Boone Dam Seepage Remediation FINAL ENVIRONMENTAL ASSESSMENT JANUARY 2016 TENNESSEE VALLEY AUTHORITY This page intentionally left blank. Document Type: EA-Administrative Record Index Field: Final Environmental Assessment Project Name: Boone Dam Seepage Remediation Project Number: 2015- 15 Boone Dam Seepage Remediation Final Environmental Assessment January 2016 For Information Contact: Matthew Higdon, NEPA Specialist Tennessee Valley Authority 400 West Summit Hill Drive, WT 11D Knoxville, Tennessee 37902-1499 Phone: 865-632-8051 Email: [email protected] Boone Dam Seepage Remediation Table Of Contents TABLE OF CONTENTS 1.0 INTRODUCTION ............................................................................................... 1-1 1.1 PROJECT LOCATION AND DESCRIPTION ..................................................... 1-1 1.2 BACKGROUND .................................................................................................. 1-7 1.2.1 Prior Related Activities and NEPA Compliance ...................................... 1-7 1.3 PURPOSE AND NEED FOR ACTION ............................................................... 1-9 1.4 SCOPE OF THIS ENVIRONMENTAL ASSESSMENT ...................................... 1-9 1.5 SIMILAR AND CONNECTED ACTIONS .......................................................... 1-10 1.5.1 Related Actions to Address Near-Term Needs ..................................... 1-10 1.5.2 Related Actions to Address Long-Term Needs .................................... 1-11 1.6 RELATED ENVIRONMENTAL REVIEWS ....................................................... 1-12 1.7 PUBLIC INVOLVEMENT .................................................................................. 1-13 2.0 DESCRIPTION OF THE PROPOSED ACTION AND ALTERNATIVES ........... 2-1 2.1 NO ACTION – NO BOONE DAM REMEDIATION AND CONTINUE INTERIM OPERATIONS .................................................................................................... 2-1 2.2 PROPOSED ACTION – REMEDIATE BOONE DAM AND RETURN TO NORMAL OPERATIONS.................................................................................... 2-2 2.2.1 Construction............................................................................................ 2-2 2.2.2 Construction Support and Management of Excess Rock and Soil ......... 2-5 2.2.3 Reservoir Drawdown and Interim Operations ......................................... 2-6 2.2.4 Summary of TVA Commitments and Proposed Mitigation Measures ..... 2-6 2.3 OTHER ALTERNATIVES EVALUATED, BUT DISMISSED FROM FURTHER CONSIDERATION ............................................................................................. 2-9 2.4 ENVIRONMENTAL RESOURCES CARRIED FORWARD .............................. 2-16 2.5 COMPARISON OF ALTERNATIVES ............................................................... 2-18 2.6 THE PREFERRED ALTERNATIVE.................................................................. 2-18 3.0 AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES .... 3-1 3.1 BACKGROUND FOR ENVIRONMENTAL ANALYSIS ....................................... 3-1 3.1.1 Boone Project Operations....................................................................... 3-1 3.1.1.1 Normal Operations (Prior to October 2014) ........................................ 3-1 3.1.1.2 Normal Flood Control Operations ....................................................... 3-4 3.1.1.3 Interim Operations during Dam Remediation ...................................... 3-5 3.1.1.4 Interim Flood Control Operations ........................................................ 3-6 3.1.2 General Characterization of Drawdown .................................................. 3-6 3.2 GEOLOGIC RESOURCES .............................................................................. 3-12 3.2.1 Affected Environment ........................................................................... 3-12 3.2.2 Environmental Consequences .............................................................. 3-13 3.2.2.1 No Action Alternative ......................................................................... 3-13 3.2.2.2 Proposed Action ................................................................................ 3-14 3.3 WATER RESOURCES ..................................................................................... 3-15 3.3.1 Affected Environment ........................................................................... 3-15 3.3.2 Environmental Consequences .............................................................. 3-24 3.3.2.1 No Action Alternative ......................................................................... 3-24 3.3.2.2 Proposed Action ................................................................................ 3-26 3.4 FLOODPLAINS AND FLOOD RISK ................................................................. 3-29 3.4.1 Affected Environment ........................................................................... 3-29 3.4.2 Environmental Consequences .............................................................. 3-31 3.4.2.1 No Action Alternative ......................................................................... 3-31 3.4.2.2 Proposed Action ................................................................................ 3-32 iv Tennessee Valley Authority Boone Dam Seepage Remediation Table Of Contents 3.5 WETLANDS ..................................................................................................... 3-34 3.5.1 Affected Environment ........................................................................... 3-34 3.5.2 Environmental Consequences .............................................................. 3-36 3.5.2.1 No Action Alternative ......................................................................... 3-36 3.5.2.2 Proposed Action ................................................................................ 3-39 3.6 TERRESTRIAL ECOLOGY .............................................................................. 3-40 3.6.1 Affected Environment ........................................................................... 3-40 3.6.2 Environmental Consequences .............................................................. 3-45 3.6.2.1 No Action Alternative ......................................................................... 3-45 3.6.2.2 Proposed Action ................................................................................ 3-46 3.7 AQUATIC ECOLOGY ....................................................................................... 3-48 3.7.1 Affected Environment ........................................................................... 3-48 3.7.2 Environmental Consequences .............................................................. 3-53 3.7.2.1 No Action Alternative ......................................................................... 3-53 3.7.2.2 Proposed Action ................................................................................ 3-55 3.8 THREATENED AND ENDANGERED SPECIES .............................................. 3-57 3.8.1 Affected Environment ........................................................................... 3-57 3.8.2 Environmental Consequences .............................................................. 3-63 3.8.2.1 No Action Alternative ......................................................................... 3-63 3.8.2.2 Proposed Action ................................................................................ 3-64 3.9 HISTORIC AND CULTURAL RESOURCES .................................................... 3-65 3.9.1 Affected Environment ........................................................................... 3-65 3.9.2 Environmental Consequences .............................................................. 3-67 3.9.2.1 No Action Alternative ......................................................................... 3-67 3.9.2.2 Proposed Action ................................................................................ 3-68 3.10 AIR QUALITY ................................................................................................... 3-69 3.10.1 Affected Environment ........................................................................... 3-69 3.10.2 Environmental Consequences .............................................................. 3-71 3.10.2.1 No Action Alternative ......................................................................... 3-71 3.10.2.2 Proposed Action ................................................................................ 3-71 3.11 SOCIOECONOMICS ........................................................................................ 3-72 3.11.1 Affected Environment ........................................................................... 3-72 3.11.2 Environmental Consequences .............................................................. 3-83 3.11.2.1 No Action Alternative ......................................................................... 3-87 3.11.2.2 Proposed Action .............................................................................. 3-100 3.12 RECREATION ................................................................................................ 3-103 3.12.1 Affected Environment ......................................................................... 3-104 3.12.2 Environmental Consequences ............................................................ 3-108 3.12.2.1 No Action Alternative ....................................................................... 3-108 3.12.3 Proposed Action