefit of considering species of concern is that by exploring alternatives early in the
planning process, it may be possible to provide long-term conservation benefits for these species
and avoid future conflicts that could otherwise develop.
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Mr, Terry K. Haussler . File No. 1-5-98-TA-027
Soil Quality
The impacts to soil quality from each alternative should be addressed. These impacts should
be related to the potential for restoring wildlife habitat types and values in all portions of the
proposed alignments following project completion. Areas of cut and fill should be identified for
each alternative, including proposed sources and disposal sites.
AkQuality
The document should include discussions of impacts to air quality from particulate and dust
emissions from road and bridge construction, as well as fugitive dust resulting from loss of
vegetative ground cover, if applicable.
Hazardous Materials
AH hazardous materials used during construction should be identified. Potential impacts of these
materials on fish and wildlife should be discussed. A contingency plan for dealing with spills and
accidents should be developed. The location and qualifications of personnel and equipment which
would respond to transportation accidents involving hazardous materials should be identified.
Noise
The EIS should address impacts of construction and highway noise on wildlife. High levels of
background noise are likely to interfere with the ability of wildlife, especially birds, to detect their
mates, young, and predators. This, in turn, may reduce reproductive success and result in a
decline in wildlife populations.
Mitigation/Compensation for Impacts
We recommend that FHWA develop measures to avoid, reduce, or compensate for direct and
indirect habitat losses and other negative impacts to fish and wildlife resources that would result
from this project. Compensation for temporal loss offish and wildlife resources, habitat
fragmentation, and other impacts could include reclamation of other Federal lands disturbed by
past activities, placement of monies into a fund for restoration, or enhancement of other disturbed
areas. Sites used to compensate for permanent or long-term impacts should be set aside in
perpetuity. The EIS should discuss mitigation/compensation measures in detail, including
restoration of areas disturbed by project construction. We recommend that only native plant
-------
Mr. Terry K. Haussler
Hle NQ ^.c^.
species indigenous to the area be used in restoration. The goal should be restoration of native
ecosystems as well as reduction of erosion potential.
Should it be determined that this project may have long-term impacts to any stream system, we
recommend that measures be developed to ensure such impacts do not occur or are reduced to
insignificant levels. The EIS should describe how impacts will be monitored over the long-term to
ensure sigmacant impacts do not occur. Monitoring levels and parameters should be described
and assurances provided that they will be implemented, not only for the life of the project but for
whatever time frame indirect impacts are likely to occur. A mechanism to ensure implementation
of additional mitigation/compensation measures should be provided in the event monitoring shows
higher levels of adverse impacts than originally anticipated. Monitoring should also be provided
to ensure success of any mitigation developed for the project.
Besides providing comments on the draft and final environmental document, we may comment on
any public notice issued by the Corps for a permit pursuant to section 404 of the Clean Water Act
for discharge of dredged or fill material into wetlands or waters of the United States We may
also comment on any public notice issued for a permit from the Nevada Division of Environmental
Prntp.rtinn
Protection.
We appreciate the opportunity to provide scoping comments on this project. If you have any
questions, please contact Michael Burroughs, in the Las Vegas Office, at (702) 646-3499.
Sincerely,
Robert D. Williams
Field Supervisor
cc:
Administrator, Nevada Division of Environmental Protection, Carson City Nevada
Administrator, Nevada Division of Wildlife, Reno, Nevada
Regional Manager, Nevada Division of Wildlife, Las Vegas Nevada
Chief, Nevada Field Office, U.S. Army Corps Of Engineers, Reno, Nevada
Deputy State Director, Resources, Land Use and Planning, Bureau of Land Management Reno
Nevada
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Mr. Terry K. Haussler File No. I-5-98-TA-027
Chief, Wetlands Section, Environmental Protection Agency, San Francisco, California
Field Supervisor, Arizona Field Office, Fish and Wildlife Service, Phoenix, Arizona
Regional Director, Fish and Wildlife Service, Albuquerque, New Mexico
Assistant Regional Director, Klamath and California Ecoregions, Fish and Wildlife Service,
Portland, Oregon
Assistant Regional Director, Interior Basin Ecoregion, Fish and Wildlife Service, Portland,
Oregon
References
Council on Environmental Quality, 1997. Considering cumulative eifects under the National
Environmental Policy Act.
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United States Department of the Interior
FISH AND WILDLIFE SERVICE
NEVADA STATE OFFICE
4600 KIETZKE LANE, SUITE 125C
RENO, NEVADA 89502-5055
September 4, 1997
File No. 1-5-97-SP-346
Mr. Terry K. Haussler
Federal Highway Administration
Post Office Box 25246
Denver, Colorado 80225-0246
Dear Mr. Haussler:
Subject: Species List for Proposed Hoover Dam Bypass, Clark County, Nevada
In response to your letter received September 2, 1997, enclosed is a list of federally listed species
that may occur in the vicinity of the proposed sites (Enclosure A). This fulfills the requirement
of the Fish and Wildlife Service to provide information on listed species pursuant to section 7(c)
of the Endangered Species Act of 1973, as amended. Enclosure B provides a discussion of the
responsibilities Federal agencies have under section 7 of the Endangered Species Act and the
conditions under which a biological assessment (BA) must be prepared by the lead Federal
agency or its designated non-Federal representative. A list of published references dealing with
the distribution, life history, and habitat requirements of the listed species is also included
(Enclosure C).
If your agency determines that a listed species may be affected by the proposed project, you
should initiate consultation pursuant to 50 CFR § 402.14. Informal consultation may be utilized
prior to a written request for formal consultation to exchange information and resolve conflicts
with respect to listed species. If a BA is required, and it is not initiated within 90 days of your
receipt of this letter, your agency should informally verify the accuracy of this list with our
office. If, through informal consultation or development of a BA, or both, the Federal agency
determines that the proposed action is not likely to adversely affect the listed species, and the
Service concurs in writing, then the consultation process is terminated and formal consultation is
not required.
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Mr. Terry K. Hausseler File No. 1-5-97-SP-346
For your consideration, Enclosure A also contains a list of other species of concern to the Service
that may occur in the project area. The Service has used information from the State and other
private interests to assess the conservation needs and status of these species. Further biological
research and field study are needed to resolve their conservation status. One potential benefit of
considering these other species of concern is that by exploring alternatives early in the planning
process, it may be possible to provide long-term conservation benefits for these species and
avoid future conflicts that could otherwise develop. We recommend that you contact the Nevada
Natural Heritage Program [1550 East College Parkway, Suite 145, Carson City, Nevada 89710,
(702) 687-4245] and the appropriate regional office of the Nevada Division of Wildlife, as well
as other local, State, and Federal agencies for data on distribution and conservation needs for
these and other species of concern.
Any type of construction or related activity may necessitate the removal of vegetation on the
project site. Destruction of bird nests and/or their contents may result if these actions are
conducted during the avian breeding season. Such destruction may be a violation of the Federal
Migratory Bird Treaty Act. We recommend that either vegetation removal be done outside the
avian breeding season, or that surveys be conducted prior to brush removal to ensure that nests
are not harmed or that activities do not result in nest failures.
Please reference File No. 1-5-97-SP-346 in future correspondence concerning this species list. If
you have any questions, please contact Stephanie Byers at (702) 784-5227.
Sincerely,
V-JChester C. Buchanan
U Acting State Supervisor
Enclosures (3)
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ENCLOSURE A
ENDANGERED AND THREATENED SPECIES
AND SPECIES OF CONCERN
FOR PROPOSED HOOVER DAM BYPASS
CLARK COUNTY, NEVADA
File Number: 1-5-97-SP-346
Endangered
Birds
Southwestern willow flycatcher Empidonax iraillu exlinna
Peregrine falcon Faico peregrinus anatum
Fishes
Devil's Hole pupfish Cyprinadon dibolis
Bonytail chub Gi7o elegans
Razorback sucker Xyrauchuen texanus
Threatened Species
Bird
Bald eagle Haliaeetus leucocephalus
Reptile
Desert Tortoise Gopherus agassizii
Species of Concern
Mammals
Spotted bat Euderma maculatwn
Greater western mastiff-bat Eumops perotis californicus
Al len 's big-eared bat Idionycteris phylloteris
California leaf-nosed bat Macrotus californicus
Small-footed myotis Myotis ciliolabntm
Long-eared myotis Myotis evotis
Fringed myotis Myolis thysanodes
Cave myotis Myotis velifer
Long-legged myotis Myotis volans
Yuma myotis Myotis yumanensis
Big free-tailed bat Nyctinomops macrotis
Pale Townsend's big-eared bat Plecottts towmendii pallescens
Birds
Western burrowing owl Athene cmicularia hypugea
Black tern Chlidonias niger
Least bittern hobrychus exilis hesperis
White-faced ibis Plegadis chihi
Reptiles
Banded Gila monster Heloderma suspectitm cinctum
Chuckwalla Sauromalus obesus
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ENCLOSURE A
1-5-97-SP-346
—continued-
Amphibian
Relict Leopard frog Rana Onca
Plants
Las Vegas bearpoppy Arctomecon californica
Threecorner milkvetch Astragalus geyeri var, triquetrus
Las Vegas catseye* Cryptantha insolita
Sticky buckwheat Eriogonum viscidulum
* Taxon may be extinct
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US.Departmenl Centra! Federal Lands 555 Zang Street
Of Transportation Highway Division P.O. Box 25246
Federal Highway Denver. Colorado 80225-0246
Administration
AUG 2 8 1997
In Reply Refer To:
HPD-16
Mr. diet Buchanen
Acting Project Leader
U.S. Fish and Wildlife Service
4600 Kietzke Lane, Suite 125-C
Reno, NV 89502
Dear Mr. Buchanen:
Subject: Hoover Dam Bypass, US 93
As you are aware, the Federal Highway Administration, in cooperation with the Nevada
Department of Transportation, Arizona Department of Transportation, Bureau of Reclamation,
and National Park Service, is proposing to construct a bridge across the Colorado River in the'
vicinity of Hoover Dam. The project also involves approximately four miles of new roadway
construction, all of which is on Federally-owned lands.
The project area is covered by the "Hoover Dam" and "Boulder City" USGS quadrangles.
Enclosed is an aerial photo showing the project location and the three alternatives being
considered. Approximate photo scale is one inch equals one-half mile.
The Bureau of Reclamation began environmental and engineering studies for this project in
1989. Enclosed is a copy of the original species list provided to the Bureau by your Phoenix
office. The project involves dealing with both state and regional boundaries and jurisdictions.
Although the original consultation was done through your Phoenix office, the Project
Management Team (PMT) has recommended that we resume the consultation process through
the Nevada side of the U.S. Fish and Wildlife Service. This recommendation was made
primarily because of the proximity of the project to your Las Vegas office. Your Albuquerque
and Portland regional offices have verbally agreed to this change. We have also made initial
contact with Dolores Savignano in your Las Vegas office.
As part of our analysis to complete the Environmental Impact Statement for this project, we
request that you advise us of any threatened or endangered plant and animal species (as well as
proposed or candidate species) that may be in the project area. We have already met with the
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Nevada Division of Wildlife and the Arizona Game and Fish Department to update them and to
discuss their concerns. If you have any questions, please contact me at 303-969-5916.
Sincerely yours,
1st
Terry K. Haussler
Project Manager
Enclosures
cc (w/enclosures):
Ms. Dolores Savignano, Office Supervisor, Fish & Wildlife Service, 1500 N, Decauter
Blvd., #1, Las Vegas, NV 89108
be (w/o enclosures):
T. Haussler
yc: reading file
Central file: Hoover Dam Road Bypass
THAUSSLER:jm:8/28/97:L\des\ad2\wp\hoover\species.wpd
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US-Deparrment Central Federal Lands 555 Zang Street
Of Transportation Highway Division P.O. Box 25246
_ . ,.,, . Denver, Colorado 80225-0246
Federal Highway
Administration
DEC 3 1 1997
In Reply Refer To:
HPD-16
Mr. Jim Garrison
Arizona State Historic Preservation Officer
1300 W.Washington
Phoenix, AZ 85007
Dear Mr. Garrison:
I enjoyed talking with Ann Howard recently regarding the proposed Hoover Dam Bypass project
on U.S. 93. The details of our taking over the lead agency status on this project were included in
our letter to you dated October 8, 1997; however, I found it very beneficial to discuss some of
the specifics with Ann. This early exchange of information will be beneficial for us to get
started in the right direction and to help us stay on schedule.
Your office is certainly familiar with the project and with the coordination that was done
between your office and the Bureau of Reclamation in the early 90's. Our goal is to update
Reclamation's studies, complete the consultation work, and deliver a final EIS in January 1999.
Following arc the key items that 1 discussed with Ann:
• We plan to stake the three alternative alignments in January" With these staked
alignments, we will confirm the corridor that Reclamation surveyed and also extend it by
approximately 200 feet on each side of centeriine. We are more comfortable with a wider
corridor, so that any minor alignment changes made during final design will be covered.
We will supplement the cultural resource studies that Reclamation performed in the early
90's with additional information from the wider corridor. We hope to minimize re-work
by your office and this office by accepting the site eligibility agreements reached during
your consultation with Reclamation.
• We will likely not designate a preferred alternative in our draft EIS.
• Our consultant (CH2M HILL) will be using the services of an ethnographic specialist to
assist with the Traditional Cultural Properties work. We have received numerous
ethnograpliic specialist recommendations from the Arizona Department of
Transportation.
We would appreciate any comments you have regarding our plan for updating the Section 106
studies and completing the consultation with both the Arizona and Nevada SHPO offices.
Specific comments on anything that was left unresolved during the consultation with
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Reclamation would also be appreciated. Thanks again for the early coordination on tins
important project. Please call me at 303-969-5916 if you have any questions or concern-
time throughout the development of the project.
Sincerely yours,
Terry K. Maussler, P,E.
Project Manager
cc: Brian O'Halloran, C1-I2M HILL, 2107 N. 1st Street, Ste. 210, San Jose, CA 95131-2026
be: T, Haussler
R. Gushing
yc: reading file
TKHAUSSLERrjm: 12/3 l/97:L\des\AD2\WP\Hoover\azshpo.wpd
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US Department Central Federal Lands 555 Zang Sfreel
Of Transportation Highway Division P.O. Box 25246
- . .... , Denver, Colorado 80225-0246
Federal Highway
Administration
DEC 2 2 1997
In Reply Refer To:
HPD-16
Ms. Alice M. Baldrica
Deputy State Historic Preservation Officer
Nevada State Historic Preservation Office
100 N. Stewart Street
Carson City, NV 89701-4285
Dear Ms. Baldrica:
I enjoyed talking with you and Gene Hattori this week regarding the Hoover Dam Bypass
project. I also appreciate the Hoover Dam Historic Landmark information that you furnished in
October. This early exchange of information will be beneficial for us to get started in the right
direction and to help us stay on schedule.
Your office is certainly familiar with the project and with the coordination that was done
between your office and the Bureau of Reclamation in the early 90's. Our goal is to update
Reclamation's studies, complete the consultation work, and deliver a Final EIS in January of
1999.
We plan to stake the three alternative alignments in January. With these slaked alignments, we
will confirm the corridor that Reclamation surveyed and also extend it by approximately 200 feet
on each side of centerline. We are more comfortable with a wider corridor, so that any minor
alignment changes made during final design will be covered.
Following is a summary of the key points of our discussion this week:
• We should contact Scott Brooks-Miller in your office at 702-687-7601 for anything
related to "visual effects."
* We should contact Gene Hattori in your office at 702-687-6362 for coordination related
to cultural resources.
• We will likely not designate a preferred alternative in our Draft EIS. Consultation
required under the National Historic Protection Act will not begin until we have a
preferred alternative.
« We understand that many of your records, site forms, etc, are housed at the Harry Reid
Center in Las Vegas. Your recommendation was for us to update the original site forms
on a "Condition Report", which is an abbreviated form that is accessible by computer.
Any new sites that are identified will be recorded in your current format.
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Our consultant (CH2M HILL) will be using the services of an ethnographic specialist to
asSlst m our TCP consultation. You mentioned Mr, Richard Stouflel, an ethnographic
specialist from Arizona, who will be added to our list of possible resources.
Thanks again for the earl> coordination on this important project. Please call me at
303-969-5916 if you have any questions or concerns at any time throughout the development
of this project.
Sincerely yours,
Terry K. Haussier, P.E.
Project Manager
cc: Brian O'Halloran, CJI2M HILL, 2107 N. 1st Street, Ste. 210, San Jose, CA 95131-2026
be: T. Haussler
R. Gushing
yc: reading file
TKHAUSSLERym: 12/22/97:L\des\AD2\WP\Hoovcr\nvslipo wpd
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DESCRIPTION OF THE PROPOSED ACTION
The BR is seeking a permanent solution to the high volume of vehicular traffic
now us^ng U.S. Highway 93 across Hoover Dam and the Colorado River on the
Nevada/Arizona border (Figure 1). When the dam was constructed in 1935 there
was very little traffic. During 1990, an average of 8,204 vehicles per day
crossed the dam. The hazard to public safety has increased dramatically
During 1989, there were 50 accidents in the project area, 22 involved semi-
tractor trailers. A serious environmental accident could occur if a truck
containing volatile fuel, chemicals, or hazardous waste lost its load on the
top of the dam and the material entered Lake Mead or the Colorado River
Public Law 98-381, dated August 17, 1984, authorized the Secretary of the
Interior to construct a Colorado River bridge crossing, including suitable
approach spans, immediately downstream from Hoover Dam for the purposes of
alleviating traffic congestion and reducing safety hazards.
The proposed action is the construction of a bridge crossing the Colorado
River approximately 1,500 feet downstream of Hoover Dam. The Sugar loaf
Alternative was selected for the proposed action. The action would require
the constructing about 2.2 miles of highway approach in Nevada, a 1,900-foot
bridge, and approximately 1.1 miles of highway approach in Arizona.
Construction time is estimated to be five to six years.
Highway Approach Construction
In Nevada the new approach would leave the existing highway about 1,000 feet
east of the Goldstrike Casino (Figure 2). The new highway would be located
immediately south of existing U.S. Highway 93 until it reaches the BR
warehouse area. It would then make a sweeping turn to head directly southeast
toward the Colorado River. The new road would cross the existing BR service
road before Coining existing U.S. Highway 93 for approximately 1,300 feet. In
this section, a frontage road would need to be constructed along the south
side of the new highway. This frontage road would provide access to the dam
by passing beneath the new highway, thus allowing the existing highway to
continue to function as the dam access road.
From the warehouse area, the grade steepens slightly to approximately three
percent as the road would pass through a gap in the high rock ridge that
parallels the river and then would descend to the long-span bridge over the
river. On the Arizona side of the bridge, the approach road would transverse
an area of deep through-cut along the north slope of Sugarloaf Mountain. This
segment of new highway would then pass through an area containing two existing
sewage evaporation ponds that would need to be relocated. Past the sewage
ponds the highway would turn more southerly, crossing a wide ravine at a six
percent grade, and intersecting existing U.S. Highway 93 (Figure 2).
other features
On the Nevada approach a bridge, approximately 400 feet long, would cross a
bend in Goldstrike Canyon to eliminate constructing a large fill area. The
fill would have extended down into the canyon, completely covering the bottom
of the wash throughout the bend. The bridge would keep the bottom of the
canyon unchanged for drainage flows, would preserve access to the canyon, and
would provide a large opening for wildlife to cross beneath the new highway
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0.
.r ^istr rS::1^ ~ .. «« «.-«-
the Nevada highway approach.
- <-oiv aoo feet long, would cross a large ravine on
A highway bridge »W«x£f"£i¥£ «ou!d allow existing drainage flows and
- -Inf ^continue crossing beneath the new highway.
f , _.,* 4 that Balance of cut and fill would
* . . ~-4-imates indicate tnat Da-tance «*. -~~
t Preliminary engineering estimates *«""* h d to dispose of excess
occur on both highway approaches, eliminating tn
excavated material.
T- t-raffic delays are expected to occur during
No major detours, closures, or "J^ hi hway approaches. The existing highway
construction of **«"'"*",9, nterferenCe, except during construction at the
passes), and one tunnel (whi ch wou as o
continuous fencing would be P^=^ al°^ncin would continue approximately
wildlife to the crossing structures. Fenc ing existing U.S.
3,300 feet beyond the inter se £«« £ ^JJ ^ocSed to provide means of
right-of-way area.
The following measures would be undertaken to minimise the effects of the
proposed action to the desert tortoise:
Arizona Game and Fish Department.
To compensate for habitat lost, BR would contribute to a section 7
desert tortoise conservation fund.
Any tortoises found in the construction right-of-way would be moved
according to protocol prescribed by the Service.
A qualified tortoise biologist would be available for the handling of
tortoises found during construction
r
*
handling for removal from roadways
Measures would be ta.en to prevent road kill, in These
e likel.
P. Measures would be taen o prev
i tortoise densities and where tortoise movements would be
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measures would be designed and implemented from specifications provided
from Nevada, Arizona; and California Departments of Transportation.
SPECIES ACCOUNT AND ENVIRONMENTAL BASELINE
On August 4, 1989, the Service published an emergency rule (FWS 1989) that
afforded endangered status to the Mojave population of the desert tortoise
Subsequently, on April 2, 1990, the Mojave population of desert tortoises was
,™*e?0»3 threatened throughout its range north and west of the Colorado River
(FWS 1990). Critical habitat has not been designated in either Arizona nor
Nevada.
Although the Mojave population of desert tortoises is widely distributed, the
range of the population has been fragmented and tortoise numbers have declined
(Berry 1978, Berry 1989). Desert tortoise population declines have been
attributed to the encroachment of human activities (Berry 1978, Ber-y 1989)
These activities include collecting, motor vehicle mortality, off-highway
vehicle (OHV) mortality, and shooting. Habitat loss by development, road
construction, powerlines, pipelines, agricultural practices, mineral
extraction, and other human activities, reduces tortoise numbers. Habitat
modification by grazing, or other modification of native vegetative
communities and terrain morphology, has caused population declines (Berry
1978, Berry 1989). Further information on the range, biology, ecology, and
population status of the desert tortoise can be found in Berry (-1984), Duck
and Snider (1988), Hohman and Ohmart (1980), Karl (1983), Luckenbach (1982),
and Weinstein et aJL. (1987).
The project area is within the Black Canyon of the Colorado River which is
characterized by precipitous rocky terrain and rolling hills dissected by
desert washes. Plant communities and associated wildlife are typical for the
Eastern Mojave Desert biome, characterized by creosote bush (iarrea
tridentata) and white bursage (Ambrosia dunosa). Precipitation averages 8 to
12 inches per year in the form of rain. Within the adjacent areas of Lake
Mead National Recreation Area, the occurrence of plant and vertebrate animal
species have been documented by Miles et al. (1977). Low density populations
of desert tortoises are known to occur adjacent to the project area in the
Black Mountains, the Eldorado Mountains, and the Eldorado Valley (Rorabaugh
and Allen 1990, and Schwartz et al. 1978). The project area encompasses
portions of the threatened Mojave desert tortoise population (Nevada) and the
non-listed Sonoran desert tortoise population (Arizona).
Mojave population desert tortoises typically inhabit ereosote-burrobush or
creosote-yucca vegetation types. Mojave population tortoises prefer bajadas
and desert washes where soils range from sandy-loam to light gravel-clay which
are optimal for burrow construction. Sonoran population tortoises are found
on some steep rocky slopes of mountain ranges, primarily in Arizona uplands
vegetation dominated by palo verde and saguaro cactus. However, the
populations on both sides of the river in the Black Mountains are apparently
more similar to the Mojave populations which typically inhabit less steep
areas. The Black Mountains in Arizona are vegetatively similar to mountains
of the Mojave Desert (Bureau of Land Management 1988). Thus, the low density
population found in the project areas is probably a function of low habitat
suitability and could be rated as marginal. Due to the steep, rocky nature of
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,
I
*
th. project area and the degree of existing disturbance, the area probably
could never support more than low density populations.
x -Distribution and
Goldstrike canyon and PntO ^* 2n.i~i» <* 5 scat<
FFPECTS oy THE PROPOSED ACTIOM ON LISTEP SPECIES
action is not expected to reduce habitat quality or ^*f^n areas ot
„,
alignment are relatively undisturbed desert tortoise habitat, tortoises may
wander into the project area during construction.
be taken to protect these areas from indirect impacts of construction.
The width of the construction right-of-way would average 300 feet Roughly
half of this area would be out of the roadway and would be restored if
impacted? ?e*porary disturbance would result from heavy equipment operation
and blasting.
The construction of the new highway may affect Mojave
<^^:^^^
or Uipment. A BRPesti,natl indicated that five Mojave desert tortoises may
be affected by construction.
In addition to construction related impacts and loss of hab itat, there could
be mortality associated with road kills along the new f^hway. After
construction is completed, the more efficient nature of the bridge and ^gh
could allow vehicles to travel at higher rates of sp eed An greased br ak
distance resulting from higher attainable automobile speeds could result in
increased tortoise deaths from vehicular crushing.
The proposed action will not isolate desert tortoise populations.
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CUMULATIVE EFFECTS
Cumulative effects are those effects of future non-federal (State, local
government, or private) activities on endangered and threatened species or
critical habitat that are reasonably certain to occur in the foreseeable
future. Future Federal actions are subject to the consultation requirements
established in section 7 of the Act and, therefore, are not considered
cumulative to the proposed action.
Outdoor recreational activities, which may increase with an increased human
population, have the potential to impact adversely desert tortoise habitat in
the area. Off-road vehicle use occurs in the area. Off-road vehicles can
kill tortoises on the surface or in burrows, damage their burrows and nests;
damage vegetation used by the tortoise for cover or food; and compact the soil
and inhibit the germination of plants used by the tortoises. Soil compaction
may also interfere with tortoises being able to dig burrows.
Recreational target shooting occurs in the area and could harm desert
tortoises. Other general recreational use, including camping, picnicking,
sightseeing, hiking, bird watching, horse riding, and rock and mineral
collecting can result in desert tortoise habitat destruction. Other human
impacts associated with increased development include take of desert tortoises
for pets, vandalism, and fire.
INCIDENTAL TAKE
Sections 4(d) and 9 of the Act, prohibit any taking (harass, harm, pursue,
hunt, shoot, wound, kill, trap, capture or collect, or attempt to engage in
any such conduct) of listed species without a special exemption. -Harm" is
further defined to include significant habitat modification or degradation
that results in death or injury to listed species by significantly impairing
behavioral patterns such as breeding, feeding, or sheltering. "Harass" is
defined as actions that create the likelihood of injury to listed species to
such an extent as to significantly disrupt normal behavioral patterns which
include, but are not limited to, breeding, feeding, or sheltering. Under the
terms of sections 7(b)(4) and 7{o)(2) of the Act, taking that is incidental
to, and not intended as part of the agency action, is not considered a
prohibited taking provided that such taking is in compliance with this
incidental take statement. The measures described below are nondiscretionary
and must be undertaken by the agency or made a binding condition of any grant
or permit issued to the applicant, as appropriate.
The Service anticipates that the following take could occur as a result of the
activities associated with the proposed project over the next 100 years. The
level of take is based on the analysis of impacts provided above, results of
tortoise surveys, the protective and mitigative measures offered by BR, and
the duration of the project.
1. A maximum of 80 acres of Hojave desert tortoise habitat are
anticipated to be destroyed and, therefore, taken during
construction of the Sugarloaf Alternative of the Colorado River
Bridge Crossing project.
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2 Five Mojave tortoises are anticipated to be taken in the form of
direct mortality through accidental death during ^
construction/rehabilitation activities.
•» Pive tortoises are anticipated to be taken in the form of
3- harassment through the removal of tortoises fro* harm's way during
construction/rehabilitation activities.
4 An undeterminable number of sheltersites, neats, and eggs are
anticipated to be taken during construction/rehabilitation
activities.
5 TWO tortoises per year are anticipated to be taken in the form of
£rect mortally from vehicles associated with the bridge and
approach highway.
6 An unknown number of tortoises are anticipated to be taken in the ^
form of indirect mortality through predation by ravens of coyotes
by trash at the project site resulting from project related
operations.
7. An unguantifiable number of tortoises are anticipated to be taken
indirectly in the form of harm through fragmentation of habitat and
increased noise associated with operation of construction equipment
and motor vehicles.
REASONABLE AND PRUDENT MEASURES
The Service believes that the following reasonable and prudent measures are
I
The Servce eeves
necessarj and appropriate to minimize the take authorized by this Biological
Opinion.
1 Measures will be taken to minimize mortality or harm to tortoises
by any activity during construction or operation of the proposed
project.
2. Measures will be taken to minimize habitat disturbance due to
project-related activities.
3 Measures will be taken to minimize predation of desert tortoises by
ravens or coyotes drawn to the project site during construction and
operation of the proposed project.
TERMS AND CONDITIONS
To be exempt from the prohibitions of section 9 of the Act, the BR must ensure
the compliance with the following terms and conditions, which implement the
reasonable and prudent measures described above.
1. To implement reasonable and prudent measure number 1, the following
terms and conditions shall be implemented.
a.
construction projects generally have a greater negative effect on
individual tortoises during the active period and construction
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related desert tortoise mortality is reported to be less during
periods of estivation and hibernation- The Service considers the
period between March 1 and November 1 to be the desert tortoise
activity period. During the tortoise active period, the
construction right-of-way shall be inspected for tortoises and
their burrows not more than three working days prior to any surface
disturbing activities. The inspection shall be conducted by a
qualified tortoise biologist and shall provide 100 percent coverage
of the right-of-way.
During clearance surveys, if tortoises are encountered within
harm's way, they shall be removed from danger. Tortoises and eggs
removed from the project area will be relocated to undisturbed
habitat within 1000 feet of the collection site, well away from the
project area. Tortoises removed from the project will be placed in
the shade of a shrub or in an unoccupied burrow similar to the one
where it was found, or in an artificially constructed burrow
following the protocol provided in Appendix A. Tortoises shall be
purposefully moved only by qualified tortoise biologists, solely
for the purpose of moving them from harm. The definition of "take"
includes capture. Therefore, any unauthorized person who removes a
tortoise from the site could violate section 9 of the Act.
If any tortoises are found within construction areas after the
initial removal of tortoises, all activity will cease until the
tortoise moves from potential harm of its own volition or a
qualified biologist can move it safely. Tortoises shall be moved
in accordance with Term and Condition l.a.
Construction and maintenance personnel working in desert tortoise
habitat will be informed that desert tortoises may occur in the
right-of-way and requested to refrain from harming or harassing
them.
d. Tortoise burrows within or just outside of the right-of-way that
can be avoided during construction activities shall be clearly
marked to prevent crushing during construction.
e. The area around and underneath every vehicle or piece of equipment
shall be inspected for tortoises before being moved. Tortoises
shall be moved in accordance with Terms and Conditions l.a. and
l.b.
f. Following construction, all areas requiring maintenance shall be
inspected for tortoises by a qualified tortoise biologist not more
than one working day prior to the initiation of the work. Any
tortoises located shall be removed in accordance with Terms and
Conditions l.a. and l.b.
g. Alternatively to Term and Condition l.a. above, a temporary or
permanent tortoise barrier may be installed around the perimeter of
the project area prior to the onset of any construction activities.
Following the installation of the tortoise-proof barrier, a
qualifies tortoise biologist shall thoroughly search all areas
inside the barrier for tortoises, using techniques providing 100
c.
-------
2.
r
I
L
boundaries.
percent coverage of all areas. Areas shall ^^^SU.*1"""
unless no tortoises are found on une j • *_ • i and
shall be removed in accordance with Terms an
l.b.
To implement reasonable and prudent measure number 2, the following
terms and conditions shall be implemented:
I
I
h Prior to initiation of surface-disturbing activities or right-of-
t Issuance within the project area, BR shall transfer $25,920
an account administered by the Bureau of Land Management,
ltx Source Area for mitigation for the destruction of Mo^ave
toise habitat within the project boundaries. The »*££*«»
rate is based 5324 per acre of habitat for 80 acres of long term
disturbance of habitat and will be indexed for infl«t«n based on
the Bureau of Labor Statistics Consumer Price Index. These funds
shall be directly deposited into BLM's desert tortoise compensation
fund number AZ-010-7122-5442 administered by BLM for the purpose of
securing tortoise management areas, habitat enhancement, and
tortoise research. Proposed expenditures shall be approved by the
Service.
Total payments must be made prior to construction initiation.
SJ-nTif -de directly, shall be by certified ch.ok or money
order payable to Bureau of Land Management, AZ-010-7122-5442, and
delivered to:
Area Manager
Shivwits Resource Area
225 N. Bluff Street
St. George, Utah 84770
The payment, shall be accompanied by a letter from BR that identifies the
projecfand the biological opinion that is directing the payment, the amount
of payment enclosed, and the number of the check or money order. The cover
letLfshall also identify the address of the lead BR °»««i*£**!i£d"11
of the Service office issuing the biological opinion. This information will
be used to notify the BR and Service that payment has been received.
3. To implement reasonable and prudent measure number 3, the following term
and condition shall be implemented:
A litter control program shall be implemented during construction that
will include the use of covered, raven-proof trash receptacles, removal
of trash from the construction site to the trash receptacles following
the close of each working day, and proper disposal of trash in a
designated solid waste disposal facility at the end of each work week.
-------
REPORTING REQUIREMENTS
Upon locating dead, injured, or sick Mojave desert tortoises, initial
notification must be made to the Service's Division of Law Enforcement
Special Agent, Edward Dominguez, Las Vegas (Telephone: 702/338-6380) '
Instructions for proper handling and disposition of such specimens will be
issued by the Division of Law Enforcement consistent with the provisions of
this incidental take statement. Care must be taken when handling sick or
in3ured animals to ensure effective treatment and care, and in handling dead
specimens to preserve biological material in the best possible condition All
tortoise remains will be frozen immediately and provided to an institution
holding appropriate Federal and State permits per their instructions.
Prior to construction, the BR will make arrangements with the institution
regarding proper disposition of potential museum specimens, should no
institutions want the tortoise specimens, the remains may be dispoged of in
any appropriate manner. In conjunction with the care of sick pr injured
^K^8!3' °u the preservation of biological materials from a dead tortoise,
the BR has the responsibility to ensure that information relative to the date,
time and location of the tortoise when found, and possible cause of injury or
death of each tortoise is recorded and provided to the Service. Should
injured animals be treated by a veterinarian and survive, the Service should
be contacted regarding final disposition of these tortoises. The Service
contact person is Jay Slack, Arizona Ecological Services office, Phoenix
Arizona (Telephone: 602/379-4720).
The BR will notify this office of all tortoises killed, injured, or removed
from the project area within 3 days of each occurrence. The BR will submit
annual reports (each calendar year) to the Service concerning all tortoise-
related activities undertaken in association with this project. Within 30
days after the completion of the project, the BR will provide the Service with
a report detailing all tortoise-related activities undertaken in association
with this project, including tortoise biologist activities, actual number of
tortoises injured, killed, or moved, and effectiveness of the terms and
conditions provided in this Biological Opinion.
If, during the course of the action, the .amount or extent of the incidental
take limit is exceeded, the BR shall immediately notify the Service in
writing. If the incidental take limit is exceeded, to avoid violation of
section 9 of the Act, the BR must immediately cease the activity resulting in
the take and reinitiate consultation with the Service. Operations must be
stopped in the interim period between initiation and completion of the new
consultation if it is determined by the Service that the impact of the
additional take will cause an irreversible and adverse impact on the species.
The BR should provide an explanation for the causes of the additional take.
CONSERVATION RECOMMENDATTONS
Sections 2{c) and 7(a)(l) of the Act direct Federal agencies to use their
authorities to further the purposes of the Act by carrying out conservation
programs for the benefit of endangered and threatened species. The term
-conservation recommendations" has been defined as the Service's suggestions
regarding discretionary agency activities to minimize or avoid adverse effects
of a proposed action on listed species, critical habitat, or regarding
10
-------
--
for the
the agency's section 7(a)(l}
The BE should initiate a monitoring program designed to determine the effects
of the project on the local tortoise population.
S^esL no;ifTcario; of the implementation of any conservation
I recommendations.
t
CONCLUSION
ds concludes formal consultation on the Sugarloaf Alternative of the
of the agency action that »ay Impact listed speeds
habitat in a
I
I
Action! ''we would appreciate notification of your final decision on this
action.
CANDIDATE SPECIES
For BR to fulfill the intent of the proposed action by compensating for the
loss of sonoran desert tortoise habitat, the Service suggests the following
conservation recommendation:
The BH should transfer $5,000 into an account administered by the Bureau of
,
Land Management, Shivwitz Resource Area for mitigation f«.th«
The mitigation rate
,
sonoran tortoise habitat within the project boundaries
is based 5125 per acre of habitat for 40 acres of long term
habitat. This rate was determined by the compensation formula developed by
aa.
the Desert Tortoise Compensation Team (1991). These funds should be
--7122 5442
e eser
deposited into BLM's desert tortoise compensation fund number AZ-010-
administered by BLM for the purpose of securing tortoise management a
habitat enhancement, and tortoise research. Proposed expenditures should be
approved by the Service.
Total payments should be made prior to construction initiation.
made directly, should be by certified check or money order payable to Bureau
of Land Management, AZ-010-7122-5442, and delivered to:
Area Manager
Shivwits Resource Area
225 N. Bluff Street
St. George, Utah 84770
11
-------
We appreciate the assistance and cooperation of your staff throughout this
fileUnuSern2-21-8r* ^ ^^ Writt6n C0mmunication' Plea^e referencfour
_ * jr "^ Oz. iU2rtJrl63r 2LSSX3t^^nC6* nloiAe*^ *^nT^*-^
*J"SV S lap* If f^*» —™*»«*w'v-f jjx^^osm wun^a1
Sam F. Spiller
cc: Director, Arizona Game and Fish Department, Phoenix, Arizona
Director, Nevada Department of Wildlife, Reno Nevada
State Director, Bureau of Land Management, Phoenix, Arizona
R^fT^6"*' Lake.Mead Na*ional Recreation Area, Boulder City, Nevada
Regional Director, Fish and Wildlife, Albuquerque, New Mexico (£si
Senior Resident Agent, Division of Law Enforcement, Fish and Wildlife
Service, Reno, Nevada
Field Supervisor, Fish and Wildlife Service, Reno, Nevada
Field Supervisor, Fish and Wildlife Service, Salt Lake City, Utah
Field Supervisor, Fish and Wildlife Service, Ventura, California
12
-------
CITED
t
, Tortoise Council on Order No. 11310-0083-81.
t .„,.„, v « 1989. (GoEherus sSSSSiSi) ' desert tortoise. Pp. 5-7. In I. R.
..
S? Kelvyn Press, Inc., Broadview, Illinois 203 pp.
Desert tortoise habitat management on
- «— -•
I
Washington, D.c.
Desert Tortoise Compensation Team. August 1991. Compensation for the desert
tortoise. Desert Tortoise Management Oversight Group. 17 pp.
nuck T A and J. Snider. 1988. An analysis of a desert tortoise population
'and nabttat on the Beaver Dan, Slope, Arizona. Part I, ^^eld-
Report to the BLM, Arizona Strip District, St. George, Utah.
and Wildlife Service. 1989. Endangered and threatened wildlife and
plantst Emergency determination of endangered status for the Mc^ave
population of the desert tortoise. 54 FR 32326. August 4, 1989.
Fish and Wildlife Service. 1990. Endangered and threatened wildlife and
plants: Determination of threatened status for the Mojave population of
the desert tortoise. 55 FR 12178.
April 2, 1990.
Honman. J. and R. D. Ohmart. 1980. Ecology of the desert tortoise (Gopherus
aaassizii) on the Beaver Dam Slope, Arizona. Unpublished Report
Contact NO! YA-510-PH7-54 submitted to the Bureau of Land Management,
Arizona Strip District, St. George, Utah-
A E 1983. The distribution, relative densities, and habitat
'associations of the desert tortoise, Gopherus agassizii, in
Thesis, California State University, Northridge, California.
Luckenbach, R. A. 1982. Ecology and management of the desert
icabhiru. a0aSSizii> in California. Pp. 1-37 In: North *
Tortoises: Conservation and Ecology. R. B. Bury (ed.J. U. S. Fish and
Wildlife Service Wildlife Resource. Kept. 12.
Niles, W. E., C. L. Douglas, J. Holland, C. Downer, J. Blake, J. Schwartz, w
G Austin. 1977. The biota of Lake Mead National Recreation Area,
Nevada/Arizona: Project Report No. 1, annotated checklist a«j
bibliography. Lake Mead Project Technical **P°^fS<*"^: SfSST*
National Park Resources Study Unit. University of Nevada, Las Vegas.
13
-------
Rorabaugh, J. and J. Allen. 1990. Desert tortoise occurrences proposed
Highway 93-466 Hoover Dam bypass routes. Bureau of Reclamation, Xuma,
Arizona.
Schwartz, J., G. T. Austin, and C. L. Douglas. 1978. Amphibians, reptiles
and mammals of the Lake Mead Recreation Area. Lake Mead Project
Technical Report Series, Report No. 2. Cooperative National Park
Resources Study Unit. University of Nevada, Las Vegas.
U.S. Department of the Interior, Bureau of Reclamation. 1993. Biological
Assessment: Probable Effects on Listed and Candidate Species Colorado
River Bridge Crossing - Hoover Dam. Bureau of Reclamation, Lower
Colorado Regional Office, Boulder City Nevada, October 1992. 25 pp.
Weinstein, M., K. H. Berry, and F. B. Turner. 1987. An analysis of habitat
relationships of the desert tortoise in California. A report prepared
for Southern California Edison Company.
96 pp.
14
-------
-------
,f ARIZONA
STATE
PARKS
BOO W. WASHINGTON
SUITE 415
PHOENIX ARIZONA 85007
TELEPHONE 602-S42-4174
I
E
RFE SYMINGTON
GOVERNOR
STATE PARKS
BOARD MEMBERS
DEAN M, FLAKE
CHAIR
SNOWFLAXE
ELIZABETH TEA
VICE CH*m
DUNCAN
31LL1E A. GENTRY
SECRETARY
SCOTTSOAIJE
j. RUKIN JELKS
ELGIN
WILLIAM G. ROE
TUCSON
RONALD PIES
TEUPE
M. JEAN HASSELL
STATE WHO COUMISSIONEB
KENNETH E. TRAVOUS
EXECUTIVE DIRECTOR
COURTLAND NELSON
DSPUTY OWECTOB
June 10, 1992
William E. Rinne
Regional Environmental Officer
DOl'Bureau of Reclamation
Lower Colorado Regional Office
P O Box 61^70
Boulder City. Nevada 89006-1470
River Bridge Crossing/Hoover Dam Project
Survey Report; DO1-BR
Dear Mr. Rinne:
Comments pursuant ot 36 CFR Pan 800:
of
in Arizona was identified within the
area.
aaree with the agency that the Kingman SwitchyardyTransformer
also
NV DO -6(ASM). dr HI test borings, are eligible as comnbut.ng
elements to a potential historic district focused on the construction.
operation, and maintenance of Hoover Dam.
not aoree
, that the remaining four sites (NV DD:15 17.
'
p
is lacking from the Agency's cover letter.
K ?n&° '^n £ o. "he^ta Once me presence o. ,he P^ssibie
Si has teen addressed, .hen I will be better able ID evaluate the
eligibility of this site.
CONSERVI
«•« H.STO.C ««..
-------
William E. Rinne
June 10, 1992
Page Two
5, I also note that the archaeologist states that NV DD:14:17(ASM> need-?
lk^hm^anaHnnHPh,°109rlPhed- ^^ *™* **™**rtS includeSite
^n ?3^f ^on^P ,0t^raphs {see attached SHPO Policy Statement dated
January 2, 1992); «f this has not been done, please ensure that adeauate
recordation of NV DD:14:17(ASM) occurs. adequate
6. I note that a site sketch map is also missing tor NV DD:14:19(ASM1
the hisune trash scatter associated with the construction of Hoover Dam.
7. For A2 F:2:87(ASM), the archaeologist states that the site needs
systematic photography and mapping; again, if this historic road has not
been adequately photodocumented and mapped, please ensure that this
occurs.
I look forward to further consultation on the eligibility of sites NV DD-15
17. and 19(ASM) and AZ F:2:87(ASM). Once eligibly^ defiminaUons '
have been made and the alignment/crossing has been selected, then we
look forward to consulting with the agency on project effect.
We appreciate your cooperation with this.office in complying with the
h.stor.c preservation requirements for federal undertakings. If you have
any questions or concerns, please contact me or Teresa Hoffman/Acting
Chief. Historic Preservation Section, at 542-4174 or 542-4009.
Sincerely,
Ann Valdo Howard
Archaeologist
-------
TUB-
United States Department of the Interior ™l
BUREAU OF RECLAMATION
Lower Colorado Regional Office
P.O. Box 61470
Boulder City, NV 89006-1470
. LC-158A MAY 5 1992
1 ENV-3.00
Mr. Ronald H. James
L Nevada State Historic
Preservation Officer
123 West Nye Lane, Room 208
Capitol Complex
Carson City NV 89710
Subject: Colorado Bridge Crossing/Hoover Dam
(Cultural Resources)
Dear Mr. James:
As you are aware, the Bureau of Reclamation (Reclamation) is
proposing to construct a bridge that spans the Colorado River in _
?he vicinity of Hoover Dam (Project). Enclosed for your review
and comment is a cultural resource report with associated site
files. As part of Reclamation's on-going Section 106
T ' consultation with your office for this Project, Reclamation
i reauests your concurrence with our determinations of eligibility
* ^cultural resource sites located within the Nevada side of the
Project area.
£ A preliminary Class III survey was conducted to identify cultural
resources that might be impacted during construction of the
bridge and highway. Three possible highway routes and bridge
crossing locations were investigated comprising approximately
145 acres surveyed. A 200-foot-wide corridor was inspected for
each proposed route. Rugged or inaccessible terrain was not
inspected for safety considerations. A total of *4-Jd^^B!^re
sites are located within the Project area of which 36 sites were
identified as a result of this survey. Refinements to tne
highway routes have been made since this survey was conducted and
those changes are so noted in the report.
A total of 34 previously and newly identified sites located in
Nevada were evaluated for National Register of Historic Places
(Register) eligibility. Five features wer^ P^0^ , ij*5tv
as contributing elements of the Register eligible ^Ider City
f: Water System. They have since been issued site numbers and are
•> recorded as:
t 26CK4697 - Booster/Relay Station; 26CK4744 - Foundations;
26CK4745 - Intake/Foundations; 26CK4767 - Culvert; and
26CK4768 - Foundations.
-------
Although not individually eligible, 23 sites are eligible as
contributing elements to-a potential historic district focused on
the construction, operation, and maintenance of Hoover Dam. The
boundaries for such a district have not been determined although
historic contexts do exist. Three of the sites are located
within or partially within the Hoover Dam National Historic
Landmark boundaries and are here considered as contributing
elements to Hoover Dam:
26CK4753 - Diversion Channel; 26CK4754 - Retaining Wall; and
26CK4765 - Transmission Switchyard.
The remaining 20 eligible sites which contribute to. a potential
historic district beyond the Landmark boundaries are:
Campsite;
Culvert/Ditch;
Cantilevered Walk;
Explosives Bunker;
Tunnel;
Gauging Station;
26CK4695 -
26CK4740 -
26CK4742 -
26CK4746 -
26CK4748 -
26CK4755 -
Stone Dams;
26CK4766 - Scenic.Overlook,
26CK4696 - Log Bridge;
26CK4741 - Retaining Wall;
26CK4743 - Wooden Ladders;
26CK4747 - Wooden Scaffold;
26CK4749 - Gauging station;
26CK4756 through 26CK4762 -
26CK4764 - Cable Car; and
Six sites are determined not eligible. They ..are:
26CK4698 - Cairn;
26CK4750 - Tailings;
26CK4752 - Dugout; and
26CK4739 - Foundations;
26CK4751 - R.R. Grade;
26CK4753 - Trash Scatter.
As per 36 CFR 60, Reclamation wishes to'consult with your agency
on Reclamation's determination of eligibility for the above
listed sites. Reclamation looks forward to receiving your
comments and concurrence on Reclamation's determinations. The
Arizona State Historic Preservation Officer is being consulted
with a similar submission for those sites located on the Arizona
side of the Project area.
If you have any questions, please contact Mr. William White,
Archeologist, at 702-293-8705.
Sincerely, •' .
JOHN E. PETERSON H
.William E. Rinne
Environmental Officer
Enclosures 3
be: .Assistant Commissioner - Resources Management
[Attention: D-5530 (Queen)
-------
StATE OF NEVADA
"BOS MCUJEB
I
I
DEPARTMENT OF CONSERVATION AND NATURAL ^OCT
DIVISION OF HISTORIC PRESERVATION AND ARCHEOMg^-'f
RONALD M. JAMES
Slat* Hi»t«f c l>n»crMwer Colorado Regional Office
Bureau of Reclamation i *«'-& i.D.
P.O. Box 61470 n^pi
Boulder City. NV 89006-1470 ' -^
Dear Mr. Rinne:
The Division of Historic Preservation and Archeology has reviewed the following repon
submitted by the Bureau of Reclamation (BOR):
Colorado Bridge Crossing/Hoover Dam Project. Bridge Crossing and Highway
Alignment Survey.
The Division concurs that the following sites are eligible for inclusion in the National
Register of Historic Places as contributing elements to a potential Hoover Dam historic
district under criterion c.:
26Ck4695:26Ck4696; 26Ck4740:26CW741:26Ck4742:26Ck4743:26Ck4746;
^6Ck4747- 26Ck4748- 26Ck4749; 26CU753; 26Ck4754:26Ck4755:26Ck4756:
^6Ck4757: 26Ck4758:. 26Ck4759:, 26Ck4760; 26Ck476l; 26Ck4762; 26Ck4764:
26Ck4765:26Ck4766.
The Division cannot concur that the following sites are not eligible for inclusion in the
National Register of Historic Places:
26Ck4698; 26Ck4739; 26Ck4750:26Ck4751:26Ck4752; 26Ck4753.
and
*e ome
Justification is needed for considering these sites as non- contributing elements to the
p^Sd Hoover Dam historic district. Mr. Queen (BOR) has suggested tnati tae .s
wbedigible as contributing elements to the district, and tt 1S unclear ^»
^nsi^red eligible and some Ire not. For example both diversion canals a
26Ck4740) arl functionally similar, are in good condmon. an d vpn^ J
ordam construction. Why « one (26Ck4740) considered eligible while = *e o
t { 26Ck4753) considered not eligible for the National Register as a contributing dement to
; wahThe dam seems to be an integral feature associated with dam construction. It is an
-------
William E. Rinne
June 4, 1992
Page Two
interesting interpretive feature that provides some insight into dam construction technology
Was there a rail line or tram associated with transfer of waste from the construction ate1* If
so, is this feature recorded?
Much of the site data presented with your submission is tna
-------
on octo^ 2, ».l.
for the location of the
National Par* Service
4--«« i^riuded- Jim Garrison, Arizona
Participants in the meetxng included Huston, NPS,
SHPO; Michelle McFadden , Nevada SHPO^ Ann^ National Recreatxon
Ian Francisco; Gary Bunney, VPS, "J^"^. Pr.oject Manager;
I^ea; Kris Mills, Re^a^a|n°fne2irSohn Petlrson, Reclamation
Lucy Gonyea, ^clamationgginegj a°eclamation Architectural
^i SflfiaB Whi4e, Kecla.ation Archeolog.st
The purpose of tne -et ing was
withthe Project and *o °bta« vx^ ± frQm ^ SHPos at
the various options. It xs rex tion/s planning efforts to
ra/eff eSffo the Hoover Da, (Da,) National
Landmark (Landmark) . _
s °
discussion at Boulder City.
XC »91 a
.
enclose* with .rackets („,
Tour:
+n -j-h^ three proposed bridge crossing
Participants were gke^to the ^f^p^ p
locations; Gold Stride, &"9*^ h ieal information for each
Point. Kris Mills PJ^f^^^telthf participants to get a
-
. e
- -
OF EECLAMATION
-------
• Sugarloaf Mountain: How will the Gold Strike bridge
construction interfere with raft launching (NPS)? 9
Tools and equipment used for bridge construction could fc*» A
problem Reclamation Safety Standards retire toa? n"et?b^
potentially dangerous situation. (Kris Mills)-?
• Promontory Point: What will be the level of the deck at
this crossing (NPS)? aecic at
1460 feet (Kris Mills).
BQUldey Citv Meeting?
£esenta£on 2"t£tS2£L'2'iS! Sf.*^ »ee«^ «*h a brief
The main purpose for this Project is one of safety at
nar,- - aona storc
Landmark but is also Reclamation's Landmark— An image of the Dam
effi Seal* WS are Very pr°Ud of it: ™* ^ant lo
2iscusse^ the Pr°Ject Management Team (PMT)
s a «?* exPlained that ^e PMT's main functions are to be
»^f JH StSdlts are completed, develop a funding agreement, and
manage the Project through design and construction.
that *here are «any considerations in addition to
ba™ significance and Landmark status that must be
toaianeed in the selection of the crossing location-
construct ability, cost, park land acreage (section 4f ) and
* ?fldlife and vegetation. [HI noted Sat th4 SSld
l! .
2S«!?«i oration was most problematic with regard to Bighorn sheep
crossing. Sugarloaf is also problematic, but adverse If f ects ca£
for^m tolay.^ hist°rical consideration is the
2ff2 SS^JiffSL^iSrg" for
September 1992, with a Record of Decision in October 1992.
-------
Kris briefly explained the Pf°-- f^f
preliminary design in support of the EIS.
* "*
«. alternatives under
routes south of Gold
more impact on
trc.rjLK.ts \.aujw -— - —'- ._„«>, rrr-«»ater imoact to NFS land.
the environment, and had a much ^ter impac^ ioriti2ed in
Section 4(f) ^^i^f^^LS aSeaae of NFS land. The Phase A
order of impacts to the lea*t ^ea|Jee routes in the vicinity of
I study determined ™| |^tgd ,from ftirther consideration.
« s
"rid9e
close proximity to the Dam.
..
-
r Sid Strike canyon (steel arch, concrete arch).
Comments / Questions :
f * uv.^4- -ic -»->i«* first view of the Dam from this
1
%?£
visible from the bridge for safety reasons (Kris
conSLSed ?TtS elimination and _ final selection of the
three locations proposed here. (Kris Hills)
Kris then turned the meeting over to John Peterson.
nothina official; but is intended as a "straw pole." It will
Se PM^ to consider the input of the SHPOs early in the
-------
process and thereby minimize the effects of this Pr-o-i^t- «« 4-v,
historical significance of the Landmark? Project on the
John had prepared a flip-chart that listed each crossing
Following are some of the comments made as the opinions were
SS? recofded on the fliP charts. At this time? on?y toe two
SHPOs and Ann Huston, NPS, were offering comments.
General Comments:
- It was generally felt that the computer generated qranhics
provide the viewer with a distorted and somewhat deceive
perspective for bridge types and crossing locations in
relation to the Landmark. The on-site tour provided the
best "feeling" for the magnitude of the bridge^nSLrk
relationship. Another shared concern was the deck
"i™ n °* *$* ^oaontory Point and Sugarloaf bridges as
»™?^?™ering the.Land»ark. [On-site..visit also changed
preliminary conceptions as to the visibility of the bridge
in relation to the Dam at proposed locations CNPJS)].
Promontory Point:
- There was a unanimous opinion that this location would
have an ad verse effed- on the Landmark. All agreed that
this was a bad choice for a bridge of any type! The
crossing is too close and would compete with the Landmark.
- Of the three bridge types discussed for this location, the
concrete cable-stayed type was preferred to the steel arch?
The suspension bridge appears to be unacceptable from the
participants perspective.
f°r ^ suspension bridge included: Way too busy
Dam (SHPOS);" no' toL is not
Comments for the steel arch bridge included: The arch is
(^vada SHPO) ' SuPP°rt above the deck would
-------
TABLE 1
FLIP CHARTS
LOOATIOB
Nevada (NV)
Arizona (AZ)
National Park (NFS)
DESIGN PREFERENCE
Suspension
Steel Arch
concrete Cable Stay
UPS
AZ NVf [NPS]
AZ, NV, NPS
NV
J
MOPMTAIN
Nevada
Arizona
NPS
DESIGN PREFERENCE
Steel Arch
Concrete Cable Stay
MedJXIB
-
AZ, NPS, NV
1
GOLD
Effect
*o
Effect
DESIGN PREFERENCE
^ » K
Concrete Arch
Steel Arch
Nevada
Arizona
NPS
NV
AZ, [NPS]
[NPS3
L
-------
..
-
(NeSala S^PO } ] lif tin* *** transference of Dam motifs
(Neaa
Sugarloaf Mountain
SET
by all, over the
S°" °V6f facilities that extend out
from the powerhouse (NPS)].
f°r the steel arcn include: Arch is less of a
-------
i
i
I
(Arizona SHPO,; elevated •£"£*£? (
against the skyline »hen £ e^° briage a color to match the
imposing "*<»£££ I'iors^oula make it recede into the
SndtngYandscaS (Nevada SHPO, .
. counts on
this iocation
Gold Strike canyon:
. Of the two bridge types, f°-^°anf ^S^on
was generally favored over^the other andv«ea ^ ^
acceptable. The Nevada SHPO slign y legs -^^ and
that c ona
acceptable. Te e legs -^^ a
in the fact that c|£ro™ding environment. The teizona
E53-s «,
the setting.
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I
Advisory
Council On
Historic
Preservation
DEC 18 1
Si. .
The Old Post Office Building
1100 Pennsylvania Avenue. NW. *809
Washington. DC 20004
sifetgn f •-. J z J
December 11, 1991
William E. Rinne
Regional Environmental Officer
Bureau of Reclamation
Lower Colorado Regional -Office
P.O. BOX 61470
Boulder City, NV 89006-1470
Dear Mr. Rinne:
reviews concerning this undertaking.
Project Review at (303) 231-5320 or FTS 554-5320
I
Sincerely,
* See October 2,1991, meeting notes.
Claudia Nissley
Director, Western Office
of Project Review
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««« «IIJ-PS STATE OF NEVADA RONAU3M. JAMES
BOB MTI1 PR Statm Historic />rw«»*«lon 0
I
I
DEPARTMENT OF CONSERVATION AND NATURAL RESOURCES
' DIVISION OF HISTORIC PRESERVATION AND ARCHEOLOGY
I 123 W. Nye Lane. Room 208
Capitol Complex
\ CaxsoQ City. Nc**da 89710
I (702) 687-5138
November 6, 1991 . //"" /A
William E. Rinne • .
Regional Environmental Officer .. . .
Bureau of Reclamation _:—^
Lower Colorado Regional Office . ..^:jf
P.O. Box 61470
Boulder City, NV 89006-1470
Dear Mr. Rinne:
We have reviewed the letters * and photographic docximentatior
forwarded by you to our office regarding the barrier-free access
alterations to Building 100 of the Date Street Complex, Bouldes
City. The Division concurs with your no adverse effect
determination for this undertaking. The alterations appear tc
have been sensitively completed and are in compliance with the
Secretary of the Interior's Standards for Rehabilitation. W«
appreciate the Bureau of Reclamation's efforts to keep our office
informed of the progress on the undertaking.
Regarding a second project, the review cf the draft notes for the
Hoover Dam Bridge Crossing, Michelle McFadden of our staff has
penned a few comments on the copy we have enclosed. If you have
any questions regarding her comments, please contact her at
(702) 687-5138. Again, we wish to thank you for providing the
opportunity for early consultation on an extremely important
project.
We look forward to working with you in the future.
Sincerely,
Alice M. Baldrica
Deputy State Historic Preservation Officer
See October 2,1991, meeting notes.
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*
t
L
I
I
ARIZONA
STATE
PARKS
800 W.WASHINGTON
SUITE 415
PHOENIX, ARIZONA 85007
TELEPHONE €02-542-4174
RFE SYMINGTON
GOVERNOR
STATE PARKS
BOARD MEMBERS
RONALD PIES
CHAIR
7EMPE
DEAN M. FLAKE
VCE CHAIR
SNOWFLAXE
ELIZABETH TEA
SECRETARY
DUNCAN
BILUE A. GENTRY
SC9T7SOALE
22 October 1991
B OFiCJAl FM CO
RECEIVED OCT 24 !
REPLY DATE
DATE I INITIALS
\
No. v r
FolOct i.O
Keyword
William E. Rinne
Regional Environmental Officer
Lower Colorado Regional Office
Bureau of Reclamation
PO Box 61407
Boulder City, NV 89006-1470
Attention: William White
RE: Hoover Dam NHL, New Vehicular Bridge,DO!-BR
Dear Mr. Rinne:
I have reviewed the draft meeting notes'concerning the Hoover Dam
Bridge Crossings and Bridge Types held in Boulder City on October 2,
1991 I feel these notes reflect an accurate account of the facts and
feelings of the meeting. The only correction I have is on page four where
under Promontory Point, Design Preference, Steel Arch AZ should be
high not NV.
Thank you for the opportunity to review this draft.
Sincerely,
James Garrison
Historical Architect
for Shereen Lemer, Ph.D.
State Historic Preservation Officer
J. RUK1N JELKS
WILLIAM G. ROE
TUCSON
M. JEAN HASSELL
STATE UNO COMMISSIONER
KENNETH c.. TnAVOUS
EXECUTIVE OtRECTOfi
* See October 2,1991, meeting notes.
CCURTLAND NELSON
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UNITED STATES
DEPARTMENT OF THE INTERIOR
FISH AND WILDUFE SERVICE
ECOLOGICAL SERVICES
3616 W. Thomas, Suite 6
c, Arizona 85019
2-21-89-1-170
June 19, 1991
vj
i
t
Regional Director, Bureau of Reclamation, Boulder City, Nevada
Acting Field Supervisor
MEMORANDUM
TO:
FROM:
SUBJECT:
information difficult.
Tne FVS appreciates tbe level °££tg™0i%0 ™f ^ PS« Jfaperiesf**
species ana unrv- w-m facilitate formal consultation. If wfi c
believe this preliminary "orx »iiA 4.a\.j.j.j.w --ii- t^v ciart or
be of further assistance, please contact Debra Bills, Jay Slack.
(Telephone: 602/379-4720 or FTS 261-4720).
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cc:
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i
LC-155
ENV-7.00
Memorandum
To: Mr. Sam Spiller, Field supervisor, Division^of
Ecological Services, Fish and Wildlife Service,
3516 West Thomas Road, Suite 6, Phoenix AZ 85019
From: Regional Director
Subject: Biological Assessment on Threatened and Endangered
Species for Proposed Colorado River Bridge - Hoover Dam
Project {Your Memorandum Dated August 23, 1989)
(Biological Assessment)
we have evaluated the potential impacts of the proposed subject
oroject to those species which were listed as being potentially
affected. Subsequent to this evaluation and in consideration of
the incorporated "conservation measures, it is our opinion that
none of the species listed would be put in jeopardy? therefore,
consultation as outlined in Section 7 of the Endangered Species
Act of 1973, as amended, is not required.
Please notify us with a letter of concurrence or non-concurrence
at your earliest convenience. If you have any questions
concerning the enclosed biological assessment, please contact
Mr. Michael Walker at FTS 598-~526.
ROBERT J.TOWLES
Enclosure
220 (w/encl)
Daily
150-Chrono
WBR:MTWal Jeer: ait: 05-09-91: 293-8526
(155:BIOASS-B)
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BOS
STATE OF NEVADA
RONALD M. JAMES
i Hiftonc PI •••••lion O.
DEPARTMENT OF CONSERVATION AND NATURAL RESOURCES
DIVISION OF HISTORIC PRESERVATION AND ARCHEOLOGY
123 W. Nyc Lam*. Room 208
Capitol Complex
Camon City, Nvrada 89710
> ... (702) 687-5138
July 5, 1990
William E. Rinne
Environmental Officer
Bureau of Reclamation
Lower Colorado Regional Office
?. O. Box 427
Boulder City, NV 39005
Dear Mr. Rinne:
OFFICIAL FILE COP1
U.S. Bureau of Reclaim
lower Colorado Recii
RBBVED JUL 9
This letter is in response to the information 'y°u forwarded us
regarding a new crossing of the Colorado River in the vicinity of
Hoover Dam. We understand that the existing situation with
traffic congestion and hazards at the Dam have led the Bureau of
Reclamation and other state and federal agencies to search for a
satisfactory solution to this problem. Hoover Dam is a National
Historic Landmark and the construction of a new bridge near the
Dam or widening the crest of the Dam will require the Bureau cf
Reclamation to consider the effects of the undertaking on this
landmark.
The Division sees the widening of the crest as the most serious
threat to the integrity of Hoover Dam. Without reviewing
specific plans, my general impression would be that the widening
would result in an adverse effect that would be. difficult to
mitigate. I am more favorably inclined toward a bridge spannina
the canyon or Lake Mead. Although the Bureau would have to
examine the effects of the construction and use if either the
Lake Mead or Gold Strike Canyon alternative were selected, visual
impacts would be easier and less costly to treat and would result
in fewer effects to the Dam.
These comments are only preliminary, based on the brief
descriptions forwarded to the Division. As plans are developed
and an alternative selected, , please feel free to discuss
potential effects with the Division's architectural historian.
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f
i
UNITED STATES
DEPARTMENT OF THE INTERIOR
FISH AND WILDLIFE SERVICE
ECOLOGICAL SERVICES
3616 W. Thomas, Suite 6
Phoenix, Arizona 85019
August 23, 1989
••r-
RECET. ED
rJ.auG 231
MEMORANDUM
/ / 1
T- 6* IX<
- * v
!
r
lorn- i
TO: Regional Environmental Officer, Lover Colorado Reg
Bureau of Reclamation, Boulder City, Nevada
FROM: Acting Field Supervisor
SUBJECT: Response for List of Threatened and Endangered .Species
for the Proposed Black Canyon Bridge Project
This responds to your request of July 28, 1989 for information on species
listed or proposed to be listed as threatened or endangered that may be in
the-vicinity.
The following species may be present in the area of the proposed project:
the endangered peregrine falcon (Falco oerecrrinus anatum), bonytaii chub
(Gila elccdns). Devil's Hole pupfish (Cvprinodon diabolis), and Hohave
populations of the desert tortoise (Xerobates aqassizii) .
Also, present in the project area are the Category 1 razorback sucker
(Xvrauchen texanus) and the Category 2 desert tortoise '(Xerobates acrassizii).
Sonoran population, whose listing is warranted but precluded. Candidate
category'1 species are those for which sufficient information exists to
support their listing as endangered or threatened. Development of proposed
rules for these species is anticipated. Category 2 species are those for
which sufficient information to list the species as threatened or endangered
is not available. Candidate species are not protected under the Endangered
Species Act'and information on their status is provided for your planning
purposes only.
If we may be of further assistance, please contact Debra Bills or me
(Telephone FTS 261-4720) .
Sincerely,
Gilbert D. Metz,
cc: Regional Director, Fish and Wildlife Service, Aliuquer
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