US Army Corp of Engineers, Proposed Center Hill Tainter Gate Replacement, Environmental Assessment
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Environmental Assessment Spillway Gate Replacements Center Hill Dam and Reservoir April 2021 For Information, Contact: Chip Hall, Biologist U.S. Army Corps of Engineers Nashville District 110 9th Avenue South Room A410 Nashville, Tennessee 37203-3817 Telephone: (615) 736-7666 Email: [email protected] Center Hill Dam Spillway Gate Replacement Environmental Assessment U.S. Army Corps of Engineers, Nashville District Table of Contents Summary .......................................................................................................................................... 1 SECTION 1 – PROJECT DESCRIPTION ...................................................................................... 1 1.1 Authorization ........................................................................................................ 1 1.2 Purpose and Need ................................................................................................. 2 SECTION 2 – PROPOSED ALTERNATIVES ............................................................................... 3 2.1 No Action Alternative (NAA) .............................................................................. 3 2.2 Proposed Action Alternative (PAA) – Replace Spillway Gates .......................... 3 SECTION 3 – ENVIRONMENTAL SETTING AND CONSEQUENCES .................................... 5 3.1 Recreation and Scenic Resources ......................................................................... 6 3.2 Water Quality and Aquatic Recourses ................................................................. 7 3.3 Flood Risk Management ...................................................................................... 9 3.4 Climate and Physiography ................................................................................. 10 3.5 Terrestrial Resources .......................................................................................... 10 3.6 Federally Listed Species..................................................................................... 12 3.7 Cultural Resources ............................................................................................. 14 3.8 Hazardous, Toxic, and Radioactive Waste......................................................... 15 3.9 Health and Safety ............................................................................................... 15 3.10 Socioeconomics .................................................................................................. 15 3.11 Air Quality.......................................................................................................... 16 SECTION 4 – STATUS OF ENVIRONMENTAL COMPLIANCE ............................................ 16 4.1 Clean Water Act ................................................................................................. 17 4.2 National Historic Preservation Act. ................................................................... 17 SECTION 5 – PUBLIC AND AGENCY COORDINATION ....................................................... 17 5.1 Scoping Letter and Responses............................................................................ 17 5.2 30-Day Public Review of the Environmental Assessment................................. 17 SECTION 6 – CONCLUSIONS .................................................................................................... 17 SECTION 7 – REFERENCES ....................................................................................................... 19 i Center Hill Dam Spillway Gate Replacement Environmental Assessment U.S. Army Corps of Engineers, Nashville District Figures Figure 1. Project Vicinity Map. .......................................................................................... 2 Figure 2. Proposed Laydown Area .................................................................................... 4 Figure 3. Conceptual Work Platform and Barge ................................................................ 5 Figure 4. Proposed Laydown Area, Road Access, and Launching Ramp ........................ 12 Tables Table 1. Federally Listed Species Recorded Near Center Hill Dam ................................ 13 Table 2. Environmental Compliance. ............................................................................... 16 Appendix A – Scoping Notice and Mailing List Appendix B – Clean Water Act Documents Appendix C – National Historic Preservation Act Compliance Appendix D – Unsigned Finding of No Significant Impact ii Center Hill Dam Spillway Gate Replacement Environmental Assessment U.S. Army Corps of Engineers, Nashville District Acronyms CEQ – Council on Environmental Quality CEN – Center Hill Dam and Reservoir CFR – Code of Federal Regulations DO – Dissolved Oxygen EA – Environmental Assessment ER – Engineer Regulation ESA – Environmental Species Act FEA – Finite Element Analyses HTRW – Hazardous, Toxic or Radioactive Waste NAA – No Action Alternative NAAQS – National Ambient Air Quality Standards NEPA – National Environmental Policy Act NHPA – National Historic Preservation Act NRHP – National Register of Historic Places PAA – Proposed Action Alternative TWRA – Tennessee Wildlife Resource Agency USFWS – U.S. Fish and Wildlife Service WOL – Wolf Creek/Lake Cumberland Dam and Reservoir iii Center Hill Dam Spillway Gate Replacement Environmental Assessment U.S. Army Corps of Engineers, Nashville District Summary The US Army Corps of Engineers-Nashville District is proposing to replace the tainter gates (gates that allow water to spill over the dam) at Center Hill Dam/Reservoir (CEN) in Dekalb County, near Lancaster, Tennessee. Center Hill Dam in combination with Wolf Creek Dam/Lake Cumberland (WOL), in Kentucky, control 63% of the drainage area above Nashville, TN, and their combined operation significantly reduces flood risk in the Middle Tennessee region, as their combined storage capacity is 8 million acre-feet (2 million at CEN). CEN has 8 tainter gates that control water flow through the spillway. The tainter gates are conventional non-overflow radial type gates with a radius of 32.5 feet. Each tainter gate measures 50 feet wide and 37 feet tall. As tainter gate design criteria was updated based on trunnion friction issues experienced at other dams around the world, the need for project-specific structural analysis of tainter gates in the Nashville District was recognized. The analyses proved that critical members of the Center Hill gates were undersized and subject to overstress. Information for this Environmental Assessment (EA) was collected from federal, state, and local agencies and websites. The EA examines potential effects of the Proposed Action Alternative (replace all 8 tainter gates and the No Action Alternative (repair gates as malfunctions occur in the future). Resources that are examined or evaluated for potential effects include, but are not limited to recreation and scenic resources, aquatic resources and water quality, flood risk management, wetlands, navigation, climate, physiology, terrestrial resources, threatened and endangered species, cultural resources, hazardous toxic and radioactive waste (HTRW), human health and safety, socioeconomics, and air quality. Agency coordination and compliance issues have been identified and initial contacts made with appropriate agencies. Input through scoping and public coordination has been conducted to solicit any public or resource agency concerns that may need to be considered in preparation of the EA. SECTION 1 – PROJECT DESCRIPTION 1.1 Authorization The CEN project was authorized as a part of the ultimate plan for development of the water resources of the Cumberland River Basin by the Flood Control Act of 1938 (Public Law 761, 75th Congress, 3rd Session) and the Rivers and Harbors Act of 1946 (Public Law 525, 79th Congress, 2nd Session). This EA is being conducted under the Corps’ ongoing operation and maintenance authorities. This document serves to evaluate the impacts of the proposed spillway gate replacements at Center Hill Dam/Reservoir in Dekalb County, Tennessee near Lancaster. This EA was prepared by the Nashville District pursuant to the National Environmental Policy Act (NEPA), Council for Environmental Quality (CEQ) regulations (40 Code of Federal Regulations (CFR) 1500-1508), and the Corps’ Engineer Regulation (ER) 200-2-2, “Policies and Procedures for Implementing NEPA”. iii Center Hill Dam Spillway Gate Replacement Environmental Assessment U.S. Army Corps of Engineers, Nashville District Figure 1. Project Vicinity Map. 1.2 Purpose and Need CEN is a large, high head dam located near Lancaster, Tennessee at Caney Fork River Mile 26.6 (see Figure 1). It controls runoff from a drainage area of 2,174 square miles. The dam is a combination earth fill and concrete structure 2,160 feet long and 250 feet high, with a gated spillway structure. The Center Hill Dam’s tailwater extends 26.6 miles to the junction of the Cumberland River/Old Hickory Lake at Cumberland River Mile 309.2, just over four miles below Cordell Hull Dam. Construction began in March 1942 and was delayed for three years by World War II. Dam closure was started 27 November 1948 and filling the reservoir was completed December 1949. The first power unit was placed in commercial production in December 1950. There are 8 Tainter gates at CEN that control the flow of water through the spillway. The Tainter gates are conventional non-overflow radial type gates with a radius of 32.5 feet. Each Tainter gate measures 50 feet wide and