United States Department of Agriculture Forest Service Incline Lake Dam Project Environmental Assessment Lake Tahoe Basin Management Unit Pacific Southwest Region Washoe County, Nevada August 2014 For More Information Contact: Matt Dickinson USDA Forest Service Lake Tahoe Basin Management Unit 35 College Drive South Lake Tahoe, CA 96150 530-543-2857 http://www.fs.fed.us/r5/ltbmu/ The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410, or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. Contents Page Summary ............................................................................................................................... S-1 Chapter 1 Introduction ........................................................................................................... 1-1 1.1 Document Structure .................................................................................................. 1-1 1.2 Background ................................................................................................................ 1-1 1.3 Overview of the Existing Condition ........................................................................... 1-2 1.4 Desired Conditions .................................................................................................... 1-5 1.5 Purpose and Need for Action .................................................................................... 1-5 1.6 Proposed Action ........................................................................................................ 1-5 1.7 Decision Framework .................................................................................................. 1-5 1.8 Public Involvement .................................................................................................... 1-5 1.9 Issues ......................................................................................................................... 1-6 1.10 Analysis Framework .................................................................................................. 1-6 1.11 Applicable Laws, Regulations, and Policies ............................................................... 1-7 Chapter 2 Alternatives, Including the Proposed Action ..................................................................... 2-1 2.1 Alternatives Considered in Detail .................................................................................... 2-1 2.1.1 Alternative 1 – No Action .................................................................................... 2-1 2.1.2 Alternative 2 – Proposed Action ......................................................................... 2-5 2.1.3 Alternative 3 ..................................................................................................... 2-10 2.1.4 Project Design Features and Best Management Practices ............................... 2-16 2.2 Monitoring ..................................................................................................................... 2-21 2.3 Comparison of Alternatives ........................................................................................... 2-22 2.4 Alternatives Considered, but Not in Detail .................................................................... 2-27 Chapter 3 Affected Environment and Environmental Consequences ......................................... 3-1 3.0 Introduction ............................................................................................................... 3-1 3.0.1 Organization of Chapter 3 ................................................................................... 3-1 3.0.2 Projects Considered for Cumulative Effects ....................................................... 3-2 3.0.2.1 Past Projects ...................................................................................................... 3-2 3.0.2.2 Present Projects ................................................................................................ 3-3 3.0.2.3 Projects in the Planning Stage .......................................................................... 3-3 3.0.3 Assumptions Common to All Alternatives .......................................................... 3-3 Section 3.1 Aquatic Wildlife ...................................................................................................... 3-4 3.1.1 Introduction ............................................................................................................... 3-4 Environmental Assessment August 2014 i Incline Lake Dam Project USDA Forest Service Contents 3.1.2 Overview of the Affected Environment .................................................................... 3-8 3.1.3 Environmental Consequences ................................................................................. 3-14 Alternative 1 – No Action ........................................................................................ 3-14 Alternative 2 – Proposed Action ............................................................................. 3-17 Alternative 3 ............................................................................................................ 3-20 3.1.4 Analytical Conclusions ............................................................................................. 3-24 Section 3.2 Botanical Resources .............................................................................................. 3-26 3.2.1 Introduction ............................................................................................................. 3-26 3.2.2 Overview of the Affected Environment .................................................................. 3-32 3.2.3 Environmental Consequences ................................................................................. 3-34 General Effects to TEPCS Botanical Species ............................................................ 3-34 Effects to Bolander’s Candle-moss .......................................................................... 3-41 Effects to Whitebark Pine ........................................................................................ 3-42 TEPCS Botanical species with suitable habitat, but no known occurrences in project area ..................................................................................... 3-43 Other botanical resources ....................................................................................... 3-44 3.2.4 Analytical Conclusions ............................................................................................. 3-44 Section 3.3 Cultural Resources ................................................................................................ 3-46 3.3.1 Introduction ............................................................................................................. 3-46 3.3.2 Overview of the Affected Environment .................................................................. 3-47 3.3.3 Environmental Consequences ................................................................................. 3-47 3.3.4 Analytical Conclusions ............................................................................................. 3-47 Section 3.4 Hydrology and Soils Resources .............................................................................. 3-48 3.4.1 Introduction ............................................................................................................. 3-48 3.4.2 Overview of the Affected Environment .................................................................. 3-48 3.4.3 Environmental Consequences ................................................................................. 3-57 Alternative 1 – No Action ........................................................................................ 3-57 Alternative 2 – Proposed Action ............................................................................. 3-58 Alternative 3 ............................................................................................................ 3-62 3.4.4 Analytical Conclusions ............................................................................................. 3-67 Section 3.5 Invasive Plants ...................................................................................................... 3-69 3.5.1 Introduction ............................................................................................................. 3-69 3.5.2 Overview of the Affected Environment .................................................................. 3-70 3.5.3 Environmental Consequences ................................................................................. 3-71 Habitat Alteration Expected ...................................................................................