Allen Fossil Plant

As part of its compliance with the Tennessee Department of Environment and Conservation (TDEC) Commissioner's Order, TVA is currently conducting environmental studies at the former Allen Fossil Plant. Learn more about the TDEC Order.

The individual environmental studies, their definition and any status updates on its progress are listed below. In addition, each of the studies are described in more detail within the Environmental Investigation Plan and the Public Meeting Presentation.

Questions

Questions about the EIP, the process or the activities currently underway can be sent to: TDECorder@tva.com.

Documents

Remedial Investigations

Environmental Investigations

Definition: The constituents found in CCR are also found in nature. This investigation would compare CCR constituent levels in background soil to other soils to determine if they are higher than natural levels. This study would also help determine to what extent CCR constituents also occur naturally in native soils in the area.

Anticipated fieldwork: Summer 2019.

Definition: Surface streams are evaluated to determine the health of aquatic wildlife upstream, downstream, and adjacent to the fossil plant site. These evaluations have two parts: (1) testing mayflies for bioaccumulation of CCR constituents; and (2) counting the types and numbers of different benthic macroinvertebrates in the surface streams adjacent to the fossil plant site to determine benthic community diversity.

These studies are not being conducted at this site, based upon the Environmental Investigation Plan developed under the direction of TDEC.

Definition: Sediment samples are taken from the river bottom to determine whether CCR materials and/or constituents have migrated from the site to the waterways and other surface waters.

These studies are not being conducted at this site, based upon the Environmental Investigation Plan developed under the direction of TDEC.

Definition: The ash and pore water in the landfills and surface impoundments at the fossil plant site are tested for CCR constituent levels. The ash is also subjected to leachability tests to determine the amount of CCR that can possibly leach and enter the pore water in the landfills and impoundments.

Data available at completion of study.

Definition: Surveys of the fossil plant site track the location and quantity of CCR to aid the overall site management, developing 3-dimensional model of CCR units and confirming the CCR volumes.

Anticipated fieldwork: Summer 2019.

Definition: Dye trace studies are used to investigate how water moves underground. An environmentally safe dye is released into an area, and the amount of time it takes for the dye to appear at the collection spot – and how much makes it there – are used to determine the flow path and the speed of the flow.

These studies are not being conducted at this site, based upon the Environmental Investigation Plan developed under the direction of TDEC.

Definition: Exploratory drilling helps better understand what is in and under each CCR unit. It tells us (1) what is there: material types (CCR, soil) and properties (strength, permeability, etc.); (2) where it is (material locations); and (3) where the water level(s) are (material saturation).

Anticipated fieldwork: Summer 2019.

Definition: Existing geotechnical borings, laboratory testing results, slope stability analyses, etc. were reviewed for adequate documentation, appropriate methods and representative conditions. Existing data, if evaluated and found to be adequate, are used to support EIP information request responses.

Data available at completion of study.

Definition: Fish are captured using electroshocking and gill netting, with tissue samples then being taken. The tissue samples are tested to determine the bioaccumulation of CCR constituents in the fishs.

These studies are not being conducted at this site, based upon the Environmental Investigation Plan developed under the direction of TDEC.

Definition: Groundwater samples are collected frequently to test for a number of quality measures. By testing groundwater regularly, TVA can track compliance with regulatory permits and requirements.

Anticipated fieldwork: Fall 2019 — Fall 2020.

Definition: These investigations consist of installing monitoring wells to collect information about groundwater. This helps to better understand how groundwater moves in a particular area, as well as how it interacts with the surrounding soils and rocks. This will also be used to study water quality changes.

Anticipated fieldwork: Summer — Fall 2019.

Definition: A visual inspection will be conducted by walking the dikes and toes of the landfills and impoundments at the fossil plant site to identify potentially active seeps. Water quality measurements will be taken at surface stream banks to identify potential seeps at inaccessible areas. The soils and water at active seep areas are tested for CCR constituent levels.

Anticipated fieldwork: Spring 2019.

Definition: These analyses help determine that the slopes of the CCR units are stable. Multiple locations around each CCR unit are checked for stability. Normal (long-term) conditions and earthquake conditions are evaluated through this processs.

Anticipated fieldwork: Fall — Winter 2019.

Definition: Surface stream sampling is conducted in streams and rivers upstream, downstream, and adjacent to the fossil plant site to determine CCR constituent levels.

These studies are not being conducted at this site, based upon the Environmental Investigation Plan developed under the direction of TDEC.

Definition: Water balance studies are used to better understand how water moves into, stays within and leaves a defined area that can be as large as a valley or watershed, or as small as a single piece of land. From a big picture perspective, these studies are used to measure all of the sources of water entering this area (rainfall, rivers, etc.) and how much leaves. The studies can also be used to see the effect human activities are having on these flows and how they are changing over time.

These studies are not being conducted at this site, based upon the Environmental Investigation Plan developed under the direction of TDEC.

Definition: A water use survey is an investigation of private water supplies (e.g., domestic wells, springs) located within a 1/2- to 1-mile radius of the fossil plant site. It is used to evaluate the quality of groundwater used in these private wells.

Data available at completion of study.

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TDEC Investigative Process

TDEC process