Boone Dam Seepage Remediation Supplemental Environmental Assessment
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Document Type: EA-Administrative Record Index Field: Supplemental Environmental Assessment Project Name: Boone Dam Seepage Remediation Project Number: 2015-15 Boone Dam Seepage Remediation Vegetation Management – Herbicide Use Supplemental Environmental Assessment June 2020 For Information Contact: Matthew Higdon NEPA Specialist Tennessee Valley Authority 400 West Summit Hill Drive, WT11B Knoxville, Tennessee 37902-1499 Email: [email protected] This page intentionally left blank. TABLE OF CONTENTS 1.0 INTRODUCTION .................................................................................................. 1 1.1 BACKGROUND .................................................................................................. 2 1.2 PURPOSE AND NEED FOR ACTION ................................................................ 3 1.3 RELATED ENVIRONMENTAL REVIEWS........................................................... 3 1.4 SCOPE OF THIS ENVIRONMENTAL ASSESSMENT ........................................ 4 1.5 CONSULTATION REQUIREMENTS AND NECESSARY PERMITS................... 5 1.6 PUBLIC NOTIFICATION ..................................................................................... 5 2.0 DESCRIPTION OF ALTERNATIVES CONSIDERED .......................................... 6 2.1 NO ACTION ALTERNATIVE ............................................................................... 6 2.2 TVA’S PROPOSED ACTION – HERBICIDE USE FOR VEGETATION MANAGEMENT .................................................................................................. 6 2.2.1 Project Description .................................................................................. 7 2.2.2 Summary of Proposed Mitigation Measures and TVA Commitments ....... 9 2.3 ALTERNATIVES CONSIDERED BUT NOT CARRIED FORWARD ...................11 2.4 ENVIRONMENTAL ISSUES AND COMPARISON OF ALTERNATIVES ...........12 3.0 AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES ..... 16 3.1 TERRESTRIAL ECOLOGY ................................................................................16 3.1.1 Affected Environment .............................................................................16 3.1.2 Environmental Consequences ................................................................17 3.1.2.1 No Action Alternative ............................................................................ 17 3.1.2.2 Proposed Action ................................................................................... 17 3.2 AQUATIC ECOLOGY ........................................................................................19 3.2.1 Affected Environment .............................................................................19 3.2.2 Environmental Consequences ................................................................20 3.2.2.1 No Action Alternative ............................................................................ 20 3.2.2.2 Proposed Action ................................................................................... 20 3.3 THREATENED AND ENDANGERED SPECIES ................................................21 3.3.1 Affected Environment .............................................................................21 3.3.2 Environmental Consequences ................................................................24 3.3.2.1 No Action Alternative ............................................................................ 24 3.3.2.2 Proposed Action ................................................................................... 24 3.4 SURFACE WATER RESOURCES ....................................................................26 3.4.1 Affected Environment .............................................................................26 3.4.2 Environmental Consequences ................................................................27 3.4.2.1 No Action Alternative ............................................................................ 27 3.4.2.2 Proposed Action ................................................................................... 27 3.5 HISTORIC AND CULTURAL RESOURCES ......................................................30 3.5.1 Affected Environment .............................................................................30 3.5.2 Environmental Consequences ................................................................30 3.5.2.1 No Action Alternative ............................................................................ 31 3.5.2.2 Proposed Action ................................................................................... 31 3.6 HEALTH AND SAFETY .....................................................................................31 3.6.1 Affected Environment .............................................................................31 3.6.1.1 No Action Alternative ............................................................................ 32 3.6.1.2 Proposed Action ................................................................................... 32 4.0 LIST OF PREPARERS ...................................................................................... 36 i 5.0 REFERENCES ................................................................................................... 38 LIST OF TABLES Table 2-1: Comparison of Impacts of the No Action Alternative and the Proposed Action ........13 Table 3-1. Federally listed terrestrial animal species reported from Sullivan and Washington Counties, Tennessee and other species of conservation concern documented within three miles of Boone Dam Remediation and Reservoir Drawdown Herbicide Use for Vegetation Management Supplemental Environmental Assessment 1 .....................23 LIST OF ATTACHMENTS Attachment A – Vegetation Management Areas (South Holston River and Watauga River Areas) Attachment B – TVA Bat Strategy Form ii LIST OF ACRONYMS Acronym Definition BMP best management practices CFR Code of Federal Regulations EA Environmental Assessment EIS Environmental Impact Statement EPA Environmental Protection Agency ESA Endangered Species Act FIFRA Federal Insecticide, Fungicide, and Rodenticide Act FONSI Finding of No Significant Impact HUC Hydrologic Unit Code IRRM Interim Risk Reduction Measure mgd million gallons per day NEPA National Environmental Policy Act NHPA National Historic Preservation Act NPDES National Pollutant Discharge Elimination System NRHP National Register of Historic Places PA Programmatic Agreement RLMP Reservoir Land Management Plan SHPO State Historic Preservation Officer TDEC Tennessee Department of Environment and Conservation TVA Tennessee Valley Authority TWRA Tennessee Wildlife Resources Agency USFWS U.S. Fish and Wildlife Service iii Supplemental EA Purpose and Need CHAPTER 1 – PURPOSE AND NEED FOR ACTION 1.0 INTRODUCTION In January 2016, TVA completed an Environmental Assessment (EA) considering its proposal to address and remediate seepage occurring at TVA’s Boone Dam, which is a multipurpose dam on the South Fork Holston River on the border between Sullivan and Washington Counties in upper East Tennessee. The EA concluded that TVA’s proposal to construct a composite seepage barrier along the crest of the dam embankment and the associated construction activities on TVA’s reservation and adjoining and nearby TVA lands would not result in significant environmental impacts. The EA addressed managing vegetation that would grow in exposed shoreline areas during the extended drawdown of the reservoir. The 2016 EA stated that: TVA proposes to implement a Vegetation Management Plan to manage the successional vegetation on much of the exposed reservoir bottom. TVA would work with private landowners to manage this growth with annual or periodic mowing or bushwhacking. When approved by the landowner, TVA would use mechanical means, including tractors with bush hog attachments, extendable hydraulic arms, and other equipment to ensure safety. Mowing may occur from small barges along the reservation where access may be too hazardous. Mowing vegetation on the exposed reservoir bottom would not be intended to eliminate the vegetation. Such vegetation may also be beneficial, by enhancing wildlife habitat, reducing erosion during the drawdown, and improving fish habitat after the reservoir is returned to normal water levels. TVA’s two primary objectives are to remove tree species from the newly exposed reservoir bottom areas that normally do not establish due to season pool levels and to avoid having trees mature during the drawdown period to heights that would create navigation and public safety problems once the waters are returned to normal levels. In preparation of conducting these activities, TVA tested and demonstrated several mechanical methods of vegetation management for their efficiency, ease of delivery, and maneuverability on steep slopes. TVA also evaluated the methods considering worker safety and the level of ground disturbance caused by the mechanical equipment. TVA determined that skid steer mounted mulchers/bush whackers were most suitable for the mechanical removal of vegetation. Tractors and excavators equipped with long reach or side arm equipment were found to be unsafe on many slopes and increased rutting and soil disturbance. In 2019, working with landowners and stakeholders, TVA began clearing vegetation on exposed reservoir bottom areas around the reservoir. TVA identified areas for treatment, concentrating clearing activities in embayments with dense vegetation growth as well as areas identified by the public and stakeholders. In 2019, TVA