ENVIRONMENTAL ASSESSMENT FHWA-NV-EA 07.02 EA: 73215 October 2008 Federal Highway Administration and Nevada Department of Transportation in cooperation with the Bureau of Land Management Interstate 15 South Corridor Improvement Sloan Road to Tropicana Avenue Clark County, Nevada Alternative), the existing environment that could be affected by the project, the potential impacts from each of the alternatives, and the proposed mitigation measures. NDOT, with FHWA, is proposing to improve 12 miles of the I-15 corridor from Sloan Road to Tropicana Avenue, including Las Vegas Boulevard South between Sloan Road and Sunset Road. Improvements proposed for I-15 consist of expanding the freeway to a ten-lane facility (five general purpose lanes in each direction) from Sloan Road to Blue Diamond Road, and a ten-lane facility (five general purpose lanes in each direction) with collector-distributor (C-D) lanes from Blue Diamond Road to Tropicana Avenue. The I-15 South corridor includes Las Vegas Boulevard South, which would be improved to a six-lane facility (three lanes in each direction) from Sloan Road to Sunset Road, and separated by an open median designated for future use by the Regional Transportation Commission of Southern Nevada’s (RTC) Regional Fixed Guideway system. New service interchanges are proposed along I-15 at Bermuda Road, Starr Avenue, and Cactus Avenue; a reconstructed interchange at Sloan Road; a reconstructed overpass at Warm Springs Road;1 and new overpasses at Pebble Road and Sunset Road. Improvements would be made to the Blue Diamond Road (SR 160) interchange and the I-15/I-215 Beltway system interchange. A park-and-ride lot is proposed in the southwest quadrant of Las Vegas Boulevard and St. Rose Parkway. Transportation System Management (TSM) measures, including dynamic message signs and ramp metering to improve traffic operations, would also be incorporated. 1 Reconstruction of the Warm Springs Road overpass was previously studied and approved in the SR 160 EA and would be constructed as part of this project (FHWA and NDOT, 2004. Environmental Assessment for SR 160 Widening & I-15 Interchange Improvements, I-15 to Rainbow Boulevard, Clark County, Nevada. FHWA-NV-EA 04.03. April). CONTENTS LIST OF MITIGATION MEASURES ........................................................................................................ v 1. PROPOSED ACTION ........................................................................................................................... 1 1.1 Description ................................................................................................................................ 1 1.2 Purpose and Need...................................................................................................................... 2 1.3 Alternatives ............................................................................................................................. 15 2. ENVIRONMENTAL IMPACTS AND MITIGATION....................................................................... 49 2.1 Areas of No Impact ................................................................................................................. 49 2.2 Biological Resources............................................................................................................... 49 2.3 Social Considerations.............................................................................................................. 51 2.4 Visual Resources ..................................................................................................................... 55 2.5 Air Quality............................................................................................................................... 57 2.6 Noise........................................................................................................................................ 69 2.7 Floodplain and Hydrologic Assessment.................................................................................. 78 2.8 Water Resources...................................................................................................................... 80 2.9 Cumulative Impact Analysis ...................................................................................................83 3. AGENCY COORDINATION AND PUBLIC INVOLVEMENT....................................................... 87 3.1 Intent-to-Study Letter.............................................................................................................. 87 3.2 Information Meeting................................................................................................................ 87 3.3 Technical Advisory Committee............................................................................................... 87 3.4 BLM Coordination .................................................................................................................. 87 APPENDIXES A Intent-to-Study Letter B Comments and Responses C Cooperating Agency D Section 7 Consultation Correspondence E Procedures for Abatement of Highway Traffic Noise and Construction Noise F SHPO Concurrence Letter and Native American Consultation Letters i TABLES 1 I-15 South Corridor Mainline Peak-Hour Traffic Operations Analysis......................................... 13 2 I-15 South Corridor Intersection Level of Service......................................................................... 14 3 Relocations and Areas of New Right-of-Way ............................................................................... 52 4 National Ambient Air Quality Standards....................................................................................... 57 5 Year 2030 CO Concentrations....................................................................................................... 58 6 Noise Abatement Criteria .............................................................................................................. 69 7 Typical Sounds and Their Corresponding Noise Levels................................................................ 70 8 Noise Measurements...................................................................................................................... 71 9 Predicted Noise Levels and Soundwall Locations......................................................................... 72 FIGURES 1 Project Location............................................................................................................................... 3 2a Projected Casino/Employment Growth ...........................................................................................5 2b Projected Residential Growth .......................................................................................................... 7 3 Planned Local Street Network ......................................................................................................... 9 4 Levels of Service............................................................................................................................ 11 5 I-15 No Build Alternative Cross Section ....................................................................................... 21 6 Las Vegas Boulevard South No Build Alternative Cross Section ................................................. 23 7 I-15 Build Alternative Cross Section............................................................................................. 25 8 Las Vegas Boulevard South Build Alternative Cross Section....................................................... 27 9 Local Streets Build Alternative Cross Section............................................................................... 29 10a-10i Build Alternative..........................................................................................................31 through 47 11 Land Use........................................................................................................................................ 53 12 Total Mobile Source Air Toxics (MSATs) I-15 Mainline Segments 1 to 6 .................................. 63 13 Total Mobile Source Air Toxics (MSATs) I-15 Mainline Segments 7 to 13 ................................ 65 14 I-15 South Corridor – All Freeway Mainline Segments Mobile Source Air Toxics (MSATs) ..... 67 15 I-15 South Corridor – Arterials in Affected Network Mobile Source Air Toxics (MSATs)......... 67 16 U.S. Annual Vehicle Miles Traveled (VMT) vs. Mobile Source Air Toxics Emissions, 2000-2020 ...................................................................................................................................... 67 17 FEMA Floodplain Map.................................................................................................................. 81 ii ACRONYMS & ABBREVIATIONS ADT average daily traffic APE Area of Potential Effects BLM Bureau of Land Management BMPs Best Management Practices CAAAs 1990 Clean Air Act Amendments CCDAQEM Clark County Department of Air Quality and Environmental Management CCRFCD Clark County Regional Flood Control District C-D collector-distributor CEQ Council on Environmental Quality CFR Code of Federal Regulations cfs cubic feet per second CO carbon monoxide dBA A-weighted decibel DOT United States Department of Transportation DPM diesel particulate matter EA Environmental Assessment EB eastbound EIS Environmental Impact Statement EPA United States Environmental Protection Agency FAA Federal Aviation Administration FAST Freeway and Arterial System of Transportation