HomeMy WebLinkAboutNC0000396_SARP_Rev 0_Narrative_20161219SITE ANALYSIS AND REMOVAL PLAN
ASHEVILLE STEAM ELECTRIC GENERATING PLANT
REVISION 0
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Amec Foster Wheeler Environment & Infrastructure, Inc. December 2016
Duke Energy Coal Combustion Residuals Management Program
Asheville Steam Electric Generating Plant Site Analysis and Removal Plan
Revision 0
i
EXECUTIVE SUMMARY
Amec Foster Wheeler Environment & Infrastructure, Inc. (Amec Foster Wheeler) has prepared
this Site Analysis and Removal Plan (Removal Plan) in support of the proposed closure of the
Coal Combustion Residuals (CCR) Basins (Ash Basins) at the Asheville Steam Electric
Generating Plant (Asheville Plant) located near Arden, North Carolina. The purpose of this
Removal Plan is to seek the North Carolina Department of Environmental Quality’s (NCDEQ)
concurrence with the Duke Energy Progress, LLC (Duke) plan for closure of the Ash Basins
located at the Asheville Plant. This Removal Plan is submitted to NCDEQ on behalf of Duke.
The work to be performed in support of the closure of the Ash Basins is summarized in this
document, which is consistent with the requirements of the Hazardous and Solid Waste
Management System: Disposal of Coal Combustion Residuals from Electric Utilities Rule (CCR
Rule) [EPA, 2015] and the NC Coal Ash Management Act (CAMA). This Removal Plan is based
on engineering and environmental factors minimizing the impacts to communities and managing
cost. The drawings presented herein are accurate at the time of preparing this Removal Plan
and are subject to change pending further discussion with Duke. The closure option entails
excavation of CCR within the Ash Basins and transport for beneficial use or placement in an off-
site permitted landfill.
The two Ash Basins located at the Asheville Plant include: (i) the 1982 Ash Basin; and (ii) the
1964 Ash Basin. Excavation of the 1982 Ash Basin was completed on September 30, 2016, and
the basin was turned over for dam decommissioning and the construction of a natural gas
combined cycle plant after an independent qualified professional engineer concluded that
primary source ash had been removed from the basin. Duke estimates the tonnage of ash in the
1964 Ash Basin to be approximately 2.9 million tons as of December 31, 2016. Subsequent to
removal of the ash pursuant to the Coal Combustion Residual Removal Verification Procedure,
Duke will implement its Excavation Soil Sampling Plan, as referenced in the Construction
Quality Assurance Plan, in a manner that meets the closure performance standards set out in
Part II, Section 3.(c) of CAMA and Section 257.102(c) of the CCR Rule.
Assessment activities for the Asheville Plant were performed by SynTerra, Corp. (SynTerra) and
were reported in a Comprehensive Site Assessment (CSA) report dated August 23, 2015, a
CSA Supplement 1 dated August 31, 2016, a Corrective Action Plan (CAP) Part 1 dated
November 20, 2015, and a CAP Part 2 dated February 19, 2016. Groundwater receptor surveys
were conducted for the site. In addition to identification of receptors, the compiled data was
used to develop a description of the site, surrounding area, geology, and hydrogeology,
including a Site Hydrogeologic Conceptual Model (SCM). The Constituents of Interest (COI)
identified from the Asheville Plant ash material and pore water sample analyses include
antimony, arsenic, boron, chromium, cobalt, iron, manganese, sulfate, thallium, TDS, vanadium,
and pH. These COIs are identified as exceeding either the 2L or Interim Maximum Allowable
Concentrations (IMAC) in at least one ash pore water monitoring well. Groundwater trend
analysis modeling showed that COIs with exceedances of the 2L or IMAC are identified in all
compliance boundary wells at statistically elevated values over concentrations observed in
designated background wells.
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A preliminary geotechnical evaluation was performed and is presented in this Removal Plan.
The results of the investigations indicate that the subsurface materials primarily consist of, from
top to bottom, CCR (within the 1964 Ash Basin) or Dike Fill (at the perimeters of the basins) and
residual soils (sitting on bedrock). A partially weathered rock zone was encountered at the
transition between the residual soils and the bedrock (gray to dark gray, fine to medium-grained
gneiss).
The closure of the Ash Basins will entail the following activities: CCR will be excavated and
transported from the site for beneficial use or placement in an off-site permitted landfill. Per the
current plan, after establishing the final design grades, the footprints of the 1982 Ash Basin will
become the site for a planned combined cycle plant, and the 1964 Ash Basin footprint will be
graded to drain. The potential future use of the 1964 Ash Basin is undetermined at this time.
This Removal Plan also presents a summary of the engineering evaluation and analyses
performed, as well as a Construction Quality Assurance (CQA) Plan.
The Wastewater and Stormwater Plans, including a plan for obtaining the required permits, are
described in a preliminary manner in this Removal Plan. These plans will be developed and
submitted under a separate cover. Anticipated permits required for closure of the Ash Basins are
identified and listed in this Removal Plan.
A Post-Closure Care Plan is provided, including the groundwater monitoring program currently
under evaluation by NCDEQ. This Removal Plan presents the estimated milestones related to
basin closure and post-closure activities.
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LIST OF ACRONYMS AND ABBREVIATIONS
Acronym/
Abbreviation Definition
µg/L Microgram per liter
2B NCAC Title 15A, Subchapter 2B. Surface Water and Wetland Standards
2L NCAC Title 15A, Subchapter 2L. Groundwater Classification and
Standards
ASTM American Society for Testing Materials
CAMA Coal Ash Management Act
CAP Corrective Action Plan
CCP Coal Combustion Products
CCR Coal Combustion Residual
CCR Rule Coal Combustion Residuals Rule
CFR Code of Federal Regulations
CMS Closure Model Scenario
cm/sec centimeters per second
CMP Corrugated Metal Pipe
COI Constituent of Interest
CQA Construction Quality Assurance
CSA Comprehensive Site Assessment
CY Cubic Yards
DWQ Division of Water Quality
DWR Division of Water Resources (formerly DWQ)
EDXRF
EMP
Energy Dispersive X-Ray Fluorescence
Effectiveness Monitoring Plan
EPSC Erosion Prevention and Sediment Control
FGD Flue Gas Desulfurization
gal/min gallons per minute
GAP Groundwater Assessment Work Plan
GIS Geographic Information System
HDPE High Density Polyethylene
IMAC
IMP
Interim Maximum Allowable Concentrations
Interim Monitoring Plan
MDE Maximum Design Earthquake
mL/g milliliters per gram
MPD Master Programmatic Document
MSD Metropolitan Sewerage District
MW Megawatt
NAVD 88 North American Vertical Datum of 1988
NCDENR North Carolina Department of Environment and Natural Resources
NCDEQ North Carolina Department of Environmental Quality (formerly NCDENR)
NOI Notice of Inspection
NPDES National Pollutant Discharge Elimination System
O&M Operations and Maintenance
OM&M Operations Maintenance and Monitoring
pcf Pounds per Cubic Foot
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Asheville Steam Electric Generating Plant Site Analysis and Removal Plan
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Acronym/
Abbreviation Definition
Plant Asheville Steam Electric Generating Plant
PMP Probable Maximum Precipitation
psf Pounds per Square Foot
PWR Partially Weathered Rock
RCP Reinforced Concrete Pipe
RSL USEPA Regional Screening Level
S.B. Senate Bill
SCM Site Conceptual Model
SPLP Synthetic Precipitation Leaching
SPT Standard Penetration Test
TBD To be determined
TDS Total Dissolved Solids
TOC Total Organic Carbon
Tsf Tons per square foot
UNCC University of North Carolina, Charlotte
USACE U.S. Army Corps of Engineers
USEPA U.S. Environmental Protection Agency
USGS U.S. Geological Survey
XRD X-Ray Diffraction
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TABLE OF CONTENTS
RECORD OF REVISION ........................................................................................................... ix
1.INTRODUCTION ............................................................................................................. 1
1.1 Site Analysis and Removal Plan Objectives ....................................................................... 1
1.2 Document Organization ...................................................................................................... 1
2.GOVERNING REGULATIONS ........................................................................................ 2
2.1 Federal CCR Rules ............................................................................................................. 2
2.2 North Carolina ..................................................................................................................... 2
3.FACILITY DESCRIPTION AND EXISTING SITE FEATURES ........................................ 5
3.1 Surface Impoundment Description ...................................................................................... 5
3.1.1 Site History and Operations ................................................................................... 5
3.1.2 Estimated Volume of CCR Materials in Impoundments ........................................ 7
3.1.3 Description of Surface Impoundment Structural Integrity ...................................... 8
3.1.4 Sources of Discharges into Surface Impoundments.............................................. 9
3.1.5 Existing Liner System ............................................................................................ 9
3.1.6 Inspection and Monitoring Summary ..................................................................... 9
3.2 Site Maps .......................................................................................................................... 13
3.2.1 Summary of Existing CCR Impoundment Related Structures ............................. 13
3.2.2 Receptor Survey .................................................................................................. 14
3.2.3 Existing On-Site Landfills ..................................................................................... 17
3.3 Monitoring and Sampling Location Plan ........................................................................... 17
3.3.1 Interim Groundwater Monitoring Plan .................................................................. 17
4.RESULTS OF HYDROGEOLOGIC, GEOLOGIC, AND GEOTECHNICAL
INVESTIGATIONS ........................................................................................................ 19
4.1 Hydrogeology and Geologic Descriptions ......................................................................... 19
4.1.1 Regional Geology ................................................................................................ 19
4.1.2 Regional Hydrogeology ........................................................................................ 19
4.2 Stratigraphy of the Geologic Units Underlying Surface Impoundments ........................... 20
4.3 Hydraulic Conductivity Information ................................................................................... 20
4.4 Geotechnical Properties .................................................................................................... 21
4.5 Chemical Analysis of Impoundment Water, CCR Materials and CCR Affected Soil ........ 31
4.5.1 Source Area(s) Characterization.......................................................................... 31
4.5.2 Surface Water and Sediment Assessment .......................................................... 33
4.6 Historical Groundwater Sampling Results ........................................................................ 34
4.6.1 Summary of Surficial Aquifer Results .................................................................. 35
4.6.2 Summary of Transitional Zone Aquifer Results ................................................... 36
4.6.3 Summary of Bedrock Aquifer Results .................................................................. 37
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4.7 Groundwater Potentiometric Contour Maps ..................................................................... 37
4.8 Figures: Cross Sections Vertical and Horizontal Extent of CCR within the Impoundments
.......................................................................................................................................... 39
5.GROUNDWATER MODELING ANALYSIS................................................................... 41
5.1 Site Conceptual Model ...................................................................................................... 42
5.2 Geochemical Modeling ..................................................................................................... 44
5.2.1 Soil Sorption Evaluation ....................................................................................... 44
5.2.2 Geochemical Numerical Modeling Analysis ......................................................... 46
5.3 Numerical Groundwater and Transport Modeling ............................................................. 47
5.3.1 Numerical Groundwater Flow Model Description ................................................ 48
5.3.2 Numerical Groundwater Transport Model Description ......................................... 49
5.4 Groundwater Chemistry Effects ........................................................................................ 49
5.5 Groundwater Trend Analysis Methods .............................................................................. 52
6.BENEFICIAL REUSE AND FUTURE USE ................................................................... 53
6.1 CCR Material Reuse ......................................................................................................... 53
6.2 Site Future Use ................................................................................................................. 53
7.CLOSURE DESIGN DOCUMENTS .............................................................................. 54
7.1 Engineering Evaluations and Analyses ............................................................................ 54
7.2 Site Analysis and Removal Plan Drawings ....................................................................... 54
7.3 Construction Quality Assurance Plan ............................................................................... 54
8.MANAGEMENT OF WASTEWATER AND STORMWATER ........................................ 55
8.1 Stormwater Management .................................................................................................. 55
8.2 Wastewater Management ................................................................................................. 55
9.DESCRIPTION OF FINAL DISPOSITION OF CCR MATERIALS ................................. 56
10.APPLICABLE PERMITS FOR CLOSURE .................................................................... 57
11.POST CLOSURE MONITORING AND CARE ............................................................... 58
11.1 Groundwater Monitoring Program ..................................................................................... 58
12.PROJECT MILESTONES AND COST ESTIMATES ..................................................... 60
12.1 Project Schedule ............................................................................................................... 60
12.2 Closure and Post-Closure Cost Estimate ......................................................................... 60
13.REFERENCED DOCUMENTS ...................................................................................... 61
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Tables
Table 2-1 Federal CCR Rule Closure Plan Requirements, Summary and Cross
Reference Table
Table 2-2 NC CAMA Closure Plan Requirements, Summary and Cross Reference
Table
Table 3-1 1982 Ash Basin Dam Summary Recommendations (Amec Foster
Wheeler 2016b)
Table 3-2 1964 Ash Basin Dam Summary Recommendations (Amec Foster
Wheeler 2016b)
Table 4-1 Summary of Hydraulic Conductivity Geometric Mean Monitoring W ell Slug
Testing Results for Each Hydrogeologic Zone
Table 4-2 Unit Weight and Shear Strength Parameters for the 1982 Ash Basin Dam
Table 4-3 Unit Weight and Shear Strength Parameters for the 1964 Ash Basin Dam
Table 4-4 Unit Weight and Shear Strength Parameters for the Separator Dike
Table 4-5 Index Property Test Results of Materials in 1982 Ash Basin
Table 4-6 Index Property Test Results of Materials in 1964 Ash Basin
Figures
Figure 1 Site Location Map
Figure 2 Site Overview Aerial Plan
Figure 3 CCR Impoundment Related Structures
Figure 4 Boring Location Map 1982 and 1964 Ash Basins
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Appendices
Appendix A Waste Inventory Analysis (1964 Ash Basin)
Appendix B SynTerra Comprehensive Site Assessment Report Tables and Figures
Appendix C SynTerra Corrective Action Plan Tables and Figures
Appendix D Engineering Evaluations and Analyses of Closure Design Grading Plans for the
1982 Ash Basin
Appendix E Dam Decommissioning and Ash Removal Closure Plan Drawings for the 1982
Ash Basin
Appendix F Construction Quality Assurance Plan
Appendix G Post-Closure Operations Maintenance and Monitoring (OM&M) Plan
Appendix H Closure and Post-Closure Care Cost Estimates (to be added at a later date)
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RECORD OF REVISION
Revision
Number
Revision
Date
Section
Revised
Reason for
Revision Description of Revision
0 12/2016 N/A N/A Initial Issue
1
2
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1. INTRODUCTION
Duke intends to close the 1982 and 1964 Ash Basins at the Asheville Steam Electric Generating
Plant (Plant). Both basins will be closed by removal of the coal ash for transport for beneficial
use or an off-site fully lined landfill. The purpose of this document is to outline and present the
plan and objectives to achieve closure for the ash basins and meet the requirements of the
North Carolina Coal Ash Management Act (CAMA) and the Coal Combustion Residuals (CCR)
Rule (CCR Rule).
1.1 Site Analysis and Removal Plan Objectives
The objective of this Site Analysis and Removal Plan (Removal Plan) is to set out the process for
closing the 1982 and 1964 Ash Basins at the Plant in accordance with applicable regulations,
including the Hazardous and Solid Waste Management System: Disposal of Coal Combustion
Residuals from Electric Utilities Rule (CCR Rule) (EPA, 2015) and the North Carolina Coal Ash
Management Act (CAMA) for closure of CCR surface impoundments.
1.2 Document Organization
Although closure of the CCR surface impoundments at the Asheville facility is solely controlled by
Part II, Sections 3.(b) and 3.(c) of CAMA (and not N.C.G.S. § 130A-309.214), for purposes of
consistency with the closure plans for those non-high-priority Duke facilities to which N.C.G.S. §
130A-309.214 applies, this Removal Plan is structured to follow generally the closure plan
elements set forth in N.C.G.S § 130A-309.214(a)(4).
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2. GOVERNING REGULATIONS
2.1 Federal CCR Rules
The CCR Rule was published in the Federal Register on April 17, 2015. This rule regulates CCR
as a nonhazardous waste under Subtitle D of the Resource Conservation and Recovery Act.
The effective date of the rule is October 19, 2015.
Written closure plan requirements are set forth in 40 CFR § 257.102(b)(1) of the CCR Rule and
are summarized in Table 2-1 of this document. Table 2-1 provides a cross reference between
each regulatory closure plan requirement and the corresponding Removal Plan section(s) where
that requirement is addressed.
The CCR Rule requires that a history of construction be developed for each CCR unit as
described in 40 CFR § 257.73(c)(1), and 40 CFR §257.105(f)(9) requires that this history of
construction be maintained in the facility’s written operating record. In addition, §§ 257.106(f)(8)
and 257.107(f)(8) require notification of the availability of the history of construction to the State
Director and posting of this information on the publicly accessible CCR Website, respectively.
The History of Construction Report (Amec Foster Wheeler 2016a) has been developed as a
primary source of information reported in the Removal Plan and to satisfy these record keeping
requirements.
2.2 North Carolina
In August 2014, the North Carolina General Assembly passed Senate Bill (S.B.) 729 (known as
CAMA), which lists specific regulatory requirements for CCR surface impoundment closure. For
the Plant, “surface impoundment,” as defined in N.C.G.S. § 130A-309.201(6), is interpreted to
include the 1982 Ash Basin and 1964 Ash Basin. Part II, Section 3(b) of CAMA deems the Plant
a “high-priority” site and specifically requires closure by August 1, 2019, which entails
dewatering the ash basins to the maximum extent practicable and removing and transferring
CCR from basins to a lined landfill or structural fill. However, the North Carolina Mountain
Energy Act of 2015 extended the closure date to August 1, 2022. Note that ash removal is
required to be complete by August 1, 2022; however, dam decommissioning and final grading of
the former ash basin areas and completion of corrective actions to restore groundwater quality,
if needed, as provided in N.C.G.S. § 130A-309.204, may extend beyond this date. CAMA’s
closure plan requirements applicable to non-high-priority sites were codified at N.C.G.S. §
130A-309.214(a)(4), which requires plans for such sites to include the elements listed below.
Although, as noted in Section 1.2 above, N.C.G.S. § 130A-309.214 is not specifically applicable
to the Plant, which is a high-priority site required to close pursuant to Part II, Sections 3.(b) and
3.(c) of CAMA, this Removal Plan relies on N.C.G.S. § 130A-309.214(a)(4) solely to inform its
organization.
A closure plan will be required for each CCR surface impoundment subject to N.C.G.S. § 130A-
309.214(a)(4) regardless of its risk classification. CAMA defines the requirements for these
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closure plans in N.C.G.S. §130A-309.214(a)(4). The CAMA closure plan regulations are
summarized in Table 2-2 for reference. The Closure Plan shall include the following:
Facility description;
Site maps;
Hydrogeologic, geologic, geotechnical characterization results;
Groundwater potentiometric maps and extent of contaminants of concern;
Groundwater modeling;
Description of beneficial reuse plans;
Removal Plan drawings, design documents, and specifications;
Description of the construction quality assurance and quality control program;
Description of wastewater disposal and stormwater management provisions;
Description of how the final disposition of CCR will be provided;
List of applicable permits to complete closure;
Description of post-closure monitoring and care plans;
Estimated closure and post-closure milestone dates;
Estimated costs of assessment, corrective action, closure and post-closure care; and
Future site use description.
In addition to the closure pathway and closure plan requirements, CAMA outlines groundwater
assessment and corrective action requirements summarized as follows:
Submit Groundwater Assessment Plans by December 31, 2014;
Within 180 days of Groundwater Assessment Plan approval, complete a groundwater
assessment and submit a Groundwater Assessment Report; and
Provide a Corrective Action Plan (if required) within 90 days (and no later than 180 days)
of Groundwater Assessment Report completion.
The groundwater assessment and corrective action activities for the Plant are currently being
developed by SynTerra Corp. (SynTerra). The Comprehensive Site Assessment (CSA) Report
for the Plant was completed on August 23, 2015 (SynTerra 2015a). Duke has been in
correspondence with the NCDEQ and has received permission to submit a Corrective Action
Plan (CAP) in two parts. The first part of the CAP was submitted on November 20, 2015, and
includes background information; a brief summary of the CSA findings; a brief description of site
geology and hydrogeology; a summary of the previously completed receptor survey; a
description of NCAC Title 15A Subchapter 2L. Groundwater Standards (2L Standards) and
NCAC Title 15A NCAC Subchapter 2B. Surface Water Standards (2B Standards) exceedances;
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proposed site-specific groundwater background concentrations; a description of the site
conceptual model; and groundwater flow, and transport modeling (SynTerra 2015b). The second
part of the CAP was submitted on February 19, 2016, and includes risk assessment, alternative
methods for achieving restoration, conceptual plans for recommended corrective actions,
implementation schedule, and a plan for future monitoring and reporting (SynTerra 2016a).
The CSA Supplement 1 was also issued on August 31, 2016, and addresses the following
(SynTerra 2016b):
Summary of groundwater monitoring data through July 2016;
Reponses to NCDEQ review comments pertaining to the CSA;
Update on the development of provisional background groundwater concentrations
(through April 2016 data);
Findings from assessment activities conducted since the submittal of the CSA report,
including data gaps previously identified in the CSA; and
Description of planned additional assessment activities.
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3. FACILITY DESCRIPTION AND EXISTING SITE FEATURES
3.1 Surface Impoundment Description
3.1.1 Site History and Operations
The Plant is a coal-combustion generating facility that began commercial operation in 1964. Ash
basins, which support operations at the Plant, were expanded or otherwise modified in 1971,
1999, and 2000. As shown on Figure 1, the facility is located in Buncombe County in Western
North Carolina, approximately 8 miles south of the City of Asheville, and is within the U.S.
Geological Survey (USGS) Skyland Quadrangle. The center of the facility is at the approximate
coordinates: latitude 35°28’N, longitude 82°32’W. The Plant is situated on approximately 786
acres, including areas on both sides of Interstate 26 (I-26).
The Plant consists of two coal-fired generating units with a combined power generating capacity
of 376 megawatts (MW), two combustion turbine units with a combined 324 MW capacity, two
CCR units known as the 1982 Ash Basin and the 1964 Ash Basin, and obtains makeup water
from Lake Julian. Figure 2 includes an aerial photo of the Plant that also shows the associated
and surrounding features.
The two ash basin dams fall under the jurisdiction of the NCDEQ Division of Energy, Mineral
and Land Resources, Land Quality Section, Dams Program and are listed under State ID
Number BUNCO-089 (1982 Ash Basin) and BUNCO-097 (1964 Ash Basin). According to the
current NCDEQ hazard-rating criteria, the dams are considered to be large, high-hazard
structures, falling under Class C dam classification based on potential breach impacts to
potential loss of life and/or economic damage.
Fly ash and bottom ash have been deposited within the facility’s two ash basins by hydraulic
sluicing. Ash is currently sluiced to the Rim Ditch system, where it is dewatered and temporarily
stored within the 1964 Ash Basin. Ash is later removed and transported off-site for beneficial
reuse or proper disposal. Decant water from the Rim Ditch is pumped through a center pond
filter system to the stilling basin located to the north of the 1964 Ash Basin, and then out through
NPDES Outfall 001. Some stormwater and wastewater from portions of the Plant site is routed
into the Duck Pond and then pumped into to the head of the Rim Ditch for treatment.
Following is a brief summary from the History of Construction report (Amec Foster Wheeler
2016a) of each of the Ash Basins.
1964 Ash Basin and Equalization Basin
The 1964 Ash Basin Dam was part of the original steam plant construction designed by Ebasco
in 1962. The dam was constructed as a compacted, random earth fill embankment with a design
crest elevation of approximately 2125 feet. The 1964 Ash Basin has a drainage area of
approximately 75 acres according to the NCDEQ dam database.
In 1970–71, the dam was extended and raised approximately 30 feet to a planned crest
elevation of 2157.5 feet to provide additional ash storage. This raising necessitated a separator
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dike east of the main dam. Recent survey information shows a spot crest low point elevation of
approximately 2157.3 feet (North American Vertical Datum of 1988 [NAVD 88]). Sluicing of ash
to the 1964 Ash Basin ceased in 1982 with the construction of the 1982 Ash Basin.
In 2005, an engineered wetlands treatment system for flue gas desulfurization (FGD) process
wastewater was constructed within the northwestern portion of the 1964 Ash Basin. The system
consisted of two equalization basins that routed wastewater from the FGD process to a series of
lined ponds that contained vegetation to treat the wastewater. The constructed wetlands and
equalization basins were designed by Parsons E&C (now known as Worley Parsons).
In 2012, a 1964 Dam improvement project was initiated to improve the stability of the dam. This
improvement project included:
Extension of the core of the dam along the crest;
Installation of a toe drain along the base of the downstream slope of the dam that routes
collected water into an existing concrete structure;
Abandonment of the 30-inch-diameter concrete spillway pipe and riser by grouting in-
place;
Construction of a riprap buttress along the toe of the dam; and
Modification of the path for discharge from the wetlands system and 1982 Ash Basin.
In parallel with the dam improvements, a drainage improvement project designed by MACTEC
(now Amec Foster Wheeler) was completed to redirect the outflow from the 1982 Ash Basin
riser structure into buried piping (high density polyethylene [HDPE] encased in flowable fill)
installed within the 1964 Ash Basin area to the interior of the Duck Pond, and from the Duck
Pond to a new outlet structure at the French Broad River. With this project, the spillway for the
1964 Ash Basin is located within the Duck Pond in the northeast corner of the basin and
connected to the drainage pipe system installed in 2012. For more detailed information and area
capacity curves for the basin, refer to the History of Construction report (Amec Foster Wheeler
2016a).
The equalization basins and engineered wetlands were removed to provide an area to
temporarily place ash excavated from the 1982 Ash Basin. During 2016, wastewater flows and
treatment were adjusted to facilitate the excavation of the 1982 Basin. The center pond filters
were constructed at the end of the Rim Ditch and commissioned to replace the treatment
provided by the Duck Pond. Infrastructure was developed to dewater the Duck Pond to the head
of the Rim Ditch, and subsequently, the low volume waste and stormwater that flowed into the
1982 Basin and pumped to the Rim Ditch was re-routed to the Duck Pond. All treated effluent is
discharged to Outfall 001.
1982 Ash Basin and Separator Dike
The 1982 Ash Basin Dam was designed by CP&L Engineers and W.L. Wells in 1981. The ash
basin dam was constructed of compacted random earth fill in 1981–82 and ash storage began
in 1982 (when the 1964 Ash Basin was removed from service).
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Duke Energy Coal Combustion Residuals Management Program
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The dam is approximately 1500 feet long with a design crest elevation at 2165 feet. Recent
survey information before dam decommissioning activities began showed spot elevations
ranging from 2164.5 feet to 2165.7 feet (NAVD 88). The west end of the dam joins the abutment
of the 1964 Ash Basin Dam and the east end ties into a natural knoll. An internal drainage
blanket connected to toe-drainage piping provides seepage control. The 1982 Ash Basin has a
drainage area of approximately 70 acres, according to the NCDEQ dam database.
When the 1964 Ash Basin dam was raised in 1970–71, a Separator Dike was constructed
across a topographic low area on the east side of the 1964 Ash Basin. The 1982 Ash Basin
design included raising the Separator Dike due to the planned higher crest elevation of the 1982
Ash Basin Dam. The Separator Dike was built on a native soil base; fill for the dike was not
placed on ash.
The outfall skimmer was near the southwest corner of the 1982 Ash Basin. It connected to a
drainage pipe that was installed in 2012 that runs below the constructed wetlands (now
removed) and the northern portion of the 1964 Ash Basin, before connecting to a stilling basin
and concrete outfall structure at the French Broad River. For more detailed information and area
capacity curves for the basin, refer to the History of Construction report (Amec Foster Wheeler
2016a).
The 1982 Ash Basin began to reach capacity in 2007. To facilitate continued Plant operations,
an ash excavation plan was developed to increase ash storage capacity. As part of this plan,
ash was transported to the Asheville Regional Airport (Airport) and beneficially used as
structural fill. The structural fill project areas 1, 4, and 3 were completed in 2015. In October
2015, operations began to transport ash to an off-site fully lined landfill near Homer, Georgia. As
ash removal operations were conducted within the 1982 Ash Basin, the outfall skimmer was
disconnected from the drainage pipe, because sufficient volume existed in the 1982 Ash Basin
to store the PMP storm event. Ash removal within the 1982 Ash Basin was completed on
September 30, 2016, and decommissioning of the dam is currently underway.
3.1.2 Estimated Volume of CCR Materials in Impoundments
The volume of CCR material contained in the ash basins is presented below. Throughout this
document, ash volumes are expressed as tons using the conversion of 1.2 tons per cubic yard
(tons/yd3). Excavation of the 1982 Ash Basin was completed on September 30, 2016, and the
Basin was turned over for dam decommissioning and the construction of a natural gas
combined cycle plant.
The volume of ash currently in the 1964 Ash Basin is estimated to be approximately 2,900,000
tons as of December 31, 2016 (Duke Energy 2016). A Waste Inventory Analysis, dated January
2015 (Amec Foster Wheeler 2015c), was performed for the 1964 Ash Basin. Since that date
some ash from the 1982 Ash Basin was temporarily placed in the 1964 Ash Basin ash stack in
2016. The plant also continues to generate ash resulting from the operation of the coal-fired
units, until they are retired from operation. The Waste Inventory Analysis is an estimation of the
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volume of ash present at the time, but does not include the subsequent ash placed within the
basin due to ash stacking operations or generation ash production.
The Waste Inventory Analysis calculations were performed using historical ground surface
topographic information from historical design drawings or USGS mapping, and used AutoCAD
Civil 3D software to compare the historical ground surface elevation contours with current
conditions. In these calculations, an approximate pre-fill ground surface was generated, and
pre-fill grades were compared to current North Carolina Flood Plain Mapping LIDAR
topography. The Waste Inventory Analysis for the 1964 Ash Basin (including report and
calculations) is included with this document as Appendix A. All of the ash will be removed from
the 1964 Ash Basin prior to dam decommissioning and ash basin closure.
3.1.3 Description of Surface Impoundment Structural Integrity
A Reconstitution of Ash Basin Design (Amec Foster Wheeler 2015e) was performed for the
1982 and 1964 Ash Basins that compiled and analyzed pertinent information regarding the
integrity of the embankments. As summarized below, this report examined the geotechnical
properties, structural elements (spillways), and hydrology and hydraulics of the basins. The
report compiled and analyzed existing reports and evaluations for the ash basins, and
addressed data gaps with additional analyses and conclusions for the site. Additional
information is presented in the History of Construction Report (Amec Foster Wheeler 2016a) in
reference to the hydrologic and hydraulic studies performed after the issuance of the
Reconstitution of Ash Basin Design report.
In addition, an additional geotechnical stability analysis was performed by AECOM (AECOM
2016) for the 1964 Ash Basin dam. This analysis analyzed the potential for liquefaction and
seismic stability of the embankment to determine if stability improvements to the dam were
needed. Based on a review of the historical documents and additional data gathered, the
following conclusions were reached for the ash basins and related structures:
Geotechnical analyses show:
The minimum factors of safety for the 1964 Ash Basin Dam, 1982 Ash Basin Dam, the
Separator Dike and the Equalization Basin dike were greater than the target factor of
safety requirements for applicable loading conditions at all locations analyzed.
Seismic Site Class C and D were determined to be appropriate for the 1982
Dam/Separator Dike and Equalization Basin/1964 Dam area, respectively, prior to
analysis of liquefaction.
Based on the Standard Penetration Test (SPT) analyses, widespread liquefaction of the
foundation soils of the embankments is not anticipated for the design seismic event. The
dams and dikes are not susceptible to liquefaction, and post-earthquake shearing
failures of the impoundments are not anticipated. Displacements of the dam/dike crests
are not expected.
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Structural analyses show:
The riser structure at the former Duck Pond within the 1964 Ash Basin could not be
evaluated due to lack of information regarding the timber pile foundation system. By
inspection, it was concluded that this structure was not designed for seismic events and
it would likely fail under seismic loading conditions.
The 1982 Ash Basin riser and outfall pipe were determined to be in poor condition.
However, those structures have been abandoned as of the date of this Removal Plan.
Hydrologic and Hydraulic:
All ash has been removed from the 1982 Ash Basin, and dam decommissioning
activities are currently underway. The drawings for the dam decommissioning (Appendix
E) address the sequencing of grading for removal of the embankment and backfilling to
prohibit impounding water, and management of stormwater during this process.
The total storm volume in the 1964 Ash Basin for the full PMP event is approximately
183.7 acre feet, and the available storage volume is approximately 192.9 acre feet
(Amec Foster Wheeler 2016a).
3.1.4 Sources of Discharges into Surface Impoundments
The 1964 Ash Basin currently receives low volume stormwater, sluice water, and stormwater
from the switchyards and gypsum pad. Both ash basins receive stormwater from their
associated drainage areas. The sluicing operations and effluent discharges from the Plant have
historically been routed to the ash basins. However, only the 1964 Ash Basin currently supports
ongoing operations with the Duck Pond and the Rim Ditch. Ash is directed to the Rim Ditch,
where generation ash is sluiced, recovered, and temporarily placed in the 1964 Ash Basin.
The discharge of effluent from the Plant’s operation is permitted under NPDES Permit
NC0000396 authorized by the NCDEQ Division of Water Resources (DWR).
3.1.5 Existing Liner System
Based on historical documents, the 1982 and 1964 Ash Basins are not lined.
3.1.6 Inspection and Monitoring Summary
Weekly, monthly, and annual inspections of the ash management facilities are conducted at the
Plant consistent with the North Carolina CAMA and CCR Rule and in accordance with the
Operations & Maintenance (O&M) Manual (Amec Foster Wheeler 2015d). The findings
presented in this section are tracked and resolved in the pertinent work management system.
Independent third-party inspections are performed once every year to promote the design,
operation, and maintenance of the surface impoundment in accordance with generally accepted
engineering standards.
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Annual inspections are performed to gather information on the current condition of the dams
and appurtenant works. This information is then used to establish needed repairs and repair
schedules, to assess the safety and operational adequacy of the dam, and to assess
compliance activities with respect to applicable permits, environmental and dam regulations.
Annual inspections are also performed to evaluate previous repairs.
In May 2016, an annual inspection of the Plant ash basin dams was performed (Amec Foster
Wheeler 2016b). This inspection included observations of the ash basin dams, discharge
towers, and drainage pipes. In addition to the field observations of the physical features of the
impoundments, this annual inspection included a review of available design documents and
inspection records. This report included findings from previous inspections including, but not
limited to, the following documents:
AMEC Environment & Infrastructure, Inc., “2014 Annual Ash Basin Dam Inspection,
Asheville Steam Electric Station,” January 14, 2015;
Amec Foster Wheeler, “2015 Annual Ash Basin Dam Inspection, Asheville Plant,” May 9,
2016;
AMEC Environment & Infrastructure, Inc., “2012 Five-Year Independent Consultant
Inspection, Cooling Lake Dam and Ash Pond Dams, Asheville Steam Electric Plant,”
February 19, 2013;
S&ME Inc., “Construction Repair Certification Report, 1964 Ash Basin Dam
Improvements (Phase II), Progress Energy Asheville Plant,” December 18, 2012;
NCDENR Notice of Inspection Reports for 1964 Ash Pond Dam (BUNCO-097) dated
April 30, 2010; May 6, 2011; February 22, 2012; April 19, 2013; and April 1, 2014;
AMEC Environment & Infrastructure, Inc., “2013 Report of Limited Field Inspection,
Cooling Lake Dam and Ash Pond Dams, Duke Energy Progress – Asheville Steam
Electric Plant,” August 5, 2013;
AMEC Environment & Infrastructure, Inc., “2014 Report of Limited Field Inspection,
Cooling Lake Dam and Ash Pond Dams, Duke Energy Progress – Asheville Steam
Electric Plant,” August 28, 2014;
AMEC Environment & Infrastructure, Inc., “Asheville Plant, BUNCO-089-H, BUNCO-097-
H Observations, 8/27/2014 through 10/2/2014, Buncombe County, North Carolina,”
September 8, 2014, through October 6, 2014;
NCDENR Notice of Inspection Reports for 1982 Ash Pond Dam (BUNCO-089) dated
May 5, 2010; May 6, 2011; February 22, 2012; April 19, 2013; and April 1, 2014;
Dewberry & Davis, Inc., “Final Coal Combustion Waste Impoundment Dam Assessment
Report, Site 7, 1982 Pond & 1964 Pond, Progress Energy Carolinas, Asheville, North
Carolina,” Revised Final September 11, 2009;
Stantec, “Asheville Plant – Field Reconnaissance,” 2014.
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The 2016 annual inspection, dated September 12, 2016, states that the “inspection did not
identify features or conditions in the inspected ash basin dams, their outlet structures or their
spillways that indicate an imminent threat of impending failure hazard. Review of critical
analyses suggests the design conforms to current engineering state of practice to a degree that
no immediate actions are required other than the recent and ongoing surveillance and
monitoring activities already being practiced.”
Summary recommendations were developed for both the 1982 and 1964 Ash Basin Dams. The
recommendations are summarized in Table 3-1 and Table 3-2 for the 1982 and 1964 Ash Basin
Dams, respectively.
Table 3-1: 1982 Ash Basin Dam Summary Recommendations (Amec Foster Wheeler
2016b)
Ref. No. Recommendations 2016 Annual Inspection Status
1982 AP-
2009-1
(EPA)
Take precautions to not mow slope when wet or
take necessary measures to not create ruts up and
down slope.
No ruts observed along slope of
embankment.
1982 AP-
2009-2 (EPA)
Vegetative cover needs to be established in bare
areas.
Bare areas noted during weekly
inspections are seeded as required to
establish vegetation. Bare areas were not
observed during the annual inspection.
1982 AP-
2009-3 (EPA)
Small animal burrows found on downstream slope
should be filled with appropriate material.
Animal burrows observed and filled with
appropriate material as necessary.
Continue monitoring
1982 AP-
2010
(NCDENR)
Animals should be removed from dam and burrows
repaired.
Animal burrows observed and filled with
appropriate material as necessary.
Continue monitoring.
1982 AP-
2010-2013
(NCDENR)
Monitor wet area noted about halfway up
downstream slope near left abutment.
No wet area noted on downstream slope.
Monitoring of this area continues with
weekly inspections.
1982 AP-
2012-2014
(NCDENR)
Monitor wetness noted at toe on right abutment and
near toe drains.
No wet area noted at the toe on right
abutment and near the toe drains.
Monitoring of this area continues.
1982 AP-
2012-1
Plant personnel should continue to perform their
monthly inspections and measurements at the weir
and piezometers. The measurements at the weir
should not be performed during or within about 12
hours after rainfall events.
Inspections and monthly measurements
are continuing.
1982 AP-
2012-2
Cut trees and bushes growing within the riprap lined
upstream slope. The grass and weeds growing in
this area do not need to be cut or killed.
Ash excavation continues. Upper portion of
upstream face has established vegetation.
Vegetation should be established in lower
portion of upstream face. (Note: As of
December 2016, ash excavation is
complete and dam decommissioning
activities are in progress.)
1982 AP-
2014-1a
(NCDENR)
Repair rutted area along left abutment toe road. Continue to monitor and repair erosion
areas as necessary.
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Ref. No. Recommendations 2016 Annual Inspection Status
1982 AP –
2014-1b
(NCDENR)
Monitor mole holes noted on downstream slope. No evidence of mole activity during
inspection.
1982 AP-
2014-2
Slope protection should be implemented on the
upstream face of the dam during the ash removal
process.
Ash excavation continues. Upper portion of
upstream face has established vegetation.
Vegetation should be established in lower
portion of upstream face. (Note: As of
December 2016, ash excavation is
complete and dam decommissioning
activities are in progress.)
1982 AP-
2014-4
(Stantec
ASH-5)
Establish grass vegetation or other erosion control
measures on external slope of separator dike.
Continue to monitor and establish
vegetation and other erosion control
measures as necessary. (Note: As of
December 2016, Riprap has been added to
this slope in lieu of vegetation repairs.)
1982 AP
2014-8
Monthly inspection of the dam and measurements of
water elevations at the piezometers and seepage
flow at the weirs should continue
Inspections and measurements are
continuing.
Table 3-2: 1964 Ash Basin Dam Summary Recommendations (Amec Foster Wheeler
2016b)
Ref. No. Recommendations 2016 Annual Inspection Status
1964 AP-
2009-2 (EPA)
Establish a program to have rip-rapped slope
cleared of vegetation at least once every year.
Riprap slope is sprayed with herbicide as
necessary to kill vegetation.
1964 AP-
2010&2011-1
(NCDENR) &
2014-1
Monitor seepage at toe of dam on right abutment
where 1971 section over 1964 section begins.
This area of seepage is monitored for change
during monthly and weekly inspections. Observed
to be similar to previous inspections.
1964 AP-
2012-1
Recommended that safety inspection of the 1964
Ash Pond Dam should continue annually.
Annual inspections performed by Amec Foster
Wheeler.
1964 AP-
2012-2
Regularly remove trees and bushes from the face
of the dam.
D/S Slope of dam is sprayed with herbicide as
necessary to kill young trees and bushes.
1964 AP-
2012-4
Consider installing a flow monitoring weir at the
outfall from the concrete structure that collects
flow from the toe drains.
Flow meters that were previously installed at toe
drain outlets and flow rates are recorded monthly
by Duke personnel.
1964 AP-
2014-2
Consider installing a flow monitoring device at the
outfall of the corrugated HDPE culvert beneath
the toe road along the right abutment to monitor
seepage from the upstream area where 1971
section over 1964 section begins. In the interim,
measure flow with pan and stopwatch.
Flow monitoring device installed in October 2015.
Flow is visually monitored and recorded during
weekly inspections. Flow is collected into a two
inch diameter PVC pipe and discharges into the
toe drain outlet structure.
1964 AP-
2014-4
(Stantec
ASH-6)
Future inspections of the pipe should be
performed without water flowing. (Note: this
refers to Stantec’s Video inspection of the HDPE
pipe installed in 2012 between MH#1 in 1964
pond and the new stilling basin outside the 1964
pond.)
Future inspection videos should be performed at
a 5-year interval with no flow in the pipe.
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Ref. No. Recommendations 2016 Annual Inspection Status
1964 AP-
2014-5
Stability analyses should be performed to
improve the adequacy of supporting technical
documentation.
Additional analysis performed by AECOM. Based
on report dated March 31, 2016, the 1964 Ash
Pond Dam is stable for the static and seismic
loading conditions outlined in the Duke
programmatic guidelines and CCR Rules.
2015-1
Structural
(Amec Foster
Wheeler)
The riser structure at the Duck Pond within the
1964 Ash Pond could not be evaluated due to
lack of information regarding the timber pile
foundation system. By inspection, we conclude
that this structure was not designed for seismic
events and it would likely fail under seismic
loading conditions.
Duke evaluating condition to determine
appropriate action.
2015-2
Geotechnical
(Amec Foster
Wheeler)
Slope Stability Analyses: The pseudo seismic
acceleration must be updated to meet the
requirements of the MPD. Slope stability
analyses should be performed for the section at
stations 10+00 (where an alluvial layer was
indicated) and 13+50 for the downstream section
under static and pseudo static load cases.
Additional analysis performed by AECOM. Based
on report dated March 31, 2016, the 1964 Ash
Pond Dam is stable for the static and seismic
loading conditions outlined in the Duke
programmatic guidelines and CCR Rules.
2016-1 (Duke
Energy weekly
inspections)
Small section of riprap on southern downstream
slope near abutment road has bare soil. Bare soil
should be covered with additional riprap.
Area should be repaired in near future (Duke
Work Order # 9583222-3).
2016-2 (Duke
Energy weekly
inspections)
Northern upstream slope has areas of bare soil
and erosion rills in where grading has occurred
from the temporary ash stacking project. These
areas shall be revegetated.
Bare areas on the northern upstream slope will
be revegetated in near future.
2016-3 (Duke
Energy weekly
inspections)
Erosion along south abutment road. Erosion shall be continued to be monitored and
repaired as necessary.
2016-3 (Duke
Energy weekly
inspections)
Seepage noted on divider dike on downstream
slope into the 1982 basin.
The seep will continue to be monitored during
weekly inspections. No flow was observed during
the annual inspection.
3.2 Site Maps
3.2.1 Summary of Existing CCR Impoundment Related Structures
A site map that includes a summary of the CCR impoundment-related structures is included as
Figure 3. This map illustrates the following features that are associated with the CCR units:
Property boundary (determined from Buncombe County GIS);
Location of main steam Plant;
Identification of the CCR surface impoundments and their approximate boundaries;
500-foot compliance boundary for the basins (developed from SynTerra information);
Location of the existing Primary Spillway System and associated features;
Locations of the Rim Ditch and Decant Basin operations;
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Location of center pond filter system and associated features;
Drainage culverts downstream of the Ash Basins and under Interstate I-26.
3.2.2 Receptor Survey
SynTerra completed a report, Drinking Water Well and Receptor Survey for Asheville Steam
Electric Plant, September 2014 (SynTerra 2014a), and later updated it with the Supplement to
Drinking Water Well and Receptor Survey for Asheville Steam Electric Plant, November 2014
(SynTerra 2014b). The receptor surveys were further updated in the CSA under Section 4.0
(SynTerra 2015a) and in the CSA Supplement 1 (SynTerra 2016b), and Receptor Information
with human and ecological receptors, pathways, and their risks associated with exposure to coal
ash-derived constituents that maybe present in soil, sediments, surface water, and groundwater
are described in Section 5.0 of the CAP part 2 (SynTerra 2016a). Results of the two receptor
surveys, and risk assessment updates from the CSA, CAP parts 1 and 2 are herein referred to
collectively as receptor surveys, are summarized as follows.
Completion of the receptor surveys included the collection, compilation, and assessment of
electronic and field data. Publicly available electronic data used in receptor surveys includes the
following sources:
NCDEQ Division of Environmental Health;
NC OneMap GeoSpatial Portal;
DWR Source Water Assessment Program online database;
County geographic information system;
Environmental Data Resources, Inc.;
USGS National Hydrography Dataset.
In addition to the collection and assessment of electronic data, SynTerra completed a visual
reconnaissance by driving along public roadways and obtaining information from local property
owners using questionnaires. These activities were completed within an approximate 0.5-mile
radius of the facility compliance boundary. The goals of these surveys were to identify land
development and use, and additional potential water supply wells, including detailed well
completion information when possible.
The entire dataset for the receptor surveys was collected to satisfy requirements stipulated by
the following:
CAMA 2014 – North Carolina S.B. 729;
Notice of Regulatory Requirements received by Duke on August 13, 2014.
In addition to identification of receptors, the compiled data was used to develop a description of
the site, surrounding area, geology, and hydrogeology, including a Site Hydrogeologic
Conceptual Model (SCM) which are documented in Sections 4.0 and 5.0 of this document.
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The results of the receptor surveys conclude the following:
No public municipal water supply wells exist within the 0.5-mile radius of the compliance
boundary. The closest public municipal water supply wells are more than 2 miles from
the Site, and produce water from bedrock at depths between 320 to 500 feet below
ground surface in areas separated from groundwater near the Asheville Plant by
topographic and groundwater divides including the French Broad River;
Forty private water supply wells and 3 springs were identified within the 0.5-mile radius
of the compliance boundary (Figure B-1, Appendix B). However, most of the
residences receive potable water from municipal water lines, and not all private water
wells have been field verified. Additionally, most of these wells are potentially isolated by
topographic and groundwater divides, including being west of the French Broad River, or
are upgradient of the groundwater flow direction (Figure B-1, Appendix B);
Four of the water supply wells had iron, manganese, sulfate, and TDS above 2L, and
NCDEQ recommended that the associated residents use an alternate drinking water
supply;
Five of the 40 private water supply wells within the 0.5-mile radius of the compliance
boundary are on the east side of the French Broad River, south of the ash basin along
the residential road Bear Leah Trail. A municipal water supply line was completed in
2016 (Figure B-1, Appendix B), and the existing private wells along Bear Leah Trail
were abandoned in 2016 (SynTerra 2016b);
Human health exposure media includes potentially impacted groundwater, soil, surface
water and sediments with exposure pathways including ingestion, inhalation and dermal
contact of the exposure media;
Potential ecological receptors include aquatic (e.g., fish, benthic invertebrates), semi-
aquatic (e.g., piscivorous birds and mammals), and terrestrial (e.g., terrestrial
invertebrates, plants, mammals, passerine birds, raptors) receptors;
While some constituents are found in various media at greater concentrations in the
source areas relative to background, many constituents that exceed screening criteria
occur at naturally elevated levels.
The identified public and private water supply wells are listed in Table B-3 of Appendix B. The
table summarizes the following information:
Map well ID (for figures referenced within the report);
Property address;
Property owner;
Parcel ID number;
Source of drinking water;
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Well use;
Approximate distance from compliance boundary (feet);
Well depth (feet);
Well casing or open hole depth (feet).
Six of the private water supply wells (DW-3, DW-14, DW -19, DW-27, DW-32, and DW-34)
identified within the 0.5-mile radius of the compliance boundary were sampled by NCDEQ for
water quality parameters and constituents, including drinking water constituents and
parameters, presented in Table B-1, Appendix B, between February and July 2015. Two of the
sampled wells (DW-3 and DW-19) are on the east side of the French Broad River and south of
the Plant. The other four sampled wells (DW-14, DW-27, DW-32, and DW-34) are west of the
French Broad River, and south and west of the Plant (Figure B-1, Appendix B). Analytical
results are further discussed in the CSA.
In 2016, Duke began assessing the water supply wells to understand if the concentrations
reflect natural conditions or other potential source areas west of the French Broad River (such
as agricultural run-off, use of pesticides, or detergents in septic tank systems). Groundwater
underflow across the French Broad River would not be anticipated under natural conditions.
Therefore, the assessment is focused on understanding the reason for the constituent
concentrations observed (SynTerra 2016b).
Duke collected additional groundwater samples from the former water supply wells on Bear
Leah Trail prior to well abandonment and from water supply wells located on the west side of
the French Broad River (AS-9, AS-11, AS-13, AS-14, and AS-20) using the available well
pumps. Analytical results are further discussed in the CSA Supplement 1, and results are
depicted on Figures 1-14, 1-20, 1-23, 1-47, and 1-50 (Appendix B).
The risk assessment synopsis in Section 5.0 of part 2 of the CAP also states that media
exposure estimates were less than their respective risk-based concentrations (RBCs) for current
use exposure to groundwater with respect to construction and commercial worker exposure via
dermal and incidental ingestion pathways. Additionally, Haley and Aldrich (2015) performed an
analysis of the groundwater data collected by NCDEQ from 8 private drinking water wells
located less than 0.5 miles of the Asheville facility, and 13 private drinking water wells located
within a 2 to 10 mile radius of the Asheville facility that concluded the testing provided no
evidence for a coal ash management unit release related impact. However, based on lowest
observed adverse effect level-derived toxicity reference values, the baseline ecological risk
assessment identified potential risk to wildlife from barium, manganese, molybdenum, selenium,
and vanadium in seeps and seep soils within the immediate ash basin area (SynTerra 2016a).
The settling pond was also identified as a potential risk to wildlife associated with selenium
exposure, and in the French Broad River the selenium lowest observed adverse effect level-
based HQ was 1 for the meadow vole receptor. However, SynTerra states that the food chain
model for risk is an over estimate and selenium is not expected to pose unacceptable risks to
ecological receptors in the French Broad River floodplain.
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Part 2 of the CAP, Section 2.6, also states numerous wells have been abandoned since
completion of the CSA and are provided in Appendix A of Part 2 of the CAP.
3.2.3 Existing On-Site Landfills
No existing on-site landfills are present at the Asheville Plant.
3.3 Monitoring and Sampling Location Plan
SynTerra provided a groundwater monitoring and sampling location plan in the CSA for future
monitoring. The monitoring well locations of both historical and planned sampling are shown on
Figure 2-1 and Figure 16-1 of Appendix B.
3.3.1 Interim Groundwater Monitoring Plan
The groundwater monitoring and sampling location plan is a longer-term, future sampling plan
described under Section 16.0 of the CSA. The goals of this plan are to collect sufficient data to
determine site-specific background water quality concentrations, support current interpretations
of Site data, and to monitor for temporal trends.
The Interim Groundwater Monitoring Plan recommends a total of 46 monitoring well locations
within 5 different geologic units including (Table 16-2 and Figure 16-1, Appendix B):
Alluvium – 9 monitoring wells;
Transition Zone – 17 monitoring wells;
Saprolite – 8 monitoring wells;
Bedrock – 12 monitoring wells.
The groundwater monitoring wells were also selected to include a combination of the above
geologic units for groundwater monitoring in areas based on the following rationales:
Determine background concentrations upland of basins – 9 monitoring wells;
Downslope of the ash basin, both next to the French Broad River (13 monitoring wells)
and southwest (8 monitoring wells) of the Site – 21 monitoring wells;
Monitor contaminant migration south (2 monitoring wells), east (2 monitoring wells), and
northwest (5 monitoring wells) of the basins – 9 monitoring wells;
Next to 1964 basin, to monitor intersecting flow path to French Broad River – 7
monitoring wells.
The recommended parameter and constituent list includes a set of 6 field parameters, a suite of
21 inorganic constituents, major cations and anions, nitrate, total dissolved solids (TDS), total
organic carbon (TOC), and total suspended solids (Table 16-1, Appendix B). Analytical
methods and associated reporting limits are also provided for each parameter and constituent
(Table 16-1, Appendix B).
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The Interim Groundwater Monitoring Plan recommends a triannual groundwater sampling
frequency intended to provide insight into potential seasonal trends, if any.
The Interim Groundwater Monitoring Plan presented in Section 16.0 of the CSA described
above will be superseded by the updated Interim Monitoring Plan (IMP), and a post-closure
Effectiveness Monitoring Program (EMP) described in Section 9.0 of Part 2 of the CAP, if and
when the proposed remedial actions are accepted as proposed in Part 2 of the CAP. The IMP
and EMP proposed in Part 2 of the CAP are described in further detail under Section 11 of this
document.
Additional characterization of the bedrock flow system beneath the ash basins and at a
background location was requested by NCDEQ (SynTerra 2016b). Monitoring well ABMW-11BR
was installed at a central location within the 1964 and 1982 Ash Basin waste boundary (Figure
1-2, Appendix B). ABMW-11BR has been sampled twice since installation. Monitoring well CB-
1BRL was also installed at a background location (Figure 1-2, Appendix B).
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4. RESULTS OF HYDROGEOLOGIC, GEOLOGIC, AND GEOTECHNICAL
INVESTIGATIONS
The information in this section is a summary based on the Phase 2 Reconstitution Report
(Amec Foster Wheeler 2015e), CSA report (SynTerra 2015a), and CSA Supplement 1
(SynTerra 2016b). More detailed descriptions can be found in the original reports.
4.1 Hydrogeology and Geologic Descriptions
4.1.1 Regional Geology
The Plant is within the Blue Ridge Physiographic Province of North Carolina. This province is
characterized by a mountainous vegetated terrain with elevations ranging from 1,500 feet above
mean sea level at the base of the escarpment to summit altitudes of over 6,000 feet.
The formations that underlie the Blue Ridge Physiographic Province primarily consist of
complexly folded and faulted metamorphic and igneous rock with some sedimentary rock that
make up the Blue Ridge geologic belt. The Blue Ridge geologic belt complexity is a result of
extensive sheet thrusting, and is bounded to the southeast by the Brevard zone, a zone of major
southwest–northeast faulting, and to the northwest by the Valley and Ridge Physiographic
province in eastern Tennessee that are composed of low angle thrust faults. Within the Brevard
zone, there are two major thrust faults approximately 1.3 miles southeast of the site (Figure 6-1,
Appendix B). Since their deformation and Cenozoic uplift, this assemblage of metasedimentary
and metavolcanic rock has been exposed and subjected to an extended period of erosion, and
the erosion has produced a rugged terrain, consisting of steep mountains, intermittent basins,
and trench valleys.
4.1.2 Regional Hydrogeology
Due to the geologic complexity of the Blue Ridge Physiographic Province, numerous studies
have been conducted, including the USGS Regional Aquifer-System Analysis, which refers to
hydrogeologic terranes instead of identifying specific aquifers and confining units for the
province. Groundwater occurrence in the Blue Ridge Physiographic Province has been grouped
into two hydrogeologic terranes identified by rock types and median well yields:
1. Gneiss-granite terrane having an interquartile well yield of approximately 8 to 32 gallons
per minute (gal/min);
2. Schist-sandstone terrane having an interquartile well yield of approximately 10 to 61
gal/min.
Groundwater resides within the soil/saprolite regolith and is hydrologically connected with the
underlying fractured bedrock forming a composite water-table aquifer system. Local
groundwater flow is primarily influenced by 1) the soil/saprolite regolith thickness, and its
existence, and 2) the nature of the parent bedrock. Typically, topographic highs exhibit thinner
soil/saprolite zones, and topographic lows exhibit thicker soil/saprolite zones, with gneiss and
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schist rock sources having thicker soils and relatively higher fracture densities compared to
unaltered igneous rocks, including granite. The higher fracture density and thicker soil zones of
the gneiss and schist bedrock provide efficient transition zones with less clay, and may facilitate
both rapid lateral groundwater movement along unweathered bedrock and vertical groundwater
movement to underlying fractured rock.
Groundwater flow is also influenced in the area by precipitation serving as recharge, seasonal
water table fluctuations with highs in the winter and lows in the fall, flow boundaries such as
rivers, and topography where ridges can serve as groundwater divides. In general, groundwater
flow in the area can be classified as a slope-aquifer system.
4.2 Stratigraphy of the Geologic Units Underlying Surface Impoundments
The stratigraphy of geologic units underlying the surface impoundments is similar in
characteristics described for the local and regional geology. A comparison of preconstruction
topography before installation of the ash basin to current elevations is consistent with measured
ash thickness in core samples and indicates ash depth generally mimics the historical land
surface. Borings drilled within the ash basins indicated a distinct contact between the ash and
underlying soils without visible evidence of ash staining into underlying soils (Section 7 of CSA
report).
In particular, the ash basins directly overly the local residual soils (Section 7 of CSA report).
Toward the Lake Julian dam, ash overlies saprolite with increasing thickness (Figure 6-3 and
Figure 6-4, Appendix B). The saprolite within the ash basin is underlain by transition zone
media and a bedrock of mica gneiss, a member of the late Precambrian Ashe Metamorphic
Suite. The Geologic Map of the Skyland Quadrangle (Dabbagh 1981) describes the underlying
bedrock as being mainly composed of gray to dark gray, fine- to medium-grained gneiss. Of
note is a shear zone trending northeast-southwest, which is mapped to underlie the
approximate northwestern side of the 1982 Ash Basin.
4.3 Hydraulic Conductivity Information
The horizontal hydraulic conductivities of the site hydrogeologic zones were determined from in-
situ field slug testing of wells in accordance with the Groundwater Assessment Work Plan (GAP)
Section 7.1.4 (Table 6-5, Appendix B). The slug tests were performed in accordance with the
documented standard ASTM D4044-96 (Appendix C of CSA report [SynTerra 2015a]). A total of
143 slug tests was performed at 47 well locations (Table 4-1). The tests were analyzed primarily
by the Hvorslev analytical solution, with some well tests analyzed by the Bouwer-Rice analytical
solution for wells that were not fully penetrating (Appendix G of CSA report [SynTerra 2015a])
according to the methodology described in Appendix C of the CSA report. Locations of tested
wells are shown on Figure 2-1 of Appendix B.
The slug testing results listed in Table 6-5 of Appendix B includes individual well test hydraulic
conductivity results, calculated geometric means for repeated testing of individual wells and for
each hydrogeologic zone having multiple well results, and minimum and maximum values for
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individual wells and for each hydrogeologic zone. Testing results include testing of wells
completed in hydrogeologic zones below the ash basins and in the surrounding area (Figure 2-
1, Appendix B).
Table 4-1: Summary of Hydraulic Conductivity Geometric Mean Monitoring Well Slug
Testing Results for Each Hydrogeologic Zone
Hydrogeologic
Zone
Number of Wells
Tested
Number of Slug
Tests
Hydraulic
Conductivity
Geometric Mean
(cm/sec)
Hydraulic
Conductivity
Geometric Mean
(ft/day)
Ash Basins 3 7 1.52E-04 4.32E-01
Alluvium 2 15 3.21E-03 9.09E+00
Saprolite 7 25 2.83E-04 8.01E-01
Transition Zone 18 57 3.09E-04 8.76E-01
Bedrock 17 39 4.77E-04 1.35E+00
The results of slug testing indicate spatial variability throughout the site and between different
hydrogeologic zones. Slug testing of alluvial deposits indicated approximately an order of
magnitude higher hydraulic conductivity than other hydrogeologic zones (Table 4-1).
The hydraulic conductivity values for wells screened in the transition zone spanned three orders
of magnitude from 1.1 × 10E-5 to 1.3 × 10E-2 centimeters per second (cm/sec), with a mean of
3.1 × 10E-4 cm/sec (Table 6-5, Appendix B). The large range in results reflects the degree of
weathering which can be highly variable within the transition zone and related to the degree of
infilling of fractures, varying amounts of clays, and other weathering products.
In addition to in-situ, horizontal hydraulic conductivity slug testing, three laboratory vertical
hydraulic conductivity tests were performed on cores collected in Shelby tubes. These
laboratory tests are reflective of site conditions because the ash basin is not lined (Table 6-6,
Appendix B). A 2.5-foot core was collected from bore hole ABMW-02SB, and 2-foot cores were
collected from both ABMW-07 and MW-16SB (Table 6-6, Appendix B). The intervals selected
for testing the core represent three distinct zones: saprolite, ash, and alluvium, with values of
2.60E-06, 8.60E-06, and 4.80E-07 cm/sec, respectively. The vertical conductivity testing results
are one to two orders of magnitude lower than horizontal conductivity values from in-situ slug
testing, supporting a predominantly lateral groundwater flow in the Site area. In addition, the
results support a predominantly lateral migration of COIs relative to vertical migration.
4.4 Geotechnical Properties
Subsurface investigations were performed as part of previous design and reconstitution projects
at the Asheville Steam Electric Generating Plant. A summary of available boring, monitoring
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well, and piezometer locations involving the ash basins is shown on Figure 4. In these
investigations, geotechnical properties were developed to characterize the soils and ash present
at the site. As previously discussed, there is no liner underneath the ash basins. For this
Removal Plan, the geotechnical properties listed below were gathered from the following
previous reports:
Amec Foster Wheeler, “Subsurface Exploration and Laboratory Testing Data Report,
Landfill Development and Ash Basin Closure,” August 2015;
Amec Foster Wheeler, “Phase 2 Reconstitution of Ash Pond Designs, Final Report
Submittal, Revision B, Asheville Steam Station,” July 17, 2015;
S&ME, Inc., “Subsurface Investigation and Slope Stability Analysis of 1964 Ash Basin
Dike,” December 28, 2009;
S&ME, Inc. “1964 Ash Basin Dam Improvement Design – Appendix I – Slope Stability
Analysis Discussion and Summary,” December 28, 2009;
MACTEC Engineering and Consulting, Inc., “Geotechnical Exploration Data Report,
Asheville FGD Project, Constructed Wetlands System,” October 18, 2004;
MACTEC Engineering and Consulting, Inc., “Report of Geotechnical Exploration,
1982/1964 Ash Pond Drainage Modification Project,” January 19, 2011;
MACTEC Engineering and Consulting, Inc., “Final Report for Task ASH-1 Issue,” August
2014;
Law Engineering, Inc., “Stability Analysis of Downstream Slope, 1982 Ash Pond Dike,”
September 30, 1992;
AMEC, “Asheville Steam Plant, Final Report for Task ASH-2 Issue,” August 26, 2014.
1982 Ash Basin Dam
Design parameters for the 1982 Ash Basin Dam were developed from the analysis completed
by Law Engineering (1992) and from the Phase 2 Reconstitution of Design report (Amec Foster
Wheeler 2015e). The following material properties were developed from these analyses:
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Table 4-2: Unit Weight and Shear Strength Parameters for the 1982 Ash Basin Dam
Material Description
Unit
Weight
Shear Strength
Effective R-Envelope
(pcf) c’
(psf)
Ф’
(degree)
c’
(psf)
Ф’
(degree)
Embankment 120 400 33.9 0 32.8
Sand Drain 120 0 36 0 36
Foundation Soil 130 400 32 650 30
Partially Weathered Rock 135 10,000 45 10,000 45
*Note: Material Description information is included in the Phase 2 Reconstitution Report (Amec
Foster Wheeler 2015e).
1964 Ash Basin Dam
The subsurface stratigraphy for the dam has been based on the stability analysis completed for
the 1964 Ash Pond Dam (S&ME 2009) and on the Phase 2 Reconstitution of Design report
(Amec Foster Wheeler 2015e). The following material properties were developed from this
analysis:
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Table 4-3: Unit Weight and Shear Strength Parameters for the 1964 Ash Basin Dam
Material Description
Unit
Weight
Shear Strength
Effective R-Envelope
(pcf) c’
(psf)
Ф’
(degree)
c’
(psf)
Ф’
(degree)
Zone 1 - Core 120 200 32 600 17
Zone 2 - Rock Shell 120 0 47 0 47
Zone 3 – Mixed Fill 120 0 40 440 24
Zone 4 – Drainage Zone 120 0 36 0 36
Upstream Rockfill 120 0 40 0 40
Ash Fill 120 0 30 0 30
Ash (Above Water) 85 0 30 0 30
Ash (Below Water) 85 0 30 0 20
Ash Stack 85 0 30 0 30
Original 1964 Dike Fill 120 0 40 420 21
1971 Cofferdam Fill 120 0 30 300 20
Stilling Pond Embankment 120 140 33 400 20
Alluvium 120 50 28 50 24
Residual Soil 120 115 35 330 25
Partially Weathered Rock 120 1000 40 1000 40
*Note: Zone and Material Description information is included in the Phase 2 Reconstitution Report
(Amec Foster Wheeler 2015e)
Separator Dike
The design parameters for the Separator Dike were developed from the Final Report for Task
ASH-2 Issue (AMEC 2014b) and from the Phase 2 Reconstitution of Design report (Amec
Foster Wheeler 2015e). The following material properties were developed from these analyses:
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Table 4-4: Unit Weight and Shear Strength Parameters for the Separator Dike
Material Description
Unit
Weight
Shear Strength
Effective R-Envelope
(pcf) c’
(psf)
Ф’
(degree)
c’
(psf)
Ф’
(degree)
Embankment 120 400 33.9 0 32.8
Zone 3 120 0 40 435 24.4
Ash 85 210 28.8 40 19.4
Zone 1 120 200 32 1000 16.9
Foundation Soil 130 400 32 650 30
Partially Weathered Rock 135 10,000 45 10,000 45
*Note: Zone and Material Description information is included in the Phase 2 Reconstitution
Report (Amec Foster Wheeler 2015e).
Residual Materials in 1982 Ash Basin
Amec Foster Wheeler drilled an additional 30 borings within the limits of the 1982 Ash Basin.
Laboratory tests were performed on samples collected from these borings. The samples
generally consisted of ash fill within the basin, and residual materials from the original ground
underlying the basin. Since ash removal was completed on September 30, 2016, Table 4-5 only
lists the material properties that were developed for the residual materials from these analyses.
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TABLE 4-5
Index Property Test Results of Materials in 1982 Ash Basin
Boring Sample
Type
Sample
Depth
(Feet bgs)
Visual Identification
Natural
Moisture
Content,
%
Dry
Unit
Weight,
pcf
Atterberg Limits Percent
Finer Than
No. 200
Sieve
Other Test Liquid
Limit
Plastic
Limit
Plasticity
Index
BL-1A UD-1 15-17 Yellowish Brown Silt with Sand (ML)-
RESIDUUM
74.8*
81.6* NP NP NP 82.8 S.G. = 3.00
k
BL-8 Bulk-1 0-10 Brown Silty Sand (SM) - RESIDUUM 22.7* NP NP NP 41.1 S.G. = 2.72
P
BL-14 Bulk-1 0-8.9 Brown Silty Sand (SM) - RESIDUUM 12.9
12.7* NP NP NP 27.7 S.G. = 2.78
P
BL-19 Bulk-1 0-10 Brown Silty Sand (SM) - RESIDUUM 17.8 NP NP NP 36.2 S.G. = 2.73
P
SPT-Standard Penetration Test/Split-Spoon; UD-Undisturbed Sample; Prepared/Date: H. Benkhayal/7-29-2015
P - Moisture-Density Relationship Test; NP-Non Plastic; Checked/Date: C. Tockstein/7-29-2015
k – Hydraulic Conductivity Test; S.G.-Specific Gravity Test
*Result obtained from a different laboratory test method (i.e., Hydraulic Conductivity, Atterberg limit test, etc.)
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CCR and Residual Materials in 1964 Ash Basin
A subsurface investigation was performed by Amec Foster Wheeler in 2015 with the intent of
providing additional information for the development of closure and/or landfill options for the ash
basins. As part of this investigation, 10 borings were drilled within the limits of the 1964 Ash
Basin. Laboratory tests were performed on samples collected from these borings. The samples
generally consisted of ash fill within the basin, and residual materials from the orig inal ground
underlying the basin. The following material properties were developed from these analyses:
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TABLE 4-6
Index Property Test Results of Materials in 1964 Ash Basin
Boring Sample
Type
Sample
Depth
(Feet
bgs)
Visual Identification
Natural
Moisture
Content,
%
Dry Unit
Weight,
pcf
Atterberg Limits Percent
Finer Than
No. 200
Sieve
Other Test Liquid
Limit
Plastic
Limit
Plasticity
Index
BC-2 UD-1 21-23 Dark Gray Sandy Silt (ML) - Fly Ash -
FILL 26.7* NP NP NP 55.4 S.G. = 2.15
BC-2 UD-2 51-53 Brown Micaceous Silty Sand (SM) -
RESIDUUM
18.5*
20.5* NP NP NP 13.7 S.G. = 2.81
k
BC-4 SPT-1 3.5-5 Light to Dark Gray Sandy Silt - Fly Ash -
FILL 35.5
BC-4 SPT-2 8.5-10 Light to Dark Gray Sandy Silt - Fly Ash -
FILL 35.4
BC-4 SPT-3 13.5-15 Dark Gray Sandy Silt - Fly Ash - FILL 34.3
BC-4 SPT-4 18.5-20 Dark Gray Sandy Silt - Fly Ash - FILL 40.9
BC-4 SPT-6 28.5-30 Dark Gray Sandy Silt - Fly Ash - FILL 47.0
BC-4 SPT-8 40-41.5 Dark Gray Sandy Silt - Fly Ash - FILL 46.8
BC-4 SPT-10 48.5-50 Dark Gray Sandy Silt - Fly Ash - FILL 45.5
BC-4 SPT-12 58.5-60 Dark Gray Silty Sand with Gravel - Fly
Ash - FILL 38.4
BC-4 SPT-14A 68.5-69.2 Light to Dark Gray Sandy Silt - Fly Ash -
FILL 37.7
BC-4 SPT-14A 69.2-70 Reddish Brown Sandy Lean Clay -
RESIDUUM 24.8
BC-4 SPT-16 78.5-79 Dark Gray and Brown Silty Sand -
RESIDUUM 29.8
SPT-Standard Penetration Test/Split-Spoon; UD-Undisturbed Sample; Prepared/Date: H. Benkhayal/7-29-2015
P – Moisture-Density Relationship Test; NP-Non Plastic; k – Hydraulic Conductivity Test; Checked/Date: C. Tockstein/7-29-2015
S.G.-Specific Gravity Test *Result obtained from a different laboratory test method (i.e. Hydraulic Conductivity, Atterberg limit t est, etc.)
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TABLE 4-6 (Continued)
Index Property Test Results of Materials in 1964 Ash Basin
Boring Sample
Type
Sample
Depth
(Feet
bgs)
Visual Identification
Natural
Moisture
Content,
%
Dry Unit
Weight,
pcf
Atterberg Limits Percent
Finer
Than No.
200 Sieve
Other Test Liquid
Limit
Plastic
Limit
Plasticity
Index
BC-4 UD-1 20-22 Dark Gray Silty Sand (SM) - Fly Ash -
FILL 18.0* NP NP NP 43.8 S.G. = 2.34
BC-5 Bulk-1 28.5-38.5 Dark Gray Silt with Sand (ML) -Fly Ash
- FILL 31.3* NP NP NP 80.5 S.G. = 2.26
P
BC-7 Bulk-1 5-15 Dark Gray Silt (ML) - Fly Ash - FILL 25.6* NP NP NP 84.8 S.G. = 2.34
P
BC-8 UD-1 26-28 Reddish Brown Silty Sand (SM) -
RESIDUUM 14.8* NP NP NP 30.1 S.G. = 2.73
k
BC-8 UD-2 55.5-57.5 Gray Micaceous Silty Sand (SM) -
RESIDUUM
27.5*
32.5* NP NP NP 25.3 S.G. = 2.80
k
BC-9 SPT-1 5-6.5 Very Dark Gray Sandy Silt – Fly Ash -
FILL 32.4
BC-9 SPT-2 8.5-10 Very Dark Gray Sandy Silt – Fly Ash -
FILL 42.2
BC-9 SPT-3 13.5-15 Very Dark Gray Sandy Silt – Fly Ash -
FILL 39.3
BC-9 SPT-4 18.5-20 Very Dark Gray Sandy Silt – Fly Ash -
FILL 32.5
BC-9 SPT-5 23.5-25 Very Dark Gray Sandy Silt – Fly Ash -
FILL 51.9
BC-9 SPT-6 28.5-30 Very Dark Gray Sandy Silt – Fly Ash -
FILL 43.6
BC-9 SPT-7 33.5-35 Very Dark Gray Sandy Silt – Fly Ash -
FILL 58.1
SPT-Standard Penetration Test/Split-Spoon; UD-Undisturbed Sample; Prepared/Date: H. Benkhayal/7-29-2015
P - Moisture-Density Relationship Test; NP-Non Plastic; k – Hydraulic Conductivity Test; Checked/Date: C. Tockstein/7-29-2015
S.G.-Specific Gravity Test *Result obtained from a different laboratory test method (i.e. Hydraulic Conductivity, Atterberg limit test, etc.
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TABLE 4-6 (Continued)
Index Property Test Results of Materials in 1964 Ash Basin
Boring Sample
Type
Sample
Depth
(Feet
bgs)
Visual Identification
Natural
Moisture
Content,
%
Dry Unit
Weight,
pcf
Atterberg Limits
Percent
Finer
Than No.
200 Sieve
Other Test
BC-9 SPT-9 43.5-45 Very Dark Gray Sandy Silt – Fly Ash -
FILL 78.5
BC-9 SPT-11 53.5-55
Strong Brown, Yellow, and Dark
Reddish Brown Sandy Silt -
RESIDUUM
23.4
BC-9 SPT-13 63.5-65 White, Strong Brown, and Very Dark
Gray Sandy Silt - RESIDUUM 40.7
BC-10 Bulk-1 13.5-23.5 Dark Gray Silt (ML) - Fly Ash - FILL 27.9* NP NP NP 86.1 S.G. = 2.30
P
BC-10 UD-1 35-37 Gray Silt (ML) - Fly Ash - FILL 26.8* NP NP NP 97.8 S.G. = 2.31
SPT-Standard Penetration Test/Split-Spoon; UD-Undisturbed Sample; Prepared/Date: H. Benkhayal/7-29-2015
P - Moisture-Density Relationship Test; NP-Non Plastic; k – Hydraulic Conductivity Test; Checked/Date: C. Tockstein/7-29-2015
S.G.-Specific Gravity Test *Result obtained from a different laboratory test method (i.e. Hydraulic Conductivity, Atterberg limit test, etc.)
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4.5 Chemical Analysis of Impoundment Water, CCR Materials and CCR Affected
Soil
Source area characterization of the site is described in the CSA (SynTerra 2015a) and
supplemented by the CAP Part 1 (SynTerra 2015b). The characterization includes the collection
and analysis of soil, groundwater, surface water, and sediment samples from the ash basins and
surrounding area to identify provisional background concentrations and the extent of impacts.
Sample locations are identified on Figure 2-1, Appendix B. Development of groundwater
provisional background concentrations for key constituents is an ongoing process that primarily
entails collection of sufficient groundwater samples to provide statistically meaningful results.
The long-term goal is to calculate upper prediction limits for the pool of background data to be
used for comparison to samples collected from monitoring wells located hydraulically
downgradient of the ash basins. EPA guidance documents indicate that eight to 10 rounds of
background sample data are necessary to develop meaningful provisional background
concentrations. Six rounds of background sample data are included in the CSA Supplement 1
(SynTerra 2016b), and results are tabulated in Tables 4-1 through 4-8 (Appendix B).The
analysis of CCR ash and pore water from the ash basins resulted in the identification of Site-
specific constituents of interest (COIs). The COls are constituents that are associated with the
ash basin and are elevated above background values. Some COIs are also identified in water
quality samples collected from background monitoring wells, and they require careful
examination to determine their origin and source. The COIs identified from the Asheville Plant
ash material and pore water sample analyses include antimony, arsenic, boron, chromium,
cobalt, iron, manganese, sulfate, thallium, TDS, vanadium, and pH. These COIs are identified
as exceeding either the 2L or Interim Maximum Allowable Concentrations (IMAC) in at least one
ash pore water monitoring well (CSA report [SynTerra 2015a]).
4.5.1 Source Area(s) Characterization
Included in this section are the results of the ash basin and seep source area characterization,
as presented in the CSA Report (SynTerra 2015a). Media sampled by SynTerra included ash
matrix, ash porewater, settling basin surface water, and seep water.
CCR Ash Materials Chemical Analyses Results
A total of 10 borings and 13 monitoring wells were drilled and installed using rotary sonic drilling
with continuous sample recovery (Section 7 of CSA report [SynTerra 2015a]). The drilling
locations were divided between the 1964 (borings AB-01 and AB-03 and monitoring wells
ABMW-02, ABMW-02S, ABMW-04, ABMW-04D, and ABMW-04BR) and the 1982 (borings
AB-09 and AB-10 and monitoring wells ABMW-05S, ABMW-05D, ABMW-05BR, ABMW-06BR,
ABMW-07, ABMW-07S, ABMW-07BR and ABMW-08) ash basins (Appendix E of the CSA
report). During this drilling program, ash samples were collected from the basin in accordance
with GAP Section 7.1.1 for analysis of total metals, U.S. Environmental Protection Agency
(USEPA) Synthetic Precipitation Leaching Procedure (SPLP), and Energy Dispersive X-Ray
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Fluorescence (EDXRF) with documented methodologies in Appendix C of the CSA report
(SynTerra 2015a).
Results from 16 ash samples were analyzed for total metals, and results identified 14
constituents (aluminum, antimony, arsenic, barium, beryllium, cobalt, copper, iron, lead,
manganese, mercury, molybdenum, selenium, and vanadium) at levels exceeding one or more
of the USEPA Soil Regional Screening Level (Table 7-4, Appendix B). Ash samples from the
basin were also analyzed for TOC content and resulted in values from 9,630 to 87,800
milligrams per kilogram.
Results from eight ash samples tested using the SPLP method were compared to the 2L for
informational purposes and values of antimony, arsenic, chromium, cobalt, iron, manganese,
nitrate, selenium, thallium, and vanadium were typically in exceedance of the 2L reference
values. However, boron in ash SPLP leachate was not in exceedance of the 2L value. These
results were also compared to background soil values. The comparison of ash SPLP leachate
results to background soil values indicates the following:
Antimony, arsenic, selenium, and vanadium values in SPLP leachate from ash are
higher than background soils. However, these metals are typically not detected in
background soils, with the exception of vanadium and sporadic selenium.
Boron, chromium, cobalt, iron, lead, manganese, nitrate, and thallium leachate results
indicate similar ranges of concentrations from soils and ash.
While the above metals are identified as being elevated in the SPLP leachate of ash samples,
SPLP concentrations in soil samples collected from below the ash basins do not suggest
migration of these metals from the source material.
Results from three ash samples analyzed by EDXRF indicate whole rock metal oxide (Table 7-
6, Appendix B) and elemental content (Table 7-7, Appendix B). The results indicate the ash
primarily consists of oxides of silicon (SiO2), aluminum (Al2O3), and iron (Fe2O3) (Figure 7-1,
Appendix B).
Results from chemical analyses of ash samples collected throughout the ash basins indicate
aluminum, arsenic, barium, cobalt, iron, lead, manganese, mercury, selenium, and vanadium
are above either the USEPA Regional Screening Level (RSL) for Protection of Groundwater or
Residential Health.
CCR Ash Impoundment Pore Water Chemical Analyses Results
Ash pore water quality samples were collected for analysis of the expanded analyte list, metals
speciation, and radiological parameters. The samples were collected from ash basin monitoring
wells ABMW-02 and ABMW-04 in the 1964 Ash Basin (Table 7-8, Appendix B), and from
monitoring wells ABMW-08, P-100, P-101, and P-103 in the 1982 Ash Basin. The results
indicate that antimony, arsenic, boron, chromium, cobalt, iron, manganese, sulfate, thallium,
TDS, vanadium, and pH are above the 2L or IMAC in ash pore water (Table 7-9, Appendix B).
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Analysis of the analytical results using published methods referenced in the CSA also indicate
that the redox state of pore water within both the ash basins is anoxic, with some mixed anoxic
processes identified at well ABMW-04 in the 1964 basin (Table 7-8, Appendix B).
Speciation results of arsenic, chromium, iron, manganese, and selenium are provided for wells
ABMW-02 and ABMW-04 (Table 7-10, Appendix B). The results indicate that trivalent iron is
the predominant species of iron in both well pore water samples, and hexavalent chromium is
below the USEPA tapwater screening level of 0.035 microgram per liter (µg/L) in ash pore water.
Settling Basin Surface Water Characteristics
One surface water sample was collected from the settling basin located within the 1964 Ash
Basin, SW-05 (Table 9-3, Appendix B) [SynTerra 2015a]. Most of the constituent detections
above the 2L or 2B values were from this sample. SynTerra noted no corrective action is
necessary because the wastewater from this basin is under a NPDES permit.
Summary of CCR Waste Boundary Seep Water Sediment Characteristics
Seeps have been documented and sampled by SynTerra (Figure 2-1, Appendix B). Seep data
includes results from the June 2014 Asheville Seep Monitoring Report (SynTerra 2014c) with
samples from 17 representative seeps below (downgradient of) the ash basins, NCDENR seep
sampling in 2014 (Table 9-4, Appendix B), and seep results from 11 seeps that confirm the
extent of impacted groundwater with COI values above the 2L or IMAC (Table 9-2, Appendix
B). Concentrations from seep P-01 are consistent with background surface waters (Figures 9-1
and 9-2, Appendix B). SynTerra also compared the results of the 11 seep samples in Table 9-
2, Appendix B, to North Carolina Administrative Code (NCAC) Surface Water (2B) values.
4.5.2 Surface Water and Sediment Assessment
Summary of Surface Water Characteristics
Samples of sediment, surface water, and seeps were collected in August 2015 and analyzed for
water quality (Figure 2-1, Appendix B). Sediment samples were collected from the same
locations of surface water and seep sample water quality collection (Figure 2-1, Appendix B).
Sediment sample results from background locations exceed one or more RSLs for a few COIs
including aluminum, cobalt, iron, and manganese (Table 9-1, Appendix B). The sediment
samples collected from seeps below (downgradient of) the ash basins exceeded the RSL for
COIs including aluminum, antimony, arsenic, barium, cobalt, copper, iron, manganese, mercury,
molybdenum, nickel, selenium, and thallium in at least one sample. The side-gradient sediment
sample results from SW-01 are generally similar to background values except for elevated
aluminum and barium.
SynTerra provided results for surface water samples collected from the French Broad River
(upstream and downstream from the Site), Lake Julian, and areas within the French Broad River
floodplain. Two samples, one from upstream of the French Broad River (FB-01) and the other
from Lake Julian (SW-06), serve as background locations for comparison. Surface water sample
results to seep sample results are compared in Piper diagrams (Figures 9-1 and 9-2, Appendix
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B). The upstream and downstream French Broad River samples did not vary. However, thallium
was detected only at the upstream site (0.202 µg/L), which may indicate other potential sources
of thallium outside the ash basins. The surface water samples that have concentrations greater
than 2B values are listed in Table 9-5, Appendix B. Surface water sample results for
constituents that are elevated compared to background and lack a 2B value include boron, iron,
manganese, sulfate, TDS, and vanadium.
In part 2 of the CAP, Section 2.5, SynTerra reports that additional seep, surface water, and
sediment data was collected in November 2015 with a seep inspection performed on November
19, 2015. The results of an initial screening of the data indicates no substantial variation from
August 2015 with no newly identified seeps.
To further refine knowledge of hydrogeologic conditions, ten stream gauges were installed in
March 2016. Gauges were co-located with CSA surface water sample locations A-01, A-02, B-
01, C-01, and D-01, spanning the eastern side of the French Broad River along the western
stretch of the property boundary. Gauges were also co-located at SD-01 and N-01, representing
the western portion of Powell Creek below the Lake Julian dam. A gauge was placed in the
outfall area of the 1964 dam, correlating to surface water sample location C-02. Stream gauge
survey information is provided in Table 1-1 (Appendix B). Four surface water features (two
springs and two surface water drainages) were sampled as part of the additional assessment
west of the French Broad River (SynTerra 2016b). The purpose of collecting surface water
samples is to evaluate the contribution of agricultural and domestic activities to observed
concentrations of boron in water supply wells. The primary area targeted for investigation is
located on the same parcel as AS-14 (115 Justin Trail). In May 2016, four surface water
samples were collected in upgradient, sidegradient, and downgradient areas to agricultural
fields. Data is presented in Table 3-1 (Appendix B).
4.6 Historical Groundwater Sampling Results
A detailed description of groundwater characterization from the installation and sampling of
47 new monitoring wells and 36 existing monitoring wells is provided in Section 10 of CSA
report (SynTerra 2015a). A summary of those findings is provided in this section.
The sampling locations and dates are listed in Table 10-1 of Appendix B, and the full
parameter list with analytical methods and reporting limits are listed in Table 10-2 of Appendix
B. Analytical results are listed in Table 10-3 of Appendix B.
The results of groundwater sampling indicate that 18 analytes exceed the 2L or IMAC in
groundwater at the Site (Table 10-4, Appendix B). The area of groundwater concentrations
exceeding 2L is identified under the ash basins and to the west along groundwater flow lines up
to the French Broad River (Figure ES-1, Appendix B). Five of the 18 parameters (pH, cobalt,
iron, manganese, and vanadium) exceed the 2L or IMAC in one or more background wells. In
2013, chromium was sporadically detected above the 2L limit at background monitoring well CB-
01. While concentrations for 18 parameters are in exceedance of 2L or IMAC values, no private
or public wells are within the impacted area (Figures ES-1, and 10-5 to 10-56, Appendix B).
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The speciation data results are presented in Table 10-3 of Appendix B and indicate the
following:
Background groundwater is oxic, with oxic and mixed conditions in groundwater
upgradient of the ash basins.
Groundwater beneath the ash basins is anoxic and mixed anoxic.
Downgradient and side gradient groundwater is variable.
Part 2 of the CAP, Section 2.6, discusses additional characterization of the bedrock flow system
beneath the ash basins at a background location is included within data gap activities as
requested by NCDEQ. The information collected during the data gap activities is not expected to
substantially alter the groundwater corrective action plans proposed in Part 2 of the CAP. The
data gap activities include confirmation sampling on a private water supply well located on the
west side of the French Broad River, and confirmed initial results of iron, manganese, and TDS
at levels greater than the 2L standard, and boron elevated above background but below the 2L
standard. Additionally, a third and fourth set of CSA groundwater data was collected in
December 2015 and January 2016 for comparison to the initial two sets of data and to
supplement background data. Six rounds of monitoring for CSA parameters have been
completed through July 2016 and Tables 1-2 through 1-5 (Appendix B) provide a summary of
groundwater from all sampling events completed to date (e.g., CSA and NPDES programs) that
exceed 2L or IMAC for each of the primary hydrogeologic flow zones (surficial transition zone,
and bedrock). Additional sampling is scheduled in September and November of 2016 from
select Asheville wells (Table 1-8, Appendix B). Additional data from sampling results and
results of analysis are included in the CSA Supplement 1 (SynTerra, 2016b). CAMA sampling
locations are summarized in Table 1-8 (Appendix B) with locations and rationale for inclusion.
Background wells CB-09 (saprolite), CB-09SL (lower saprolite), CB-09BR (bedrock), CB-01
(surficial), CB-01D (transition zone), AMW-03B (bedrock), and MW-10 (alluvial) are planned to
be monitored to provide a more robust data set for provisional background concentration
evaluation. Groundwater data reported from previous rounds of monitoring from the majority of
wells across the site is consistent and confirms the current understanding of site conditions,
specifically the extent of impact to groundwater from ash basin-sourced constituents (e.g.,
boron). However, monitoring of select wells along the east side of the French Broad River and
west of the ash basins is anticipated to be ongoing in 2016. Data gap wells installed in 2016
(ABMW-11BR, MW-18BRL) are also included in the 2016 sampling program.
4.6.1 Summary of Surficial Aquifer Results
Surficial aquifer samples were collected from 27 saprolite monitoring wells and 9 alluvial
monitoring wells. The results indicate that impacts downgradient of the ash basins and
wastewater treatment constructed wetlands from leaching of the source areas are migrating
toward the French Broad River resulting in 17 parameters in the saprolite, and 11 parameters in
the alluvium that exceed 2L or IMAC (Table 10-4, Appendix B). SynTerra reports that the wells
completed within the surficial zone downgradient of the ash basin and the wastewater treatment
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constructed wetlands are the most impacted by leaching from the source areas. The CSA
Supplement 1 reports the following results for background data. Surficial groundwater is
represented by alluvial well MW-10 and saprolite wells CB-1, CB-09, CB-9SL, and MW-24S,
and provisional background concentrations were calculated for those wells. Exceedances above
2L and IMAC values were noted for pH (all wells), hexavalent chromium (MW -10, CB-9, CB-
9SL, and MW-24S); chromium (CB-1), cobalt (MW-10, CB-1, CB-9. MW-24S), iron (all wells),
manganese (MW-10, CB-1, CB-9, MW-24S), and vanadium (CB-9).
The CSA Supplement 1 reports the following results for downgradient wells. Concentrations of
boron, cadmium, chloride, cobalt, iron, manganese, hexavalent chromium, selenium, strontium,
sulfate, thallium, TDS, and vanadium have been detected in alluvial monitoring wells in excess
of the 2L, IMAC values. In general, concentrations within the floodplain area of the French
Broad River have remained relatively stable, with one exception at CB-6. Concentrations of
cobalt, manganese, sulfate and TDS increased substantially between July and November 2015,
January 2016, and April 2016. These increases can be correlated to a decrease in pH from 5.9
to 3.4. The pH at CB-6 was 4.7 in July 2016. Concentrations of antimony, boron, cobalt,
hexavalent chromium, iron, manganese, nitrate, sulfate, TDS, thallium, and vanadium have
been detected in saprolite monitoring wells in excess of the 2L and IMAC values; however, none
of these constituents exceeded corresponding provisional background concentrations beyond
the compliance boundary. In general, concentrations within saprolite wells have remained stable
with slight increases of boron noted in wells MW-8S and MW-9S and slight increases of boron,
sulfate, and TDS in GW-3. Figure 1-81 (Appendix B) presents a piper diagram that indicates
samples from the alluvial and saprolite flow zones appear to be divided into two sub-groups,
sulfate and chloride type. Samples collected downgradient of the 1964 Ash Basin are dominated
by chloride, while those collected downgradient from the 1982 Ash Basin are more associated
with sulfate type water. This difference is attributed to the former wetland treatment areas
recently removed from the 1964 Ash Basin.
4.6.2 Summary of Transitional Zone Aquifer Results
In general, the distribution of parameters in exceedance of the 2L or IMAC in the transition zone
samples mimics those identified in the surficial aquifer, but at reduced concentrations. Twenty-
four wells within the transition zone were sampled, and boron, chromium, cobalt, iron,
manganese, nickel, nitrate, selenium, sulfate, thallium, TDS, and vanadium were detected at
concentrations greater than the 2L or IMAC. One well, MW -09D, showed concentrations of
chloride and selenium greater than the 2L.
The CSA Supplement 1 reports transition zone groundwater is represented by one monitoring
well, CB-1, and provisional background concentrations were determined for this well.
Exceedances above 2L or IMAC are noted for pH, cobalt, iron, manganese, and vanadium.
Downgradient results indicate concentrations of boron, chloride, chromium, cobalt, hexavalent
chromium, iron, manganese, nitrate, nickel, selenium, sulfate, TDS, thallium, and vanadium
have been detected in transition zone monitoring wells in excess of 2L and IMAC values. Of
these constituents, cobalt, iron, manganese, and vanadium are detected greater than
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provisional background concentrations (which are greater that the 2L or IMAC values)
downgradient of the 1964 and 1982 Ash Basins beyond the compliance boundary in transition
zone wells. Concentrations of boron, chloride, sulfate, and TDS beyond the compliance
boundary are greater than provisional background concentrations, but less than 2L. In general,
concentrations within transition zone wells have remained stable. Figure 1-82 (Appendix B)
presents a piper diagram that indicates samples from the transitional flow zone associated with
the 1982 Ash Basin tend to show sulfate type characteristics, while those associated with the
1964 Ash Basin tend to be associated with chloride type water. Groundwater from background
locations and unaffected areas near each ash basin are characterized by calcium bicarbonate
type groundwater, typical of shallow fresh groundwater.
4.6.3 Summary of Bedrock Aquifer Results
Bedrock groundwater samples were collected from 20 wells and indicated exceedances of 2L or
IMAC for 9 parameters, and most have exceedances of cobalt, iron, manganese, and vanadium
(Table 10-4, Appendix B). Boron was only detected in a quarter of the bedrock wells sampled,
and sulfate was detected above the 2L at MW-18BR.
The CSA Supplement 1 presents data from two background monitoring wells, CB-9BR and
AMW-3B, and provisional background concentrations were determined for these wells.
Exceedances above 2L and IMAC values were noted for pH (both wells); hexavalent chromium
(both wells), iron (both wells); manganese (both wells); and vanadium (both wells).
Concentrations of boron, chloride, chromium, cobalt, hexavalent chromium, iron, manganese,
selenium, sulfate, TDS, thallium, and vanadium have been detected in bedrock monitoring wells
in excess of 2L or IMAC values. Iron and manganese have been detected in exceedance of 2L
and provisional background concentrations beyond the compliance boundary to the south of the
1982 Ash Basin. Chloride, strontium, and TDS are found at levels greater than the provisional
background concentration beyond the compliance boundary west of the 1964 Ash Basin and
south of the 1982 Ash Basin. In general, concentrations within bedrock wells have remained
stable with a few exceptions. Initial monitoring indicates increasing concentrations are noted in
downgradient monitoring wells of the 1964 Ash Basin: MW-9BR (boron, chloride, iron,
manganese, sulfate, strontium, and TDS) and GW-2 (boron chromium, iron, manganese,
sulfate, and strontium). However, these data sets are limited, and further monitoring will
determine if these increases are trends. Similar to the transition zone, bedrock groundwater is
consistent with calcium-bicarbonate type water. The distinction of the 1964 Ash Basin
groundwater (chloride-type) and the 1982 Ash Basin groundwater (sulfate type) is evident and
most clearly defined in this flow zone. Groundwater downgradient of the ash basins is
characteristic of calcium – sulfate type water (Figure 1-83, Appendix B).
4.7 Groundwater Potentiometric Contour Maps
Existing site wells and piezometers have been used to monitor groundwater levels in and
around the 1982 and 1964 Ash Basins. During monthly site visits, the wells and piezometers are
gauged using a water-level meter to measure the depth to water to the nearest 0.01 foot. All
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measurements are referenced to the top of riser casing and recorded on a well gauging form.
Groundwater gauging data from June 2015 were used to develop surficial (alluvium, saprolite,
and transition zone) and bedrock water-level maps (Figure 6-10 and Figure 6-11, respectively,
Appendix B). And groundwater gauging data from December 2015 were used to develop an
updated surficial (alluvium, saprolite, and transition zone) and bedrock water-level maps
provided in Part 2 of the CAP (Figure 2-1 and Figure 2-2, respectively, Appendix C). The
surficial potentiometric data was combined with the transition zone data because the aquifers do
not appear to be isolated.
Groundwater flow remains consistently to the west and southwest toward the French Broad
River. During the April to July 2015 data collection period, the groundwater hydraulic gradient
calculated from the northeast edge of the 1982 Ash Basin to the dam wall along the southwest
edge of the basin averaged 0.03 foot/foot. During this same four-month period, the hydraulic
gradient calculated from the dam wall along the southwest edge of the 1982 Ash Basin to the
wells along the French Broad River averaged 0.06 foot/foot.
For the June 2015 contour figures, water levels in a combined 107 wells and piezometers were
gauged within a 24-hour period on June 29, 2015. This provided a snapshot in time of the
groundwater elevation data for the multiple flow systems observed at the Site (Table 6-2,
Appendix B).
The potentiometric surfaces developed from the June 2015 water level measurements for the
combined surficial/transition zone and bedrock hydrogeologic zones indicate a substantial
variability in the Site horizontal gradients (Table 6-2, Figures 6-10 and 6-11, and Appendix B).
The horizontal gradients were used with Site-specific slug test hydraulic conductivity values and
average porosities to calculate groundwater flow velocities at the Site (Appendix G of CSA
report). The resulting groundwater flow velocities range from 0.61 foot to 3,266 feet per year.
The highest values are observed near the ash basins due to the increased hydraulic gradients
that are related to the location of the basins at topographic highs.
Vertical groundwater gradients were also calculated using select well pairs (Table 6-4,
Appendix B). The wells in upland areas indicate downward vertical gradients of 0.9 foot, and
the remaining well clusters show vertical gradients near equilibrium (Section 6, CSA report
[SynTerra 2015a]).
The CSA Supplement 1 presents the following additional information. A comprehensive, site-
wide round of water level measurements from all site monitoring wells was collected during a
24-hour period on December 17, 2015 for comparison to previous measurements collected
during June 2015 for the CSA. The water level data are presented in Table 1-6 (Appendix B).
No significant changes in water levels or groundwater flow directions were noted in December
2015 as compared to the June 2015 water level map included in the CSA Report (SynTerra,
2015a). However, it was also noted that the recent ash excavation and dewatering of the 1982
Ash Basin has effectively lowered the potentiometric surface in adjacent downgradient
compliance wells (CB-2, CB-3R) that have had significant decreases in water elevation since
the basin dewatering began in 2012. Hydrograph data is shown on Figure 1-80 (Appendix B),
and is summarized in the CSA Supplement 1.
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4.8 Figures: Cross Sections Vertical and Horizontal Extent of CCR within the
Impoundments
As previously discussed, groundwater at the site generally flows from east to west, from the ash
basins toward the French Broad River, following topography. Similarly, the COIs are expected to
be highest near the ash basins with transport toward the west. The area of groundwater
concentrations exceeding 2L are identified under the ash basins and to the west along
groundwater flow lines up to the French Broad River (Figure ES-1, Appendix B).
The vertical and horizontal extent of ash at the Site is illustrated in relation to local
hydrogeologic zones underlying and surrounding the ash basins, including the vertical extent of
areas where groundwater quality standards exceed the 2L or IMAC standards in plan layout
view and in cross-sections developed form the drilling and monitoring program (CSA report
[SynTerra 2015a]). Relevant available figures from the CSA report (Appendix B) are listed
below.
Plan Layout Figures (Appendix B):
o General Site map with cross-section lines, well locations, and boundaries,
Figure 2-1;
o Geologic map with ash basin delineations, Figure 6-1;
o Surficial soil exceedances of COIs, Figure 8-3;
o Groundwater 2L exceedances for ash pore water, surficial, transition zone, and
bedrock wells, Figures 10-1 to 10-4;
o Ash pore water well isoconcentration maps of antimony, arsenic, boron, chloride,
chromium, cobalt, iron, manganese, pH, sulfate, thallium, TDS, and vanadium,
Figures 10-5 to 10-17;
o Surficial groundwater well isoconcentration maps of antimony, arsenic, boron,
chloride, chromium, cobalt, iron, manganese, pH, sulfate, thallium, TDS, and
vanadium, Figures 10-18 to 10-30;
o Transition zone groundwater well isoconcentration maps of antimony, arsenic,
boron, chloride, chromium, cobalt, iron, manganese, pH, sulfate, thallium, TDS,
and vanadium, Figures 10-31 to 10-43;
o Bedrock groundwater well isoconcentration maps of antimony, arsenic, boron,
chloride, chromium, cobalt, iron, manganese, pH, sulfate, thallium, TDS, and
vanadium, Figures 10-44 to 10-56;
o Detection monitoring results for ash, surficial, transition zone, and bedrock wells,
Figures 10-57 to 10-60;
o Assessment monitoring results for ash, surficial, transition zone, and bedrock
wells, Figures 10-61 to 10-64.
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Cross-section Figures (Section line locations depicted in Figure 2-1, Appendix B):
o Geology and water level, Figures 6-3 and 6-4;
o Geology and water level with photographs of core, Figures 6-5 to 6-9;
o Conceptual Site model with area of COIs greater than 2L and IMAC, Figure 6-
12;
o Geology and water level with groundwater and soil analytical results for sampled
monitoring wells and borings, Figures 8-1 and 8-2;
o Geology and water level with individual COIs (antimony, arsenic, boron,
chromium, chloride, cobalt, iron, manganese, sulfate, TDS, thallium, vanadium,
Figures 11-1 to 11-12.
The CSA Supplement 1 contains updated geologic cross sections for various COI’s.
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5. GROUNDWATER MODELING ANALYSIS
As previously discussed in Section 2.2, NCDEQ granted permission for Duke to submit the
CAP in two phases. Part 1 of the CAP was submitted on November 20, 2015. Part 1 includes
background information, a brief summary of the CSA findings, a brief description of site geology
and hydrogeology, a summary of the previously completed receptor survey, a description of 2L
and 2B exceedances, proposed site-specific groundwater background concentrations, a
detailed description of the site conceptual model, geochemical assessment and modeling, and
numerical groundwater flow and transport modeling used to evaluate the effects of various
potential closure options on groundwater and surface water quality.
The second part of the CAP was submitted on February 19, 2016, and identifies updated
numerical modeling results, alternative corrective actions, the proposed corrective action,
conceptual plans for recommended corrective actions, implementation schedule, and a plan for
future monitoring and reporting.
The groundwater modeling analysis prepared by SynTerra is presented as a combination of
assessments including the following:
SCM development;
Geochemical assessment and modeling;
Numerical flow and transport modeling.
The information from each of the above assessments was successively used to develop the
next in order to develop a complete model of the system.
Modeling in Part 1 of the CAP was used to assess source handling and control options with the
following scenarios:
Existing Conditions;
Capping Ash Basins;
Removal of Ash.
Ash removal by excavation with lowering of the dams, and installation of drains was proposed
as the recommended source control option and modeling in Part 2 of the CAP addresses
alternative remedial alternatives to restore groundwater after ash removal including:
Monitored Natural Attenuation;
Groundwater Extraction;
In-Situ Chemical Immobilization;
Permeable Reactive Barrier.
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The modeling results were then used to select the final combined recommended remedial
approach following specific alternative evaluation criteria described in detail in Section 6.0 of the
CAP Part 2:
Effectiveness;
Implementability/Feasibility;
Environmental Sustainability;
Cost; and
Community Acceptance.
Modeling applied with the above alternative evaluation criteria, resulted in selection of monitored
natural attenuation as the proposed groundwater restoration alternative. After initial selection of
Monitored Natural Attenuation, the modeling results were used to assess the effectiveness
against the EPA guidance methods for monitored natural attenuation using a tiered approach.
The four tiered objectives from EPA cited by SynTerra are:
I. Demonstration that the ground-water plume is not expanding and that sorption
of the contaminant onto aquifer solids is occurring where immobilization is the
predominant attenuation process;
II. Determination of the mechanism and rate of the attenuation process;
III. Determination of the capacity of the aquifer to attenuate the mass of the
contaminant within the plume and the stability of the immobilized contaminant to
resist re-mobilization, and;
IV. Design performance monitoring program based on the mechanistic
understanding developed for the attenuation process, and establish a
contingency plan tailored to the site-specific characteristics.
The final result of the modeling efforts by SynTerra is the recommendation for ash removal, dam
lowering, and installation of drains, followed by monitored natural attenuation.
The following section presents the SCM. Predictions for post-closure groundwater elevations
are included in the figure, “Predicted Post-Closure Groundwater Elevation, Asheville Steam
Electric Plant, Arden, North Carolina,” included in Appendix B.
Each assessment detailed in Part 1 and 2 of the CAP is summarized in the following sections.
5.1 Site Conceptual Model
SynTerra developed and summarized the components of a SCM for the Asheville Plant area in
Section 11 of the CSA report, and Section 3 of the CAP Part 1 (SynTerra 2015b), and used it as
the basis for the development of the numerical groundwater transport model presented in Part 1
of the CAP. The SCM was developed from data (discussed in Section 4) generated during
previous assessments and existing groundwater monitoring data. The SCM was modified based
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on the results of the 2015 groundwater assessment activities and included geochemical testing
and analysis described in Part 1 of the CAP and further refined in Part 2 of the CAP.
The SCM identifies the following key aspects for model development and predictions of potential
impacts:
The two ash basins, designated as the 1964 and 1982 ash basins, and a constructed
wetlands used for FGD treatment within a portion of the 1964 ash basin, are identified as
the source of potential COIs;
Groundwater wells immediately downgradient of the constructed wetlands indicate
potential impact from FGD blowdown wastewater;
The subsurface geology at the Asheville Plant is composed of alluvium in the French
Broad River valley, saprolite, a transition zone, and fractured shallow bedrock;
Groundwater flow is unconfined and generally follows topography;
Groundwater flow is from the east and dominated by Lake Julian at higher elevation
(2160.7 feet mean sea level [MSL]), and discharges to the French Broad River in the
west at lower elevation (2030 feet MSL), that then flows north;
The primary factor in constituent transport across the site is hydraulic control, with the
hydraulic head at Lake Julian and significant topographic relief driving groundwater flow
through the system from the ash basin to the French Broad River;
Groundwater flow from the Lake Julian area to the French Broad River occurs over less
than half a mile;
Groundwater is significantly influenced by the unlined, secondary settling basin at the
northeastern corner of the 1964 ash basin with an average water level of 2137 f eet MSL;
Groundwater is recharged by Lake Julian and aerial precipitation that also occurs within
the ash basins;
Coal ash is primarily above the existing water table, but historically would have been
below the water table during sluicing operations;
The ash basin source areas discharge pore water to the subsurface beneath the basins
and via seeps through the embankments;
Forty-one private water wells have been identified within one-half mile of the site, with
more than half on the west side of the French Broad River, and a large number south of
the site;
The primary site-specific COIs identified as being above 2L or IMAC standards in ash
pore water are: antimony, arsenic, boron, chromium, cobalt, iron, manganese, sulfate,
thallium, TDS, vanadium, and pH;
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Boron and cobalt are the most prevalent COIs in downgradient groundwater. The
identified boron plume extends to saprolite, the transition zone and bedrock
groundwater, and to wells west of the French Broad River;
Boron concentrations are elevated in a localized area downgradient from the northwest
corner of the constructed wetlands, but are typically significantly below 2L standards and
generally less than the detection limit in background wells;
Cobalt is identified in groundwater throughout the site at concentrations above the IMAC
without a distinct plume, having similar values identified in background wells and ash
pore water, and transition concentrations that often exceed ash pore water values;
Boron, chloride, cobalt, sulfate, and TDS were selected as a subset of site-specific COIs
to represent the extent of contamination for further modeling because values of other
COIs either do not significantly exceed background levels, and/or no discernable existing
associated plume is downgradient from the ash basins.
5.2 Geochemical Modeling
The geochemical modeling detailed in Part 1 of the CAP (SynTerra 2015b) provides qualitative
and quantitative estimations of key COIs behavior in the Site environment. The geochemical
modeling and assessment results were performed to address site-specific processes and
characteristics identified in the SCM. Part 1 of the CAP presents a detailed discussion of the
geochemical properties of the COIs in relation to site-specific materials and how these
properties relate to the retention and mobility of these constituents. The mobility of the COIs is
addressed in a detailed soil sorption evaluation provided in Part 1 of the CAP, (Appendix B) that
had the objective of providing site-specific sorption coefficients (Kd) for each COI for use in
numerical modeling and incorporates effects related to oxidation/reduction potential (EH) and
pH. In Part 2 of the CAP, geochemical modeling was used to assess alternative groundwater
restoration scenarios and to assess site specific monitored natural attenuation against the EPA
tiered approach for monitored natural attenuation.
5.2.1 Soil Sorption Evaluation
SynTerra contracted the University of North Carolina at Charlotte (UNCC) to perform and
analyze soil sorption characteristics. UNCC developed Kd values for COIs using 12 soil samples
collected during the geotechnical and environmental exploration program at the site between
March 13 and January 2, 2015 (Table 1 of Appendix C). The 12 soil samples were selected to
represent the saturated zone beneath and downgradient of the ash basin. The solutions used in
both the batch and column sorption testing were generated in the laboratory as synthetic
groundwater with targeted COI concentrations (Table 2 of Appendix C). The leachates of the
batch and column testing were analyzed for 13 analytes (arsenic, beryllium, boron, cadmium,
chromium, cobalt, antimony, iron, manganese, nickel, selenium, thallium, and vanadium).
Desorption assessment was subsequently performed on column tests by application of six pore
volumes of laboratory-grade water to assess the potential for COI mobilization after sorption.
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Leaching analysis of two ash samples from each basin, 1982 and 1964, was also conducted
using standard Methods 1313 and 1316 to assess the source of COIs.
The soil sorption evaluation by UNCC assumed that metal oxy-hydroxide phases of iron,
manganese, and aluminum in the soil samples are the most important phases in terms of
sorption of COIs, and provided quantitative analysis of these phases in the soil samples.
UNCC identified general concerns with applying batch and column testing results to the field
results, and key findings of the soil sorption evaluation.
Soil Sorption Evaluation General Comments:
The synthetic groundwater used differs from in-situ groundwater chemistry, and the soil
samples were originally exposed to different geochemical conditions before testing;
The geochemical interaction of COIs with the soils in the same testing solution may
result in different sorption characteristics;
Tests were performed at atmospheric conditions, and redox conditions were not adjusted
to represent field conditions. The sorption results are reflective of the redox conditions in
the lab and may not be representative of other redox conditions;
The soil samples were sieved to less than 0.30 millimeter before testing, which could
affect the laboratory-determined Kd value.
Soil Sorption Evaluation Key Findings:
The batch and column testing for most COIs yielded results that were typically within one
order of magnitude difference for each COI, with the exception of cadmium, chromium,
cobalt, nickel and vanadium, which spanned two orders of magnitude;
The batch test for boron was inconclusive. A Kd value could not be determined due to
non-linear behavior, negligible sorption, and/or leaching of boron from the soil sample.
The column experiment for boron produced a Kd range from less than 10 to 75 milliliters
per gram (mL/g);
Iron and manganese were not included in the synthetic groundwater solution, but their
presence in leachates provide insight into their potential for leaching;
Ash leaching tests indicated negligible (close to the detection limit of 1 part per billion)
leaching of beryllium, cadmium, cobalt, copper, nickel, lead, thallium and zinc;
Ash leaching tests indicated increased concentrations of arsenic, boron, chromium, iron,
molybdenum, selenium, and vanadium in the leachate solution, and the leachate
concentrations of these COIs were higher for the 1982 basin test compared to the 1964
basin test.
An addendum to the initial UNCC soil sorption evaluation study was provided in Part 2 of the
CAP to include calculation of three sorption isotherm equations for the batch testing data
provided in Part 1 of the CAP. Isotherm equations are presented in Appendix D of Part 2 of the
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CAP. Linear, linear with irreversible sorption fraction, and Freundlich sorption isotherms
equations for antimony, arsenic, beryllium, boron, cadmium, chromium, cobalt, nickel, selenium,
thallium, and vanadium are included in tabular and graphical format.
5.2.2 Geochemical Numerical Modeling Analysis
In addition to the geochemical sorption testing and analysis performed by UNCC, SynTerra
contracted Brian Powell, Ph.D., to perform a geochemical assessment and modeling of the
overall mobility of COIs at the site. The results of this testing and analysis are presented in
detail in Appendix C of Part 1 of the CAP and updated with modeling results using additional site
specific data in Appendix C of Part 2 of the CAP. The geochemical assessment and modeling
includes the sorption processes performed by UNCC and precipitation/coprecipitation reactions
involving COIs and mineral phases. This assessment also accounted for geochemical reactions
and COI speciation influenced by the pH and EH of the pore water at the site. The geochemical
modeling was performed using the USGS program PHREEQC and the results were compared
to the UNCC Soil sorption evaluation study results (Table 5.1 of Appendix C). In Part 1 of the
CAP sorption was modeled as being associated only with hydrous ferric oxide (HFO) using
values based on the measured extractable iron content of the aquifer solids in site samples. In
Part 2 of the CAP additional data, including extractable iron and aluminum concentrations, was
used in the numerical modeling of COIs to account for HFO, gibbsite (HAO), and potential
variations in site specific pH and EH, using averages, minimums and maximums to bracket
values, that could occur due to system changes associated with remediation. The CAP Part 2
assessment compares Kd values obtained from PHREEQC simulations of sorption with sorption
identified in Part 1 of the CAP from UNCC laboratory batch testing.
In summary, the geochemical modeling identified the following results:
Boron as borate, barium, and zinc were identified as being relatively mobile with low Kd
values;
Boron has the lowest experimentally and simulated Kd, and therefore is assumed to be a
conservative representation of known areas of groundwater impact;
Arsenic, iron, manganese, selenium, and vanadium also were identified as having low Kd
values, but were predicted for the “worst case” scenario. The modeled EH and pH
conditions similar to those during the UNCC laboratory testing produced generally
similar results as the UNCC tests for these COIs;
The modeled and the experimental boron sorption were significantly different (1000x),
where boron sorption was underpredicted by the modeling. In either case, boron is
considered highly mobile under site conditions;
Sorption processes were identified as a dominant removal mechanism, and the number
of sorption sites required for complete removal of the total of all constituents in solution
is calculated as less than 1% of the available sorption sites. It is concluded that sufficient
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sorption capacity exists for removal of high concentrations of all COIs (Table 6.2
Appendix C).
Recommendations and limitations of the geochemical modeling from Part 1 of the CAP include:
Consideration of aluminum oxide surface for sorption should be included to improve
predictions, and may in part be related to the observed differences between
experimental and modeled Kd values for boron;
Additional studies to identify sorption site density of solid phases for soils are needed to
verify assumptions on site densities used in modeling;
Additional speciation data is needed to verify predicted oxidation states of arsenic,
selenium, vanadium, and other redox-sensitive COIs under site conditions;
Predictive geochemical modeling using fixed EH and pH site-specific conditions could be
used to verify observed field data for model verification;
A statistical analysis of the correlation between dissolved COIs and dissolved organic
carbon in pore waters is recommended to identify potentially associated sorption
relationship to COI mobility.
Part 2 of the CAP addressed some of the above recommendations and limitations including:
Assessment of aluminum oxide surface sorption;
Incorporation of additional data to support sorption site density;
Incorporation of pH and EH data to support predicted oxidation states for redox-sensitive
COIs under site conditions.
5.3 Numerical Groundwater and Transport Modeling
SynTerra provided a detailed numerical groundwater flow and transport model report in
Appendix D of Part 1 of the CAP (SynTerra 2015b) and updated modeling results in Part 2 of the
CAP (SynTerra 2016a). The model was based on the SCM and geochemical modeling and
assessment using MODFLOW to simulate hydrologic flow, and MT3DMS to simulate COI
transport. The numerical flow and transport models were developed such that the key site-
specific geological and hydrogeological features identified in the SCM and geochemical
assessment influencing the migration, chemical, and physical characteristics of contaminants
are represented.
The described numerical groundwater model is a three-dimensional groundwater flow and
contaminant fate and transport model having the objective of predicting the following in support
of the CAP:
Predict concentrations of the COIs at the compliance boundary or other locations of
interest over time;
Estimate the groundwater flow and constituent loading to surface water discharge areas;
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Predict approximate groundwater elevations in the ash for the proposed corrective
action;
Predict fate and transport of COIs for the different remedial alternatives for groundwater
restoration.
The model and model report were developed in general accordance with the guidelines found in
the memorandum Groundwater Modeling Policy, issued by NCDEQ DWQ on May 31, 2007
(DEQ modeling guidelines).
5.3.1 Numerical Groundwater Flow Model Description
The MODFLOW model includes the following features:
The model covers an area of approximately 802.5 acres centered on the site, and
includes Lake Julian and the French Broad River as constant-head boundary conditions
to the east and west, respectively;
Surface topography was interpolated from NCDOT LIDAR data;
Ash basin top elevations, for both the 1964 and 1982 ash basins, came from site-specific
survey data;
Geologic grids developed from interpolation between well boring logs and represented
by 16 model layers were discretized horizontally at a 40-foot by 40-foot spacing,
resulting in 240,202 active cells;
Hydraulic conductivities were determined through calibration;
Recharge was set as 6 inches per year for upland areas, and 1 inch per year historically
at the Plant site for the dams of Lake Julian and the two ash basins to represent the
impervious nature of the facility and compacted soils. The ash basins during current
conditions had infiltration rates of 6 and 12 inches per year for the 1982 and 1964
basins, respectively. Final basin recharge rates ranged from 12 to 24 inches per year;
The settling pond in the 1964 basin and dewatering basin in the 1982 basin were also
set as constant-head boundaries within the model;
Creeks and drains determined from LIDAR elevations were assigned in the model using
the MODFLOW DRAIN feature;
Steady-state flow calibration targets included 97 water level measurements taken in
June 2015.
Sensitivity analysis of the flow model was performed after calibration. The results indicated that
the numeric flow model is insensitive to small changes in the main hydraulic conductivity
parameters, the model is more sensitive to changes in the bedrock hydraulic conductivity value
compared to shallow layers, and the uncertainty is likely a factor of 2 or more, but less than an
order of magnitude.
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5.3.2 Numerical Groundwater Transport Model Description
Transport was assessed using MT3DMS with the MODFLOW-generated transient flow velocity
fields representing the time from January 1964 to July 2015. The transient flow field began with
steady-state conditions, followed by development history of the 1964 and 1982 ash basins
broken into three successive periods:
1. High infiltration rate in the 1964 basin representing ash sluicing from 1964 to 1982;
2. Increased infiltration rate in the 1982 basin from 1982 to 2013;
3. Current basin infiltration rates from 2013 to 2015.
The combined CAP Part 1 and 2 transport modeling took into account the following
characteristics:
Boron, chloride, cobalt, manganese, sulfate, and TDS selected as a subset of site-
specific COIs to represent the extent of contamination for modeling;
Source concentrations in the ash basins identified in ash pore water samples;
Soil-water distribution coefficients (Kd) for the lowest UNCC cobalt value (2.5 mL/g), and
a default low value of 0.1 mL/g to represent boron and sulfate retardation consistent with
other sites;
Longitudinal, transverse and vertical dispersivity of 20 f eet, 2 feet, and 0.2 feet,
respectively;
Effective porosity of 0.2 in unconsolidated layers and 0.001 in bedrock layers;
Soil dry bulk density of 1.6 g/mL.
Initial background COI concentrations were set as zero concentration to represent no impacts in
1964. The saturated cells within layers 3–7 underlying the ash basins were assigned constant
concentrations to represent the source of COIs. The report notes that the placement of constant
concentrations several feet deeper than the ash basins potentially results in an overestimate of
the COIs in groundwater below the basins. The transport of COIs was then calibrated to
concentrations measured in samples from 98 monitoring wells in June 2015.
The calibrated model comparison of simulated to measured boron, chloride, cobalt, sulfate, and
TDS concentrations is listed in Tables 6, 7, 8, 9, and 10 of Appendix C, respectively.
5.4 Groundwater Chemistry Effects
Predictions of groundwater chemistry effects were modeled for three possible source control
scenarios presented in Part 1 of the CAP:
1. Closure Model Scenario #1 (CMS1) – no further action;
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2. Closure Model Scenario #2 (CMS2) – complete ash removal from the 1982 and 1964
Ash Basins, installation of drains along the bottom of the former ash basins, and
backfilling and regrading of the former ash basins with clean fill to 2110 feet and 2120
feet MSL based on the Amec Foster Wheeler Environment & Infrastructure (Amec
Foster Wheeler) ash basin closure design (2015) (Figure 29 of Appendix C);
3. Closure Model Scenario #3 (CMS3) – adds an impermeable surface cap to CMS1.
All source control scenario predictions were used to provide simulated results through year
2045, and results in Appendix D of the CAP Part 1 are presented at 5 years (2020), 15 years
(2030), and 30 years (2045). Results provided in the CAP Part 1 are only presented for boron
under the assumption that it provides the most conservative estimate of widespread transport.
Boron is considered the most conservative COI based on laboratory sorption evaluation and
geochemical modeling. However, updated modeling results are provided in the CAP Part 2 to
address potential source contribution of manganese, sulfate and TDS concentrations by
applying observed concentrations to model simulations for these constituents. A manganese
concentrations of 7000 µg/L in the western parts of the 1964 and 1982 basins, and a
manganese concentration of 1000 µg/L for the eastern parts of the basins.
The model report results for the CMS1 scenario indicate that the boron plume is stabilized after
30 years, and little change occurs. This is because the boron plume has already reached the
French Broad River from the 1964 ash basin, while the boron plume from the 1984 basin
recedes due to reduced infiltration through the ash basin.
The model results for the CMS2 scenario indicate little effect on the boron plume within the first
2 years, but by 2030 the simulation predicts that the boron plume in the shallower part of the
system will be significantly reduced (Figure 39 of Appendix C), as will the southern area of the
deeper part of the system (Figure 40 of Appendix C). By year 2045, the simulation predicts
that the extent of boron will be greatly reduced, both horizontally and vertically (Figures 41 and
42 of Appendix C). The dominant concentration reduction mechanism is dilution by flushing of
groundwater from upgradient toward the French Broad River. The remaining boron is identified
in lower conductivity zones which receive less flushing.
The model results for CMS3 are relatively similar to those identified for CMS1 with the exception
that the boron plume is slightly reduced for CMS3 compared to CMS1.
While predictions are based on the conservative nature of boron, Part 1 of the CAP identified
that the pH and oxidation/reduction potential has a fundamental influence on the extent of
contaminant mobility for redox sensitive COIs.
Part 2 of the CAP addressed alternative corrective action measures for groundwater restoration
which required additional numerical transport modeling of fate and transport of COPCs to
evaluate the effectiveness of the different remedial alternatives.
The alternative corrective action measures evaluated are:
Monitored Natural Attenuation (MNA);
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Groundwater Extraction (recovery wells or trenches) with fracture enhancement option;
In-Situ Chemical Immobilization;
Permeable Reactive Barrier.
Each alternative was evaluated and discussed in Section 6.0 of Part 2 of the CAP including
model simulations to support the final recommended approach.
The groundwater extraction simulation included a line of 10 bedrock pumping wells covering
800 feet located beyond the northwest corner of the 1964 ash basin along the access road near
the toe of the 1964 dam, and eighty feet into the saturated bedrock. The simulation indicated
that each of the 10 wells was able to sustain a pumping rate of 0.3 gpm for a combined total of 3
gpm resulting in drawdown of 10 to 20 feet in each well. The boron transport simulation with
source excavation. MNA, and groundwater extraction indicates that the bulk of the boron plume
mass is removed by the year 2030 with some smaller areas of boron mass remaining through
2045. A comparison of simulated boron concentrations over time resulting from source
excavation with monitored natural attenuation (MNA), and with groundwater extraction is
provided in Figure 3-1 in Part 2 of the CAP.
Section 7.0 of Part 2 of the CAP provides the final proposed corrective actions based on data
and numerical modeling assessment from both Parts 1 and 2 of the CAP, with subsequent
evaluation of each piece to assure compliance in a timely manner, and includes the following:
Source Control – ash basin closure and source removal. Soils left on site after ash
removal will be sampled and analyzed, and results will be incorporated into fate and
transport modeling to assess the potential for modification to the corrective actions;
Elimination of Potential Receptors – installation of the Bear Leah Trail public water
supply line has resulted in replacing five private water wells that are planned for
subsequent geophysical survey and abandonment;
Monitored Natural Attenuation – SynTerra identified that the groundwater impacted by
the ash basin does not pose unacceptable risks to either human health or ecological
receptors further discussed in Section 5 of Part 2 of the CAP. And as supported by
groundwater flow and geochemical modeling, attenuation of COPCs will be achieved by
a combination of dilution, dispersion, and limited sorption.
Simulated manganese concentrations, and updated simulations of sulfate and TDS are provided
in Appendix B of Part 2 of the CAP.
The results of modeling the monitored natural attenuation alternative are presented in Figure 3-
1 of Part 2 of the CAP for predictions at years 2020, 2030, and 2045.
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5.5 Groundwater Trend Analysis Methods
The CSA Report indicates that historical analytical results from compliance and voluntary
groundwater monitoring wells were used to assess background groundwater quality and assess
results against existing IMAC and 2L values. Compliance groundwater monitoring wells were
sampled as part of the CSA Report to supplement the expanded groundwater assessment.
Time series plots of existing data comparing compliance, background wells, and 2L standards,
where applicable, were shown on Figures H1 through H21 of Appendix B.
Groundwater monitoring data collected from the four compliance monitoring wells were
evaluated by SynTerra using interwell prediction limits (parametric, nonparametric, and Poisson)
to compare background well data (CB-01 and CB-09) to the results for the most recently
available sample data from compliance wells collected in April 2015. The detailed description is
in Section 10.0 of the CSA (SynTerra 2015a).
Before statistical assessment, the dataset was assessed and treated using guidance from
ASTM D6312-98 and USEPA 2007. COIs with exceedances of the 2L or IMAC are identified in
all compliance boundary wells at statistically elevated values over concentrations observed in
designated background wells CB-01 and CB-09 (Table 2-2, Appendix B).
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6. BENEFICIAL REUSE AND FUTURE USE
6.1 CCR Material Reuse
From 2007 through summer 2015, a portion of the CCR materials from the 1982 Ash Basin was
excavated and transported to the Asheville Regional Airport for beneficial use. The airport
extended its runway/taxiway network by using the CCR as permitted structural fill in compliance
with existing permits. Ash transport to the Asheville Regional Airport ended in summer 2015.
Duke considers CCR beneficial use in an environmentally responsible manner for ash that is
produced at its plants or is removed from existing ash basins. Ash basin closure by removal
presents the opportunity for CCR beneficial use. Duke has a team dedicated to identifying
beneficial use opportunities and evaluating their feasibility. Consistent with North Carolina
CAMA requirements, Part III, Section 4(e), Duke issued a request for proposals to conduct a
beneficial use market analysis, study the feasibility and advisability of installing existing
beneficiation technologies, and examine innovative technologies.
At this time, no CCR beneficial use opportunities have been identified for the remaining CCR
materials. Findings indicate that large-scale beneficiation technologies are not feasible to install
at this time.
6.2 Site Future Use
The anticipated future use of the 1964 Ash Basin is undetermined at this time. Possibilities for
this Ash Basin include but are not limited to a permitted structural fill, a solar farm, or simply
being reseeded with grass. The closure design of the 1964 Ash Basin is planned to include a
balanced breach, in which the impoundment will be excavated to a design elevation. The basin
will be backfilled to promote drainage, resulting in a non-impounding structure. The backfill will
also be graded in a way to allow stormwater flows from the basin to pass through an existing
culvert under I-26.
In contrast to the 1964 Ash Basin, the closure plans for the 1982 Ash Basin were developed to
facilitate the construction of the proposed Combined Cycle Plant. This Plant will be located
within the footprint of the 1982 Ash Basin. The closure design of the 1982 Ash Basin includes a
dam breach to an elevation of 2106 feet, with an engineered fill to this same minimum elevation
within the existing Ash Basin. After completion of the balanced breach, additional fill will be
placed to facilitate construction of the Combined Cycle Plant to design grades.
After the completion of the Combined Cycle Plant, the existing coal-fired generating plant will be
decommissioned. Duke intends to cease operation of the coal-fired units in accordance with
CAMA, but specific details of future decommissioning and demolition have not been developed
at this time. The property deed will be recorded to document the site conditions at the time of
closure.
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7. CLOSURE DESIGN DOCUMENTS
7.1 Engineering Evaluations and Analyses
As part of the closure design process, engineering evaluations and analyses (calculations) were
developed for the 1982 Ash Basin and are included in Appendix D. Engineering evaluations
and analyses will be developed in the future for the 1964 Ash Basin. The basins are required to
be closed by 2022, and each basin must be closed such that it will not impound water. Ash has
been removed from the 1982 Ash Basin, and dam decommissioning is currently underway.
Excavation of the 1982 Ash Basin was completed on September 30, 2016. The ash basin was
then turned over for dam decommissioning and construction of the natural gas combined cycle
plant. The proposed decommissioning of this ash basin dam is shown on the drawings
referenced in Section 7.2. Additional fill will be placed to support a combined cycle plant. To
construct the fill, the existing embankment will be breached to create a non-impounding
structure, and this material will be placed in the existing ash basin. Borrow material will also be
obtained from onsite borrow areas to support the combined cycle plant construction. This
borrow material will be placed and compacted in accordance with the CQA Plan referenced in
Section 7.3. Drainage ditches are also incorporated into the final configuration to route the 100
year – 24 hour flow to an existing culvert under I-26.
7.2 Site Analysis and Removal Plan Drawings
The design drawings associated with the dam decommissioning of the 1982 Ash Basin are
included in Appendix E. These drawings were developed for three separate submittals and
resulting approvals from NCDEQ: 1) Decommissioning and Ash Removal Closure Plan
drawings, 2) Erosion and Sediment Control Plan drawings, and 3) Stormwater Management
Plan drawings.
Design drawings for the dam decommissioning of the 1964 Ash Basin will be prepared and
submitted to NCDEQ at a later date.
7.3 Construction Quality Assurance Plan
The purpose of the CQA Plan is to identify the quality assurance procedures, standards, and
methods that will be employed during the project to provide assurance that the requirements of
the drawings, specifications, and regulatory permits are met. The CQA Plan is specific to the
Asheville 1982 and 1964 Ash Basins Closure Design, and is prepared in compliance with
CAMA. The CQA Plan is included and attached to this document in Appendix F.
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8. MANAGEMENT OF WASTEWATER AND STORMWATER
8.1 Stormwater Management
Ash removal within the 1982 Ash Basin is complete, and dam decommissioning activities are
currently underway to prepare the site for construction of a natural gas combined cycle plant. At
the conclusion of dam decommissioning activities, stormwater flows will exit the basin through
permitted stormwater channels along the toe of the dam breach. Stormwater management for
the 1982 Ash Basin is detailed on the drawings in Appendix E.
Stormwater from the 1964 Ash Basin currently drains to the Duck Pond within the ash basin.
The goal of the 1964 Ash Basin decommissioning is to return the former ash basin to a natural
state where stormwater is discharged via sheet flow to the receiving water(s), such as the
French Broad River, and eliminate the requirement for an NPDES stormwater permit. To
accomplish this, multiple phases of decommissioning work are required. The following section
provides additional details for the current wastewater and stormwater management operations
within the 1964 Ash Basin.
8.2 Wastewater Management
The Rim Ditch system receives the sluiced ash and water from the Plant. Water from the Rim
Ditch is pumped through a center pond filter system to the stilling basin located to the north of
the 1964 Ash Basin, and then out through NPDES Outfall 001. The wastewater treatment
system will continue to be operated in this manner until such time that the coal fired plant is
retired, and ash and effluent discharges from the plant to the 1964 Ash Basin cease.
Subsequent to plant and Rim Ditch retirement, additional water management and treatment
systems will be required in accordance with the DEQ letter from Jeff Poupart, Water Quality
Permitting Section Chief, to Duke Energy on July 20, 2016 regarding decanting of coal ash
impoundments. Management of wastewater will also be addressed as the coal operations
become inactive.
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9. DESCRIPTION OF FINAL DISPOSITION OF CCR MATERIALS
From early 2007 through summer 2015, the CCR materials from the 1982 Ash Basin were
excavated and transported by truck to the Asheville Regional Airport and beneficially reused as
structural fill. The airport used the ash for projects aimed at extending the runway/taxiway
network. The off-site removal details for the Asheville Regional Airport are presented below:
Facility location and name: Asheville Regional Airport, 61 Terminal Drive, Fletcher, NC
28732;
Facility permit number: Structural Fill Permit # WQ0000020;
Facility type: Permitted structural fill for runway/taxiway construction.
Beginning in fall 2015, Duke started transporting the remaining CCR in the 1982 Ash Basin to
an off-site fully lined landfill near Homer, Georgia. From February 2016 through October 2016,
ash was transported to an additional landfill located in Mooresboro, North Carolina. Currently,
ash from the 1964 Ash Basin is being transported to the landfill near Homer, Georgia. The off-
site removal details for the Georgia landfill are presented below:
Facility location and name: R&B Landfill, 610 Bennett Road, Homer, GA 30547;
Facility permit number: Permit 006-009D(MSWL);
Facility type: Solid Waste Handling - Permitted landfill.
The off-site removal details for the North Carolina landfill are presented below:
Facility location and name: Duke Energy Rogers CCP Landfill, 573 Duke Power Rd,
Mooresboro, NC 28114;
Facility permit number: Solid Waste Management Facility Permit No. 8106;
Facility type: Solid Waste Management Facility.
Duke continues to consider future disposal and/or beneficial reuse opportunities.
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10. APPLICABLE PERMITS FOR CLOSURE
Implementation of the Ash Basin closure at the Asheville Steam Electric Generating Plant will
require permits issued by regulatory authorities. A list of the anticipated permits required for
closure is below:
Dam Breach Certificate of Approval to Repair/Modify for Decommissioning Dam
Structures;
Discharge Permits for Wastewater and Stormwater;
Solid Waste Permits for Landfills and Structural Fills (by others); and
Erosion and Sedimentation Control Permits.
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11. POST CLOSURE MONITORING AND CARE
The Post-Closure Operations Maintenance and Monitoring (OM&M) Plan is provided as
Appendix G. The default post-closure period is 30 years; however, opportunities to modify and
reduce the post-closure period for various requirements including groundwater and surface
water monitoring are possible. The Post-Closure OM&M Plan addresses the following:
Description of the closure components;
Regular inspections and maintenance of the stormwater and erosion control measures;
Post-closure inspection checklist to guide post-closure inspections;
Continuation of the groundwater and surface water monitoring and assessment program;
Provide means and methods of managing affected groundwater and stormwater;
Maintaining the groundwater monitoring system;
Facility contact information;
Description of planned post-closure uses.
11.1 Groundwater Monitoring Program
The (CSA report [SynTerra 2015a]) provides an interim groundwater monitoring plan to bridge
the gap between completion of CSA Report activities and implementation of the pending
Groundwater Monitoring Plan and CAP. The interim groundwater monitoring plan provided in the
CSA is also summarized in Section 3.3.2 of this document. The proposed constituents,
parameters, and sampling locations for the interim groundwater monitoring plan were presented
in Section 16.0 of the CSA report (SynTerra 2015a) and is updated in Part 2 of the CAP in
relation to proposed remedial actions.
With the submittal of part 2 of the CAP SynTerra has provided a proposed updated Interim
Monitoring Plan (IMP), and a post-closure Effectiveness Monitoring Program (EMP) as required
by CAMA in Section 9.0 of Part 2 of the CAP. The EMP is to begin after implementation of the
basin closure groundwater Corrective Action Plan, with the IMP being implemented within 30
days of CAP approval by CAMA.
The proposed updated IMP consists of sampling groundwater and surface water for the
constituents listed in Part 2 of the CAP (Table 9-1 of Appendix C) on a semi-annual basis, with
the sampling frequency of background wells being modified to achieve a minimum of eight sets
of data prior to implementation of the EMP. Reporting will be annually. The IMP will also be
periodically evaluated and modified as needed. The proposed IMP sampling locations for
groundwater are provided in Table 9-2 of Appendix C, and surface water and seep sampling
locations are provided in Table 9-3 of Appendix C. Groundwater, surface water, and seep
sample locations are presented spatially in Figure 9-1 of Appendix C.
Amec Foster Wheeler Environment & Infrastructure, Inc. December 2016
Duke Energy Coal Combustion Residuals Management Program
Asheville Steam Electric Generating Plant Site Analysis and Removal Plan
Revision 0
59
The proposed EMP program also consists of sampling groundwater and surface water for the
constituents listed in Table 9-1 of Appendix C on a semi-annual basis, and is intended to
support triannual NPDES compliance monitoring with a reduced frequency if monitoring results
are consistent with modeling results provided in Section 6.0 of Part 2 of the CAP. Reporting will
be annually. The EMP will also be evaluated periodically and modified as needed. The proposed
EMP sampling locations for groundwater are provided in Table 9-2 of Appendix C, and surface
water and seep sampling locations are provided in Table 9-3 of Appendix C. Groundwater,
surface water, and seep sample locations are presented spatially in Figure 9-1 of Appendix C.
Additional monitoring locations may be required once the final corrective action plan is selected
and implemented. Additionally, the EMP is designed to meet the requirements of the Tier 4
monitoring and the USEPA established eight objectives for performance. However, additional
analysis is required to achieve all the objectives and the EMP reports will include two phases to
address these.
A Sampling and Analysis Plan (SAP) will be developed and adhered to once approved and prior
to implementation of both the IMP and EMP. Currently, groundwater samples are planned to be
collected using low-flow sampling techniques in accordance with the NCDEQ conditionally
approved June 10, 2015, low flow sampling program provided in Appendix G of Part 2 of the
CAP.
Implementation of the IMP or EMP is scheduled to begin in the month April or November
following the CAP approval. Subsequent sampling events will then follow on subsequent April
and November months. The data will be reviewed annually to confirm the corrective actions are
effective at protecting human health and the environment.
Amec Foster Wheeler Environment & Infrastructure, Inc. December 2016
Duke Energy Coal Combustion Residuals Management Program
Asheville Steam Electric Generating Plant Site Analysis and Removal Plan
Revision 0
60
12. PROJECT MILESTONES AND COST ESTIMATES
12.1 Project Schedule
CAMA deems the Asheville Plant a “high-priority” site, which specifically requires closure of the
ash basins pursuant to Part II, Section 3(c). The CAMA closure definition of dewatering to the
maximum extent practicable and removing and transferring CCR to a landfill or structural fill is
demonstrated in the proposed schedule. Groundwater assessment and corrective action is
ongoing, and the requirements and time for restoring groundwater quality are currently
unknown.
The anticipated milestones are defined and shown below. The Dam Decommissioning Plan for
the1982 Ash Basin has been approved by NCDEQ, and ash removal is complete. Note that the
milestones are subject to change when not required by regulations.
The Anticipated Activities include the following items:
Submit updated Excavation Plan annually;
Site Analysis and Removal Plan submission and concurrence;
Water Management Plan submission and approval;
End stormwater discharge into impoundments;
Cease operation of coal-fired units at the Plant;
Completion of 1964 Ash Basin Ash Removal per NC Regulations;
1964 Ash Basin Dam Decommissioning Plan submission and approval;
1964 Ash Basin Erosion & Sediment Control Plan submission and approval;
1964 Ash Basin Stormwater Management Plan submission and approval;
Closure Certification (milestone);
Closure Permit Issued (milestone);
Impoundments closed pursuant to Part II, Sections 3(b) and 3(c) of the Act;
Basin closure (groundwater compliance met); and
Beginning of Post-Closure Care Period.
12.2 Closure and Post-Closure Cost Estimate
Duke is preparing closure and post-closure care cost estimates at a level of detail and from the
perspective that sufficient funding will be set aside in a financial assurance mechanism for a
third-party (other than the owner) to complete the scope of work. The cost estimates will be
included as Appendix H of this Removal Plan at a later date.
Amec Foster Wheeler Environment & Infrastructure, Inc. December 2016
Duke Energy Coal Combustion Residuals Management Program
Asheville Steam Electric Generating Plant Site Analysis and Removal Plan
Revision 0
61
13. REFERENCED DOCUMENTS
AECOM, “Additional Seismic Stability Evaluation, Asheville Steam Station, 1964 Ash Pond Dam
(Issue ASH-202),” March 31, 2016.
AMEC Environment & Infrastructure, Inc. (Amec Foster Wheeler), “2012 Five-Year Independent
Consultant Inspection, Cooling Lake Dam and Ash Pond Dams, Asheville Steam Electric
Plant”, February 19, 2013.
AMEC Environment & Infrastructure, Inc. (Amec Foster Wheeler), “2013 Report of Limited Field
Inspection, Cooling Lake Dam and Ash Pond Dams, Duke Energy Progress – Asheville
Steam Electric Plant”, August 5, 2013.
AMEC Environment & Infrastructure, Inc. (Amec Foster Wheeler) “2014 Annual Ash Basin Dam
Inspection, Asheville Steam Electric Station,” January 14, 2015.
AMEC Environment & Infrastructure, Inc. (Amec Foster Wheeler), “2014 Report of Limited Field
Inspection, Cooling Lake Dam and Ash Pond Dams, Duke Energy Progress – Asheville
Steam Electric Plant”, August 28, 2014.
AMEC Environment & Infrastructure, Inc. (Amec Foster Wheeler), “Asheville Plant, BUNCO-
089-H, BUNCO-097-H Observations, 8/27/2014 through 10/2/2004, Buncombe County,
North Carolina”, September 8, 2014 through October 6, 2014.
AMEC Environment & Infrastructure, Inc. (Amec Foster Wheeler), “Final Report for Task ASH-1
Issue,” August 2014 (2014a).
AMEC Environment & Infrastructure, Inc. (Amec Foster Wheeler), “Asheville Steam Plant, Final
Report for Task ASH-2 Issue,” August 26, 2014 (2014b).
Amec Foster Wheeler, “2015 Annual Ash Basin Dam Inspection, Asheville Plant,” May 9, 2016.
Amec Foster Wheeler, “2016 Annual Ash Basin Dam Inspection, Asheville Plant,” September 12,
2016 (2016b).
Amec Foster Wheeler, “Asheville Plant Operations & Maintenance Manual, Rev. 3,” March 31,
2015 (2015d).
Amec Foster Wheeler, “CCR Unit History of Construction, Asheville Steam Electric Generating
Plant,” October 12, 2016 (2016a).
Amec Foster Wheeler, “Letter Report – Waste Strategy Analysis (Revised), Asheville Steam
Station,” January 14, 2015 (2015c).
Amec Foster Wheeler, “Phase 2 Reconstitution of Ash Pond Designs, Final Report Submittal,
Revision B, Asheville Steam Station,” July 17, 2015 (2015e).
Amec Foster Wheeler, “Subsurface Exploration and Laboratory Testing Data Report, Landfill
Development and Ash Basin Closure,” August 2015.
Amec Foster Wheeler Environment & Infrastructure, Inc. December 2016
Duke Energy Coal Combustion Residuals Management Program
Asheville Steam Electric Generating Plant Site Analysis and Removal Plan
Revision 0
62
Amec Foster Wheeler, “Waste Inventory Analysis, Remaining Ash Volume Calculations for 1982
Basin,” December 8, 2015 (2015b).
Dewberry & Davis, Inc., “Final Coal Combustion Waste Impoundment Dam Assessment Report,
Site 7, 1982 Pond & 1964 Pond, Progress Energy Carolinas, Asheville, North Carolina”,
Revised Final September 11, 2009.
Duke Energy, “Asheville Steam Electric Generating Plant, Coal Ash Excavation Plan,”
December 2016.
Law Engineering, Inc. (Amec Foster Wheeler), “Stability Analysis of Downstream Slope, 1982
Ash Pond Dike,” September 30, 1992.
MACTEC Engineering and Consulting, Inc. (Amec Foster Wheeler), “Geotechnical Exploration
Data Report, Asheville FGD Project, Constructed Wetlands System,” October 18, 2004.
MACTEC Engineering and Consulting, Inc. (Amec Foster Wheeler), “Report of Geotechnical
Exploration, 1982/1964 Ash Pond Drainage Modification Project,” January 19, 2011.
NCDENR Notice of Inspection Reports for 1964 Ash Pond Dam (BUNCO-097) dated April 30,
2010; May 6, 2011; February 22, 2012; April 19, 2013; and April1, 2014.
NCDENR Notice of Inspection Reports for 1982 Ash Pond Dam (BUNCO-089) dated May 5,
2010; May 6, 2011; February 22, 2012; April 19, 2013; and, April1, 2014.
S&ME, Inc. “1964 Ash Basin Dam Improvement Design – Appendix I – Slope Stability Analysis
Discussion and Summary,” December 28, 2009.
S&ME Inc., “Construction Repair Certification Report, 1964 Ash Basin Dam Improvements
(Phase II), Progress Energy Asheville Plant”, December 18, 2012.
S&ME, Inc., “Subsurface Investigation and Slope Stability Analysis of 1964 Ash Basin Dike,”
December 28, 2009.
Stantec, “Asheville Plant – Field Reconnaissance”, 2014.
SynTerra Corp., “Comprehensive Site Assessment Report, Duke Energy Asheville Steam
Electric Plant,” August 23, 2015 (2015a).
SynTerra Corp., “Comprehensive Site Assessment Supplement 1, Duke Energy Asheville Steam
Electric Plant,” August 31, 2016 (2016b).
SynTerra Corp., “Corrective Action Plan, Part 1, Duke Energy Asheville Steam Electric Plant,”
November 20, 2015 (2015b).
SynTerra Corp., “Corrective Action Plan, Part 2, Duke Energy Asheville Steam Electric Plant,”
February 19, 2016 (2016a).
SynTerra Corp., “Drinking Water Well and Receptor Survey for Asheville Steam Electric Plant,”
September 2014 (2014a).
Amec Foster Wheeler Environment & Infrastructure, Inc. December 2016
Duke Energy Coal Combustion Residuals Management Program
Asheville Steam Electric Generating Plant Site Analysis and Removal Plan
Revision 0
63
SynTerra Corp., “Seep Monitoring Report – June 2014 for Asheville Steam Electric Plant,” July
2014 (2014c).
SynTerra Corp., “Supplement to Drinking Water Well and Receptor Survey for Asheville Steam
Electric Plant,” November 2014 (2014b).
Amec Foster Wheeler Environment & Infrastructure, Inc. December 2016
Duke Energy Coal Combustion Residuals Management Program
Asheville Steam Electric Generating Plant Site Analysis and Removal Plan
Revision 0
TABLES
December 2016
Ta
b
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2 ‐1:
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CC
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Hazardous Waste, Landfill, Surface Impoundments
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(b
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(i
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Cl
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a
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in
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al
l
of
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fo
l
l
o
w
i
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g
:
December 2016
Ta
b
l
e
2 ‐2:
NC
CA
M
A
Cl
o
s
u
r
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Pl
a
n
Re
q
u
i
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m
e
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t
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Su
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An
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an
d
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Pl
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t
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a
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En
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g
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No
.
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s
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t
i
o
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Corresponding Closure Plan Section
1
S
i
t
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hi
s
t
o
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an
d
hi
s
t
o
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y
of
si
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a
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s
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g
de
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n
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d
di
s
p
o
s
e
d
of
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s
t
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l
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2
E
s
t
i
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t
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d
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l
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m
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of
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t
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r
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t
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in
th
e
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p
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m
e
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t
.
3.1.2
3
A
n
a
l
y
s
i
s
of
th
e
st
r
u
c
t
u
r
a
l
in
t
e
g
r
i
t
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of
di
k
e
s
or
da
m
s
as
s
o
c
i
a
t
e
d
wi
t
h
im
p
o
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n
d
m
e
n
t
.
3.1.3
4
A
l
l
so
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r
c
e
s
of
di
s
c
h
a
r
g
e
in
t
o
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p
o
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n
d
m
e
n
t
,
in
c
l
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d
i
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g
vo
l
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m
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an
d
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a
r
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e
r
i
s
t
i
c
s
of
ea
c
h
di
s
c
h
a
r
g
e
.
3.1.4
5
W
h
e
t
h
e
r
th
e
im
p
o
u
n
d
m
e
n
t
is
li
n
e
d
,
an
d
,
if
so
,
th
e
co
m
p
o
s
i
t
i
o
n
th
e
r
e
o
f
.
3.1.5
6A
su
m
m
a
r
y
of
al
l
in
f
o
r
m
a
t
i
o
n
av
a
i
l
a
b
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n
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r
n
i
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th
e
im
p
o
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m
e
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t
as
a re
s
u
l
t
of
in
s
p
e
c
t
i
o
n
s
an
d
mo
n
i
t
o
r
i
n
g
co
n
d
u
c
t
e
d
pu
r
s
u
a
n
t
to
th
i
s
Pa
r
t
an
d
ot
h
e
r
w
i
s
e
av
a
i
l
a
b
l
e
.
3.1.6
1
Al
l
st
r
u
c
t
u
r
e
s
as
s
o
c
i
a
t
e
d
wi
t
h
th
e
op
e
r
a
t
i
o
n
of
an
y
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
su
r
f
a
c
e
im
p
o
u
n
d
m
e
n
t
lo
c
a
t
e
d
on
th
e
si
t
e
.
Fo
r
pu
r
p
o
s
e
s
of
th
i
s
su
b
‐su
b
d
i
v
i
s
i
o
n
,
th
e
te
r
m
"s
i
t
e
"
me
a
n
s
th
e
la
n
d
or
wa
t
e
r
s
wi
t
h
i
n
th
e
pr
o
p
e
r
t
y
bo
u
n
d
a
r
y
of
th
e
ap
p
l
i
c
a
b
l
e
el
e
c
t
r
i
c
ge
n
e
r
a
t
i
n
g
st
a
t
i
o
n
.
3.2.1
2
Al
l
cu
r
r
e
n
t
an
d
fo
r
m
e
r
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
di
s
p
o
s
a
l
an
d
st
o
r
a
g
e
ar
e
a
s
on
th
e
si
t
e
,
in
c
l
u
d
i
n
g
de
t
a
i
l
s
co
n
c
e
r
n
i
n
g
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
pr
o
d
u
c
e
d
hi
s
t
o
r
i
c
a
l
l
y
by
th
e
el
e
c
t
r
i
c
ge
n
e
r
a
t
i
n
g
st
a
t
i
o
n
an
d
di
s
p
o
s
e
d
of
th
r
o
u
g
h
tr
a
n
s
f
e
r
to
st
r
u
c
t
u
r
a
l
fi
l
l
s
.
3.2.1
3
T
h
e
pr
o
p
e
r
t
y
bo
u
n
d
a
r
y
fo
r
th
e
ap
p
l
i
c
a
b
l
e
si
t
e
,
in
c
l
u
d
i
n
g
es
t
a
b
l
i
s
h
e
d
co
m
p
l
i
a
n
c
e
bo
u
n
d
a
r
i
e
s
wi
t
h
i
n
th
e
si
t
e
.
3.3
4
A
l
l
po
t
e
n
t
i
a
l
re
c
e
p
t
o
r
s
wi
t
h
i
n
2,
6
4
0
fe
e
t
fr
o
m
es
t
a
b
l
i
s
h
e
d
co
m
p
l
i
a
n
c
e
bo
u
n
d
a
r
i
e
s
.
3.2.2
5
T
o
p
o
g
r
a
p
h
i
c
co
n
t
o
u
r
in
t
e
r
v
a
l
s
of
th
e
si
t
e
sh
a
l
l
be
se
l
e
c
t
e
d
to
en
a
b
l
e
an
ac
c
u
r
a
t
e
re
p
r
e
s
e
n
t
a
t
i
o
n
of
si
t
e
fe
a
t
u
r
e
s
an
d
te
r
r
a
i
n
an
d
in
mo
s
t
ca
s
e
s
sh
o
u
l
d
be
le
s
s
th
a
n
20
‐fo
o
t
in
t
e
r
v
a
l
s
.
3
.
3
6
Lo
c
a
t
i
o
n
s
of
al
l
sa
n
i
t
a
r
y
la
n
d
f
i
l
l
s
pe
r
m
i
t
t
e
d
pu
r
s
u
a
n
t
to
th
i
s
Ar
t
i
c
l
e
on
th
e
si
t
e
th
a
t
ar
e
ac
t
i
v
e
l
y
re
c
e
i
v
i
n
g
wa
s
t
e
or
ar
e
cl
o
s
e
d
,
as
we
l
l
as
th
e
es
t
a
b
l
i
s
h
e
d
co
m
p
l
i
a
n
c
e
bo
u
n
d
a
r
i
e
s
an
d
co
m
p
o
n
e
n
t
s
of
as
s
o
c
i
a
t
e
d
gr
o
u
n
d
w
a
t
e
r
an
d
su
r
f
a
c
e
wa
t
e
r
mo
n
i
t
o
r
i
n
g
sy
s
t
e
m
s
.
3.2.3
7
A
l
l
ex
i
s
t
i
n
g
an
d
pr
o
p
o
s
e
d
gr
o
u
n
d
w
a
t
e
r
mo
n
i
t
o
r
i
n
g
we
l
l
s
as
s
o
c
i
a
t
e
d
wi
t
h
an
y
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
su
r
f
a
c
e
im
p
o
u
n
d
m
e
n
t
on
th
e
si
t
e
.
3.3
8
A
l
l
ex
i
s
t
i
n
g
an
d
pr
o
p
o
s
e
d
su
r
f
a
c
e
wa
t
e
r
sa
m
p
l
e
co
l
l
e
c
t
i
o
n
lo
c
a
t
i
o
n
s
as
s
o
c
i
a
t
e
d
wi
t
h
an
y
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
su
r
f
a
c
e
im
p
o
u
n
d
m
e
n
t
on
th
e
si
t
e
.
3.3
1A
de
s
c
r
i
p
t
i
o
n
of
th
e
hy
d
r
o
g
e
o
l
o
g
y
an
d
ge
o
l
o
g
y
of
th
e
si
t
e
.
4.1
2A
de
s
c
r
i
p
t
i
o
n
of
th
e
st
r
a
t
i
g
r
a
p
h
y
of
th
e
ge
o
l
o
g
i
c
un
i
t
s
un
d
e
r
l
y
i
n
g
ea
c
h
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
su
r
f
a
c
e
im
p
o
u
n
d
m
e
n
t
lo
c
a
t
e
d
on
th
e
si
t
e
.
4.2
3
Th
e
sa
t
u
r
a
t
e
d
hy
d
r
a
u
l
i
c
co
n
d
u
c
t
i
v
i
t
y
fo
r
(i
)
th
e
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
wi
t
h
i
n
an
y
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
su
r
f
a
c
e
im
p
o
u
n
d
m
e
n
t
lo
c
a
t
e
d
on
th
e
si
t
e
an
d
(i
i
)
th
e
sa
t
u
r
a
t
e
d
hy
d
r
a
u
l
i
c
co
n
d
u
c
t
i
v
i
t
y
of
an
y
ex
i
s
t
i
n
g
li
n
e
r
in
s
t
a
l
l
e
d
at
an
im
p
o
u
n
d
m
e
n
t
,
if
an
y
.
4.3
4
Th
e
ge
o
t
e
c
h
n
i
c
a
l
pr
o
p
e
r
t
i
e
s
fo
r
(i
)
th
e
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
wi
t
h
i
n
an
y
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
su
r
f
a
c
e
im
p
o
u
n
d
m
e
n
t
lo
c
a
t
e
d
on
th
e
si
t
e
,
(i
i
)
th
e
ge
o
t
e
c
h
n
i
c
a
l
pr
o
p
e
r
t
i
e
s
of
an
y
ex
i
s
t
i
n
g
li
n
e
r
in
s
t
a
l
l
e
d
at
an
im
p
o
u
n
d
m
e
n
t
,
if
an
y
,
an
d
(i
i
i
)
th
e
up
p
e
r
m
o
s
t
id
e
n
t
i
f
i
e
d
st
r
a
t
i
g
r
a
p
h
i
c
un
i
t
un
d
e
r
l
y
i
n
g
th
e
im
p
o
u
n
d
m
e
n
t
,
in
c
l
u
d
i
n
g
th
e
so
i
l
cl
a
s
s
i
f
i
c
a
t
i
o
n
ba
s
e
d
up
o
n
th
e
Un
i
f
i
e
d
So
i
l
Cl
a
s
s
i
f
i
c
a
t
i
o
n
Sy
s
t
e
m
,
in
‐pl
a
c
e
mo
i
s
t
u
r
e
co
n
t
e
n
t
,
pa
r
t
i
c
l
e
si
z
e
di
s
t
r
i
b
u
t
i
o
n
,
At
t
e
r
b
e
r
g
li
m
i
t
s
,
sp
e
c
i
f
i
c
gr
a
v
i
t
y
,
ef
f
e
c
t
i
v
e
fr
i
c
t
i
o
n
an
g
l
e
,
ma
x
i
m
u
m
dr
y
de
n
s
i
t
y
,
op
t
i
m
u
m
mo
i
s
t
u
r
e
co
n
t
e
n
t
,
an
d
pe
r
m
e
a
b
i
l
i
t
y
.
4.4
5A
ch
e
m
i
c
a
l
an
a
l
y
s
i
s
of
th
e
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
su
r
f
a
c
e
im
p
o
u
n
d
m
e
n
t
,
in
c
l
u
d
i
n
g
wa
t
e
r
,
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
,
an
d
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
‐af
f
e
c
t
e
d
so
i
l
.
4.5
6
Id
e
n
t
i
f
i
c
a
t
i
o
n
of
al
l
su
b
s
t
a
n
c
e
s
wi
t
h
co
n
c
e
n
t
r
a
t
i
o
n
s
de
t
e
r
m
i
n
e
d
to
be
in
ex
c
e
s
s
of
th
e
gr
o
u
n
d
w
a
t
e
r
qu
a
l
i
t
y
st
a
n
d
a
r
d
s
fo
r
th
e
su
b
s
t
a
n
c
e
es
t
a
b
l
i
s
h
e
d
by
Su
b
c
h
a
p
t
e
r
L of
Ch
a
p
t
e
r
2 of
Ti
t
l
e
15
A
of
th
e
No
r
t
h
Ca
r
o
l
i
n
a
Ad
m
i
n
i
s
t
r
a
t
i
v
e
Co
d
e
,
in
c
l
u
d
i
n
g
al
l
la
b
o
r
a
t
o
r
y
re
s
u
l
t
s
fo
r
th
e
s
e
an
a
l
y
s
e
s
.
4.6
7
S
u
m
m
a
r
y
ta
b
l
e
s
of
hi
s
t
o
r
i
c
a
l
re
c
o
r
d
s
of
gr
o
u
n
d
w
a
t
e
r
sa
m
p
l
i
n
g
re
s
u
l
t
s
.
4.6
8
A ma
p
th
a
t
il
l
u
s
t
r
a
t
e
s
th
e
po
t
e
n
t
i
o
m
e
t
r
i
c
co
n
t
o
u
r
s
an
d
fl
o
w
di
r
e
c
t
i
o
n
s
fo
r
al
l
id
e
n
t
i
f
i
e
d
aq
u
i
f
e
r
s
un
d
e
r
l
y
i
n
g
im
p
o
u
n
d
m
e
n
t
s
(s
h
a
l
l
o
w
,
in
t
e
r
m
e
d
i
a
t
e
,
an
d
de
e
p
)
an
d
th
e
ho
r
i
z
o
n
t
a
l
ex
t
e
n
t
of
ar
e
a
s
wh
e
r
e
gr
o
u
n
d
w
a
t
e
r
qu
a
l
i
t
y
st
a
n
d
a
r
d
s
es
t
a
b
l
i
s
h
e
d
by
Su
b
c
h
a
p
t
e
r
L of
Ch
a
p
t
e
r
2 of
Ti
t
l
e
15
A
of
th
e
No
r
t
h
Ca
r
o
l
i
n
a
Ad
m
i
n
i
s
t
r
a
t
i
v
e
Co
d
e
fo
r
a su
b
s
t
a
n
c
e
ar
e
ex
c
e
e
d
e
d
.
4.7
9
Cr
o
s
s
‐se
c
t
i
o
n
s
th
a
t
il
l
u
s
t
r
a
t
e
th
e
fo
l
l
o
w
i
n
g
:
th
e
ve
r
t
i
c
a
l
an
d
ho
r
i
z
o
n
t
a
l
ex
t
e
n
t
of
th
e
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
wi
t
h
i
n
an
im
p
o
u
n
d
m
e
n
t
;
st
r
a
t
i
g
r
a
p
h
y
of
th
e
ge
o
l
o
g
i
c
un
i
t
s
un
d
e
r
l
y
i
n
g
an
im
p
o
u
n
d
m
e
n
t
;
an
d
th
e
ve
r
t
i
c
a
l
ex
t
e
n
t
of
ar
e
a
s
wh
e
r
e
gr
o
u
n
d
w
a
t
e
r
qu
a
l
i
t
y
st
a
n
d
a
r
d
s
es
t
a
b
l
i
s
h
e
d
by
Su
b
c
h
a
p
t
e
r
L of
Ch
a
p
t
e
r
2 of
Ti
t
l
e
15
A
of
th
e
No
r
t
h
Ca
r
o
l
i
n
a
Ad
m
i
n
i
s
t
r
a
t
i
v
e
Co
d
e
fo
r
a su
b
s
t
a
n
c
e
ar
e
ex
c
e
e
d
e
d
.
4.8
d.
1
An
ac
c
o
u
n
t
of
th
e
de
s
i
g
n
of
th
e
pr
o
p
o
s
e
d
Cl
o
s
u
r
e
Pl
a
n
th
a
t
is
ba
s
e
d
on
th
e
si
t
e
hy
d
r
o
g
e
o
l
o
g
i
c
co
n
c
e
p
t
u
a
l
mo
d
e
l
de
v
e
l
o
p
e
d
an
d
in
c
l
u
d
e
s
(i
)
pr
e
d
i
c
t
i
o
n
s
on
po
s
t
‐cl
o
s
u
r
e
gr
o
u
n
d
w
a
t
e
r
el
e
v
a
t
i
o
n
s
an
d
gr
o
u
n
d
w
a
t
e
r
fl
o
w
di
r
e
c
t
i
o
n
s
an
d
ve
l
o
c
i
t
i
e
s
,
in
c
l
u
d
i
n
g
th
e
ef
f
e
c
t
s
on
an
d
fr
o
m
th
e
po
t
e
n
t
i
a
l
re
c
e
p
t
o
r
s
an
d
(i
i
)
pr
e
d
i
c
t
i
o
n
s
at
th
e
co
m
p
l
i
a
n
c
e
bo
u
n
d
a
r
y
fo
r
su
b
s
t
a
n
c
e
s
wi
t
h
co
n
c
e
n
t
r
a
t
i
o
n
s
de
t
e
r
m
i
n
e
d
to
be
in
ex
c
e
s
s
of
th
e
gr
o
u
n
d
w
a
t
e
r
qu
a
l
i
t
y
st
a
n
d
a
r
d
s
fo
r
th
e
su
b
s
t
a
n
c
e
es
t
a
b
l
i
s
h
e
d
by
Su
b
c
h
a
p
t
e
r
L of
Ch
a
p
t
e
r
2 of
Ti
t
l
e
15
A
of
th
e
No
r
t
h
Ca
r
o
l
i
n
a
Ad
m
i
n
i
s
t
r
a
t
i
v
e
Co
d
e
.
5.1
2
Pr
e
d
i
c
t
i
o
n
s
th
a
t
in
c
l
u
d
e
th
e
ef
f
e
c
t
s
on
th
e
gr
o
u
n
d
w
a
t
e
r
ch
e
m
i
s
t
r
y
an
d
sh
o
u
l
d
de
s
c
r
i
b
e
mi
g
r
a
t
i
o
n
,
co
n
c
e
n
t
r
a
t
i
o
n
,
mo
b
i
l
i
z
a
t
i
o
n
,
an
d
fa
t
e
fo
r
su
b
s
t
a
n
c
e
s
wi
t
h
co
n
c
e
n
t
r
a
t
i
o
n
s
de
t
e
r
m
i
n
e
d
to
be
in
ex
c
e
s
s
of
th
e
gr
o
u
n
d
w
a
t
e
r
qu
a
l
i
t
y
st
a
n
d
a
r
d
s
fo
r
th
e
su
b
s
t
a
n
c
e
es
t
a
b
l
i
s
h
e
d
by
Su
b
c
h
a
p
t
e
r
L of
Ch
a
p
t
e
r
2 of
Ti
t
l
e
15
A
of
th
e
No
r
t
h
Ca
r
o
l
i
n
a
Ad
m
i
n
i
s
t
r
a
t
i
v
e
Co
d
e
pr
e
‐
an
d
po
s
t
‐cl
o
s
u
r
e
,
in
c
l
u
d
i
n
g
th
e
ef
f
e
c
t
s
on
an
d
fr
o
m
po
t
e
n
t
i
a
l
re
c
e
p
t
o
r
s
.
5.2
3
A de
s
c
r
i
p
t
i
o
n
of
th
e
gr
o
u
n
d
w
a
t
e
r
tr
e
n
d
an
a
l
y
s
i
s
me
t
h
o
d
s
us
e
d
to
de
m
o
n
s
t
r
a
t
e
co
m
p
l
i
a
n
c
e
wi
t
h
gr
o
u
n
d
w
a
t
e
r
qu
a
l
i
t
y
st
a
n
d
a
r
d
s
fo
r
th
e
su
b
s
t
a
n
c
e
es
t
a
b
l
i
s
h
e
d
by
Su
b
c
h
a
p
t
e
r
L of
Ch
a
p
t
e
r
2 of
Ti
t
l
e
15
A
of
th
e
No
r
t
h
Ca
r
o
l
i
n
a
Ad
m
i
n
i
s
t
r
a
t
i
v
e
Co
d
e
an
d
re
q
u
i
r
e
m
e
n
t
s
fo
r
co
r
r
e
c
t
i
v
e
ac
t
i
o
n
of
gr
o
u
n
d
w
a
t
e
r
co
n
t
a
m
i
n
a
t
i
o
n
es
t
a
b
l
i
s
h
e
d
by
Su
b
c
h
a
p
t
e
r
L of
Ch
a
p
t
e
r
2 of
Ti
t
l
e
15
A
of
th
e
No
r
t
h
Ca
r
o
l
i
n
a
Ad
m
i
n
i
s
t
r
a
t
i
v
e
Co
d
e
.
5.3
Pa
r
t
II
.
Pr
o
v
i
s
i
o
n
s
fo
r
Co
m
p
r
e
h
e
n
s
i
v
e
Ma
n
a
g
e
m
e
n
t
of
Co
a
l
Co
m
b
u
s
t
i
o
n
Re
s
i
d
u
a
l
s
§ 13
0
A
‐30
9
.
2
1
4
(
a
)
(
4
)
Cl
o
s
u
r
e
Pl
a
n
s
fo
r
al
l
im
p
o
u
n
d
m
e
n
t
s
sh
a
l
l
in
c
l
u
d
e
al
l
of
th
e
fo
l
l
o
w
i
n
g
:
a.
Fa
c
i
l
i
t
y
an
d
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
su
r
f
a
c
e
im
p
o
u
n
d
m
e
n
t
de
s
c
r
i
p
t
i
o
n
.
– A de
s
c
r
i
p
t
i
o
n
of
th
e
op
e
r
a
t
i
o
n
of
th
e
si
t
e
th
a
t
sh
a
l
l
in
c
l
u
d
e
,
at
a mi
n
i
m
u
m
,
al
l
of
th
e
fo
l
l
o
w
i
n
g
:
b.
Si
t
e
ma
p
s
,
wh
i
c
h
,
at
a mi
n
i
m
u
m
,
il
l
u
s
t
r
a
t
e
al
l
of
th
e
fo
l
l
o
w
i
n
g
:
Th
e
re
s
u
l
t
s
of
gr
o
u
n
d
w
a
t
e
r
mo
d
e
l
i
n
g
of
th
e
si
t
e
th
a
t
sh
a
l
l
in
c
l
u
d
e
,
at
a mi
n
i
m
u
m
,
al
l
of
th
e
fo
l
l
o
w
i
n
g
:
c.
Th
e
re
s
u
l
t
s
of
a hy
d
r
o
g
e
o
l
o
g
i
c
,
ge
o
l
o
g
i
c
,
an
d
ge
o
t
e
c
h
n
i
c
a
l
in
v
e
s
t
i
g
a
t
i
o
n
of
th
e
si
t
e
,
in
c
l
u
d
i
n
g
,
at
a mi
n
i
m
u
m
,
al
l
of
th
e
fo
l
l
o
w
i
n
g
:
December 2016
Ta
b
l
e
2 ‐2:
NC
CA
M
A
Cl
o
s
u
r
e
Pl
a
n
Re
q
u
i
r
e
m
e
n
t
s
Su
m
m
a
r
y
an
d
Cr
o
s
s
Re
f
e
r
e
n
c
e
Ta
b
l
e
As
h
Ba
s
i
n
Si
t
e
An
a
l
y
s
i
s
an
d
Re
m
o
v
a
l
Pl
a
n
‐
As
h
e
v
i
l
l
e
St
e
a
m
El
e
c
t
r
i
c
Ge
n
e
r
a
t
i
n
g
Pl
a
n
t
Du
k
e
En
e
r
g
y
No
.
D
e
s
c
r
i
p
t
i
o
n
Corresponding Closure Plan Section
e.
A de
s
c
r
i
p
t
i
o
n
of
an
y
pl
a
n
s
fo
r
be
n
e
f
i
c
i
a
l
us
e
of
th
e
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
in
co
m
p
l
i
a
n
c
e
wi
t
h
th
e
re
q
u
i
r
e
m
e
n
t
s
of
Se
c
t
i
o
n
.1
7
0
0
of
Su
b
c
h
a
p
t
e
r
B of
Ch
a
p
t
e
r
13
of
Ti
t
l
e
15
A
of
th
e
No
r
t
h
Ca
r
o
l
i
n
a
Ad
m
i
n
i
s
t
r
a
t
i
v
e
Co
d
e
(R
e
q
u
i
r
e
m
e
n
t
s
fo
r
Be
n
e
f
i
c
i
a
l
Us
e
of
Co
a
l
Co
m
b
u
s
t
i
o
n
By
‐Pr
o
d
u
c
t
s
)
an
d
Se
c
t
i
o
n
.1
2
0
5
of
Su
b
c
h
a
p
t
e
r
T of
Ch
a
p
t
e
r
2 of
Ti
t
l
e
15
A
of
th
e
No
r
t
h
Ca
r
o
l
i
n
a
Ad
m
i
n
i
s
t
r
a
t
i
v
e
Co
d
e
(C
o
a
l
Co
m
b
u
s
t
i
o
n
Pr
o
d
u
c
t
s
Ma
n
a
g
e
m
e
n
t
)
.
6.1
f.
Al
l
en
g
i
n
e
e
r
i
n
g
dr
a
w
i
n
g
s
,
sc
h
e
m
a
t
i
c
s
,
an
d
sp
e
c
i
f
i
c
a
t
i
o
n
s
fo
r
th
e
pr
o
p
o
s
e
d
Cl
o
s
u
r
e
Pl
a
n
.
If
re
q
u
i
r
e
d
by
Ch
a
p
t
e
r
89
C
of
th
e
Ge
n
e
r
a
l
St
a
t
u
t
e
s
,
en
g
i
n
e
e
r
i
n
g
de
s
i
g
n
do
c
u
m
e
n
t
s
sh
o
u
l
d
be
pr
e
p
a
r
e
d
,
si
g
n
e
d
,
an
d
se
a
l
e
d
by
a pr
o
f
e
s
s
i
o
n
a
l
en
g
i
n
e
e
r
.
7.1, 7.2
g.
A de
s
c
r
i
p
t
i
o
n
of
th
e
co
n
s
t
r
u
c
t
i
o
n
qu
a
l
i
t
y
as
s
u
r
a
n
c
e
an
d
qu
a
l
i
t
y
co
n
t
r
o
l
pr
o
g
r
a
m
to
be
im
p
l
e
m
e
n
t
e
d
in
co
n
j
u
n
c
t
i
o
n
wi
t
h
th
e
Cl
o
s
u
r
e
Pl
a
n
,
in
c
l
u
d
i
n
g
th
e
re
s
p
o
n
s
i
b
i
l
i
t
i
e
s
an
d
au
t
h
o
r
i
t
i
e
s
fo
r
mo
n
i
t
o
r
i
n
g
an
d
te
s
t
i
n
g
ac
t
i
v
i
t
i
e
s
,
sa
m
p
l
i
n
g
st
r
a
t
e
g
i
e
s
,
an
d
re
p
o
r
t
i
n
g
re
q
u
i
r
e
m
e
n
t
s
.
7.3
h.
A
de
s
c
r
i
p
t
i
o
n
of
th
e
pr
o
v
i
s
i
o
n
s
fo
r
di
s
p
o
s
a
l
of
wa
s
t
e
w
a
t
e
r
an
d
ma
n
a
g
e
m
e
n
t
of
st
o
r
m
w
a
t
e
r
an
d
th
e
pl
a
n
fo
r
ob
t
a
i
n
i
n
g
al
l
re
q
u
i
r
e
d
pe
r
m
i
t
s
.
8
i.
A de
s
c
r
i
p
t
i
o
n
of
th
e
pr
o
v
i
s
i
o
n
s
fo
r
th
e
fi
n
a
l
di
s
p
o
s
i
t
i
o
n
of
th
e
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
.
If
th
e
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
ar
e
to
be
re
m
o
v
e
d
,
th
e
ow
n
e
r
mu
s
t
id
e
n
t
i
f
y
(i
)
th
e
lo
c
a
t
i
o
n
an
d
pe
r
m
i
t
nu
m
b
e
r
fo
r
th
e
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
la
n
d
f
i
l
l
s
,
in
d
u
s
t
r
i
a
l
la
n
d
f
i
l
l
s
,
or
mu
n
i
c
i
p
a
l
so
l
i
d
wa
s
t
e
la
n
d
f
i
l
l
s
in
wh
i
c
h
th
e
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
wi
l
l
be
di
s
p
o
s
e
d
an
d
(i
i
)
in
th
e
ca
s
e
wh
e
r
e
th
e
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
ar
e
pl
a
n
n
e
d
fo
r
be
n
e
f
i
c
i
a
l
us
e
,
th
e
lo
c
a
t
i
o
n
an
d
ma
n
n
e
r
in
wh
i
c
h
th
e
re
s
i
d
u
a
l
s
wi
l
l
be
te
m
p
o
r
a
r
i
l
y
st
o
r
e
d
.
If
th
e
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
ar
e
to
be
le
f
t
in
th
e
im
p
o
u
n
d
m
e
n
t
,
th
e
ow
n
e
r
mu
s
t
(i
)
in
th
e
ca
s
e
of
cl
o
s
u
r
e
pu
r
s
u
a
n
t
to
su
b
‐su
b
d
i
v
i
s
i
o
n
(a
)
(
1
)
a
.
of
th
i
s
se
c
t
i
o
n
,
pr
o
v
i
d
e
a de
s
c
r
i
p
t
i
o
n
of
ho
w
th
e
as
h
wi
l
l
be
st
a
b
i
l
i
z
e
d
pr
i
o
r
to
co
m
p
l
e
t
i
o
n
of
cl
o
s
u
r
e
in
ac
c
o
r
d
a
n
c
e
wi
t
h
cl
o
s
u
r
e
an
d
po
s
t
‐cl
o
s
u
r
e
re
q
u
i
r
e
m
e
n
t
s
es
t
a
b
l
i
s
h
e
d
by
Se
c
t
i
o
n
.1
6
2
7
of
Su
b
c
h
a
p
t
e
r
B of
Ch
a
p
t
e
r
13
of
Ti
t
l
e
15
A
of
th
e
No
r
t
h
Ca
r
o
l
i
n
a
Ad
m
i
n
i
s
t
r
a
t
i
v
e
Co
d
e
an
d
(i
i
)
in
th
e
ca
s
e
of
cl
o
s
u
r
e
pu
r
s
u
a
n
t
to
su
b
‐su
b
d
i
v
i
s
i
o
n
(a
)
(
1
)
b
.
of
th
i
s
se
c
t
i
o
n
,
pr
o
v
i
d
e
a de
s
c
r
i
p
t
i
o
n
of
ho
w
th
e
as
h
wi
l
l
be
st
a
b
i
l
i
z
e
d
pr
e
‐
an
d
po
s
t
‐cl
o
s
u
r
e
.
If
th
e
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
ar
e
to
be
le
f
t
in
th
e
im
p
o
u
n
d
m
e
n
t
,
th
e
ow
n
e
r
mu
s
t
pr
o
v
i
d
e
an
es
t
i
m
a
t
e
of
th
e
vo
l
u
m
e
of
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
re
m
a
i
n
i
n
g
.
9
j.
A
li
s
t
of
al
l
pe
r
m
i
t
s
th
a
t
wi
l
l
ne
e
d
to
be
ac
q
u
i
r
e
d
or
mo
d
i
f
i
e
d
to
co
m
p
l
e
t
e
cl
o
s
u
r
e
ac
t
i
v
i
t
i
e
s
.
10
k.
A de
s
c
r
i
p
t
i
o
n
of
th
e
pl
a
n
fo
r
po
s
t
‐cl
o
s
u
r
e
mo
n
i
t
o
r
i
n
g
an
d
ca
r
e
fo
r
an
im
p
o
u
n
d
m
e
n
t
fo
r
a mi
n
i
m
u
m
of
30
ye
a
r
s
.
Th
e
le
n
g
t
h
of
th
e
po
s
t
‐cl
o
s
u
r
e
ca
r
e
pe
r
i
o
d
ma
y
be
(i
)
pr
o
p
o
s
e
d
to
be
de
c
r
e
a
s
e
d
or
th
e
fr
e
q
u
e
n
c
y
an
d
pa
r
a
m
e
t
e
r
li
s
t
mo
d
i
f
i
e
d
if
th
e
ow
n
e
r
de
m
o
n
s
t
r
a
t
e
s
th
a
t
th
e
re
d
u
c
e
d
pe
r
i
o
d
or
mo
d
i
f
i
c
a
t
i
o
n
s
ar
e
su
f
f
i
c
i
e
n
t
to
pr
o
t
e
c
t
pu
b
l
i
c
he
a
l
t
h
,
sa
f
e
t
y
,
an
d
we
l
f
a
r
e
;
th
e
en
v
i
r
o
n
m
e
n
t
;
an
d
na
t
u
r
a
l
re
s
o
u
r
c
e
s
an
d
(i
i
)
in
c
r
e
a
s
e
d
by
th
e
De
p
a
r
t
m
e
n
t
at
th
e
en
d
of
th
e
po
s
t
‐cl
o
s
u
r
e
mo
n
i
t
o
r
i
n
g
an
d
ca
r
e
pe
r
i
o
d
if
th
e
r
e
ar
e
st
a
t
i
s
t
i
c
a
l
l
y
si
g
n
i
f
i
c
a
n
t
in
c
r
e
a
s
i
n
g
gr
o
u
n
d
w
a
t
e
r
qu
a
l
i
t
y
tr
e
n
d
s
or
if
co
n
t
a
m
i
n
a
n
t
co
n
c
e
n
t
r
a
t
i
o
n
s
ha
v
e
no
t
de
c
r
e
a
s
e
d
to
a le
v
e
l
pr
o
t
e
c
t
i
v
e
of
pu
b
l
i
c
he
a
l
t
h
,
sa
f
e
t
y
,
an
d
we
l
f
a
r
e
;
th
e
en
v
i
r
o
n
m
e
n
t
;
an
d
na
t
u
r
a
l
re
s
o
u
r
c
e
s
.
If
th
e
ow
n
e
r
de
t
e
r
m
i
n
e
s
th
a
t
th
e
po
s
t
‐cl
o
s
u
r
e
ca
r
e
mo
n
i
t
o
r
i
n
g
an
d
ca
r
e
pe
r
i
o
d
is
no
lo
n
g
e
r
ne
e
d
e
d
an
d
th
e
De
p
a
r
t
m
e
n
t
ag
r
e
e
s
,
th
e
ow
n
e
r
sh
a
l
l
pr
o
v
i
d
e
a ce
r
t
i
f
i
c
a
t
i
o
n
,
si
g
n
e
d
an
d
se
a
l
e
d
by
a
pr
o
f
e
s
s
i
o
n
a
l
en
g
i
n
e
e
r
,
ve
r
i
f
y
i
n
g
th
a
t
po
s
t
‐cl
o
s
u
r
e
mo
n
i
t
o
r
i
n
g
an
d
ca
r
e
ha
s
be
e
n
co
m
p
l
e
t
e
d
in
ac
c
o
r
d
a
n
c
e
wi
t
h
th
e
po
s
t
‐cl
o
s
u
r
e
pl
a
n
.
If
re
q
u
i
r
e
d
by
Ch
a
p
t
e
r
89
C
of
th
e
Ge
n
e
r
a
l
St
a
t
u
t
e
s
,
th
e
pr
o
p
o
s
e
d
pl
a
n
fo
r
po
s
t
‐cl
o
s
u
r
e
mo
n
i
t
o
r
i
n
g
an
d
ca
r
e
sh
o
u
l
d
be
si
g
n
e
d
an
d
se
a
l
e
d
by
a pr
o
f
e
s
s
i
o
n
a
l
en
g
i
n
e
e
r
.
Th
e
pl
a
n
sh
a
l
l
in
c
l
u
d
e
,
at
a mi
n
i
m
u
m
,
al
l
of
th
e
fo
l
l
o
w
i
n
g
:
11
1A
de
m
o
n
s
t
r
a
t
i
o
n
of
th
e
lo
n
g
‐te
r
m
co
n
t
r
o
l
of
al
l
le
a
c
h
a
t
e
,
af
f
e
c
t
e
d
gr
o
u
n
d
w
a
t
e
r
,
an
d
st
o
r
m
w
a
t
e
r
.
11
2
A de
s
c
r
i
p
t
i
o
n
of
a gr
o
u
n
d
w
a
t
e
r
mo
n
i
t
o
r
i
n
g
pr
o
g
r
a
m
th
a
t
in
c
l
u
d
e
s
(i
)
po
s
t
‐cl
o
s
u
r
e
gr
o
u
n
d
w
a
t
e
r
mo
n
i
t
o
r
i
n
g
,
in
c
l
u
d
i
n
g
pa
r
a
m
e
t
e
r
s
to
be
sa
m
p
l
e
d
an
d
sa
m
p
l
i
n
g
sc
h
e
d
u
l
e
s
;
(i
i
)
an
y
ad
d
i
t
i
o
n
a
l
mo
n
i
t
o
r
i
n
g
we
l
l
in
s
t
a
l
l
a
t
i
o
n
s
,
in
c
l
u
d
i
n
g
a ma
p
wi
t
h
th
e
pr
o
p
o
s
e
d
lo
c
a
t
i
o
n
s
an
d
we
l
l
co
n
s
t
r
u
c
t
i
o
n
de
t
a
i
l
s
;
an
d
(i
i
i
)
th
e
ac
t
i
o
n
s
pr
o
p
o
s
e
d
to
mi
t
i
g
a
t
e
st
a
t
i
s
t
i
c
a
l
l
y
si
g
n
i
f
i
c
a
n
t
in
c
r
e
a
s
i
n
g
gr
o
u
n
d
w
a
t
e
r
qu
a
l
i
t
y
tr
e
n
d
s
.
11.1
l.
A
n
es
t
i
m
a
t
e
of
th
e
mi
l
e
s
t
o
n
e
da
t
e
s
fo
r
al
l
ac
t
i
v
i
t
i
e
s
re
l
a
t
e
d
to
cl
o
s
u
r
e
an
d
po
s
t
‐cl
o
s
u
r
e
.
12.1
m.
P
r
o
j
e
c
t
e
d
co
s
t
s
of
as
s
e
s
s
m
e
n
t
,
co
r
r
e
c
t
i
v
e
ac
t
i
o
n
,
cl
o
s
u
r
e
,
an
d
po
s
t
‐cl
o
s
u
r
e
ca
r
e
fo
r
ea
c
h
co
a
l
co
m
b
u
s
t
i
o
n
re
s
i
d
u
a
l
s
su
r
f
a
c
e
im
p
o
u
n
d
m
e
n
t
.
12.2
n.
A de
s
c
r
i
p
t
i
o
n
of
th
e
an
t
i
c
i
p
a
t
e
d
fu
t
u
r
e
us
e
of
th
e
si
t
e
an
d
th
e
ne
c
e
s
s
i
t
y
fo
r
th
e
im
p
l
e
m
e
n
t
a
t
i
o
n
of
in
s
t
i
t
u
t
i
o
n
a
l
co
n
t
r
o
l
s
fo
l
l
o
w
i
n
g
cl
o
s
u
r
e
,
in
c
l
u
d
i
n
g
pr
o
p
e
r
t
y
us
e
re
s
t
r
i
c
t
i
o
n
s
,
an
d
re
q
u
i
r
e
m
e
n
t
s
fo
r
re
c
o
r
d
a
t
i
o
n
of
no
t
i
c
e
s
do
c
u
m
e
n
t
i
n
g
th
e
pr
e
s
e
n
c
e
of
co
n
t
a
m
i
n
a
t
i
o
n
,
if
ap
p
l
i
c
a
b
l
e
,
or
hi
s
t
o
r
i
c
a
l
si
t
e
us
e
.
6.2
§ 13
0
A
‐30
9
.
2
1
2
(
b
)
(
3
)
No
la
t
e
r
th
a
n
60
da
y
s
af
t
e
r
re
c
e
i
p
t
of
a pr
o
p
o
s
e
d
Cl
o
s
u
r
e
Pl
a
n
,
th
e
De
p
a
r
t
m
e
n
t
sh
a
l
l
co
n
d
u
c
t
a pu
b
l
i
c
me
e
t
i
n
g
in
th
e
co
u
n
t
y
or
co
u
n
t
i
e
s
pr
o
p
o
s
e
d
Cl
o
s
u
r
e
Pl
a
n
an
d
al
t
e
r
n
a
t
i
v
e
s
to
th
e
pu
b
l
i
c
.
§ 13
0
A
‐30
9
.
2
1
2
(
d
)
Wi
t
h
i
n
30
da
y
s
of
it
s
ap
p
r
o
v
a
l
of
a Co
a
l
Co
m
b
u
s
t
i
o
n
Re
s
i
d
u
a
l
s
Su
r
f
a
c
e
Im
p
o
u
n
d
m
e
n
t
Cl
o
s
u
r
e
Pl
a
n
,
th
e
De
p
a
r
t
m
e
n
t
sh
a
l
l
su
b
m
i
t
th
e
Cl
o
s
u
r
e
Pl
a
n
to
th
e
Co
a
l
As
h
Ma
n
a
g
e
m
e
n
t
Co
m
m
i
s
s
i
o
n
.
No
t
e
:
Al
t
h
o
u
g
h
it
is
no
t
ma
n
d
a
t
e
d
by
CA
M
A
,
Du
k
e
En
e
r
g
y
is
su
b
m
i
t
t
i
n
g
th
i
s
Cl
o
s
u
r
e
Pl
a
n
to
th
e
No
r
t
h
Ca
r
o
l
i
n
a
De
p
a
r
t
m
e
n
t
of
En
v
i
r
o
n
m
e
n
t
a
l
Qu
a
l
i
t
y
(f
o
r
m
e
r
l
y
NC
D
E
N
R
)
to
as
s
i
s
t
th
e
de
p
a
r
t
m
e
n
t
wi
t
h
id
e
n
t
i
f
y
i
n
g
ar
e
a
s
wh
e
r
e
it
s
pe
r
m
i
t
t
i
n
g
ac
t
i
o
n
s
will be crucial in allowing
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Amec Foster Wheeler Environment & Infrastructure, Inc. December 2016
Duke Energy Coal Combustion Residuals Management Program
Asheville Steam Electric Generating Plant Site Analysis and Removal Plan
Revision 0
FIGURES
STILLING BASIN
1964 ASH BASIN
1982 ASH BASIN
N
DWG SIZE REVISION
FOR
DRAWING NO.
TITLE
FILENAME:
DWG TYPE:
JOB NO:
DATE:
SCALE:DES:
DFTR:
CHKD:
ENGR:
APPD:
A
F
E
D
C
B
2 3 4 5 7 86
4 5 7 8 9 106
A
F
C
B
11"x17"
ANSI C
Environment &
Infrastructure
SEAL
321
DWG SIZE REVISION
FOR
DRAWING NO.
TITLE
FILENAME:
DWG TYPE:
JOB NO:
DATE:
SCALE:DES:
DFTR:
CHKD:
ENGR:
APPD:
A
F
E
D
C
B
2 3 4 5 7 86
4 5 7 8 9 106
A
F
C
B
11"x17"
ANSI C
Environment &
Infrastructure
SEAL
321
NC GEOLOGY: C-247
NC ENG: F-1253
LICENSURE:
FAX: (865) 671-6254
TEL: (865) 671-6774
KNOXVILLE, TN 37922
SUITE 300
2030 FALLING WATERS
12-12-2016
7810160620
DWG
AS SHOWN
DS
MB
APT
APT
Figure 1 Site Location Map.dwg
0
1
01
F
I
G
U
R
E
1
FIGURE 1
ASHEVILLE PLANT
SKYLAND, NORTH CAROLINA
DUKE ENERGY ASHEVILLE PLANT
SITE LOCATION MAP
01FIGURE 1
750'2250'1500'0'
LEGEND
APPROXIMATE DUKE ENERGY
PROPERTY BOUNDARY
APPROXIMATE BASIN BOUNDARIES
SERVICE LAYER: CREDITS: DELORME STREET ATLAS,
ESRI ARCMAP, : 2013 NATIONAL GEOGRAPHIC SOCIETY.
CONCRETE RIM DITCH
DECANT BASIN
1982 ASH
BASIN
1964 ASH
BASIN
1964 ASH BASIN LIMITS
(APPROXIMATE)
LAKE JULIAN
SEPARATOR DIKE
1982 ASH
BASIN DAM
I
-
2
6
STEAM PLANT
DUCK
POND
1982 ASH BASIN LIMITS
(APPROXIMATE)
LAKE JULIAN
F
R
E
N
C
H
B
R
O
A
D
R
I
V
E
R
PROPERTY BOUNDARY
EXISTING STILLING BASIN
LAKE JULIAN DAM
1964 ASH BASIN DAM
FORMER WETLAND AREA
N
ISSUE/REVISION DESCRIPTIONYREVDM ENG.APPR.
CLIENT LOGO:
REVIEWED BY:
SCALE:
DATUM:
PROJECTION:
TITLE:
PROJECT:
DATE:
FIGURE NO.
REVISION NO.
PROJECT NO.:
DRAWN BY:
CLIENT:
2801 YORKMONT ROAD, SUITE 100
CHARLOTTE, NC 28208
TEL:(704) 357-8600 FAX: (704) 357-8638
LICENSURE: NC ENG: F-1253 NC GEOLOGY: C-247
Amec Foster Wheeler Environment & Infrastructure, Inc.
AS NOTED
7810160620
NA
12/12/2016
WGS84
STATE PLANE 83
APT
MB
DUKE ENERGY PROGRESS
BUNCOMBE COUNTY, NORTH CAROLINA
SITE ANALYSIS AND REMOVAL PLAN
DUKE ENERGY - ASHEVILLE STEAM ELECTRIC GENERATING PLANT
BUNCOMBE COUNTY, NORTH CAROLINA
LEGEND
ASH POND LIMITS
PROPERTY BOUNDARY
FORMER WETLAND AREA
SITE OVERVIEW AERIAL PLAN
2
NOTE:
1.AERIAL PHOTO DATED 10-2015 SOURCE BY GOOGLE EARTH PRO.
2.PROPERTY BOUNDARY OBTAINED FROM BUNCOMBE COUNTY
GIS DATA AT http://BUNCOMBECOUNTY.ORG/MAP_ALL.HTML.
I
N
T
E
R
S
T
A
T
E
2
6
I
N
T
E
R
S
T
A
T
E
2
6
F
R
E
N
C
H
B
R
O
A
D
R
I
V
E
R
F
R
E
N
C
H
B
R
O
A
D
R
I
V
E
R
MAHO
G
A
N
Y
R
O
A
D
LAKE JULIAN
LAKE JULIAN
MAH
O
G
A
N
Y
R
O
A
D
ABER
D
E
E
N
D
R
DOUGLA
S
F
I
R
A
V
E
PEPP
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R
B
U
S
H
T
R
L
NEW
R
O
C
K
W
O
O
D
R
D
NE
W
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O
C
K
W
O
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D
R
D
N
E
W
R
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C
K
W
O
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D
R
D
I
N
T
E
R
S
T
A
T
E
2
6
I
N
T
E
R
S
T
A
T
E
2
6
I
N
T
E
R
S
T
A
T
E
2
6
I
N
T
E
R
S
T
A
T
E
2
6
EXISTING CONTOURS
SEPARATOR DIKE
CONCRETE RIM DITCH
DECANT BASIN
1982 ASH BASIN
1964 ASH BASIN
1982 ASH BASIN LIMITS
(APPROXIMATE)
1964 ASH BASIN LIMITS
(APPROXIMATE)
EXISTING OVERHEAD
TRANSMISSION LINES
EXISTING WETLAND
DISCHARGE PIPE
(REMOVED)
EXISTING STILLING BASIN
EXISTING 66" RCP
PROPERTY BOUNDARY
FRENCH BROAD RIVER
LAKE JULIAN
500' COMPLIANCE BOUNDARY
ASH STACK
DUCK
POND
1964 ASH
BASIN DAM
1982 ASH
BASIN DAM
STEAM PLANT
(2) 36" HDPE RIM DITCH
SYSTEM DISCHARGE
LINES (APPROXIMATE)
(NOT IN USE)
MSD SEWER LINE
EXISTING FGD DISCHARGE
LINE (ABANDONED)
EXISTING 36" HDPE
PRIMARY SPILLWAY
EXISTING 36" RISER w/ 36" HDPE
BARREL OUTLET STRUCTURE
EXISTING PIPE 1982 BASIN PRIMARY
SPILLWAY (ABANDONED)
HISTORICAL 1964 PRIMARY SPILLWAY
30" CONC. PIPE (ABANDONED)
EXISTING OUTLET STRUCTURE
1982 BASIN PRIMARY SPILLWAY
(ABANDONED)
MH-02
CPF
S
CPFS
CPFS
CPFS
CPFS CPFS
CPFS
CPFS
CPFS CPFS CPFS
C
P
F
S
C
P
F
S
C
P
F
S
C
P
F
S
C
P
F
S
C
P
F
S
C
P
F
S
C
P
F
S
C
P
F
S
C
P
F
S
C
P
F
S
C
P
F
S
C
P
F
S
C
P
F
S
C
P
F
S
EXISTING CENTER POND
FILTER SYSTEM PUMP PAD
EXISTING 60" RCP
N
LEGEND
ASH BASIN LIMITS
PROPERTY BOUNDARY
500' COMPLIANCE BOUNDARY
CCR IMPOUNDMENT RELATED
STRUCTURES 3ISSUE/REVISION DESCRIPTIONYREVDM ENG.APPR.
CLIENT LOGO:
REVIEWED BY:
SCALE:
DATUM:
PROJECTION:
TITLE:
PROJECT:
DATE:
FIGURE NO.
REVISION NO.
PROJECT NO.:
DRAWN BY:
CLIENT:
2801 YORKMONT ROAD, SUITE 100
CHARLOTTE, NC 28208
TEL:(704) 357-8600 FAX: (704) 357-8638
LICENSURE: NC ENG: F-1253 NC GEOLOGY: C-247
Amec Foster Wheeler Environment & Infrastructure, Inc.
AS NOTED
7810160620
NA
12/12/2016
WGS84
STATE PLANE 83
APT
MB
DUKE ENERGY PROGRESS
BUNCOMBE COUNTY, NORTH CAROLINA
SITE ANALYSIS AND REMOVAL PLAN
DUKE ENERGY - ASHEVILLE STEAM ELECTRIC GENERATING PLANT
BUNCOMBE COUNTY, NORTH CAROLINA
NOTE:
1.EXISTING TOPOGRAPHY PROVIDED BY DUKE ENERGY DATED
10-22-2014 AND 2007 WITH UPDATES BY OTHERS DATED
11-09-2016, 9-22-2016, 7-27-2015.
2.PROPERTY BOUNDARY OBTAINED FROM BUNCOMBE COUNTY
GIS DATA AT http://BUNCOMBECOUNTY.ORG/MAP_ALL.HTML.
I
N
T
E
R
S
T
A
T
E
2
6
I
N
T
E
R
S
T
A
T
E
2
6
F
R
E
N
C
H
B
R
O
A
D
R
I
V
E
R
F
R
E
N
C
H
B
R
O
A
D
R
I
V
E
R
MAHO
G
A
N
Y
R
O
A
D
LAKE JULIAN
LAKE JULIAN
MAH
O
G
A
N
Y
R
O
A
D
ABER
D
E
E
N
D
R
DOUGLA
S
F
I
R
A
V
E
PEP
P
E
R
B
U
S
H
T
R
L
NEW
R
O
C
K
W
O
O
D
R
D
NE
W
R
O
C
K
W
O
O
D
R
D
N
E
W
R
O
C
K
W
O
O
D
R
D
R
O
S
E
T
T
A
L
N
NE
W
R
O
C
K
W
O
O
D
R
D
I
N
T
E
R
S
T
A
T
E
2
6
I
N
T
E
R
S
T
A
T
E
2
6
I
N
T
E
R
S
T
A
T
E
2
6
I
N
T
E
R
S
T
A
T
E
2
6
EXISTING CONTOURS
EXISTING ROAD
CONCRETE RIM DITCH
DECANT BASIN
1982 ASH BASIN
1964 ASH BASIN
DUCK POND
1982 ASH BASIN LIMITS
(APPROXIMATE)
1964 ASH BASIN LIMITS
(APPROXIMATE)
EXISTING PRIMARY SPILLWAY
EXISTING OVERHEAD
TRANSMISSION LINES
EXISTING WETLAND
DISCHARGE PIPE
EXISTING STILLING BASIN
EXISTING OUTLET STRUCTURE
1964 ASH POND
EXISTING 66" RCP
EXISTING 60" RCP
PROPERTY BOUNDARY
LAKE JULIAN
F
R
E
N
C
H
B
R
O
A
D
R
I
V
E
R
F
R
E
N
C
H
B
R
O
A
D
R
I
V
E
R
N
LEGEND
ASH BASIN LIMITS
BORE HOLE
OBSERVATION WELL
PIEZOMETER
PROPERTY BOUNDARY
BORING LOCATION MAP 1982 & 1964
ASH BASINS 4ISSUE/REVISION DESCRIPTIONYREVDM ENG.APPR.
CLIENT LOGO:
REVIEWED BY:
SCALE:
DATUM:
PROJECTION:
TITLE:
PROJECT:
DATE:
FIGURE NO.
REVISION NO.
PROJECT NO.:
DRAWN BY:
CLIENT:
2801 YORKMONT ROAD, SUITE 100
CHARLOTTE, NC 28208
TEL:(704) 357-8600 FAX: (704) 357-8638
LICENSURE: NC ENG: F-1253 NC GEOLOGY: C-247
Amec Foster Wheeler Environment & Infrastructure, Inc.
AS NOTED
7810160620
NA
12/12/2016
WGS84
STATE PLANE 83
APT
MB
DUKE ENERGY PROGRESS
BUNCOMBE COUNTY, NORTH CAROLINA
SITE ANALYSIS AND REMOVAL PLAN
DUKE ENERGY - ASHEVILLE STEAM ELECTRIC GENERATING PLANT
BUNCOMBE COUNTY, NORTH CAROLINA
NOTE:
1.EXISTING TOPOGRAPHY PROVIDED BY DUKE ENERGY DATED
10-22-2014 AND 2007 WITH UPDATES BY OTHERS DATED
11-09-2016, 9-22-2016, 7-27-2015.
2.PROPERTY BOUNDARY OBTAINED FROM BUNCOMBE COUNTY
GIS DATA AT http://BUNCOMBECOUNTY.ORG/MAP_ALL.HTML.
3.BORING LOCATIONS DETERMINED FROM COORDINATES
INCLUDED ON DRILL LOGS WHERE AVAILABLE.
4.ADDITIONAL BORING LOCATIONS WERE BASED ON DATA
PROVIDED BY DUKE ENERGY.
5.SOME PIEZOMETER / MONITORING WELL LOCATIONS ARE
SUBJECT TO BE ABANDONED AS PART OF THE CLOSURE
ACTIVITIES.
Amec Foster Wheeler Environment & Infrastructure, Inc. December 2016
Duke Energy Coal Combustion Residuals Management Program
Asheville Steam Electric Generating Plant Site Analysis and Removal Plan
Revision 0
APPENDICES