Buck CBE - Closure Report_20191230

DUKE
ENERGY,
December 30, 2019
HAND DELIVERY AND ELECTRONIC MAIL
Ms. Shelia Holman
Assistant Secretary
North Carolina Department of Environmental Quality
1611 Mail Service Center
Raleigh, NC 27699-1611
RE: Buck Steam Station Ash Basin Closure Plan
Dear Ms. Holman:
George 7. Hamrick
Senior Vice President
Coal combustion Products
400 South Tryon street, ST06A
Chadolte, NC 28202
Phone: [phone]
Email, [e-mail]
In accordance with the requirements of North Carolina General Statue § 130A-309.214(a)(4),
Closure of Coal Combustion Residuals Surface Impoundments, Duke Energy provides the
attached plan for ash basin closure by excavation.
Duke Energy remains committed to safely and permanently closing basins in ways that continue
to protect people and the environment and welcomes the opportunity to work constructively with
NCDEQ to move forward.
Respectfully submitted,
Gll�r X 111?�4
George T. Hamrick
Senior Vice President
NCDEQ cc: damsafety*ncdenr.00v, [e-mail], Ed Mussler, Steven
Lanter, Toby Vinson
Duke Energy cc: Jessica Bednarcik, Dave Renner, Dan Mc Rainey, Jim Wells, Ed Sullivan,
Michael Kafka, Randy Hart

DUKE ENERGY w.,OO.
BUCK STATION
COAL COMBUSTION RESIDUALS SURFACE
IMPOUNDMENT CLOSURE PLAN
CLOSURE BY EXCAVATION
Primary, Secondary, and Additional Primary Ash Basins
Closure Plan Report
Final Submittal
Prepared for
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iny5y
550 South Tryon Street
Charlotte, North Carolina 28202
Revision 0
Issue Date: 11 December 2019
Prepared by
Wood Environment & Infrastructure Solutions, Inc.
2801 Yorkmont Drive, Suite 100
Charlotte, North Carolina 28208
Project No. 7812180092
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Wood Environment & Infrastructure Solutions, Inc. wood
Duke Energy Coal Combustion Residuals Management Program
Buck Station Basin CAMA Closure Plan
TABLE OF CONTENTS
EXECUTIVE SUMMARY
1.0 INTRODUCTION..............................................................................................................1
1.1 Background................................................................................................................................... 1
1.2 Closure Plan Objectives................................................................................................................
1
1.3 Report Organization......................................................................................................................
2
2.0 GOVERNING LAWS........................................................................................................2
3.0 FACILITY DESCRIPTION AND EXISTING SITE FEATURES..........................................3
3.1 Surface Impoundment Description................................................................................................
3
3.1.1 Site History and Operations......................................................................................................3
3.1.2 Estimated Volume of CCR in Impoundments...........................................................................3
3.1.3 Description of Surface Impoundment Structural Integrity.........................................................4
3.1.4 Sources of Discharges into Surface Impoundments.................................................................5
3.1.5 Existing Liner System................................................................................................................5
3.1.6 Inspection and Monitoring Summary.........................................................................................5
3.2 Site Maps......................................................................................................................................
6
3.2.1 Existing CCR Impoundment Related Structures.......................................................................6
3.2.2 Receptor Survey........................................................................................................................6
3.2.3 Existing On -Site Landfills..........................................................................................................
6
3.3 Monitoring and Sampling Location Plan.......................................................................................
6
4.0 RESULTS OF HYDROGEOLOGIC, GEOLOGIC, AND GEOTECHNICAL
INVESTIGATIONS............................................................................................................7
4.1 Background...................................................................................................................................
7
4.2 Hydrogeology and Geologic Descriptions.....................................................................................
7
4.3 Stratigraphy of the Geologic Units Underlying Surface Impoundments ........................................
7
4.4 Geotechnical Properties................................................................................................................
7
4.4.1 CCR within the Basins..............................................................................................................7
4.4.2 Liner Material Properties...........................................................................................................
8
4.4.3 Subsurface Soil Properties........................................................................................................8
4.5 Chemical Analysis of Impoundment Water, CCR and CCR Affected Soil ....................................
8
4.6 Historical Groundwater Sampling Results....................................................................................
8
4.7 Groundwater Potentiometric Contour Maps..................................................................................
9
4.8 Estimated Vertical and Horizontal Extent of CCR within the Impoundments ...............................
9
5.0 GROUNDWATER MODELING ANALYSIS......................................................................9
5.1 Site Conceptual Model Predictions............................................................................................... 9
5.2 Groundwater Chemistry Effects.................................................................................................... 9
5.3 Groundwater Trend Analysis Methods.......................................................................................... 9
6.0 BENEFICIAL USE AND FUTURE USE............................................................................9
6.1 CCR Use....................................................................................................................................... 9
6.2 Site Future Use........................................................................................................................... 10
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7.0
CLOSURE DESIGN DOCUMENTS................................................................................10
7.1
Engineering Evaluations and Analyses.......................................................................................
10
7.2
Closure Plan Activities................................................................................................................
10
7.3
Design Drawings.........................................................................................................................
11
7.4
Description of Construction Quality Assurance and Plan...........................................................
12
8.0
MANAGEMENT OF WASTEWATER AND STORMWATER..........................................12
8.1
Anticipated Changes in Wastewater and Stormwater Management ..........................................
14
8.2
Wastewater and Stormwater Permitting Requirements..............................................................
15
9.0
DESCRIPTION OF FINAL DISPOSITION OF CCR........................................................15
10.0
APPLICABLE PERMITS FOR CLOSURE.....................................................................15
11.0
DESCRIPTION OF POST -CLOSURE MONITORING AND CARE.................................15
11.1
Groundwater Monitoring Program...............................................................................................
16
12.0
PROJECT MILESTONES AND COST ESTIMATES......................................................16
12.1
Project Schedule.........................................................................................................................
16
12.2
Closure and Post -Closure Cost Estimate...................................................................................
16
13.0
REFERENCES...............................................................................................................18
Tables
Table 2-1 CAMA Closure Plan Requirements Summary and Cross Reference Table
Table 4-1 Summary of Typical Material Properties
Table 10-1 Buck Station Regulatory Permits, Approvals, or Requirements for Basin Closure
by Excavation
Figures
Figure 1-1 Vicinity Map and Site Plan
Figure 1-2 Overall Existing Conditions Plan
Appendices
Appendix A
Estimated Volume of CCR in Impoundment
Appendix B
Geotechnical Data and Properties
Appendix C
Engineering Evaluations and Analyses
Appendix D
Closure Plan Drawings
Appendix E
Excavation Soil Sampling Plan
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Buck Station Basin CAMA Closure Plan
EXECUTIVE SUMMARY
In accordance with N.C.G.S. § 130A-309.214(a)(4), Duke Energy has prepared this Closure Plan
to describe the closure of the coal combustion residuals (CCR) surface impoundments (Basins)
at the Buck Station (Buck). The Buck Basins closure will consist of closure by excavation, whereby
CCR in the Basins will be excavated, processed, and transported off -site for beneficial re -use as
a concrete amendment. The removal of CCR and closure of the Basins will be in accordance with
all applicable provisions of the North Carolina Coal Ash Management Act of 2014, Sess. L. 2014-
122, as amended (codified at N.C.G.S. § 130A-309.200, et seq.) (CAMA). CCR processing will
be done using on -site STAR° (Staged Turbulent Air Reactor) Technology, a patented thermal
beneficiation process to transform CCR from the Basins into a high -quality, sustainable product
for the concrete industry.
Duke Energy will periodically review the progress of the excavation and STAR' processing as it
relates to achieving full CCR removal by the required end date of December 31, 2029. Duke
Energy will implement a concurrent excavation plan in which the remaining excavated CCR will
be transported to an approved landfill facility in order to meet the end date of December 31, 2029
for complete removal.
Buck is owned and operated by Duke Energy Progress, LLC (Duke Energy). The approximately
640-acre Buck site is located at 1555 Dukeville Road in Rowan County near Spencer, North
Carolina on the southern bank of the Yadkin River.
Commercial operations of the station began in 1926 with two coal-fired units and later expanded
to six units. Units 1 and 2 were retired in 1979, Units 3 and 4 were retired in 2011, and Units 5
and 6 were retired in 2013. There are no coal-fired units currently in operation at Buck.
This Closure Plan covers the three Basins located at Buck, impounded by 5 dam/dike structures
identified in the North Carolina Department of Environmental Quality (NCDEQ) Dam Safety
Inventory as follows:
• Primary Basin and Secondary Basin Main Dam (NC Dam Safety ID: ROWAN-047)
• Additional Primary Dam (NC Dam Safety ID: ROWAN-068)
• Additional Primary Basin to Primary Basin Dike (NC Dam Safety ID: ROWAN-069)
• Primary Basin to Secondary Basin Dike (NC Dam Safety ID: ROWAN-070)
• Divider Dike between the Primary Basin and Secondary Basin (NC Dam Safety ID:
ROWAN-071)
During operation, CCR was transported from the plant to the Basins by hydraulic (wet) sluicing.
In addition to the Basins, there is also an unlined dry CCR storage area located on the eastern
side of the Additional Primary Basin. The original CCR basin (Primary Basin) began operation in
1957. The Primary Basin was later divided into two basins (Primary Basin and the Secondary
Basin) and, in 1982, the Additional Primary Basin was constructed. The Additional Primary Basin
served as the primary CCR retention facility until the last coal-fired operating unit was retired in
March of 2013. With the permanent retirement of the coal-fired generating units, there are no
longer any CCR disposal operations within the Basins.
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The existing three Basins are unlined and contain up to 70 feet depth of CCR. Information
provided by Duke Energy (with updated inventory data through July 31, 2019) indicates that the
current estimated volume of CCR in the three Basins is approximately 6.67 million tons (5.56
million cubic yards assuming a conversion factor of 1.2 tons/cy). It should be noted that the CCR
volume/tonnage estimates are approximations since they are based on assumed pre -basin
grades.
Upon approval of the Closure Plan by NCDEQ, additional activities to complete closure of the
Basins will commence, including beginning excavation of the CCR from the Basins, establishing
final grades using soil fill where required to properly drain the Basin areas, breaching the Basin
dikes following removal of CCR (soil material removed from the Basin dikes will remain on -site
and will be incorporated into the final site grading plan), and development of stormwater features
and vegetative covers.
This document also includes a description of the future Post -Closure Care Plan, which provides
a description of the inspection, monitoring and maintenance activities required to be performed
for the Buck site for a minimum of 30 years.
This document provides a summary of properties of the site, as well as geotechnical properties
of CCR and natural soils to support engineering analyses of the closure design. These analyses
indicate that closure by excavation, as detailed in the Closure Plan, meets regulatory
requirements for the stability of the site, management of stormwater runoff, and access for
effective maintenance over the post -closure care period.
In a letter dated April 5, 2019, NCDEQ established submittal dates for an updated Comprehensive
Site Assessment (CSA) and updated Corrective Action Plan (CAP) for CCR surface
impoundments and other primary and secondary sources. Consistent with this direction, Duke
Energy will submit to NCDEQ the updated CSA for Buck by October 1, 2020, and the updated
CAP by July 1, 2021. The CAP sets out corrective action measures for the restoration of
groundwater quality as required under CAMA and the state's groundwater quality regulations.
Although this Closure Plan contains references to the CAP, all specific relevant details to
groundwater and related actions will be contained in the CAP and not in this Closure Plan.
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Buck Station Basin CAMA Closure Plan
1.0 INTRODUCTION
1.1 Background
The approximately 640-acre Buck site is located at 1555 Dukeville Road in Rowan County near
Spencer, North Carolina on the southern bank of the Yadkin River. Commercial operations of the
station began in 1926 with two coal-fired units and later expanded to six units. Units 1 and 2 were
retired in 1979, Units 3 and 4 were retired in 2011, and Units 5 and 6 were retired in 2013. All
waste flows to the Basins ceased in 2019 and there are no longer any CCR disposal operations
at Buck.
This Closure Plan is being submitted for approval by NCDEQ and reflects closure by excavation
of the CCR from the Buck site. Processing of the excavated CCR will be done using STAR'
Technology, a patented thermal beneficiation process to transform CCR from the Basins into a
high -quality, sustainable product for the concrete industry. Figure 1-1 presents a Vicinity Map
and Site Plan of Buck. Figure 1-2 presents the overall existing conditions at the site.
The Buck site has five regulated CCR impoundment structures (Figures 1-1 and 1-2). This
Closure Plan covers the three CCR basins located at the Buck Station, impounded by the five
dam/dike structures that are identified (and regulated by) the North Carolina Department of
Environmental Quality (NCDEQ) and Dam Safety as follows:
• Primary Basin and Secondary Basin Main Dam (NC Dam Safety ID: ROWAN-047)
• Additional Primary Dam (NC Dam Safety ID: ROWAN-068)
• Additional Primary Basin to Primary Basin Dike (NC Dam Safety ID: ROWAN-069)
• Primary Basin to Secondary Basin Dike (NC Dam Safety ID: ROWAN-070)
• Divider Dike between the Primary Basin and Secondary Basin (NC Dam Safety ID:
ROWAN-071)
This Closure Plan has been prepared for the review and approval of NCDEQ.
1.2 Closure Plan Objectives
The primary objective of this Closure Plan is to address the closure by excavation of CCR from
the Basins at Buck pursuant to North Carolina Coal Ash Management Act of 2014, Session L.
2014-122, as amended (CAMA). A further objective is to obtain approval from the NCDEQ to
proceed and develop the additional details (as described further within this Closure Plan) and
working documents necessary to complete the closure actions. Duke Energy is requesting
approval of this Closure Plan with the knowledge that other details will follow. This Closure Plan
describes and communicates the key actions and activities necessary to close the Basins in
accordance with the requirements for written closure plans for CCR surface impoundments in
N.C.G.S. § 130A-309.214(a)(4). Planned closure activities include:
• Removal of free water/bulk water volume via permitted outfall (i.e., decanting);
• Construction and operation of a temporary water management system (WMS) to manage
discharges in compliance with the NPDES permit during closure;
• Construction of the STAR' Unit for processing of CCR for beneficial re -use;
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• Development of sump areas in the Basins to collect and convey waters to the water
management system;
• Dewatering the CCR to allow for safe access. CCR excavation and conditioning will be
required prior to transport to the on -site STAR° system;
• Excavate CCR from the Basins, with sequencing determined for optimal progression.
Instrumentation and monitoring requirements to be developed prior to construction will be
followed to verify construction phase stability. Construction dewatering to be used as
needed to provide stable work areas and slopes;
• Complete closure by excavation verification.
• Breaching of the Basin dikes and dams; and
• Grading the perimeter dikes into each of the three basins with a grading plan that will
establish drainage to promote flow of stormwater away from the former Basins in a manner
protective of area soils and water.
1.3 Report Organization
This document is structured to follow the requirements of N.C.G.S. § 130A-309.214(a)(4).
2.0 GOVERNING LAWS
In August 2014, the North Carolina General Assembly enacted CAMA, which contains specific
statutory requirements applicable to CCR surface impoundments. Relative to the Buck Station,
"coal combustion residuals surface impoundment," as defined in N.C.G.S. § 130A-309.201(6), is
interpreted to include the plant's Basins.
In July 2016, the North Carolina General Assembly enacted House Bill 630, which added
N.C.G.S. § 130A-309.216 requiring Duke Energy to identify three sites in North Carolina at which
to install and operate Ash Beneficiation projects capable of processing CCR to specifications
appropriate for cementitious products. The statute requires Duke Energy to use commercially
reasonable efforts to produce 300,000 tons of usable CCR at each site annually. On October 5,
2016, Duke Energy selected Buck as one of the three Ash Beneficiation sites. Pursuant to
subsection (c) of N.C.G.S. § 130A-309.216, CCR surface impoundments located at a site at which
an Ash Beneficiation project is installed, and operating shall be closed no later than December
31, 2029.
The Excavation Soil Sampling Plan for Buck (presented in Appendix E), represents activities to
satisfy the requirements set forth in the NCDEQ's November 4, 2016 letter and attachment titled
"CCR Surface Impoundment Closure Guidelines for Protection of Groundwater."
In a letter dated April 5, 2019, NCDEQ established submittal dates for an updated CSA and
updated CAP for CCR surface impoundments and other primary and secondary sources.
Consistent with this direction, Duke Energy will submit to NCDEQ the updated CSA for Buck by
October 1, 2020, and the updated CAP by July 1, 2021.
In addition to the above requirements, National Pollutant Discharge Elimination System (NPDES)
permit program compliance, Special Order by Consent (which commits Duke Energy to initiate
and complete decanting of the Basins by dates certain) compliance, dam safety approvals for
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modifications to regulated CCR basin dikes, and environmental permitting requirements must be
considered as part of closure.
3.0 FACILITY DESCRIPTION AND EXISTING SITE FEATURES
3.1 Surface Impoundment Description
This section provides details on the CCR-related features at Buck.
3.1.1 Site History and Operations
Figure 1-1 shows locations of the three CCR basins (Primary, Secondary, and Additional Primary)
and five dikes (ROWAN-047, ROWAN-068, ROWAN-069, ROWAN-070, and ROWAN-071) at
the Buck site. Figure 1-2 shows the overall existing conditions at the Buck Station.
The Buck Station is located on the south bank of the Yadkin River in Rowan County, North
Carolina near the town of Spencer. Review of available information indicates that the property,
totaling approximately 640 acres, is owned by Duke Energy, and is reported to have begun
commercial operation in 1926 and, at its peak, had six coal fired units in operation with a combined
capacity of 512 megawatts. Units 1 and 2 began operation in 1926 with a combined capacity of
256 megawatts and were retired in 1979. Units 3 and 4, with a combined capacity of 113
megawatts, were retired in mid-2011, and Units 5 and 6, with a combined capacity of 143
megawatts, were retired in April 2013. The site now hosts a 620-megawatt natural gas Combined
Cycle Plant which began construction in 2008 and came on line in 2011. The CCR Basins were
constructed at the site between 1957 and 1982 as operational needs required additional CCR
disposal area. Sluicing of CCR to the Basins ceased in 2013. Process and wastewaters continued
to be treated through the Basins until 2019.
The interconnected system of CCR basins, dikes, dams, discharge structures and canals make
up the CCR basin system at Buck and this system discharges at a NPDES permitted outfall point
into the Yadkin River (currently Outfall 007). There are no longer any CCR disposal operations
within the Basins with the permanent retirement of the coal-fired units. The Basins at the Buck
Station are located in historical valley features within larger watersheds and, therefore, receive
surface water run-on flows.
3.1.2 Estimated Volume of CCR in Impoundments
Based on CCR inventory data provided by Duke Energy as of July 31, 2019, the approximate
volume of CCR in the Basins is listed in the table below. To compute the estimated volume of
CCR in place an assumed density of 1.2 tons per cubic yard was used, which is the Duke Energy
fleet wide assumption. See Appendix A for the Estimated Volume of CCR Material in the
Impoundment data sheet.
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Impoundment
Estimated CCR
Estimated CCR
Material Volume (cy)
Material Weight (tons)*
Additional Primary Basin
2,959,167
3,551,000*
Additional Primary Basin Dry
219,074
262,889*
Stack
Primary Basin
1,665,000
1,998,000*
Secondary Basin
720,000
864,000*
TOTAL
5,563,241
6,675,889*
* Estimated CCR Material is based on updated CCR inventory data provided by Duke Energy as of
July 31, 2019. To compute the estimated mass of CCR in place an assumed density of 1.2 tons
per cubic yard was used, which is the Duke Energy fleet wide assumption.
3.1.3 Description of Surface Impoundment Structural Integrity
The purpose of this section is to summarize the Basins' structural integrity evaluations based on
current existing information. This section includes brief summaries of the Geotechnical and
Hydrology and Hydraulics (H&H) capacity analyses results. Duke Energy provided Wood with
pertinent information regarding the integrity of the embankments, which had already been
compiled and analyzed. In summary, the structural integrity of the Basins and subsequent dike
inspection reports meet the regulatory requirements of EPA's CCR Rule (40 C.F.R. § 257.73).
Duke Energy's certifications of these requirements are available on Duke Energy's publicly
accessible CCR Rule Compliance Data and Information website.
• Slope Stability for Dikes ROWAN-047, 068, 069, 070, 071:
Slope stability analyses completed for the identified critical cross sections for each of the
dikes indicate that the minimum factors of safety meet programmatic criteria under static,
pseudo -static, and post -seismic conditions.
• Liquefaction Conditions (where susceptible) and Liquefaction Potential for dikes
ROWAN-047, 068, 069, 070:
Embankment and foundation soils associated with these dikes have low susceptibility to
liquefaction, and risk of excessive deformation or settlement of the embankment is
considered negligible during the Maximum Design Earthquake (MDE).
• Liquefaction Conditions (where susceptible) and Liquefaction Potential for Divider
Dike ROWAN-071:
Advanced liquefaction analysis for the CCR comprising the foundation of the Divider Dam
indicates that the CCR is not susceptible to liquefaction during the Maximum Design
Earthquake (MDE). Deformations of the embankment are predicted by fully coupled dynamic
analysis to be negligible for the MDE.
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• Hydrology and Hydraulics (H&H) Capacity Analyses:
In April 2019, the NCDEQ promulgated new dam safety rules and, per the dam safety High
Hazard Classification, each CCR Basin is required to pass a full Probable Maximum
Precipitation (PMP). Each basin is classified as high hazard by NCDEQ due to the potential
for environmental impacts greater than $200,000, if the Basin failed. The most recent study
prepared by AECOM for the Full-PMP storm event indicates that the spillway systems for the
Basins are capable safely conveying the Full-PMP storm event while also removing 80
percent of the detained storm volume within 15 days following the design storm peak, per
requirements of the North Carolina dam safety rules. The most recent analysis performed
by AECOM is included in Appendix C.
3.1.4 Sources of Discharges into Surface Impoundments
Duke Energy has decommissioned the coal-fired power plant at this site. Since it is now
permanently retired from service, CCR is no longer sluiced into the Basins. All wastewater flow
into the Additional Primary Basin ceased in April 2019. Since the Basins were constructed by
placing a dike at the downstream end of a natural drainage area, the contributing drainage area
to each of the basins is larger than the basins themselves. Thus, in addition to direct rainfall, there
is watershed run-on drainage entering the Basins during rainfall events.
3.1.5 Existing Liner System
The Basins located at the Buck Station do not include geomembrane or clay liner systems and
are considered to be unlined.
3.1.6 Inspection and Monitoring Summary
Duke Energy conducts routine weekly, monthly, and annual inspections of the Basins, consistent
with North Carolina's dam safety requirements and the federal CCR rule.
Weekly Basin inspections include observation of upstream slopes and shorelines, crest,
downstream slopes, toes, abutment contacts and adjacent drainage way(s), spillway(s) and
associated structure(s), and other structures and features of the dikes and dams.
Monthly inspections of the Basins include the weekly monitoring elements with the addition of
piezometer and observation well readings; water level gauges/sensors.
Daily inspections of the Basins are not routinely required; however, on a case -by -case basis, the
Basins may be inspected daily beginning at such times and continued for the duration as specified
by plant management. Such daily inspections might be initiated during repair activities on the dike
or dam in response to a specific imposed regulatory agency requirement.
The Basins are inspected annually by an independent third -party consultant. In a letter dated
August 13, 2014, NCDEQ requires these inspections to be conducted annually at all of Duke
Energy's CCR impoundments in North Carolina. These inspections are intended to confirm
adequacy of the design, operation, and maintenance of the surface impoundment in accordance
with accepted engineering standards. Reports are to be submitted to the NCDEQ within 30 days
of the completion of the inspection.
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The results for the annual inspections are used to identify needed repairs, repair schedules, to
assess the safety and operational adequacy of the dike or dam, and to assess compliance
activities regarding applicable permits and environmental and dam regulations. Annual
inspections are also performed to evaluate previous repairs.
The 2015 through 2019 annual inspections did not identify features or conditions in Basin
dams/dikes or their outlet structures or spillways that indicate an imminent threat of impending
failure hazard. Review of critical analyses indicated 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 underway.
Special inspections of the Basins may be performed during episodes of high -flow, earthquake,
emergency, or other extraordinary events. Visual inspections are performed after a heavy
precipitation event when accumulation of 4 inches of rainfall or greater occurs within a 24-hour
period. An internal inspection will be performed if a seismic event is detected by the U.S.
Geological Survey measuring greater than a Magnitude 3 and with an epicenter within 50 miles
of the dikes. A special inspection would also be performed during an emergency, such as when
a potential dike breach condition might be identified or when construction activities (e.g., basin
cleanout) are planned on or near the dikes. They are also determined when the ongoing
surveillance program identifies a condition or a trend that warrants special evaluation.
3.2 Site Maps
3.2.1 Existing CCR Impoundment Related Structures
A site map showing property boundary, location of the Buck Station Basins with their boundaries,
and topographic and bathymetric contours are shown on Figure 1-2.
3.2.2 Receptor Survey
This information is included as part of the updated CAP being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by July 1, 2021. The CAP is herein incorporated
by this reference, but its content is not the work product of Wood.
3.2.3 Existing On -Site Landfills
There are no known on -site landfills at the Buck Station.
3.3 Monitoring and Sampling Location Plan
This information is included as part of the updated CAP being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by July 1, 2021. The CAP is herein incorporated
by this reference, but its content is not the work product of Wood.
Locations of the existing groundwater monitoring wells are shown in Figure 4 of the Closure Plan
Drawings included in Appendix D, but the CAP should be consulted for details of well locations,
names, and status.
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4.0 RESULTS OF HYDROGEOLOGIC, GEOLOGIC, AND GEOTECHNICAL
INVESTIGATIONS
4.1 Background
An overall boring and existing monitoring well location plan indicating the locations of recent and
historical borings, monitoring wells, piezometers, and Cone Penetration Test (CPT) sounding
locations is shown on drawings included in Appendix D (Figure 4).
This section summarizes the site geology and hydrogeology; site stratigraphy of the geologic units
underlying the surface impoundments; hydraulic conductivity of CCR and the soils underlying the
surface impoundment; geotechnical properties of the CCR and the uppermost stratigraphic unit
under the surface impoundment; and the CCR and CCR-affected soils. Duke Energy provided
Wood with pertinent documentation regarding the site geology and hydrologic information, which
had already been compiled.
4.2 Hydrogeology and Geologic Descriptions
This information is included as part of the updated CSA being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by October 1, 2020. The CSA is herein
incorporated by this reference, but its content is not the work product of Wood.
4.3 Stratigraphy of the Geologic Units Underlying Surface Impoundments
This information is included as part of the updated CSA being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by October 1, 2020. The CSA is herein
incorporated by this reference, but its content is not the work product of Wood.
4.4 Geotechnical Properties
This section provides a summary of geotechnical conditions and properties found from
investigations performed within the Basins and Basin dikes areas. The presented information was
obtained from previous geotechnical investigations at the site and recent investigation activities
conducted to support the Closure Plan development. The geotechnical conditions within the
Basins generally consist of CCR (primarily interbedded layers of fly ash and bottom ash, along
with coal slag, unburned coal, and plant stormwater) placed in the Basins primarily by hydraulic
sluicing underlain by residual soil, saprolite, partially weather rock (PWR), and bedrock.
For purposes of discussion of the geotechnical properties of the materials, the saprolite material
is described as residual material. General properties of the various materials encountered within
and surrounding the Basins are described below. A range of measured material properties of
laboratory tests performed by AECOM, HDR, and Mactec for the subsurface explorations
completed within the Basins is presented in Appendix B. A summary of typical measured
properties for different material types are presented in Table 4-1. A summary of laboratory tests
data performed at the Buck Station in support of the closure design is presented in Appendix B.
4.4.1 CCR within the Basins
The CCR within the Basins consists primarily of layers and mixtures of bottom ash and fly ash.
Other CCR materials such as slag are also typically encountered. The bottom ash generally
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consists of very loose to loose, moist to wet, dark gray to gray, silty sand (SM) or silt and sandy
silt (ML). At some drilling locations, a surficial layer of CCR fill material (SP or SW or SW-SM)
was encountered that was used for boring access road construction.
The fly ash generally consists of very soft to soft, moist to wet, light to medium gray sandy silt and
silt (ML).
Further information is included as part of the updated CSA being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by October 1, 2020. The CSA is herein
incorporated by this reference, but its content is not the work product of Wood.
4.4.2 Liner Material Properties
The Basins at the Buck Station are unlined, so there are no associated material properties.
4.4.3 Subsurface Soil Properties
Alluvium: Based on information supplied by Duke Energy, alluvial soil was encountered beneath
the sluiced CCR in multiple borings in various locations within the Basins. The alluvial soil was
reported to consist of the following throughout the site:
• Loose to dense, gray, pink, white, black, orange, red, dark brown, silty fine to very coarse
sands (SP, SM, and SW) with interlayered fat clay and elastic silt. Typical thicknesses
ranged from 0.5 to 10.0 feet.
• Soft to very stiff, gray, brown, red, orange, fine to coarse sandy clays to fat clays with
interbedded layers of fine to medium sand (CL and CH) with thicknesses ranging from 5.0
to 10.0 feet.
• Very soft to very stiff, gray, brown, tan, red, fine to medium sandy clayey silts (MH and
ML) and ranged in thickness from 0.5 to 5.0 feet.
• Alluvial soils were reported in some of the monitoring well boring locations and consisted
of silty sand (SM), fat clay (CH) with elastic silt, and varied in thicknesses from 5.0 to 15.0
feet.
Residuum: The residuum (including saprolite) is the next layer encountered and generally
consists of soft to hard sandy lean clay (CL), fine sandy to clayey silt (MUMH), and silty sand
(SM)
4.5 Chemical Analysis of Impoundment Water, CCR and CCR Affected Soil
This information is included as part of the updated CSA being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by October 1, 2020. The CSA is herein
incorporated by this reference, but its content is not the work product of Wood.
4.6 Historical Groundwater Sampling Results
This information is included as part of the updated CSA being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by October 1, 2020. The CSA is herein
incorporated by this reference, but its content is not the work product of Wood.
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4.7 Groundwater Potentiometric Contour Maps
This information is included as part of the updated CSA being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by October 1, 2020. The CSA is herein
incorporated by this reference, but its content is not the work product of Wood.
4.8 Estimated Vertical and Horizontal Extent of CCR within the Impoundments
This information is included as part of the updated CSA being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by October 1, 2020. The CSA is herein
incorporated by this reference, but its content is not the work product of Wood.
5.0 GROUNDWATER MODELING ANALYSIS
This information is included as part of the updated CAP being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by July 1, 2021. The CAP is herein incorporated
by this reference, but its content is not the work product of Wood.
5.1 Site Conceptual Model Predictions
This information is included as part of the updated CAP being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by July 1, 2021. The CAP is herein incorporated
by this reference, but its content is not the work product of Wood.
5.2 Groundwater Chemistry Effects
This information is included as part of the updated CAP being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by July 1, 2021. The CAP is herein incorporated
by this reference, but its content is not the work product of Wood.
5.3 Groundwater Trend Analysis Methods
This information is included as part of the updated CAP being prepared separately by SynTerra
for Duke Energy and will be submitted to NCDEQ by July 1, 2021. The CAP is herein incorporated
by this reference, but its content is not the work product of Wood.
6.0 BENEFICIAL USE AND FUTURE USE
6.1 CCR Use
Duke Energy has developed plans for on -site recovery and reclamation/recycling of a significant
portion of the CCR at the Buck Station, in accordance with rate established by NCGS § 130A-
309.216. Duke Energy will implement a concurrent excavation plan in which the remaining
excavated CCR will be transported to an approved landfill facility in order to meet the end date of
December 31, 2029 for complete removal of the CCR.
The beneficial use activities consist of removing and transporting CCR from the Basins for
processing at a STAR° facility to be constructed on -site. The STAR' facility will process the
reclaimed CCR to a level of quality and condition suitable for future reuse in the concrete industry.
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6.2 Site Future Use
At this time, Duke Energy has not identified any future use of the land reclaimed by the dewatering
and excavation of the Basins.
Since this Closure Plan details a closure by excavation method, no recording of a notation on the
deed to the property is required.
7.0 CLOSURE DESIGN DOCUMENTS
Closure of the Basins at the Buck Station will be completed in two phases. Phase 1 is excavation
and Phase 2 will be the final decommissioning of the basin dikes and final grading.
7.1 Engineering Evaluations and Analyses
Engineering evaluations and analyses to support closure of the Basins at the Buck Station, as
detailed in this Closure Plan, are provided in Appendix C. Based on the final post -closure
configuration of the Basins and absence of engineered fill features, no geotechnical calculations
accompany the Closure Plan presented herein. Calculations related to dike removal will be
included in the dam modification permit applications.
Safe and effective access to the Basins is critical to CCR excavation and the completion of
closure. Access road locations into or across the Basins cannot be reliably established until
detailed phasing of closure is developed, and a contractor is selected to complete the work. A
variety of mitigation techniques can be applied, such as installation of a geogrid and crushed
stone aggregate, placement and spreading of dry CCR over the basin surface to establish access
and use of low ground pressure or light weight construction equipment.
Areas for stockpiling or conditioning (drying) of CCR are needed. These areas must be
established within the limits of the CCR unit and require placement or stacking of CCR excavated
from other areas of the Basins. They can be established in areas where all or most of the CCR
has been removed, or on areas where a significant depth of CCR remains in place. Sluiced CCR
forming the foundation of stockpiles or conditioning (drying) areas may be subject to bearing
capacity or slope failures from the additional vertical compressive stress imparted by the stacked
CCR and hauling equipment.
During excavation of CCR, interim or temporary excavated CCR slopes are commonly created.
These slopes vary in height and the duration they will have to stand. Some slopes are subject to
potential loading from hauling or stockpiling operations. The location and geometry of such slopes
cannot be established during design. These elements depend on the means and methods
employed by the construction contractor, site conditions, schedule, and other site conditions.
Excavation in a deep valley fill creates significant safety risks that need further evaluation and will
require the means and methods inputs from a contractor to fully address before closure
excavation work commences. A detailed phasing and excavation plan will be developed after this
Closure Plan is approved by NCDEQ.
7.2 Closure Plan Activities
The primary activities associated with closure by excavation are as follows:
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• Decant by using floating pumps, screened intakes, and pumping through the NPDES
discharge outlet.
• Install stormwater run-on diversion or retention controls, to minimize stormwater flow into
the Basins to the extent practical.
• Operation of a temporary water management system to manage all discharges in
compliance with the NPDES permit during closure.
• Construct a STAR° unit for processing CCR for beneficial re -use.
• Dewater the CCR to allow for safe access. CCR excavation and conditioning prior to
transport to the STAR' unit.
• Start CCR excavation from the Basins, with sequencing determined for optimal
progression. Instrumentation and monitoring requirements to be developed prior to
construction will be followed to verify construction phase stability. Construction dewatering
to be used as needed to provide safe and stable work areas and slopes.
• Maintain required hydraulic storage capacity throughout the excavation process.
• Manage dusting from closure activities through the use of appropriate controls.
• Complete closure by excavation verification. Grade the area to promote positive drainage
and seed for vegetative growth.
• Sequence final dam/dike breach with inflow design flood management.
Additional information and details pertaining to the closure design are provided in the Closure
Plan drawings, which can be found in Appendix D.
7.3 Design Drawings
Two sets of Closure Plan drawings can be found in Appendix D. One set is for the combined
Primary and Secondary basins, and the other set is for the Additional Primary Basin. Each set
includes the following sheets:
• Sheet 1 - Cover sheet
• Sheet 2 - General notes
• Sheet 3 - Existing overview aerial
• Sheet 4 - Existing conditions
• Sheet 5 - Estimated bottom of ash grades
• Sheet 6 — Proposed final conditions
• Sheet 7 - Cross -sections
These Closure Plan drawings will be further developed and refined to develop construction -level
drawings during subsequent stages following NCDEQ approval of the Closure Plan. In addition,
supplemental drawing sets will be prepared on an as -needed basis to support dike modification
and/or decommissioning permits, erosion, and sediment control permits, NPDES permit
modifications, and any other related permits.
Once the excavation grades shown on the Closure Plan drawings have been achieved, the
procedures described in the Duke Energy Excavation Soil Sampling Plan (Appendix E) will be
followed to confirm that closure by excavation has been achieved.
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7.4 Description of Construction Quality Assurance and Plan
A Construction Quality Assurance (CQA) Plan will be developed following NCDEQ approval of the
Closure Plan for closure of the CCR Basins located at the Buck Station site. This CQA Plan
description has been prepared to address N.C.G.S. § 130A-309.214(a)(4)(g) of CAMA, and its
purpose is to provide a description of the CQA program to be adhered to in execution of the final
closure activities at the Buck Station, being the construction of the dike breach and stormwater
channels. The CQA Plan will be a component of the dam decommissioning package and will
include a description of the roles and responsibilities for monitoring and testing activities and will
provide guidance on the methodology to be used for evaluating whether the construction has
been performed in accordance with the approved Closure Plan. The CQA Plan will also detail the
material testing frequencies; methods for transportation, handling, and storage of materials; test
methods and verifications; manufacturer, field, and laboratory testing; field activities for
construction monitoring and oversight; and reporting and documentation requirements. Technical
specifications to be developed as part of the construction -level design packages for contractor
bidding will present specific material properties and specifications.
The CQA Plan addresses the following materials and CQA activities and deliverables:
• Earthwork
• Stormwater Channels
• HDPE Piping
• As -Built Conditions
• Record Documentation Report
E:111>■►viI_1`F-ITO4►vi14LI111910]&Vi%F•'1194:7_1►I1111&11101N�NVI-AI=1V
• Existing Wastewater and Stormwater Conditions
The Basins at the Buck Station are located in historical valley features within larger watersheds
and, therefore, receive surface water run-on flows. The surrounding topography around the
Additional Primary Basin may permit some limited redirection of run-on stormwater during
excavation. However, due to the surrounding topography around the Primary/Secondary Basin, it
may not be feasible to divert, or re -direct run-on stormwater flows around the Primary/Secondary
Basins during construction. Temporary diversions and retention features can be provided in
certain areas and within the Basins during CCR excavation. Additional measures may be needed
to maintain treatment requirements.
In April 2019, NCDEQ promulgated new dam safety requirements and, per the dam safety High
Hazard Classification, each CCR basin is now required to pass a full PMP storm event. The Buck
Basins are classified as High Hazard by NCDEQ due to the potential for environmental impacts
greater than $200,000, if the Basins failed. The PMP event will produce 29.49 inches of rainfall
(HMR-51 6-hour, 10 mi2, All -Season PMP Isopluvial Map).
AECOM evaluated the site for the full PMP rainfall event and preliminary results indicated that the
Additional Primary Basin (ROWAN-069) as well as the Secondary Basin (ROWAN-047) would
safely pass the Full PMP storm event. The initial analysis indicated that the Primary Basin
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(contained by the upper portion of ROWAN-047, ROWAN-070, and ROWAN-071) would overtop
in the Full PMP storm event. AECOM subsequently developed a modification to the Primary to
Secondary Basin outfall structure. This modification, which involved lowering the stop logs in the
Primary Basin discharge structure to elevation 677 along with dredging of CCR in the vicinity of
the structure, was completed in August 2019 and the Primary Basin (contained by the upper
portion of ROWAN-047, ROWAN-070, and ROWAN-071) safely passes the Full PMP storm
event. Additional internal storage capacity will be obtained as excavation of the CCR progresses.
This analysis in in Appendix C.
The Secondary Basin has the capacity to contain the PMP storm event by maintaining the water
surface level elevation at or below El. 677.78 ft, which provides a minimum freeboard of 1.82 ft.
As part of the closure, the Basin dike will be removed by excavating an engineered breach in the
east portion. Under this post closure condition, there will be increased flow downstream of the
Basin dike compared to the existing conditions, however, this flow is not expected to have an
adverse impact on the receiving waters.
The Primary Basin has the capacity to contain the PMP storm event by maintaining the water
surface level elevation at or below El. 687.48 ft, which provides a minimum freeboard of 0.63 ft.
As part of the CCR excavation, the Divider Dike between the Primary and Secondary Basins will
be removed.
The Additional Primary Basin has the capacity to contain the PMP storm event by maintaining the
water surface level elevation at or below El. 708.81 ft, which provides a minimum freeboard of
0.59 ft. As part of the closure, the Basin dike will be removed by excavating an engineered breach
in the in the west portion. Under this post closure condition, there will be increased flow
downstream of the Basin dike compared to the existing conditions. This discharge will have to
cross Dukeville Road, located downstream of the dike, via a new culvert and will empty into a
wetland area that drains to the Yadkin River.
The Buck Station operates under a NPDES permit issued by the NCDEQ. Permit number
NC0004774, effective November 1, 2018 through October 31, 2023, authorizes a total of five
outfalls, four of which discharge into the Yadkin River. Outfall 007 is the associated outfall for the
Basin discharges.
• Wastewater and Stormwater Management During CCR Excavation
Wastewater from the Basins will be pumped, treated (if required) and discharged, meeting the
NPDES permit discharge requirements, in two phases; the Decanting phase and Dewatering
phase. In the Decanting phase, free water above the settled CCR layer will be removed from the
Basins without the mechanical disturbance of the CCR. The water management system (WMS)
during this phase consists of a temporary Level 1 physical -chemical treatment system designed
to meet the requirements of the discharge permit including continuous monitoring for pH and Total
Suspended Solids. The Buck WMS has a designed flow rate of 750 gpm. Following the Decanting
phase and as the Closure schedule dictates, the Buck site will advance into the Dewatering phase
to remove interstitial water from the Basins. During this phase, additional physical -chemical
treatment processes will be added to the WMS as necessary to maintain compliance with the
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requirements of the discharge permit. During the Dewatering phase, the Buck WMS will have a
designed flow rate of 250 to 500 gpm.
Dewatering is performed to remove the interstitial or pore water from the CCR to facilitate
excavation, to access in -place CCR or to establish safe slopes prior to and after CCR excavation.
It is anticipated that performance criteria will be established in the construction -level
documentation to identify required vertical and horizontal limits of interstitial water removal at
critical locations and for critical conditions during closure.
Excavated CCR will have to be conditioned (screened) prior to transport to the STAR' unit.
Consideration of required conditioning and management of contact water during excavation will
be included in the development of closure phasing.
• Post -Closure Stormwater Management
The post -closure grades restore much of the historical natural valley channels that will route flow
toward the dikes. Up to and including the last phase of closure before Basin dikes are breached,
the Basins will maintain the capacity to contain the full PMP storm event.
The concept plans for post -closure grading are based conservatively on 100-year storm events.
Appendix C presents the results of the post -closure stormwater management calculations.
8.1 Anticipated Changes in Wastewater and Stormwater Management
Following completion of CCR excavation operations in Additional Primary Basin, all stormwater
runoff will collect in the low point near the Additional Primary Basin Main dam (ROWAN-068) at
the north end of the basin. A pump and discharge line will be installed which will discharge at the
NPDES outfall location as clean stormwater. This pump and discharge line will remain in place
until dam decommissioning.
Closure of the Basins has necessitated changes in the management of a number of wastewater
and process streams. Wastewater and process streams previously discharging to the Basins have
been rerouted to new station outfalls.
A temporary WMS has been installed for the closure of the Basins. A floating intake suction pump
and screen has been placed at the location of the lowest elevation within the Basins. The system
design, including pump capacity and filter size, will be such that the existing NPDES Outfall 007
effluent discharge limits, or other limits as directed by the NCDEQ, will be met throughout the
duration of dewatering and closure.
Erosion and Sediment Control Plans for different phases of the excavation will be developed as
part of the excavation packages for field implementation and formal Erosion and Sediment Control
Plan permit submittal. The Basins are a NPDES permitted wastewater treatment unit. Therefore,
only activities that can impact the areas outside the Basins will need to be addressed as part of
the Erosion and Sediment Control Plan. However, water quality of discharges from the Basins
during excavation may be impacted due to activities within the Basins, and appropriate planning
and control measures will need to be implemented. This will be addressed during subsequent
stages of the design, and calculations to support the Erosion and Sediment Control Plans will be
developed during future stages of the design, which will follow NCDEQ approval of this Closure
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Plan. In addition, erosion and sediment control measures may be installed and removed in phases
as stabilization is achieved.
8.2 Wastewater and Stormwater Permitting Requirements
Information on required permits is described in Section 10.
9.0 DESCRIPTION OF FINAL DISPOSITION OF CCR
CCR materials in the Basins at the Buck Station will be excavated, processed, and beneficially
reused for Buck to achieve project goals in accordance with applicable state and federal
requirements and beneficial reuse contracts. CCR processing will be done using STAR'
Technology, a patented thermal beneficiation process to transform CCR into a high -quality,
sustainable product for the concrete industry.
An estimate of 6.68 million tons (5.56 million cubic yards) of CCR are currently stored in the
Basins at the Buck Station (refer to section 3.1.2 for a detailed discussion and to Appendix A for
quantities). At full production, the STAR' facility is designed to process 400,000 tons of CCR
material per year (based on information provided by Duke Energy). Assuming 10-years of
processing (2020-2029), this would allow approximately 4 million tons of CCR material to be
processed for beneficial re -use, leaving 2.68 million tons which would potentially require handling
by another process.
In order to meet the CCR removal deadline, Duke Energy will periodically review the progress of
the excavation and STAR° processing as it relates to achieving full CCR removal by the required
end date of December 31, 2029. Duke Energy will implement a concurrent excavation plan in
which excavated ash will be transported to a permitted facility in order to meet the end date of
December 31, 2029 for complete removal.
Vegetation encountered or removed during the progression of the work will be managed in
accordance with state regulations for handling and disposal.
10.0 APPLICABLE PERMITS FOR CLOSURE
Refer to Table 10-1 for detailed information on the potential and applicable permitting/approval
needed to implement this Closure Plan. Development of permitting package submittals and/or
regulatory approval requests will follow NCDEQ approval of the Closure Plan.
11.0 DESCRIPTION OF POST -CLOSURE MONITORING AND CARE
A Post -Closure Care Plan will be developed following NCDEQ approval of the Closure Plan for
closure of the CCR Basins located at the Buck Station site. The purpose of the Post -Closure Care
Plan will be to provide a description of the inspection, monitoring, and maintenance activities
required to be performed throughout the 30-year post -closure care period for the closed CCR
Basins at the Buck Station site. The Basins at the Buck Station site are detailed in this Closure
Plan as being closed by excavation.
The Post -Closure Care Plan will be developed to meet the requirements of N.C.G.S. § 130A-
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309.214(a)(4)(k). The items that will be included in the Post -Closure Care Plan for the Buck
Station include:
• Name, address, phone number, and email address of the responsible office or person;
• Means and methods of managing affected groundwater and stormwater;
• Maintenance of the groundwater monitoring systems;
• Groundwater and surface water monitoring and assessment program (included as part of
the CAP);
• Post -closure inspection checklist to guide post -closure inspections;
• Description of planned post -closure uses; and
• Financial assurance estimates for post -closure operations and maintenance and remedial
action.
11.1 Groundwater Monitoring Program
This information was developed by HDR in the CSA and CSA Supplement 1 Reports (2015,
2016), which are herein incorporated by this reference. This information is included as part of the
updated CSA being prepared separately by SynTerra for Duke Energy and will be submitted to
NCDEQ by October 1, 2020. The CSA is herein incorporated by this reference, but its content is
not the work product of Wood.
12.0 PROJECT MILESTONES AND COST ESTIMATES
12.1 Project Schedule
On June 30, 2017, Duke Energy selected the Buck Station as an ash beneficiation site as required
by N.C.G.S. § 130A-309.216. Excavation of CCR from the Buck site for beneficial use will occur
over multiple project phases. Activities started in April 2017 and will continue until all CCR is
removed in 2029, then continuing until approximately203O, when final site restoration is
completed.
A Closure project high-level milestone schedule has been prepared by Duke Energy and the major
activities and milestones are provided below:
Engineering, Dewatering Ongoing
Complete CCR Excavation Q4-2029
Site Restoration Q4-2030
12.2 Closure and Post -Closure Cost Estimate
Cost estimates for closure and post -closure care of the CCR Basins at Buck were developed by
Duke Energy and provided to Wood. These cost estimates are not a work product of Wood. These
are Class 5 estimates as the detailed and final design has not been developed at this stage of the
closure project. Following approval of this Closure Plan by NCDEQ and further development of
the project plans and engineering designs, the cost estimate will be refined and updated.
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wood.
The cost to complete the closure by excavation is estimated to be $532 million.
The cost to perform the 30-year post -closure activities and monitoring is estimated as $45 million.
The cost estimates include the following major activities:
• Mobilization and Site Preparation
• Dewatering, Earthwork, and Subgrade Preparation
• CCR Excavation
• Stormwater Management, Erosion and Sediment Control, and Site Restoration
• Engineering Support (Design and CQA)
• Post -Closure — Groundwater Monitoring
• Post -Closure — Operations and Maintenance
• Contingency
Corrective action costs are included as part of the updated CAP being prepared separately by
SynTerra for Duke Energy and will be submitted to NCDEQ by July 1, 2021. The CAP is herein
incorporated by this reference, but its content is not the work product of Wood.
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13.0 REFERENCES
North Carolina Department of Environmental Quality report, "Coal Combustion Residual
Impoundment Risk Classification" (2016)
North Carolina Department of Environmental Quality, 15A N.C.A.0 02K — North Carolina dam
safety rules
North Carolina Department of Environmental Quality, 15A N.C.A.C. 02L - North Carolina
groundwater rules
North Carolina General Assembly, Session Law 2014-122, Coal Ash Management Act, as
amended
United States Environmental Protection Agency, Coal Combustion Residuals (CCR) Rule 40
C.F.R. Part 257, subpart D
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Table 2-1: CAMA Closure Plan Requirements
Summary and Cross Reference Table
Duke Energy, Buck Station
No.
Description
Corresponding
Closure Plan Section
Part II. Provisions for Comprehensive Management of Coal Combustion
Residuals § 130A-309.212(a)(4) Closure Plans for all impoundments
shall include all of the following:
a. Facility and coal combustion residuals surface impoundment. — A
description of the operation of the site that shall include, at a
minimum, all of the following:
Site history and history of site operations, including details on
1
the manner in which coal combustion residuals have been
3.1.1
stored and disposed of historically.
2
Estimated volume of material contained in the impoundment.
3.1.2
3
Analysis of the structural integrity of dikes or dams associated
3.1.3
with impoundment.
4
All sources of discharge into the impoundment, including volume
3.1.4
and characteristics of each discharge.
5
Whether the impoundment is lined, and, if so, the composition
7.1
thereof.
A summary of all information available concerning the
6
impoundment as a result of inspections and monitoring
3.1.6
conducted pursuant to this Part and otherwise available.
b. Site maps, which, at a minimum, illustrate all of the following:
All structures associated with the operation of any coal
combustion residuals surface impoundment located on the site.
1
For purposes of this sub -subdivision, the term "site" means the
3.2.1
land or waters within the property boundary of the applicable
electric generating station.
All current and former coal combustion residuals disposal and
2
storage areas on the site, including details concerning coal
3.3
combustion residuals produced historically by the electric

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generating station and disposed of through transfer to structural
fills.
3
The property boundary for the applicable site, including
3.3
established compliance boundaries within the site.
4
All potential receptors within 2,640 feet from established
3 2 2
compliance boundaries.
Topographic contour intervals of the site shall be selected to
5
enable an accurate representation of site features and terrain
3.3
and in most cases should be less than 20-foot intervals.
Locations of all sanitary landfills permitted pursuant to this
Article on the site that are actively receiving waste or are closed,
6
as well as the established compliance boundaries and
3.2.3
components of associated groundwater and surface water
monitoring systems.
All existing and proposed groundwater monitoring wells
7
associated with any coal combustion residuals surface
3.3
impoundment on the site.
All existing and proposed surface water sample collection
8
locations associated with any coal combustion residuals surface
3.3
impoundment on the site.
c. The results of a hydrogeologic, geologic, and geotechnical
investigation of the site, including, at a minimum, all of the following:
1
A description of the hydrogeology and geology of the site.
4.1
A description of the stratigraphy of the geologic units underlying
2
each coal combustion residuals surface impoundment located
4.2
on the site.
The saturated hydraulic conductivity for (i) the coal combustion
residuals within any coal combustion residuals surface
3
impoundment located on the site and (ii) the saturated hydraulic
4.3
conductivity of any existing liner installed at an impoundment, if
any.
The geotechnical properties for (i) the coal combustion residuals
within any coal combustion residuals surface impoundment
located on the site, (ii) the geotechnical properties of any
4
existing liner installed at an impoundment, if any, and (iii) the
4.4
uppermost identified stratigraphic unit underlying the
impoundment, including the soil classification based upon the
Unified Soil Classification System, in -place moisture content,
particle size distribution, Atterberg limits, specific gravity,

Wood Environment & Infrastructure Solutions, Inc. Duke Energy Coal Combustion Residuals Management Program wood •
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effective friction angle, maximum dry density, optimum moisture
content, and permeability.
A chemical analysis of the coal combustion residuals surface
5
impoundment, including water, coal combustion residuals, and
4.5
coal combustion residuals -affected soil.
Identification of all substances with concentrations determined t
be in excess of the groundwater quality standards for the
6
substance established by Subchapter L of Chapter 2 of Title 15A
4.6
of the North Carolina Administrative Code, including all
laboratory results for these analyses.
7
Summary tables of historical records of groundwater sampling
4.6
results.
A map that illustrates the potentiometric contours and flow
directions for all identified aquifers underlying impoundments
8
(shallow, intermediate, and deep) and the horizontal extent of
4.7
areas where groundwater quality standards established by
Subchapter L of Chapter 2 of Title 15A of the North Carolina
Administrative Code for a substance are exceeded.
Cross -sections that illustrate the following: the vertical and
horizontal extent of the coal combustion residuals within an
impoundment; stratigraphy of the geologic units underlying an
9
impoundment; and the vertical extent of areas where
4.8
groundwater quality standards established by Subchapter L of
Chapter 2 of Title 15A of the North Carolina Administrative Code
for a substance are exceeded.
d. The results of groundwater modeling of the site that shall include, at
a minimum, all of the following:
An account of the design of the proposed Closure Plan
that is based on the site hydrogeologic conceptual model
developed and includes (i) predictions on post -closure
groundwater elevations and groundwater flow directions
and velocities, including the effects on and from the
potential receptors and
1
5.1
(ii) predictions at the compliance boundary for substances with
concentrations determined to be in excess of the groundwater
quality standards for the substance established by Subchapter L
of Chapter 2 of Title 15A of the North
Carolina Administrative Code.
2
Predictions that include the effects on the groundwater
5.2
chemistry and should describe migration, concentration,

Wood Environment & Infrastructure Solutions, Inc. Duke Energy Coal Combustion Residuals Management Program wood •
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mobilization, and fate for substances with concentrations
determined to be in excess of the groundwater quality standards
for the substance established by Subchapter L of Chapter 2 of
Title 15A of the North Carolina Administrative Code pre- and
post -closure, including the effects on and from potential
receptors.
A description of the groundwater trend analysis methods used t
demonstrate compliance with groundwater quality standards for
the substance established by Subchapter L of Chapter 2 of Title
3
15A of the North Carolina Administrative
5.3
Code and requirements for corrective action of groundwater
contamination established by Subchapter L of Chapter 2 of Title
15A of the North Carolina Administrative Code.
e. A description of any plans for beneficial use of the coal combustion
residuals in compliance with the requirements of Section .1700 of
Subchapter B of Chapter 13 of Title 15A of the North Carolina
Administrative Code (Requirements for Beneficial Use of Coal
6.1
Combustion By -Products) and Section .1205 of Subchapter T of
Chapter 2 of Title 15A of the North Carolina Administrative Code
(Coal Combustion Products Management).
f. All engineering drawings, schematics, and specifications for the
proposed Closure Plan. If required by Chapter 89C of the General
7.1, 7.2
Statutes, engineering design documents should be prepared, signed,
and sealed by a professional engineer.
g. A description of the construction quality assurance and quality control
program to be implemented in conjunction with the Closure Plan,
7.3
including the responsibilities and authorities for monitoring and
testing activities, sampling strategies, and reporting requirements.
h. A description of the provisions for disposal of wastewater and
management of stormwater and the plan for obtaining all required
8
permits.
i. A description of the provisions for the final disposition of the coal
combustion residuals. If the coal combustion residuals are to be
removed, the owner must identify (i) the location and permit number
for the coal combustion residuals landfills, industrial landfills, or
municipal solid waste landfills in which the coal combustion residuals
will be disposed and (ii) in the case where the coal combustion
9
residuals are planned for beneficial use, the location and manner in
which the residuals will be temporarily stored. If the coal combustion
residuals are to be left in the impoundment, the owner must (i) in the
case of closure pursuant to sub -subdivision (a)(1)a. of this section,
provide a description of how the ash will be stabilized prior to

Wood Environment & Infrastructure Solutions, Inc. Duke Energy Coal Combustion Residuals Management Program wood •
Buck Station Basin CAMA Closure Plan
completion of closure in accordance with closure and post -closure
requirements established by Section .1627 of Subchapter B of
Chapter 13 of Title 15A of the North Carolina Administrative Code
and (ii) in the case of closure pursuant to sub -subdivision (a)(1)b. of
this section, provide a description of how the ash will be stabilized
pre- and post -closure. If the coal combustion residuals are to be left
in the impoundment, the owner must provide an estimate of the
volume of coal combustion residuals remaining.
j. A list of all permits that will need to be acquired or modified to
10
complete closure activities.
k. A description of the plan for post -closure monitoring and care for an
impoundment for a minimum of 30 years. The length of the post -
closure care period may be (i) proposed to be decreased or the
frequency and parameter list modified if the owner demonstrates that
the reduced period or modifications are sufficient to protect public
health, safety, and welfare; the environment; and natural resources
and (ii) increased by the Department at the end of the post -closure
monitoring and care period if there are statistically significant
increasing groundwater quality trends or if contaminant
concentrations have not decreased to a level protective of public
11
health, safety, and welfare; the environment; and natural resources.
If the owner determines that the post -closure care monitoring and
care period is no longer needed and the Department agrees, the
owner shall provide a certification, signed and sealed by a
professional engineer, verifying that post -closure monitoring and care
has been completed in accordance with the post -closure plan. If
required by Chapter 89C of the General Statutes, the proposed plan
for post -closure monitoring and care should be signed and sealed by
a professional engineer. The plan shall include, at a minimum, all of
the following:
1
A demonstration of the long-term control of all leachate, affected
11.1
groundwater, and stormwater.
A description of a groundwater monitoring program that includes
(i) post -closure groundwater monitoring, including parameters to
be sampled and sampling schedules; (ii) any additional
2
monitoring well installations, including a map with the proposed
11.2
locations and well construction details; and (iii) the actions
proposed to mitigate statistically significant increasing
groundwater quality trends.
I. An estimate of the milestone dates for all activities related to closure
12.1
and post -closure.

Wood Environment & Infrastructure Solutions, Inc. Duke Energy Coal Combustion Residuals Management Program wood •
Buck Station Basin CAMA Closure Plan
m. Projected costs of assessment, corrective action, closure, and post -
closure care for each coal combustion residuals surface
12.2
impoundment.
n. A description of the anticipated future use of the site and the
necessity for the implementation of institutional controls following
closure, including property use restrictions, and requirements for
6.2
recordation of notices documenting the presence of contamination, if
applicable, or historical site use.
§ 130A-309.212(b)(3) No later than 60 days after receipt of a proposed Closure Plan, the
Department shall conduct a public meeting in the county or counties proposed Closure Plan and
alternatives to the public.
§ 130A-309.212(d) Within 30 days of its approval of a Coal Combustion Residuals Surface
Impoundment Closure Plan, the Department shall submit the Closure Plan to the Coal Ash
Management Commission.

Wood Environment & Infrastructure Solutions, Inc. Duke Energy Coal Combustion Residuals Management Program wood •
Buck Station Basin CAMA Closure Plan
Table 4-1: Summary of Typical Material Properties
Duke Energy, Buck Station
5011 Cover/Fill above or below the
Foundation Soll {saproitte/Resldual)
Sapmllte/Weathered Rock (WR}
Fill Soil within the Embankment
Foundation soil
5aprollte/weathered Rock
Properties
CCR within the Basins
Alluvial Soil below the CCR Basins
So prol ite/Residual} below the
(WR) below the
CCR Basins
below the Basins
below the Basins
Dikes
Embankmem Dikes
Embankment Dikes
Silty SA no (SM) - Pren rim i nant ly
6reak5 dowato Sandy Silt
Sri i Type
ML, MH, SM, CL, CH, and SC
bottom Ash, Si 10a ndy Silt (M I.) -
SP, SM, 5W, CL, CH, ML, ano MH
SM, SC, MH, PAL. and CL
Sidaks tldwn t0 Sandy silt antl
ML, MH, SM, CLr CH, and SC
SM, SC, MH, MI, and CL
and Silty sand with rock
silty sand with rock fragments
Predominarrtl FI Ash
fragments
Red, brown, tan, light brown, and
RI ack, gra y, dark gray, and greenish
Gray, white, black, orange, brown, and
Gray, urange, wh ite, brow n, to n, and
Gray, light green, brown, and
Red, brown, tan, light brown,
Gray, orange, white, brown, tan,
Gray, light gre-e n, brown, and
Color
dark gray
black
dark brown
blaci
orange
and dark gray
and black
orange
plasticity
NPto24-3V
Predom.narihy Yon Plastic
""
NPto 1S-33
NP-30
NP-33
LI uid Limit
NPto 313-6S
Predominantiy Non Plastic
NPto 26-68
NP-6S
NP-f3R
Plasticity Index
YP to 5 - 35
Predominantiy Non Plastic
'"
NP to 1 -25
NP -35
NP - 2S
Representative
Geometric Mean
Representative
Geometric Mean
Representative Range
Geometric Mean
Representative Range
Ran
Ran e
N at rat Moisture Ca rite nt I%}
18%- 34%
21%
11 :6- 15%
49%
11%-33%
"'
151/6- 54%
11% -34%
18%-34%
1S%-S4%
11% -36%
Fi nes Ca ate nt
421/.-85%
62%
9%-4R%
59%
2696-72%
6%-88%
42%-RS%
6%-RR%
Claycontent
12%-:;1:F
301k
1%-21%
S%
;1%-31%
1%-56%
12%-S11%
1%-SG'k
Slow Count- uncorrected N Value( bpfi
3-39
12
WOR-19
3-26
12
2.7.3
3-24
3-62
S(J/0"-6U�S"
Moist Unit Weight
Dry unit weight
4S - IG ptf
64 ptf
75 - 120 pcf
15 - 22U pcf
S peciRc Grav
2.6-2.8
2-1
2-1-2-3
2-2
2-8
2.6.3.0
••
2.G-2.8
2-G-3.0
•'
H ari ro ma l Hyd raul ie Cond uctiw by{r-m/sec]
••
•.
r.
•-
•'I
I-•
Ve rt ica l H yd rau l is Co ndu ctivit cm/setl
1.3E-0I-a.6 E-OS
9.b UE 4G
1.8E-0::-1.GE-03
I 3.30E-04
1.10E-V4
9.9E-0I-1.9E-04
4.2E-Ob-4.8E-VS
1.3E-01-5.6E-VS
'3.'iE-01-2.9E-U4
4.1E-VG-4.8E-0-:
Notes:
Out IierVaIues are not included in the table above. Please Wer10lab data summary sheets presented with laboratory data for all available values.
NP: NO Pla6tic
pcf: Pvu rids per cubic foot (I b1ft')
WOR: Weight of Rad
WOH: Weight of Hammer
bpf: Blows pr.rlout
On Iv one lab test available
•' Na lab d Ma avail.) ble

Wood Environment & Infrastructure Solutions, Inc.
Duke Energy Coal Combustion Residuals Management Program
Buck Station Basin CAMA Closure Plan
wood.
Table 10-1: Regulatory Permits, Approvals, or Requirements for Ash Basin
Closure by Excavation
General Permit
Name or Subject
Air Quality
Building Permit
CAMA Monitoring
Plan
CCR Impoundment
Closure
CCR Impoundment
Monitoring Network
Clean Water Act 401
Clean Water Act 404
Cutting Trees
Regulating
Agency
NCDEQ
Rowan
County
NCDEQ
US EPA
CCR Rule
US EPA
CCR Rule
US ACoE
US ACoE
USFWS
Duke Energy, Buck Station
Permit/Approval
Type of
Regulatory
Existing Approval
Permit No. Mechanism or
(if applicable) Not Required
Permit
modification
likely
New Permit
Written NCDEQ
DWR approval
Self -Regulating
Self -Regulating
New Permit
New Permit
Comments
Permit modification likely
due to the increased heavy
equipment vehicle traffic
and potential dust generated
during closure activities
A local building permit is
required for installation of
construction trailers
Modification or
abandonment of CAMA
program monitoring wells
require the approval of the
Division of Water Resources
(DWR)
Required postings to Public
Record
Maintain CCR GW
monitoring network and
requirements as stated in
257.90 - 257.98
Breaching of
Primary/Secondary Main
Dam (ROWAN-047) will likely
impact the Yadkin River and
will require a new permit.
Breaching of
Primary/Secondary Main
Dam (ROWAN-047) will likely
impact the Yadkin River and
will require a new permit.
Certificate of Ash Basin Dam - Permitting
Dam Safety NCDEQ Approval to is required to modify the
Modify dam in accordance with the
Dam Safety Law of 1967, 15A

Wood Environment & Infrastructure Solutions, Inc.
Duke Energy Coal Combustion Residuals Management Program
Buck Station Basin CAMA Closure Plan
Dam Safety
Dam Safety
Dam Safety
NCDEQ
NCDEQ
NCDEQ
ROWAN-047
ROWAN-068
ROWAN-069
Dam Safety I NCDEQ I ROWAN-070
Certificate of
Approval to
Modify
Certificate of
Approval to
Modify
Certificate of
Approval to
Modify
Certificate of
Approval to
Modify
wood.
NCAS 02K.0201 (b)(2); an
application must be filed
with the Division of Energy,
Mineral, and Land Resources
(DEMLR)
Main Dam - Permitting is
required to modify the dam
in accordance with the Dam
Safety Law of 1967, 15A
NCAS 02K.0201 (b)(2); an
application must be filed
with the Division of Energy,
Mineral, and Land Resources
(DEMLR)
Additional Primary Dam -
Permitting is required to
modify the dam in
accordance with the Dam
Safety Law of 1967, 15A
NCAS 02K.0201 (b)(2); an
application must be filed
with the Division of Energy,
Mineral, and Land Resources
(DEMLR)
Basin 1 to Basin 2 Dam -
Permitting is required to
modify the dam in
accordance with the Dam
Safety Law of 1967, 15A
NCAS 02K.0201 (b)(2); an
application must be filed
with the Division of Energy,
Mineral, and Land Resources
(DEMLR)
Basin 2 to Basin 3 Dam -
Permitting is required to
modify the dam in
accordance with the Dam
Safety Law of 1967, 15A
NCAS 02K.0201 (b)(2); an
application must be filed
with the Division of Energy,
Mineral, and Land Resources
(DEMLR)

Wood Environment & Infrastructure Solutions, Inc.
Duke Energy Coal Combustion Residuals Management Program
Buck Station Basin CAMA Closure Plan
Dam Safety
DOT - General
Driveway Permit
Erosion and
Sediment Control
(E&SC)
Fire Ants
NCDEQ
NCDOT
NCDOT
NCDEQ
ROWAN-071
Certificate of
Approval to
Modify
Not Anticipated
Permit not
required
Restriction not
likely
Floodplain Rowan
New Permit
Development County
wood.
Divider Dike - Permitting is
required to modify the dam
in accordance with the Dam
Safety Law of 1967, 15A
NCAS 02K.0201 (b)(2); an
application must be filed
with the Division of Energy,
Mineral, and Land Resources
(DEMLR)
Utilization of or modification
to state or federal highways
to transport CCR will require
consultation or notification
to relevant DOT agency
Land disturbance activities
outside of the ash basin will
not exceed one acre,
therefore in conformance
with 15A NCAC 04, an E&SC
Permit is not required from
Land Quality prior to
commencement of
construction in those areas.
Note that land disturbance
includes tree clearing and
grubbing and vehicular
wheel or tracking as
disturbance.
Removal from or import of
material could be restricted
dependent on the potential
for fire ants and geographic
regions involved
Flood Damage Prevention
Ordinance of Rowan County
(05-04-2009), Article 3
General Provisions, Section
C, requires a Floodplain
Development Permit prior to
any development activities
within FEMA mapped Special
Flood Hazard Areas for the
Flood Insurance Rate Maps

Wood Environment & Infrastructure Solutions, Inc.
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Buck Station Basin CAMA Closure Plan
Large Capacity
Water Supply Well
Multi -State
Agreement
NPDES (National
Pollution Discharge
Elimination System)
NPDES (National
Pollution Discharge
Elimination System)
Industrial
Stormwater
NPDES (National
Pollution Discharge
Elimination System)
Stormwater
Noxious Weeds
Railroad Easement,
Access, or Crossing
Permit
SPCC (Spill
Prevention Control
and
Countermeasure)
Plan
NCDEQ
NCDEQ
NCDEQ
NCDEQ
NCDEQ
NC0004774
New Permit
possible
Not required
Permit
modification
likely
Permit revision
likely
New Permit
possible
Not Anticipated
Modification of
existing plan
wood.
Permits are required to
construct any water supply
well or water well system
with a design capacity equal
to or greater than 100,00
gallons per day - for
dewatering outside of the
ash basin
If movement of CCR will
cross state lines, multi -state
regulations might apply
Modification of NPDES may
be necessary if new source
or outfall is created.
Revision to existing sitewide
permit or new permit may
be required for access roads,
staging areas, etc.
Permit required for
temporary and permanent
stormwater rerouting.
Removal from or import of
vegetated material could be
restricted dependent on the
vegetation and geographic
regions involved
Construction activities
adjacent to tracks/ballast or
a new railroad crossing
require an agreement or
permit
In accordance with the
federal Water Pollution
Control Act (Clean Water
Act) of 1974, Title 40, Code
of Federal Regulations, Part
112.

Wood Environment & Infrastructure Solutions, Inc.
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wood.
Threatened or
Existing Eagle Take Permit
Endangered
allows one take.
Species: Candidate
Federal and/or state
Conservation
regulations may apply
including agency
Agreement
consultation and performing
Avian Protection
Existing Eagle
site -specific surveys within
Plan(s)
NCDEQ/EPA
Take Permit is in
the proper survey period
Bird and Bat
place.
(e.g., flowering period for
Conservation
listed plant) to determine if
Strategies
Threatened or Endangered
Eagle Conservation
Species or their habitat exist
Plan
within the limits of
Eagle Take Permit
disturbance
Solid Waste Site
NCDEQ
Not Anticipated
No new CCR Landfill planned
Suitability
Solid Waste Permit
NCDEQ
Not Anticipated
No new CCR Landfill planned
to Construct
Solid Waste Permit
NCDEQ
Not Anticipated
No new CCR Landfill planned
to Operate
Solid Waste Zoning -
Rowan
Not Anticipated
No new CCR Landfill planned
County Approval
County

Wood Environment & Infrastructure Solutions, Inc. Duke Energy Coal Combustion Residuals Management Program wood •
Buck Station Basin CAMA Closure Plan
FIGURES

F�
all&
OLD SMITHFIELD ROAD
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MAP SOURCE: ESRI WORLD TOPOGRAPHIC BASEMAP
TITLE COAL COMBUSTION RESIDUALS SURFACE
wood.
IMPOUNDMENT CLOSURE PLAN
HF LEE ENERGY COMPLEX
Environment & Infrastructure Solutions
4021 STIRRUP CREEK DRIVE, SUITE 100
DURHAMNC20
VICINITY MAP AND SITE PLAN
TEL: [phone]
FAX: [phone]LICEN
FOR
NCENGSF-11253
ISSUED FOR REVIEW - NOT FOR CONSTRUCTION
NC GEOLOGY: C-247
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SCALE: AS SHOWN
DES: WMN
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REVIEWDATE:
12/10/2019
ENGR: WAW
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FILENAME: HFL_ EXISTING OVERALL AERIAL.dwg
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LEGEND TITLE COAL COMBUSTION RESIDUALS SURFACE
-100 - EXISTING MAJOR CONTOURS ¢ EXISTING ELECTRIC UTILITY POLE GEOSYNTEC BORINGS wood
IMPOUNDMENT CLOSURE PLAN
EXISTING MINOR CONTOURS ® EXISTING ELECTRIC UTILITY TOWER GEOSYNTEC CPTS & SCPTS REFERENCES: HF LEE ENERGY COMPLEX
F EXISTING GRAVEL ROAD MW e EXISTING MONITORING WELL GEOSYNTEC PIEZOMETERS 1. EXISTING TOPOGRAPHY AND SURVEY PROVIDED BY WSP DATED JULY 2015. Environment & Infrastructure Solutions
2. EDGE OF WATER PROVIDED IN SURVEY BY WSP FOR DUKE ENERGY PROGRESS, LLC. 4021 STIRRUP CREEK DRIVE, SUITE 100
EXISTING ROAD WV 9 EXISTING WATER UTILITY ® SYNTERRA MONITORING WELLS TITLED "AERIAL TOPOGRAPHIC SURVEY HF LEE ENERGY COMPLEX," REVISION 1, DATED 24 DURHAM INC 27703
OVERALL EXISTING CONDITIONS PLAN
TEL:[phone]
EXISTING TREE LINE JULY 2015, FILE NAME: "HF LEE FINAL - REV 07-27-2015.DWG". FAX: [phone]
❑T EXISTING UTILITY TELEPHONE ® S&ME MONITORING WELLS 3. LOCATION OF ANY AND ALL UTILITIES SHOWN IS BASED ON PHOTOGRAMMETRIC MAPPING LICENSURE: FOR
—X—X—X—X— EXISTING SITE FENCE — FLOOD HAZARD LINE CATLIN MONITORING WELLS AND IS APPROXIMATE. CONTRACTOR SHALL VERIFY LOCATION OF UTILITIES PRIOR TO NCNC ENG: GEOLOGY: C 247 ISSUED FOR REVIEW - NOT FOR CONSTRUCTION
COMMENCEMENT OF CONSTRUCTION.
«+E EXISTING OVERHEAD ELECTRIC LINES APPROXIMATE PROPERTY LINE EXISTING PIEZOMETERS 4. EXISTING STREAMS AND WETLANDS PROVIDED BY MCKIM & CREED DATED OCTOBER 9, SEAL SCALE: AS SHOWN DES: WMN
2017. DUKE
EXISTING WATER � � � � � APPROXIMATE LIMIT OF WASTE DWG TYPE: DWG DFTR : WMN
EXISTING WETLANDS EXISTING STREAMS ISSUED FOR ENEK%ft7YJOB NO: 7812180091 CHKD: BBC
EXISTING RIP RAP WELL LOCATIONS AS PROVIDED BY SYNTERRA TO DUKE ENERGY/WOOD REVIEW® DATE: 12/10/2019 ENGR: WAW
❑ 0 EXISTING STRUCTURES (VARIOUS) EXISTING MONITORING WELL NOT FOR FILENAME: HFL_EXISTING OVERALL TOPOGRAPHY.dwg APPD: CRK
EXISTING UTILITY LIGHT AMEC BORINGS DWG SIZE DRAWING NO. REVISION
EXISTING FIRE HYDRANT MACTECBORINGS CONSTRUCTION
o � ANSI FIGURE 1-2
s EXISTING SEWER MANHOLE LAW BORINGS 22"x34"
REV DATE JOB NO. PROJECT TYPE DES DFTR CHKD ENGR APPD DESCRIPTION
INCHES 1 2 3 TENTHS 10 20 30 4 I 5 1 7 8 9 10
I I I I I I
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Plotted By: Nichols, William Sheet Set: HF Lee Layout: EXISTING OVERALL TOPOGRAPHY December 10, 2019 10: 20: 05am Q:\duke energy\HF Lee\_7812180091_hf lee cama closure plan\Concept\HFL_EXISTING OVERALL TOPOGRAPHY.dwg