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Home My WebLink AboutWeatherspoon CBE - Closure Plan_20191230George T. Hamrick Senior Vice President Coat combustion Products (' 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: Weatherspoon Power Plant Ash Basin Closure Plan Dear Ms. Holman: 400 South Tryon Street, ST06A Charlotte, NC 28202 Phone. 980-373-M 13 Email: george. hamnck 0 duke -energy. com 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, YC"Wl'z George T. Hamrick Senior Vice President NCDEQ cc: damsafetyCncdenr.gov, de4.coalash@ncdenr.gov, 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 WEATHERSPOON STATION COAL COMBUSTION RESIDUALS SURFACE IMPOUNDMENT CLOSURE PLAN CLOSURE BY EXCAVATION 1979 Ash Basin Closure Plan Report Final Submittal Prepared for (' DUKE ENERGY., 550 South Tryon Street Charlotte, North Carolina 28202 Revision 0 Issue Date: 11 December 2019 Prepared by Wood Environment & Infrastructure Solutions, Inc. 4021 Stirrup Creek Drive, Suite 100 Durham, North Carolina 27703 Project No. 7812180072 wood. Wood Environmental & Infrastructure Solutions, Inc. WO�d Duke Energy Coal Combustion Residuals Management Program Weatherspoon Station Basin CAMA Closure Plan TABLE OF CONTENTS EXECUTIVESUMMARY............................................................................................................. 1.0 INTRODUCTION............................................................................................................... 1 1.1 Background................................................................................................................................1 1.2 Closure Plan Objectives............................................................................................................ 1 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................................................3 3.1.4 Sources of Discharges into Surface Impoundments.......................................................4 3.1.5 Existing Liner System......................................................................................................4 3.1.6 Inspection and Monitoring Summary...............................................................................4 3.2 Site Maps................................................................................................................................... 6 3.2.1 Summary of 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............................................................................................................ 6 4.1 Background................................................................................................................................6 4.2 Hydrogeology and Geologic Descriptions................................................................................. 6 4.3 Stratigraphy of the Geologic Units Underlying Surface Impoundment ...................................... 7 4.4 Geotechnical Properties............................................................................................................ 7 4.4.1 CCR Within the Basin......................................................................................................7 4.4.2 Liner Material Properties..................................................................................................7 4.4.3 Subsurface Soil Properties.............................................................................................. 7 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.............................................................................. 8 4.8 Estimated Vertical and Horizontal Extent of CCR within the Impoundments ............................ 8 5.0 GROUNDWATER MODELING ANALYSIS...................................................................... 8 5.1 Site Conceptual Model Predictions........................................................................................... 8 5.2 Groundwater Chemistry Effects................................................................................................. 8 5.3 Groundwater Trend Analysis..................................................................................................... 8 6.0 BENEFICIAL USE AND FUTURE USE............................................................................ 9 6.1 CCR Beneficial Use................................................................................................................... 9 6.2 Site Future Use.......................................................................................................................... 9 Rev. 0 11 December 2019 Wood Environmental & Infrastructure Solutions, Inc. WO�d Duke Energy Coal Combustion Residuals Management Program Weatherspoon Station Basin CAMA Closure Plan 7.0 CLOSURE DESIGN DOCUMENTS.................................................................................. 9 7.1 Engineering Evaluations and Analyses..................................................................................... 9 7.2 Closure Plan Activities............................................................................................................. 10 7.3 Design Drawings..................................................................................................................... 10 7.4 Description of Construction Quality Assurance and Plan ........................................................ 11 8.0 MANAGEMENT OF WASTEWATER AND STORMWATER...........................................11 8.1 Anticipated Changes in Wastewater and Stormwater Management ....................................... 12 8.2 Wastewater and Stormwater Permitting Requirements.......................................................... 13 9.0 DESCRIPTION OF FINAL DISPOSITION OF CCR.........................................................13 10.0 APPLICABLE PERMITS FOR CLOSURE.......................................................................13 11.0 DESCRIPTION OF POST -CLOSURE MONITORING AND CARE..................................13 11.1 Groundwater Monitoring Program........................................................................................... 14 12.0 PROJECT MILESTONES AND COST ESTIMATES........................................................14 12.1 Project Schedule..................................................................................................................... 14 12.2 Closure and Post -Closure Cost Estimate................................................................................ 14 13.0 REFERENCES.................................................................................................................16 Tables Table 2-1 CAMA Closure Plan Requirements Summary and Cross Reference Table Table 4-1 Summary of Typical Material Properties Table 10-1 Weatherspoon 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 Rev. 0 11 December 2019 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon 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 residual (CCR) surface impoundment (Basin) at the Weatherspoon Station. The Weatherspoon Station Basin closure will consist of closure by excavation, whereby CCR in the 1979 Ash Basin (Basin) will be excavated, processed, and transported off -site for beneficial re -use as a concrete amendment. Ongoing CCR removal, in accordance with an excavation plan (Geosyntec, 2017), began in August 2017. CCR is being transported to two concrete plants in South Carolina. The removal of CCR and closure of the Basin 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). Pursuant to CAMA, the Basin is required to be excavated by April 4, 2028. The Weatherspoon Station is owned and operated by Duke Energy Progress, LLC (Duke Energy) in Robeson County at 491 Power Plant Road, Lumberton, North Carolina. The station formerly operated three coal-fired units and four combustion turbine units. The coal- fired units operated from 1949 until electricity generation from the coal-fired units ceased in 2012. The combustion turbine units continue to operate. There are no coal-fired units currently in operation at the Weatherspoon Station and CCR disposal operations ceased in 2012. This Closure Plan covers the Basin located at the Weatherspoon Station. The Basin dike structure is identified in the North Carolina Department of Environmental Quality (NCDEQ) Dam Safety Inventory as the 1979 Ash Basin Dam (NC Dam Safety ID: ROBES-009). The Basin at the Weatherspoon Station was constructed as a raised dike basin, with excavated soils within the Basin used to construct the dikes. The Basin was used to store CCR that was sluiced to and deposited into the holding and settling basin (Pond 4). Materials pumped to the Basin primarily consisted of fly ash, bottom ash, coal slag, unburned coal, and stormwater from the plant. The Basin is a single perimeter unit, with internal units constructed for Basin management and water treatment. The Basin is unlined and contains up to 40 feet depth of CCR. Information provided by Duke Energy (with updated production data through July 31, 2019) indicates that the current estimated volume of CCR in the Basin is approximately 1,676,000 tons (1,396,667 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 and the site is actively beneficiating the CCR within the Basin. CCR is currently being excavated within the Basin for beneficial use (excavation begin in August 2017). Internal berms and riser structures have been removed from the internal pond areas. The primary outlet (from Pond 4) through the Main Dike remains functional. Water is collected in the south area and pumped to Pond 4 where it is treated. Upon approval of the Closure Plan by NCDEQ, additional activities to complete closure of the Basin will commence, including: completing excavation of CCR from the Basin, and establishing final grades using soil fill where required to properly drain the Basin area, breaching/removing the Basin dikes following removal Rev. 0 11 December 2019 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan 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 Post -Closure Care Plan, which provides a description of the inspection, monitoring and maintenance activities required to be performed for the Weatherspoon 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 selected 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 surface water 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 Weatherspoon by June 1, 2020, and the updated CAP by March 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. Rev. 0 11 December 2019 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan 1.0 INTRODUCTION 1.1 Background The Weatherspoon Station is located in Robeson County at 491 Power Plant Road, Lumberton, North Carolina. The facility was constructed starting in 1949. In February 2012, the three coal- fired units were retired. The coal-fired generating units have been demolished and removed from the site. There are no longer any CCR disposal operations within the Basin areas with the permanent retirement of the coal generating units. The Weatherspoon Station ceased all waste flows to the Basin in 2012. Removal of the CCR by excavation for beneficiation began in August 2017. This Closure Plan is being submitted for approval by NCDEQ and reflects closure by excavation of the CCR from the Weatherspoon site. Figure 1-1 presents a Vicinity Map and Site Plan of the Weatherspoon site The Weatherspoon Station has one regulated impoundment structure (Figures 1-1 and 1-2). This Closure Plan covers the 1979 Ash Basin (NC Dam Safety ID ROBES-009) which is regulated by NCDEQ. CCR is currently being excavated within the Basin for beneficial use (since August 2017). Internal berms and riser structures have been removed from internal pond areas. The primary outlet (from Pond 4) through the Main Dike remains functional. Water is collected during excavation in the south area and pumped to Pond 4 where it is monitored and treated prior to pumping into the permitted outfall. 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 the CCR from the Basin at the Weatherspoon Station 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 necessary working documents 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 Basin 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 volume via permitted outfall • Construction and operation of a temporary water management system (WMS) to manage discharges in compliance with the NPDES permit during closure • Dewatering to support safe excavation of CCR from the Basin • Excavation of the CCR and establishing post -excavation final grades using soils where required • Breaching of the Basin dikes Rev. 0 11 December 2019 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan • Grading dikes into the Basin with a grading plan that will establish drainage to promote flow of stormwater out of the former Basin 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 Weatherspoon Station, "coal combustion residuals surface impoundment," as defined in N.C.G.S. § 130A- 309.201(6), is interpreted to include the 1979 Ash Basin. In July 2016, the North Carolina General Assembly enacted House Bill 630, Session Law 2016- 95, amending CAMA. Pursuant to § 3.(a)(3) of this legislation, the CCR surface impoundment located at the Weatherspoon Station is deemed intermediate -risk and must be closed by removal of CCR. Duke Energy was further directed by the Amended Order Granting Motion for Partial Summary Judgment in State of North Carolina ex rel. N.C. Department of Environment and Natural Resources, Division of Environmental Quality v. Duke Energy Progress, Inc., Wake County, Case No. 13-CVS11032, to begin excavation of the CCR Basin within 10 years of April 4, 2016, and complete excavation within 12 years thereof. The Excavation Soil Sampling Plan for the Weatherspoon Station (presented in Appendix E), represents activities to satisfy the requirements set forth in 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 the Weatherspoon Station by June 1, 2020, and the updated CAP by March 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 regulation. Although this Closure Plan contains references to the CAP, all specific relevant details to groundwater and related actions are found in the CAP itself and not in this Closure Plan. 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 CCR Basin by dates certain) compliance, dam safety approvals for modifications to regulated CCR Basin dikes, and environmental permitting requirements must be considered during closure. Rev. 0 11 December 2019 2 Wood Environmental & Infrastructure Solutions, Inc. Duke Energy Coal Combustion Residuals Management Program Weatherspoon Station Basin CAMA Closure Plan 3.0 FACILITY DESCRIPTION AND EXISTING SITE FEATURES 3.1 Surface Impoundment Description wood This section provides details on the CCR-related features at the Weatherspoon Station. 3.1.1 Site History and Operations Figure 1-1 shows locations of the station and 1979 Ash Basin (ROBES-009). The Weatherspoon Station is located adjacent to the Lumber River in Robeson County, Lumberton, North Carolina. Review of available information indicates that the property, totaling approximately 903 acres, is owned by Duke Energy, and is reported to have begun commercial operation in 1949. Coal-fired operations at the Weatherspoon Station were retired in 2012, with all CCR-disposal operations ceasing in 2012. The interconnected system of internal channels and internal dikes discharges to the drainage canal flowing into the Weatherspoon Cooling Lake, then to the NPDES permitted outfall point into the Lumber River (Outfall 001). 3.1.2 Estimated Volume of CCR in Impoundments In August 2017, an ash beneficiation project began within the Basin. Based on CCR inventory data provided by Duke Energy as of July 31, 2019, the approximate volume of CCR in the Basin remaining 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 in the Impoundment data sheet. Impoundment Estimated CCR Volume (cy) Estimated CCR Weight (tons)* 1979 Ash Basin 1,396,666 1,676,000 * 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 Basin's structural integrity evaluations based on current existing information. This section includes the Geotechnical and Hydrology and Hydraulics 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 Basin, based on the CCR certification letters and subsequent dam inspection reports, meet the regulatory requirements of EPA's CCR Rule (40 C.F.R. § 257.73) with the exception of liquefaction as discussed below. Duke Energy's certifications of these requirements are available on Duke Energy's publicly accessible CCR Rule Compliance Data and Information website. Rev. 0 11 December 2019 3 Wood Environmental & Infrastructure Solutions, Inc. WO�d Duke Energy Coal Combustion Residuals Management Program Weatherspoon Station Basin CAMA Closure Plan • Slope stability Slope stability analysis results for the existing conditions global factors of safety for static long- term maximum storage pool, static maximum surcharge pool, and sudden drawdown conditions meet regulatory and programmatic criteria. • Liquefaction Conditions (where susceptible) and Liquefaction Potential In 2015, Amec Foster Wheeler (now Wood) performed a liquefaction screening analysis for the Basin dike embankment. Ground motion of the design seismic event is calculated to trigger liquefaction within granular soils for a majority of the borings analyzed (i.e., factors of safety below 1.1) using the methodology from Boulanger and Idriss (2014). Clays present beneath the dike may be subject to cyclic softening. The liquefaction -susceptible materials are in the foundation soils below the pond and the sluiced ash. The internal and external embankment dikes were not determined to have any zones of potentially liquefiable soils. The liquefaction -susceptible soils are widespread under the site, and post -earthquake failures of the impoundments could be anticipated. In such case, displacements of the dike crests could be significant, and release of impounded CCR could potentially occur. • Hydrology and Hydraulics (H&H) Capacity Analyses In April 2019, the NCDEQ promulgated new dam safety rules and, perthe dam safety High Hazard Classification, each CCR Basin is required to pass a full Probable Maximum Precipitation (PIMP). Each basin is classified as high hazard by NCDEQ due to the potential for environmental impacts greater than $200,000, if the Basin failed. In response, Hydrologic analysis was performed by Wood in March 2019 for the design storm of the full PMP which indicated that the Basin is capable of conveying the Inflow Design Flood event while maintaining adequate freeboard. Based upon the existing conditions, the Main Basin contains the entire PIMP storm event with overflow into the Pond 4 (Figure 1-2) during the design storm event. The existing conditions allow the release of over 80 percent of the inflow to Pond 4 within 15 days after the design storm begins, as required by the North Carolina dam safety rules. The results of the analyses are presented in Appendix C. 3.1.4 Sources of Discharges into Surface Impoundments The Weatherspoon coal-fired units are now permanently retired from service, CCR is no longer sluiced into the Basin, and the Basin is inactive. A perimeter dike surrounds the Basin, preventing inflow of stormwater from off -site sources. The only inflow to the Basin is from direct rainfall. 3.1.5 Existing Liner System The Basin located at the Weatherspoon Station site does not include a geomembrane or clay liner system and is considered to be unlined. The Basin was constructed directly on top of the historical ground surface. 3.1.6 Inspection and Monitoring Summary Duke Energy conducts routine weekly, monthly, and annual inspections of the Basin, consistent Rev. 0 11 December 2019 4 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan with North Carolina's dam safety requirements and the federal CCR rule. Weekly Basin inspections include observation of upstream slopes and shorelines, crests, downstream slopes, toes, abutment contacts and adjacent drainage way(s), spillway(s) and associated structure(s), and other structures and features of the dikes. Monthly inspections of the Basin include the weekly monitoring elements with the addition of piezometer and observation well readings; water level gauges/sensors; and visual observations and documentation of embankment slopes. Daily inspections of the Basin are not routinely required; however, on a case -by -case basis, the Basin 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 in response to a specific imposed regulatory agency requirement. The Basin is 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. The results for the annual inspections are used to identify needed repairs, repair schedules, to assess the safety and operational adequacy of the dike, 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 the Basin dike 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 Weatherspoon Basin 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 dike. 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 dike. The need for special inspections is also determined when the ongoing surveillance program identifies a condition or a trend that warrants special evaluation. Rev. 0 11 December 2019 5 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan 3.2 Site Maps 3.2.1 Summary of Existing CCR Impoundment Related Structures A site map showing property boundary, location of the Weatherspoon Station, and the Basin with their boundaries and topographic contours are shown on Figure 1-1 and 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 March 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 Weatherspoon 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 March 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 in Appendix D, but the CAP should be consulted for details of well locations, names, and status. 4.0 RESULTS OF HYDROGEOLOGIC, GEOLOGIC, AND GEOTECHNICAL �Iki1VA:&I1[H_,1111Eel ki K 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 (as provided by Duke Energy) is shown on Figure 4 included in Appendix D. 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 June 1, 2020. The CSA is herein incorporated by this reference, but its content is not the work product of Wood. Rev. 0 11 December 2019 6 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan 4.3 Stratigraphy of the Geologic Units Underlying Surface Impoundment 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 June 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 Basin and Basin dike 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 consists of CCR (primarily interbedded layers of fly ash and bottom ash, along with coal slag, unburned coal, and plant stormwater) placed in the Basin primarily by hydraulic sluicing underlain by residual soil, saprolite, partially weathered rock (PWR), and/or 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 Basin are described below. A range of measured material properties from laboratory tests performed by Wood, SynTerra, and S&ME for the subsurface explorations completed within the Basin is presented in Appendix B (boring locations are shown in Figure 4 of Appendix D). 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 Weatherspoon Station in support of the closure design is presented in Appendix B. 4.4.1 CCR Within the Basin The CCR within the Basin consists primarily of layers and mixtures of bottom ash and fly ash. Other CCR such as slag are also typically encountered. The bottom ash generally 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 Basin at the Weatherspoon Station is unlined, so there are no associated material properties. 4.4.3 Subsurface Soil Properties The vicinity of the Weatherspoon Station is characterized by shallow water table conditions occurring in surficial soils and unconsolidated sediments underlain by the Coastal Plain regional aquifer system. Rev. 0 11 December 2019 7 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan In the area of the plant, the surficial unconfined aquifer is the first major hydrogeologic unit. The surficial aquifer consists of Coastal Plain and Yorktown/Duplin sediments, and extends approximately 60 feet below ground surface to the Pee Dee confining unit. The Pee Dee confining unit has an average thickness of 25 feet across the region and is underlain by the Pee Dee Aquifer. 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 June 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 June 1, 2020. The CSA is herein incorporated by this reference, but its content is not the work product of Wood. 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 June 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 June 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 March 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 March 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 March 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 This information is included as part of the updated CAP being prepared separately by SynTerra Rev. 0 11 December 2019 8 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan for Duke Energy and will be submitted to NCDEQ by March 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 Beneficial Use Duke Energy has developed plans for on -site recovery and reclamation/recycling of the CCR at the Weatherspoon Station. CCR is already being excavated for off -site beneficiation. Excavated CCR is being transported by truck to two cement kilns in Holly Hill and Harleyville, South Carolina. Pursuant to CAMA, the Basin is required to be excavated by April 4, 2028. 6.2 Site Future Use Combustion turbines are still operating at the Weatherspoon Station site. Duke Energy has not identified any future use of the land reclaimed by the excavation and decommissioning of the Basin. 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 Weatherspoon Basin is being completed in two phases. Phase 1 is excavation and Phase 2 will be the final decommissioning of the Basin dikes and final grading. Excavation of CCR for transport to South Carolina for recycling is presently underway. 7.1 Engineering Evaluations and Analyses Engineering evaluations and analyses to support closure of the Weatherspoon Basin, as detailed in this Closure Plan, are provided in Appendix C. Based on the final post -closure configuration of the Basin and absence of engineered fill features, no geotechnical calculations have been included for the Closure Plan (approval stage) design. Calculations related to the dike removal will be included in the dike modification permit applications. Safe and effective access to the Basin is critical to CCR excavation and the completion of closure. A variety of mitigation techniques can be applied for internal access roads across the Basin, 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 generally 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 Basin. 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 Rev. 0 11 December 2019 9 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan 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. 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: • Decant by using floating pumps, screened intakes, and pumping. • Operation of a temporary water management system to manage all discharges in compliance with the NPDES permit during closure. • Dewatering the CCR to allow for safe access. CCR excavation and conditioning prior to transport off -site. • Continue CCR excavation from the Basin, with sequencing determined for optimal progression. Manage and control of dust -generating activities through specific site planning and mitigation. 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 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 The Closure Plan drawings found in Appendix D include the following: • Sheet 1 — Cover sheet • Sheet 2 — General Project Notes • Sheet 3 — Existing Overall 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, Rev. 0 11 December 2019 10 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan 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. 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 Basin located at the Weatherspoon 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 Weatherspoon 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 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 items that will be included in the CQA Plan will address materials and CQA activities associated with the following components: • Earthwork • Stormwater Channels • Erosion and Sediment Control • As -Built Conditions • Record Documentation Report 8.0 MANAGEMENT OF WASTEWATER AND STORMWATER • Existing Wastewater and Stormwater Management The Weatherspoon Station operates under the NPDES permit NC0005363 issued by the NCDEQ. The Permit authorizes two discharge points that flow into the Lumber River (Outfalls 001 and 003). Outfall 001 includes discharges for the cooling lake water, stormwater runoff, and CCR Basin water, and Outfall 003 authorizes emergency overflows from the cooling pond during extremely severe weather conditions. The limits and requirements stipulated for these outfalls can be found in the aforementioned permit. In April 2019, NCDEQ promulgated new dam safety requirements and, per the dam safety High Rev. 0 11 December 2019 11 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan Hazard Classification, the CCR Basin is now required to pass a full PMP storm event. The Weatherspoon Basin is classified as high hazard by NCDEQ due to the potential for environmental impacts greater than $200,000, if the Basin failed. The PMP event will produce 30.2 inches of rainfall (HMR-51, 6-hour, 10 mi2, All -Season PMP Isopluvial Map). The Basin is required to contain and safely pass the regulatory design storm event. The capacity of the existing Basin to contain and safely pass the regulatory design storm event was analyzed in March 2019 in anticipation of NCDEQ adopting new dam safety rules. NCDEQ requested that the supporting modeling information be provided in either HEC-RAS or HEC-HMS format. In accordance with the new guidelines, the Hydrologic Engineering Center Hydrologic Modeling System (HEC-HMS, version 4.3) computer program was used to perform the hydrologic & hydraulic (H&H) calculations. The modeling results indicated that the Basin has the storage capacity to hold and release the full PMP storm event. Additional internal storage capacity continues to be obtained as excavation of the CCR progresses. This analysis is in Appendix C. • Wastewater and Stormwater Management During Ash Excavation The Basin discharge will continue to be in service to meet the NPDES permit discharge requirements as it goes through the phase of interstitial water treatment and discharge via permitted outfall during CCR excavation. Dewatering of interstitial water is proceeding via mechanical pumping. The pumping system is expected to draw down the stored water after storm events and discharge via the permitted outfall. The water management system for dewatering the Basin is designed to meet the requirements of the discharge permit including continuous monitoring for pH and Total Suspended Solids. The Weatherspoon water management system has a designed flow rate of 500 gpm. Additional physical -chemical treatment processes may be added to the wastewater treatment systems as necessary to maintain compliance with the requirements of the discharge permit. Dewatering is being performed to remove the interstitial or pore water from the CCR to facilitate excavation, access in -place CCR, and establish safe slopes prior to and after CCR excavation. Post -Closure Stormwater Management The post -closure grading is anticipated to provide sheet flow to discharge points flowing to the Weatherspoon cooling lake with no detention. Up to and including the last phase of closure before the Basin dike is breached, the Basin will maintain the capacity to contain the required storm size/flows. 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 Sump pumps have been placed at locations within the Basin to facilitate the removal of interstitial water from the CCR. Effluent from the sumps is monitored for compliance with NPDES permit requirements or other limits as directed by the NCDEQ, which will be met throughout the duration Rev. 0 11 December 2019 12 Wood Environmental & Infrastructure Solutions, Inc. WO�d Duke Energy Coal Combustion Residuals Management Program Weatherspoon Station Basin CAMA Closure Plan of dewatering and closure. A temporary water management system has been installed for the closure of the Basin and will be utilized such that the NPDES Outfall 001 effluent discharge limits 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. 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 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 Additional information on required permits is described in Section 10. 9.0 DESCRIPTION OF FINAL DISPOSITION OF CCR CCR in the Weatherspoon Basin is currently being removed as part of an ash beneficiation project. CCR is presently being excavated and is being transported by truck to two cement kilns in Holly Hill and Harleyville, South Carolina. Approximately 1.68 million tons (1.4 million cubic yards) of CCR are currently (as of the date of this report) remaining in the Basin at the Weatherspoon Station (refer to section 3.1.2 for a detailed discussion and to Appendix A for quantities). The Basin is required to be excavated by April 4, 2028. Using the minimum quantity of 230,000 tons of CCR material that is contractually required to be processed per year (based on information provided by Duke Energy), the 1.68 million tons will be excavated well before the required date. 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 Basin. 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 Basin. The post -closure care plan will be developed to meet the requirements of N.C.G.S. § 130A- Rev. 0 11 December 2019 13 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan 309.214(a)(4)(k). The items that will be included in the Post -Closure Care Plan for the Weatherspoon 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 • Financial assurance estimates for post -closure operations and maintenance and remedial action 11.1 Groundwater Monitoring Program 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 March 1, 2021. The CAP 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 A Closure project high level milestone schedule has been prepared by Duke Energy and the major activities and milestones are provided below: CCR Excavation for Beneficial Use Ongoing Complete Ash Excavation Q1-2028 Site restoration Q1-2029 12.2 Closure and Post -Closure Cost Estimate Cost estimates for closure and post -closure of the Basin at Weatherspoon Station were developed by Duke Energy and provided to Wood. These are Class 5 estimates as the detailed and final design is not 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. The cost to complete the closure by excavation is estimated to be $139 million. The cost to perform the 30-year post -closure activities and monitoring is estimated as $28 million. The cost estimates include the following major activities: • Site infrastructure development for CCR excavation and transport, site preparation, and mobilization • Dewatering, earthwork, and subgrade preparation Rev. 0 11 December 2019 14 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan • CCR excavation • Stormwater management, erosion and sediment control, and site restoration • Engineering support (Design and CQA) • Closure by excavation rectification and dike decommissioning • Post -Closure — groundwater monitoring • Post -Closure — operations and maintenance • Contingency Corrective action costs are included as part of the CAP being prepared separately by SynTerra for Duke Energy and will be submitted to NCDEQ by March 1, 2021. The CAP is herein incorporated by this reference, but its content is not the work product of Wood. Rev. 0 11 December 2019 15 Wood Environmental & Infrastructure Solutions, Inc. WO�d Duke Energy Coal Combustion Residuals Management Program Weatherspoon Station Basin CAMA Closure Plan 13.0 REFERENCES Boulanger and Idriss, 2014, CPT and SPT Based Liquefaction Triggering Procedures, Report No. UCD/CGM-14/01, Center for Geotechnical Modeling, Dept. of Civil and Env, Eng., University of California, Davis (2014) North Carolina General Assembly, Session Law 2014-122, Coal Ash Management Act, as amended 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 United States Environmental Protection Agency, Coal Combustion Residuals (CCR) Rule 40 C.F.R. Part 257, subpart D Rev. 0 11 December 2019 16 Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan TABLES Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan Table 2-1: CAMA Closure Plan Requirements Summary and Cross Reference Table Duke Energy, Weatherspoon 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 the 1 manner in which coal combustion residuals have been stored and 3.1.1 disposed of historically. 2 Estimated volume of material contained in the impoundment. 3.1.2 Analysis of the structural integrity of dikes or dams associated with 3 1 impoundment. 3.1.3 4 All sources of discharge into the impoundment, including volume and 3.1.4 characteristics of each discharge. Whether the impoundment is lined, and, if so, the composition 5 thereof. 7.1 A summary of all information available concerning the impoundment 6 as a result of inspections and monitoring conducted pursuant to this 3.1.6 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 1 residuals surface impoundment located on the site. For purposes of 3.2.1 this sub -subdivision, the term "site" means the 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 generating station and disposed of through transfer to structural fills. 3 The property boundary for the applicable site, including established 3.3 compliance boundaries within the site. 4 All potential receptors within 2,640 feet from established compliance 3 2 2 boundaries. Topographic contour intervals of the site shall be selected to enable 5 an accurate representation of site features and terrain and in most 3.3 cases should be less than 20-foot intervals. Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan No. Description Corresponding Closure Plan Section Locations of all sanitary landfills permitted pursuant to this Article on 6 the site that are actively receiving waste or are closed, as well as the 3.2.3 established compliance boundaries and components of associated groundwater and surface water monitoring systems. All existing and proposed groundwater monitoring wells associated 7 with any coal combustion residuals surface impoundment on the 3.3 site. All existing and proposed surface water sample collection locations 8 associated with any coal combustion residuals surface impoundment 3.3 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 2 A description of the stratigraphy of the geologic units underlying each 4.2 coal combustion residuals surface impoundment located on the site. The saturated hydraulic conductivity for (i) the coal combustion 3 residuals within any coal combustion residuals surface impoundment 4.3 located on the site and (ii) the saturated hydraulic 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 existing liner installed at an impoundment, if any, and (iii) the uppermost identified 4 stratigraphic unit underlying the impoundment, including the soil 4.4 classification based upon the Unified Soil Classification System, in - place moisture content, particle size distribution, Atterberg limits, specific gravity, 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 coal 4.5 combustion residuals -affected soil. Identification of all substances with concentrations determined to be in excess of the groundwater quality standards for the substance 6 established by Subchapter L of Chapter 2 of Title 15A of the North 4.6 Carolina Administrative Code, including all laboratory results for these analyses. 7 Summary tables of historical records of groundwater sampling 4.6 results. Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan No. Description Corresponding Closure Plan Section A map that illustrates the potentiometric contours and flow directions for all identified aquifers underlying impoundments (shallow, $ intermediate, and deep) and the horizontal extent of areas where 4.7 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; 9 stratigraphy of the geologic units underlying an impoundment; and 4.8 the vertical extent of 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. 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 1 and from the potential receptors and (ii) predictions at the compliance 5.1 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. Predictions that include the effects on the groundwater chemistry and should describe migration, concentration, mobilization, and fate for substances with concentrations determined to be in excess of the 2 groundwater quality standards for the substance established by 5.2 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 to demonstrate compliance with groundwater quality standards for the substance established by Subchapter L of Chapter 2 of Title 15A of 3 the North Carolina Administrative Code and requirements for 5.3 corrective action of groundwater contamination established by Subchapter L of Chapter 2 of Title 15A of the North Carolina Administrative Code. Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan No. Description Corresponding Closure Plan Section 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 Combustion 6.1 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 Statutes, 7.1, 7.2 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, including 7.3 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 8 management of stormwater and the plan for obtaining all required 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 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 9 (a)(1)a. of this section, provide a description of how the ash will be stabilized prior to 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 complete 10 closure activities. Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan No. Description Corresponding Closure Plan Section 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 11 public 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. 2 A description of a groundwater monitoring program that includes (i) 11.2 post -closure groundwater monitoring, including parameters to be sampled and sampling schedules; (ii) any additional monitoring well installations, including a map with the proposed 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 and 12.1 post -closure. m. Projected costs of assessment, corrective action, closure, and post- 12.2 closure care for each coal combustion residuals surface impoundment. n. A description of the anticipated future use of the site and the necessity for 6.2 the implementation of institutional controls following closure, including property use restrictions, and requirements for 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 Environmental & Infrastructure Solutions, Inc. Duke Energy Coal Combustion Residuals Management Program �ood • Weatherspoon Station Basin CAMA Closure Plan Table 4-1: Summary of Typical Material Properties Duke Energy, Weatherspoon Station Properties CCR within the Basins" Z Foundation Soil (Residual) below the 12 [CR Basins Embankment Dike SoilZ Foundation Soil (Residual) below the Embankment Dikes' Soil Type Silty Sand (SM) - Predominantly Bottom Ash, Silt/Sandy Silt (ML) - Predominantly Fly Silty Sand [SM) or Sandy Silt [ML} Clayey Sand (SC) or Silty Sand {SM} Silty Sand {SM) or Clayey Sand (SC) Color Gray to Dark Gray Brown, tan, gray, and red Tan, red, orange, and gray Brown, tan, gray, red, and black Plasticity Predominantly Non Plastic Predominantly Non Plastic NP - 18 Predominantly Non Plastic Liquid Limit Predominantly Non Plastic Predominantly Non Plastic NP - 39 Predominantly Non Plastic Plasticity Index Predominantly Non Plastic Predominantly Non Plastic NP - 22 Predominantly Non Plastic Representative Rang a Geometric Mean Representative Range g Geometric Mean Representative Range Natural Moisture Content(%) 39%-65% 52% 11%-27% 20% 10%-19% 18%-66% Fines Content 23%-88% 55% 1%-14% 6% 3%-12% 5%-13% Clay Content 2%-17% 7% 1%-209/. 8% 6%-20% 51/D-209/. Blow Count - Uncorrected N Value {bpf} WOH - 34 4 1 - 64 7 3 - 55 1- 68 Moist Unit Weight 97 pcf * 137 pcf * 121 pcf - 135 pcf ** Dry Unit Weight 77 pcf * 122 pcf * 106 pcf - 120 pcf ** Specific Gravity i 2.1 - 2.4 2.2 1 2.5 - 2.7 2.65 * * 2.4 - 2.6 Horizontal Hydraulic Conductivity(cm/sec) 3.6E-04 * ** ** ** ** Vertical Hydraulic Conductivity(cm/sec) 1** ** ** ** 1.1E-04-9.2E-OS Notes: Outlier values were not inlcuded in the table above. For additional laboratory testing information, see attached Appendix bpf: blows per foot NP: Non Plastic pcf: Pounds per cubic Foot (lb/ft3) WOH: Weight of hammer *Only one labtest available **No lab data available 1Data obtained from lab tests performed on material obtained from the 2015 Syn-Ferra CSA Data obtained from labtest performed on material obtained from the 2012 S&ME Investigation Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan Table 10-1: Regulatory Permits, Approvals, or Requirements for Ash Basin Closure by Excavation Duke Energy, Weatherspoon Station Perm it/Approval General Permit Regulating Existing Type of Regulatory Name or Agency permit No. (if Approval Comments Subject Subj applicable) a pp ) Mechanism or Not Required Air Quality NCDEQ Not Anticipated Building Permit Robeson Not Anticipated County Modification or abandonment of CAMA program CAMA Monitoring NCDEQ Written NCDEQ DWR monitoring wells Plan approval require the approval of the Division of Water Resources (DWR) CCR Impoundment US EPA CCR Self -Regulating Required postings to Closure Rule Public Record Maintain CCR GW CCR monitoring network Impoundment US EPA CCR Self -Regulating and requirements as Monitoring Rule stated in 257.90 - Network 257.98 Clean Water Act Not Anticipated 401 Clean Water Act Not Anticipated 404 Cutting Trees Not Anticipated Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan Perm it/Approval General Permit Regulating Existing Type of Regulatory Name or Agency permit No. (if Approval Comments Subject Subj applicable) a pp ) Mechanism or Not Required Permitting is required to modify or abandon wells and instrumentation Certificate of on regulatory Dam Safety NCDEQ ROBES-009 Approval to Modify Division of dams through the Division of Energy, Mineral, and Land Resources (DEMLR) Ash Basin Dam - Permitting is required to modify the dam in accordance with the Certificate of Dam Safety Law of Dam Safety NCDEQ ROBES-009 Approval to Modify 1967, 15A NCAS 02K.0201 (b)(2); an application must be filed with the Division of Energy, Mineral, and Land Resources (DEMLR) DOT - General Not Anticipated Driveway Permit NCDOT Not Anticipated Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan Perm it/Approval General Permit Regulating Existing Type of Regulatory Name or Agency permit No. (if Approval Comments Subject Subj applicable) a pp ) Mechanism or Not Required No land disturbance activities outside of the ash basin are anticipated. In Erosion and NCDEQ and conformance with Sediment Control Robeson Not Anticipated 15A NCAC 04, no (E&SC) County E&SC Permit is anticipated to be required from Land Quality. Removal from or import of material could be restricted Fire Ants Restriction not likely dependent on the potential for fire ants and geographic regions involved No development activities are anticipated within Floodplain Robeson Not Anticipated FEMA mapped Development County Special Flood Hazard Areas for the Flood Insurance Rate Maps Multi -State Not Anticipated Agreement NPDES (National Pollution Discharge NCDEQ NC0005363 Not Anticipated Elimination System) Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan Perm it/Approval General Permit Regulating Existing Type of Regulatory Name or Agency permit No. (if Approval Comments Subj Subject a pp ) applicable) Mechanism or Not Required Removal from or import of vegetated material could be Noxious Weeds Not Anticipated restricted dependent on the vegetation and geographic regions involved Construction Railroad activities adjacent to Easement, tracks/ballast or a Not Anticipated Access, or new railroad crossing Crossing Permit require an agreement or permit In accordance with the federal Water SPCC (Spill Pollution Control Act Prevention (Clean Water Act) of Control and NCDEQ Not Anticipated 1974, Title 40, Code Countermeasure) of Federal Plan Regulations, Part 112. Wood Environmental & Infrastructure Solutions, Inc. WOO Duke Energy Coal Combustion Residuals Management Program d. Weatherspoon Station Basin CAMA Closure Plan Perm it/Approval General Permit Regulating Existing Type of Regulatory Name or Agency permit No. (if Approval Comments Subject Subj applicable) a pp ) Mechanism or Not Required Federal and/or state regulations may Threatened or apply including Endangered agency consultation Species: and performing site - Candidate specific surveys Conservation within the proper Agreement Avian NCDEQ And survey period (e.g., Protection Not Anticipated EPA flowering period for Plan(s) Bird and listed plant) to Bat Conservation determine if Strategies Eagle Threatened or Conservation Endangered Species Plan Eagle Take or their habitat exist Permit within the limits of disturbance Solid Waste Site No new CCR Landfill NCDEQ Not Anticipated Suitability planned Solid Waste No new CCR Landfill Permit to NCDEQ Not Anticipated planned Construct Solid Waste No new CCR Landfill Permit to NCDEQ Not Anticipated planned Operate County Approval Robeson No new CCR Landfill Not Anticipated - zoning County planned Wood Environmental & Infrastructure Solutions, Inc. WO�d Duke Energy Coal Combustion Residuals Management Program Weatherspoon Station Basin CAMA Closure Plan FIGURES I I I I 2 3 4 5Omni --t -i I 6 Mi •14 *; v 1� �� ly 4-*0' ` 7 8 FIGURE 1-1 REV. 1A"111111111111 •I �' _ •.j.IITl St Pacts — -. . I rd t ,1 "r. 1',:rrd.rake GiP 's. % (I ; v, v j Lund t i I i i i� At ! r Raynhsm y'� 4� r� r� (f kkDonal�3 �+ , tir r{owlaliy•9y'S W.ro.l.rtlUo W.H. WEATHERSPOON Cp a STEAM ELECTRIC PLANT J Ali I� ! J LNtle Ham-r Rock Prodondk 1 r orlllrl .1� - \ t3oadman EIIIIcn fop ;d ...'-. SITE VICINITY MAP - 111 = 5 MILES MAP SOURCE: ESRI WORLD TOPOGRAPHIC BASEMAP i^ 4i.4 S ,1 ` * '• •y go10 •t om • � ` d • } FORMER PLANT 4 r' e .CT 'J '�iy yK _ • i! �� I /l 1- A f C WETLANDS F APPROXIMATE LIMIT OF WASTE APPROXIMATE PROPERTY LINE REV DATE JOB NO. PROJECT TYPE I DES DFTR CHKD ENGR APPD I DESCRIPTION INCHES 1 2 3 TENTHS 10 20 30 4 5 6 I I I 1 I M V J C X M TITLE COAL COMBUSTION RESIDUALS SURFACE wood. IMPOUNDMENT CLOSURE PLAN F WEATHERSPOON STEAM ELECTRIC PLANT Environment& Infrastructure Solutions 5710 OLEANDER DRIVE, SUITE 110 WI ON,NC28403 TEL:EL:(91(910) 452-1185 FAX: (844) 648-9591LICEN NCENGSF-11253 NC GEOLOGY: C-247 VICINITY MAP AND SITE PLAN FOR ISSUED FOR REVIEW - NOT FOR CONSTUCTION SEAL DUKE SCALE: AS SHOWN DES: DFTR: WMN WMN DWG TYPE: DWG ISSUED FOR 4 ENERGY® CHKD: NAP JOB NO: 7810180072 REVIEW ENGR: NAP DATE: 12/10/2019 NOT FOR FILENAME: APPD: CRK CONSTRUCTION DWG SIZE DRAWING NO. REVISION ANSI 22"x34" FIGURE 1-1 8 I 9 I 10 I Plotted By: Nichols, William Sheet Set: _7812180072 WSPN CAMA Closure Plan Layout: WSPN Figure 1-1 December 10, 2019 10: 22:05am Q:\Duke Energ y\Weatherspcan \_7812180072_WSPN CAMA Closure Plan\Plansheets\Issued for Review\Figures\CAMA Figure\WSPN Figure 1-1.dwg F 2 3 4 5 6 7 8 • \ / - _ _ / r� - - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - - - - - - - 120� RISER WITH METAL SHROUD - /i - - - - - - - - - - - - - - - - i - ---- - _ - - �---------------ham _ _ --- - _ - ------ -_� - - ----_ \ 7 ----- 13 O -___-�_------- - -___ ` ' INV:118.3924"RCP - N T I \ // --------- =__ �- �4 __ -- ---- - _ WATER SURFACE % - - --- __- ~----------=140----_--- _ _ = 130=- -OVERFLOW--== ELEVATION / _ _ SPILLWAY _ _ WON yvv - w ( I I)\ �4p_`� oo RIP I � _ - _ _ / -- ,-- � � � I /////✓ %//. / //// // l ( �� J� i - - _ - - - _) (/ _ _ i I II I WITH META IFIER I 140 -� r �- I _� _�/> / J r I - - - ` - \\� / I II CLARPOND BASIN) I RISER SHROUD �- / TOP El w _ _ _ PIPE OUTLET - - ` _ )`� I INV:114.64 24" R P INV 1979 ASH BASIN :117.68 24"�cP (ROBES -009) /r�- -_- -�� 1)140f r/ �� vv� I I /III I� I IIII )/r ��\� =- = - / 30"CMP /- _ ( % If III1108.68 CONC E OUTLET \ \ _ // - - \� ^ WATER FACE \ \ \ / WATER SURFACE Ili J > INV OUT:108.53 ./ / \ � // /�� j / / / - _ - - / I / \ __= ELEVATION 132.3 \\ \\ J INV:139.70 20.5" ELEVATION 132.0 I _ w 11 \_` \ f l 1 J PIPE OUTLET INVOLjj \i 1 J �% % f/�j L� \ l�I 24" RCP ) • I o 1 (I'll ' I. / I( I I It �svvvvAl(I II J 1 1 l ovvv�// I 1 / II I1 \ \\\ - / / / 1 I \ /% //�� ` S 1 / //� /// // / / / / / � i I i III I I (( ill (� \ ✓ INTERIOR AA\ V // _ (}� I (S \ STR NO. 389 • .vvv v / � �i I / � ( - / l� Il I CONCRETE RISER BUIT DWITH IKES�� /� 11 / WATER SURFACE V I f ) ) ) 1 `OVAv V EL�ATION132.5 (2'x4' INSIDE) I ( � r-150 CCR VA\ \ // � // / . / //�// / / ✓/ j/l if I I II III / INV:139.80 20.5" i / • / J I ' • WATER SURFACEWilli ELEVATION 131.8LOWER BASIN/ / '' I I/lIII I II I f II 1I I l I I II ! (I I Ow 1I I I✓ rwLU(POND 3) UPPER BASIN p Liz(POND 1) OI1)/ I • •• • • Will / \ I,NTE'O CCRDIKES I BUIT WITH \• ' J CCR III I/ \ ��\ ~\ \ \\\ \ ` % I III I (/ • �r- I 11 I�II /// // / I - l l I / I J it (h (�� frr� \ \\\\ \ \ ( 1 I II • STR No. 6 • I / / / I MIDDLE BASIN I /1 f (POND 2) / WATER SURFACE 1�ti� \\\\ \ \ V �\ VAV (� I % I I I IIIII IIIII I I J I • • ELEVATION EVATION 131.4 \VA \\\ ACEWATER SURFII IIIII I( IJ I IIII(IIIII IIIII II II l IIl(IlIIII(I II I I1 I II I I1 I ' I I( /f // w II /,,II i\\_�\ \ �\\\ELEVATION 132.5 I 0I I /l oL �2woELEVATION 1366 0I • , , i vv� vvvvvv / 1( /� IIIII III /f STOCKPILE • I lI I ll 1 I I I I II(�r I (� '(I I \� �� \\ \ \\\\\ IIII II I 1 I , WATER SURFACE \a\ELEVATWATER SURFACEION 134.3\ ELEVATION 129.5 I I I I I I I • • ' • LU/ • I I I 111� I I � 1 v V //- -v { (( (III 1 I � .� ✓ I 1 i� - v � � �� vvvv vv vv vv IIJI 1p rl I WATER SURFACE / / \\ \VA I III�� O IW ' • \ I I I ELEVATION 132.5 10 , / I I II I 1 TRUCK LOAD OUT \ � \ ( \ 111 I (I I � I I I 1 1 I 1 /I f �� \ / . - l =--^ - _- r-- ;- = �i � -i-='% �\ �) / �\ \ � r f i( I , • , ll CENTER NV� TER I II 1 OHAUL R ` WATER SURFACE o PANT ELEVATION136.5- _ _50 -150 • . • • _ i/% / / / / I 'I • S__IIII�- ---_150 - - --- --_--_--_ ----_--_ - / �_ -/��✓,. j r v1 I STRNO.391I0 -150 - - - - - =_------= -- __ - - -- - - -- -- -----4=---- 0 -10-_ ---- -140STOCKPILE WHEEL WASH --- -- I �, •� • • • • --_ -- - r II\\\\\\\ \�11 \\\\\\ I /�---- ____\\��__ _- ___ -_____ - =- o _ 150 -----------^l i / --- \ ---``} v ~�_-ZQ • i / / • LU Illllso v� ®vvv A�vv�� - /� o / �a • IIII o • \ �� \ �\�� - = L -OHEQOzOHE - 1 4\ �� % / / - - �� _ - _ - - %__ • / I _ _-_� - _ _ __ =-_ = - STR N0. 5 / Y � IIII \\\\\\\ \�OHE OHESTR-_ ___--- ��\\�� UwY - -•= III I I \ \\\��\\\� - %/ / • - r / - _ - r� _ _ _ - _ = WEATHERSPOON ` � -` � / I • • - - - - � �-- � � OHE - \ I _ � - i �-` - - - - FAYETTEVILLE \ \ \\� c3n � N • \ \ PHI � / ' • �uj \ • 230 KV LINE 1 OHESTR f�I , / �, • �OHTR • /\ II I I �I I Lam/ I I 1 I / \ ro� • ' • • I � /%=-�_� \ \ �\��\�. I � off%_-== -'- •�'' \ ' -11 I ) \ \ / � 1 `- • 1 rl OVERALL EXISTING CONDITIONS PLAN SCALE: 1" = 100' 100 0 100 200 FT d Environment & Infrastructure Solutions 5710 OLEANDER DRIVE, SUITE 110 WILMINGTON, NC 28403 TEL: (910) 452-1185 FAX: (844) 648-9591 LICENSURE: NC ENG: F-1253 NC GEOLOGY: C-247 SEAL ISSUED FOR REVIEW NOT FOR CONSTRUCTION FIGURE 1-2 LEGEND REV. 100 EXISTING 10' CONTOUR OHE OVERHEAD ELECTRICAL LINE C WETLAND AREA EXISTING RIP RAP Y UTILITY POWER POLE TEMPORARY HAUL ROAD TEMPORARY WORKING SURFACES ( STOCKPILE, SCREEN PLANT, WHEEL WASH) - - - TEMPORARY RIM DITCH 1 TEMPORARY SUMP �J APPROXIMATE LIMIT OF WASTE • WELL LOCATIONS AS PROVIDED BY SYNTERRA TO DUKE ENERGY/WOOD MACTEC BORINGS MACTEC CPTS ip S&ME BORINGS S&ME CPTS S&ME PIEZOMETERS MCKIM & CREED SURVEY NOTES: 1. ALL DISTANCES ARE HORIZONTAL GRID IN US SURVEY FEET UNLESS OTHERWISE SHOWN. 2. COORDINATES BASED ON NC GRID NAD83/2011. 3. ELEVATIONS BASED ON NAVD88. 4. SURVEYOR HAS MADE NO INVESTIGATION OR INDEPENTENT SEARCH FOR EASEMENTS OF RECORD, ENCUMBRANCES, RESTRICTIVE COVENANTS, OWNERSHIP, TITLE EVIDENCE, OR ANY OTHER FACTS THAT AN ACCURATE AND CURRENT TITLE SEARCH MAY DISCLOSE. 5. ENVIRONMENTAL CONDITIONS WERE NOT EXAMINED OR CONSIDERED AS PART OF THIS SURVEY. NO STATEMENT IS MADE CONCERNING THE EXISTENCE OF UNDERGROUND OR OVERHEAD CONTAINERS OR FACILITIES THAT MAY AFFECT THE USE OR DEVELOPMENT OF THIS TRACT. 6. THE EXISTENCE OR NONEXISTENCE OF WETLANDS ON SUBJECT PROPERTY HAS NOT BEEN DETERMINED BY THIS SURVEY. 7. THIS MAP IS BASED ON PHOTOGRAMMETRIC MAPPING OF IMAGERY COLLECTED ON JANUARY 18, 2018. REFERENCES: 1. TOPOGRAPHY OF ASH BASIN FROM MCKIM & CREED SURVEY DATED 1-18-2018. 2. BOTTOM OF CCR ESTIMATED BASED ON DATA PROVIDED IN ASH BASIN CLOSURE PLAN, PREPARED BY S&ME, DATED JULY 2016. TITLE COAL COMBUSTION RESIDUALS SURFACE IMPOUNDMENT CLOSURE PLAN WEATHERSPOON STEAM ELECTRIC PLANT OVERALL EXISTING CONDITIONS PLAN FOR ISSUED FOR REVIEW - NOT FOR CONSTRUCTION DUKE ENEM%JY® SCALE: AS SHOWN DES: WMN DWG TYPE: DWG DFTR : WMN JOB Cl NAP DATE:012/110//20 9072 ENGR: NAP FILENAME: APPD: CRK DWG SIZE DRAWING NO. REVISION ANSI 22"x34" FIGURE 1-2 0 F REV DATE JOB NO. PROJECT TYPE DES I DFTR I CHKD I ENGR I APPD DESCRIPTION INCHES 1 2 3 TENTHS 10 20 30 4 5 6 7 8 1 1 i Plotted By: Nichols, William Sheet Set: _7812180072 WSPN CAMA Closure Plan Layout: FIGURE 4 EXISTING CONDITIONS December 10, 2019 10: 24: 52am 0: \Duke Energ y\Weatherspcon \_7812180072_WSPN CAMA Closure Plan\Plansheets\Issued for Review\Figures\FIGURE 3-1 EXISTING CONDITIONS.dwg 9 10