Johnsonville Fossil Plant - Ash Pond Dike Stabilization
Humphreys County, Tennessee
On February 10, 2010, TVA completed an environmental assessment (EA) and issued a finding of no significant impact (FONSI) for a proposal to enhance the stability of approximately 1,600 linear feet of a dike that supports the northeast side of an ash storage area at its Johnsonville Fossil Plant (JOF) located near New Johnsonville in Humphreys County, Tennessee. The FONSI and the EA, which considers the impacts of both a No Action Alternative and the Action Alternative of stabilizing the dike, are presented below.
The proposed dike stabilization is necessary to meet safety standards set by the U.S. Army Corps of Engineers (USACE) as well as to allow TVA to perform routine dike maintenance without affecting slope stability. USACE was a cooperating agency in the preparation of this EA.
The proposed action includes construction of a rock toe buttress that would provide additional stabilizing weight at the dike toe and would stabilize the steep bank above the water’s edge against erosion. The stabilization would also include placing clay to flatten the exterior slope of the dike. Seepage collection filters would be placed at several points along the toe of the dike prior to placing the soil and against the lower bank before placing the riprap. Once in place, the filters would collect water from seeps, reduce saturation of the new clay fill, and safeguard against soil piping.
PDF files require Adobe Acrobat Reader
Attachment A (PDF, 55 kb)
Summary of Geotechnical Exploration and Stability Analyses
Attachment B (PDF, 63 kb)
TVA Preliminary Categorical Exclusion Checklist No. 21069
Attachment C (PDF, 2.3 mb)
January 7, 2010, TVA Biological Assessment With Mussel and
Attachment D (PDF, 683 kb)
Tennessee Department of Environment and Conservation 401 Water
Attachment E (PDF, 6MB)
February 1, 2010, U.S. Fish and Wildlife Service Biological Opinion
For more information
or a printed copy of the documents, contact:
David Robinson, Senior NEPA Specialist
Tennessee Valley Authority
1101 Market Street, LP-5U
Chattanooga, TN 37402
Phone: (423) 751-2502; Fax: (423) 751-3230