TVA Allen Fossil Plant Remedial Investigation Work Plan

328 Pages·2017·19.32 MB·English

by  William Bracken

TVA Allen Fossil Plant
Remedial Investigation Work
Plan

Tennessee Valley Authority
Allen Fossil Plant
Memphis, Tennessee

Prepared for:
Tennessee Valley Authority
Chattanooga, Tennessee

Prepared by:
Stantec Consulting Services Inc.
8770 Guion Road, Suite B
Indianapolis, IN 46268

September 15, 2017
Sign-off Sheet
This document entitled TVA Allen Fossil Plant Remedial Investigation Work Plan was prepared by
Stantec Consulting Services Inc. (“Stantec”) for the account of TVA (the “Client”). Any reliance on this
document by any third party is strictly prohibited. The material in it reflects Stantec’s professional
judgment in light of the scope, schedule and other limitations stated in the document and in the
contract between Stantec and the Client. The opinions in the document are based on conditions
and information existing at the time the document was published and do not take into account any
subsequent changes. In preparing the document, Stantec did not verify information supplied to it by
others. Any use which a third party makes of this document is the responsibility of such third party.
Such third party agrees that Stantec shall not be responsible for costs or damages of any kind, if any,
suffered by it or any other third party as a result of decisions made or actions taken based on this
document.

Prepared by
(signature)
Matthew J. Dagon

Reviewed by
(signature)
Luisa Price

Approved by
(signature)
John W. McInnes
TVA ALLEN FOSSIL PLANT
REMEDIAL INVESTIGATION WORK PLAN
Table of Contents
September 15, 2017
Table of Contents
EXECUTIVE SUMMARY ..............................................................................................................i v
1.0 INTRODUCTION ...........................................................................................................1.1
2.0 SITE BACKGROUND .....................................................................................................2.1
2.1 SITE DESCRIPTION ........................................................................................................... 2.1
2.2 SITE OPERATIONAL HISTORY .......................................................................................... 2.1
2.3 ONGOING SITE INVESTIGATION .................................................................................... 2.2
2.4 USE OF COOLING WATER WELLS INSTALLED INTO THE MEMPHIS SAND
AQUIFER .......................................................................................................................... 2.2
3.0 CHARACTERIZATION OF ENVIRONMENTAL SETTING .................................................3.1
3.1 GEOGRAPHY .................................................................................................................. 3.1
3.2 CLIMATE .......................................................................................................................... 3.1
3.3 DEMOGRAPHY ............................................................................................................... 3.1
3.4 GEOLOGY AND SOILS ................................................................................................... 3.1
3.5 GROUNDWATER ............................................................................................................. 3.2
3.6 SURFACE WATER AND SEDIMENTS ................................................................................ 3.2
3.6.1. Mississippi River ............................................................................................. 3.2
3.6.2. McKellar Lake ............................................................................................... 3.3
3.7 ECOLOGY ....................................................................................................................... 3.3
3.7.1 Vegetation ................................................................................................... 3.3
3.7.2 Wildlife ........................................................................................................... 3.3
3.7.3 Aquatic Ecology .......................................................................................... 3.4
3.7.4 Threatened and Endangered Species ..................................................... 3.4
3.7.5 Wetlands ....................................................................................................... 3.4
4.0 SITE CONCEPTUAL MODEL ..........................................................................................4.1
4.1 SOURCE AREAS .............................................................................................................. 4.1
4.2 HYDROGEOLOGY .......................................................................................................... 4.2
4.3 SITE RELATED CHEMICALS .............................................................................................. 4.3
5.0 SITE DATA NEEDS .........................................................................................................5.1
5.1 DATA QUALITY OBJECTIVES .......................................................................................... 5.1
5.2 PHYSICAL CHARACTERIZATION ACTIVITIES ................................................................. 5.2
5.2.1 Initial Direct Push Technology Investigation ............................................. 5.2
5.2.2 Additional Direct Push Technology Investigation ................................... 5.3
5.2.3 Additional Investigation of Sewer Line ..................................................... 5.4
5.2.4 Monitoring Well Installation ........................................................................ 5.4
5.2.5 Groundwater Sampling .............................................................................. 5.8
5.2.6 Stratigraphic Soil Borings ............................................................................. 5.9
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REMEDIAL INVESTIGATION WORK PLAN
Table of Contents
September 15, 2017
5.2.7 Groundwater Modeling ............................................................................ 5.10
5.3 SAMPLING AND ANALYTICAL REQUIREMENTS .......................................................... 5.10
5.4 DATA EVALUATION AND INTERPRETATION ................................................................ 5.10
5.5 RI REPORT FORMAT ...................................................................................................... 5.11
5.6 SCHEDULE ..................................................................................................................... 5.12
6.0 REFERENCES .................................................................................................................6.1
LIST OF FIGURES
FIGURE 1 Site Location
FIGURE 2 Aerial Map – Allen Fossil Plant
FIGURE 3 DPT Sampling Locations
FIGURE 4 Proposed Monitoring Well Locations
FIGURE 5 Conceptual Cross-Section
FIGURE 6 Proposed Stratigraphic Boring Locations
FIGURE 7 ALF Remedial Investigation Schedule
LIST OF TABLES
TABLE 1 Monitoring Well Construction Summary
TABLE 2 Proposed Monitoring Well Locations, Descriptions and Rationale
TABLE 3 Monitoring Well Network Summary
LIST OF APPENDICES
Sampling and Analysis Plan
Quality Assurance Project Plan
Site-Specific Health and Safety Plan
Data Management Plan
UM-USGS Groundwater Investigation Proposal
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REMEDIAL INVESTIGATION WORK PLAN
Acronyms
September 15, 2017

Executive Summary
Groundwater monitoring wells proximal to the East Ash Disposal Area at the Allen Fossil Plant (ALF)
were sampled and have detections of arsenic, lead and fluoride at concentrations above the
United States Environmental Protection Agency (U.S. EPA) Maximum Contaminant Level (MCL). In
response, the Tennessee Department of Environment and Conservation (TDEC) issued a letter
dated July 18, 2017 requesting that the Tennessee Valley Authority (TVA) develop a Remedial
Investigation (RI) Work Plan. This work plan was originally submitted to TDEC on August 18, 2017.
Between September 5 and 15, 2017 TDEC provided their comments to the work plan, and this
version reflects revisions made in response to those comments.
The objectives of the RI Work Plan include the following:
1) Source area identification and delineation of Coal Combustion Residual (CCR)
constituents as listed in Appendices III and IV in the U.S. EPA CCR Regulations, including
arsenic, lead, and fluoride, in the subsurface soils;
2) Complete horizontal and vertical delineation of the groundwater contaminant plume(s)
for CCR constituents, including arsenic, lead, and fluoride, in the Fluvial Aquifer beneath the
Site through the installation and sampling of permanent monitoring wells;
3) Characterization of the Fluvial Aquifer with a network of shallow, intermediate, and deep
permanent monitoring wells that will provide monitoring points for the future observation of
groundwater quality and elevations at three depths within the Fluvial Aquifer. The monitoring
well network will be used to evaluate the effects of operating nearby production wells installed
in the Memphis Sand Aquifer; and
4) Completion of a three-dimensional groundwater flow and transport model for the site to
evaluate groundwater flow and transport of CCR constituents in the Fluvial Aquifer under
current conditions, as well as future conditions that may develop as a result of pumping from
the Memphis Sand Aquifer.
This Work Plan presents rationale and procedures to conduct the following:
• A screening level investigation to initially evaluate vertical and horizontal distribution of
constituents of concern (CoCs) proximal to ALF-202, ALF-203, and within the western half
of the East Ash Disposal Area;
• Installation and sampling of monitoring wells screened in the shallow, intermediate, and
deep portions of the Fluvial Aquifer;
• Evaluation of horizontal and vertical gradients within the Fluvial Aquifer;
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REMEDIAL INVESTIGATION WORK PLAN
Acronyms
September 15, 2017

• Measurement of hydraulic conductivity within the Fluvial Aquifer and underlying confining
unit; and
• A plan from the U.S. Geological Survey to assess the potential for interaction between the
Fluvial Aquifer and the Memphis Sand Aquifer (i.e., local drinking water resource) due to
proposed operation of pumping wells at the Allen Combined Cycle Plant.
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TVA ALLEN FOSSIL PLANT
REMEDIAL INVESTIGATION WORK PLAN
Acronyms
September 15, 2017

Acronyms

ACC Allen Combined Cycle Plant
ALF Allen Fossil Plant
ASTM American Society for Testing and Materials
Center for Applied Earth Science and
CAESER
Engineering Research
CCR Coal Combustion Residual
CFR Code of Federal Regulations
CoC Constituents of Concern
DO Dissolved Oxygen
DPT Direct Push Technology
DQOs Data Quality Objectives
GPS Global Positioning System
GW Groundwater
MCLs Maximum Contaminant Levels
MERAS Mississippi Embayment Regional Aquifer
System
MLGW Memphis Light, Gas and Water Division
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TVA ALLEN FOSSIL PLANT
REMEDIAL INVESTIGATION WORK PLAN
Acronyms
September 15, 2017

MRVA Memphis River Valley Alluvial
National Oceanic and Atmospheric
NOAA
Administration
National Pollutant Discharge Elimination
NPDES
System
NTUs Nephelometric Turbidity Units
ORP Oxidation-reduction potential
Pace Pace Analytical Services, LLC
PCBs Polychlorinated biphenyls
pH Negative log of hydrogen concentration
QA/QC Quality Assurance/Quality Control
QAPP Quality Assurance Project Plan
RI Remedial Investigation
S.U. Standard Units
SAP Sampling and Analysis Plan
SPLP Synthetic Precipitation Leaching Procedure
TCLP Toxicity Characteristic Leaching Procedure
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TVA ALLEN FOSSIL PLANT
REMEDIAL INVESTIGATION WORK PLAN
Acronyms
September 15, 2017

Tennessee Department of Environment and
TDEC
Conservation
TVA Tennessee Valley Authority
µg/L Micrograms per Liter
USACE United States Army Corps of Engineers
USCS Unified Soil Classification System
United States Environmental Protection
U.S. EPA
Agency
USGS United States Geological Survey

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TVA ALLEN FOSSIL PLANT
REMEDIAL INVESTIGATION WORK PLAN
Introduction
September 15, 2017

1.0 INTRODUCTION
In response to the Tennessee Department of Environment and Conservation (TDEC) letter dated
July 18, 2017, the Tennessee Valley Authority (TVA) has developed this Remedial Investigation (RI)
Work Plan to characterize groundwater quality near the East Ash Disposal Area at the Allen Fossil
Plant (ALF). This work plan was originally submitted to TDEC on August 18, 2017. Between
September 5 and 15, 2017, TDEC provided their comments to the work plan, and this version
reflects revisions made in response to those comments. The site location and surrounding area is
presented on Figure 1. Site features are presented on Figure 2.
The objectives of the RI Work Plan as specified in the TDEC letter dated July 18, 2017 include the
following:
1) Source area identification and delineation of Coal Combustion Residual (CCR)
constituents as listed in Appendices III & IV in the United States Environmental Protection
Agency (U.S. EPA) CCR Regulations, including arsenic, lead, and fluoride, in the subsurface
soils which are thought to be impacting shallow groundwater in the vicinity of the East Ash
Disposal Area at the Site;
2) Complete horizontal and vertical delineation of the groundwater contaminant plume(s)
for CCR constituents, including arsenic, lead, and fluoride, in the Fluvial Aquifer beneath the
Site, through the installation and sampling of permanent monitoring wells;
3) Characterization of the Fluvial Aquifer with a network of shallow, intermediate, and deep
permanent monitoring wells that will provide monitoring points for the future observation of
potential contaminant migration in the shallow aquifer, as well as from the shallow aquifer to
the deeper portions of the Fluvial Aquifer. The monitoring well network should be able to
detect any changes in the constituent distribution and flow gradients once the Memphis Sand
Aquifer production well operations begin; and
4) Completion of a three-dimensional groundwater flow and transport model for the Site to
evaluate groundwater flow and contaminant migration in the Fluvial Aquifer under current
conditions, as well as future conditions that may develop as a result of pumping from the
Memphis Sand Aquifer. Groundwater extraction from the three TVA Memphis Sand
production wells should be incorporated in the model at the various anticipated production
rates. At a minimum, modeling shall be conducted for a ground water withdrawal rate of
3,000,000 gallon/day and a 5,000,000 gallon/day withdrawal rate. The model should be
suitable for evaluating impacts from source contamination to the Fluvial Aquifer, potential
contaminant migration pathways from the source area, potential water quality impacts to the
Memphis Sand Aquifer, and ultimately the possibility of contaminant migration to potential
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