The URL can be used to link to this page

Home My WebLink AboutMarshall Pumping Test Work Plan_05 11 18 PUMPING TEST WORK PLAN FOR MARSHALL STEAM STATION 8320 EAST CAROLINA HIGHWAY 150 TERRELL, NORTH CAROLINA 28682 SUBMITTED: MAY 2018 PREPARED FOR DUKE ENERGY CAROLINAS, LLC Christopher H. Bruce, NC LG 2246 Sr. Geologist Brian Wilker, NC LG 2546 Project Manager Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page i P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx TABLE OF CONTENTS SECTION PAGE INTRODUCTION ......................................................................................................... 1-1 1.0 Site History, Operations, and Coal Ash Management ........................................ 1-1 1.1 Planned Pumping Tests ........................................................................................... 1-2 1.2 SITE CONCEPTUAL MODEL ................................................................................... 2-1 2.0 Site Geology and Hydrogeology ............................................................................ 2-1 2.1 2.1.1 Site Geology ......................................................................................................... 2-1 2.1.2 Site Hydrogeology .............................................................................................. 2-1 WELL INSTALLATION .............................................................................................. 3-1 3.0 Installation of Pumping and Observation Wells .................................................. 3-1 3.1 3.1.1 Ash Pumping Well Installation ......................................................................... 3-1 3.1.2 Saprolite Pumping Well Installation ................................................................ 3-2 3.1.3 Ash Observation Well Installation ................................................................... 3-2 3.1.4 Saprolite Observation Well Installation ........................................................... 3-3 Well Development .................................................................................................... 3-4 3.2 PUMPING TESTS ......................................................................................................... 4-1 4.0 Static Water Level Collection .................................................................................. 4-1 4.1 Pumping System Installation .................................................................................. 4-1 4.2 Step-Drawdown Tests .............................................................................................. 4-2 4.3 Step-Drawdown Test Recovery .............................................................................. 4-2 4.4 Constant-Rate Pumping Test .................................................................................. 4-3 4.5 WATER QUALITY MEASUREMENTS AND SAMPLING ................................. 5-1 5.0 ANALYSIS OF WATER LEVEL DATA .................................................................... 6-1 6.0 Baseline Analysis....................................................................................................... 6-1 6.1 Step-Drawdown Test Analysis ............................................................................... 6-1 6.2 Constant Discharge Rate Test Analysis ................................................................. 6-1 6.3 REFERENCES ................................................................................................................ 7-1 7.0 Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page ii P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx LIST OF FIGURES Figure 1 Site Location Map Figure 2 Marshall Plant Vicinity Map Figure 3 Location for AB-12 Well Cluster Pumping Test Figure 4 Location for AB-15 Well Cluster Pumping Test Figure 5 Location for AB-18 Well Cluster Pumping Test Figure 6 Typical Flow Meter Configuration Figure 7 Typical Step Test Drawdown Curve LIST OF TABLES Table 1 Well Construction Details Table 2 Summary of Pumping and Observation Wells Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 1-1 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx INTRODUCTION 1.0 Duke Energy Carolinas, LLC (Duke Energy) owns and operates the Marshall Steam Station (MSS, the Plant, or the Site), located at 8320 NC Highway 150 East in Terrell, Catawba County, North Carolina (Figure 1). Operations, as a coal-fired generating station, began at MSS in 1965. Four coal-fired units presently are in operation. Coal combustion residuals (CCR) consisting of bottom and fly ash material from MSS have historically been managed in the Site ash basin, located north of the station adjacent to Lake Norman. Site History, Operations, and Coal Ash Management 1.1 Marshall Steam Station (MSS) is a four-unit, coal-fired electricity-generating facility located on the west bank of Lake Norman near the town of Terrell, Catawba County, North Carolina. The entire Site, approximately 1,446 acres in area, is owned by Duke Energy. The Site is thought to have been largely undeveloped prior to Duke Energy ownership. Coal is delivered to the station by a railroad line. Operation of Unit 1 began in 1965, and operation of Unit 2 began in 1966, with each generating 350 megawatts. Operation of Unit 3 began in 1969, and operation of Unit 4 began in 1970, with each generating 648 megawatts. Improvements to the Plant since 1970 have increased the electric generating capacity to 2,090 megawatts. The MSS ash basin, which contains ash generated from the historic and active coal combustion at the Plant, is situated with MSS to the south, topographic divides located along Sherrills Ford Road to the west, Island Point Road to the north, and Duke Energy property to the east (Figure 1). The ash basin, approximately 394 acres in size, was constructed with an earthen dike. A 500-foot compliance boundary for the National Pollutant Discharge Elimination System (NPDES) groundwater monitoring well network encircles the ash basin, co-located with the property boundary on the western edge of the Site and extending to Lake Norman on the eastern edge of the Site (Figure 2). Fly ash and bottom ash from MSS was managed in the ash basin from approximately 1965 until 1984. Fly ash precipitated from flue gas and bottom ash collected in the bottom of the boilers was sluiced to the ash basin using conveyance water withdrawn from Lake Norman. Since 1984, fly ash has been disposed of in the on-site landfills and bottom ash has continued to be sluiced to the ash basin. Detailed descriptions of the Site operational history, the Site conceptual model, physical setting and features, geology/hydrogeology, and results of the findings of the Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 1-2 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx Comprehensive Site Assessment (CSA) and other Coal Ash Management Act (CAMA)- related work are documented in full in the following documents: Comprehensive Site Assessment Report - Marshall Steam Station Ash Basin (HDR, September 8, 2015a). Corrective Action Plan Part 1 - Marshall Steam Station Ash Basin (HDR, December 7, 2015b) Corrective Action Plan Part 2(included CSA Supplement 1 as Appendix A) – Marshall Steam Station Ash Basin (HDR, March 3, 2016a). Comprehensive Site Assessment Supplement 2 - Marshall Steam Station Ash Basin (HDR, August 4, 2016b). 2018 Comprehensive Site Assessment Update – Marshall Steam Station (SynTerra, January 31, 2018) Planned Pumping Tests 1.2 Ash basin pumping tests are planned to collect site specific data to further refine the groundwater flow and transport model to be used for closure planning and potential groundwater corrective action evaluation. The pumping tests would focus on evaluation of field scale horizontal and vertical variability of the hydrologic characteristics for the saturated media. Each test would provide estimates of media properties including transmissivity (T), hydraulic conductivity (K), and storativity (S). The following major tasks are anticipated for conducting ash basin pumping tests at the Marshall Steam Station: 1. Well Installation and Development 2. Static Water Level (Baseline Data) Collection 3. Pumping System Installation 4. Step-Drawdown Tests 5. Step Drawdown Test Recovery 6. Constant Rate Pumping Tests 7. Water Quality Sampling 8. Data Analysis As a portion of this scope of work, both pumping wells and observation wells have been installed at the Site (Table 1). A total of three ash pumping wells and one saprolite Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 1-3 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx pumping well have been installed at selected locations (Figures 3-5). Each pumping well was screened either wholly within ash or the underlying soil. A total of 10 new observation wells have also been installed. Additionally, 10 existing wells would be utilized as observation points during the ash pumping test (Table 2). One pumping test is estimated to take eight (8) days (72 hours for static conditions, 24 hours for step test/recovery, 72 hours for constant rate discharge test, 24 hours recovery). During this time, water levels would be monitored in selected wells using pressure transducers and manual water level readings. Groundwater samples would also be collected daily throughout the 72-hour constant rate pumping test for laboratory analysis. Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 2-1 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx SITE CONCEPTUAL MODEL 2.0 Site Geology and Hydrogeology 2.1 This section provides a brief summary of the Site geology and hydrogeology. A detailed description of the Site geology and hydrogeology can be found in the documents listed in Section 1. 2.1.1 Site Geology The subsurface at MSS is comprised of a surficial unit (soil, fill and reworked soil, alluvium, and saprolite), a transition zone, and fractured bedrock. The transition zone is comprised of partially weathered rock that is gradational between saprolite and competent bedrock. The bedrock is dominantly mica gneiss, meta-granite, and quartz-sericite schist. Shallow bedrock is fractured; however, only mildly productive fractures (providing water to wells) were observed within the top 50 – 75 feet of bedrock in previous investigations. Typically, the majority of fractures are relatively small (e.g., close and tight) and appear to be limited in connectivity between borings. Yields from pumping or packer testing are generally low. Groundwater exists under unconfined or water table conditions throughout the Site. Generally, groundwater is contained within fractures (secondary porosity) of the underlying bedrock. The fractured bedrock is overlain by a mantle of unconsolidated material known as regolith. The regolith includes residual soil and saprolite zones and, where present, alluvial deposits. Saprolite, the product of chemical weathering of the underlying bedrock, is typically composed of clay and coarser granular material and reflects the texture and structure of the rock from which it was formed. The weathering products of granitic rocks are quartz-rich and sandy textured. Rocks poor in quartz and rich in feldspar and ferro-magnesium minerals form a more clayey saprolite. 2.1.2 Site Hydrogeology The soil/saprolite regolith and the underlying fractured bedrock represent a composite water-table aquifer system. The regolith provides the majority of water storage. Based on previous investigations, the groundwater system in natural materials (soil, soil/saprolite, and bedrock) at the MSS site is consistent with the regolith-fractured rock system and is an unconfined, connected aquifer system. Regolith is underlain by a transition zone (TZ) of weathered rock that transitions to competent bedrock. The groundwater system at the MSS site is divided into three flow layers referred to in this report as the shallow, deep (TZ), Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 2-2 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx and bedrock layers, so as to distinguish unique characteristics of the connected aquifer system. The hydrogeologic characteristics of the ash basin environment are the primary control mechanisms on groundwater flow and constituent transport. The stream valley in which the ash basin was constructed is a distinct slope-aquifer system in which flow of groundwater into the ash basin and out of the ash basin is restricted to the local flow regime. Localized topographic relief results in adjacent groundwater divides associated with the natural ridges separating historic draws. Groundwater flows generally from the northwest to southeast across the Site. Active sluicing contributes to free-standing water within the ash basin and is controlled downgradient by the ash basin dam and the NPDES outfall/discharge to Lake Norman (east side of ash basin). Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 3-1 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx WELL INSTALLATION 3.0 SynTerra conducted field oversight of drilling operations and well installations at the proposed pumping test locations. SynTerra’s oversight included documentation of field observations and activities associated with boring advancement, well installation and well development activities conducted by a licensed North Carolina driller and support crew contracted by Duke Energy. Pumping well and observation well locations, a conceptual well layout, and cross-sectional view are provided on Figures 3 through 5. A summary of well construction details for the pumping wells and observation wells is included in Table 1. Installation of Pumping and Observation Wells 3.1 The pumping and observation wells were installed in April 2018 by a licensed North Carolina driller using rotary sonic drilling techniques. Continuous cores were obtained at each boring location for lithologic description. All newly installed wells were completed with concrete well pads, protective surface casings, well tags and locking caps in accordance with 15A NCAC 02C requirements. Approximate well construction details are summarized on Table 1. At the time this work plan was written, the newly installed wells had not yet been surveyed for horizontal and vertical control. Boring logs and well construction records will be included as part of a technical memorandum on the results of pumping tests, as referenced in Section 6. 3.1.1 Ash Pumping Well Installation Ash pumping wells were installed using sonic drilling techniques utilizing a nominal 13-inch core barrel. Ash pumping wells were installed approximately 30 feet away from existing well clusters AB-12, AB-15 and AB-18. Ash pumping wells at AB-12, AB-15 and AB-18 well clusters were drilled to approximately 45 feet below ground surface (bgs), 50 feet bgs and 35 feet bgs, respectively (Table 1). All three ash pumping wells were installed with screens located wholly within the ash layer with no borehole connectivity to the underlying soil. The wells were constructed of 6-inch ID, National Sanitation Foundation (NSF) grade polyvinyl chloride (PVC) (ASTM D-1785-12) schedule 40 flush-joint threaded casing terminating in a 10 foot long 0.010-inch machine-slotted wire- wrapped PVC screen, hung approximately one foot off the bottom of the boring (to allow filter material below the well screen). Packed well screens for each well were filled with clean, well-rounded, washed high grade No. 1 silica sand. The filter pack extended approximately 2-3 feet Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 3-2 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx above the top of the screen. An approximate 2-3 foot pelletized bentonite seal was placed above the filter pack. The pellets were allowed to hydrate in accordance with manufactures specifications before grouting the remainder of the annular space was filled with Agua Guard cement grout from the top of the upper bentonite seal to near ground surface. Well construction details are summarized on Table 1. These ash pumping wells are planned to be abandoned at the conclusion of the pumping test activities. 3.1.2 Saprolite Pumping Well Installation One saprolite pumping well was installed at the AB-18 well cluster location adjacent to the ash pumping well. This well was installed using temporary steel outer drill-string casing as a precautionary measure to prevent potential migration from overlying material along annular space of the borehole and beneath the ash-soil interface. Multiple drill string rods/casings were used to construct the saprolite pumping well. The largest diameter casing was a nominal 13-inch casing that was advanced a few feet into saprolite beyond the base of the ash. This casing was left in-place for the remainder of well construction activities. After removing material within the 13-inch casing, drilling resumed to the targeted depth using smaller diameter casing (nominal 10-inch diameter) to install the well into saprolite. Once at targeted depth, the well was constructed similar to the ash pumping wells, but with the bentonite seal extending from the top of the filter pack up into 13-inch casing and above the approximate depth of the ash/soil interface. After the bentonite seal was hydrated, the remainder of the annular space was filled with Agua Guard cement grout from the top of the upper bentonite seal to near ground surface and the 13-inch steel casing was removed. Well construction details are summarized on Table 1. The saprolite pumping well was screened wholly within the soil beneath the ash basin and is planned to be abandoned at the conclusion of the pumping test activities. 3.1.3 Ash Observation Well Installation Nine (9) ash observation wells were installed at the site. Four ash observation wells were installed at the AB-12 well cluster location (Figure 3); two were installed at the AB-15 well cluster (Figure 4); and three were installed at the AB- 18 well cluster (Figure 5). These wells are located at approximately either 15 or 30 feet away from the pumping well. Approximate distance from the pumping well for each observation well is provided on Table 1. Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 3-3 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx Ash observation wells were installed utilizing a nominal 6-inch core barrel. The wells were constructed of 2-inch ID, NSF-grade PVC schedule 40 flush-joint threaded casing terminating in a 5-foot long 0.010-inch machine-slotted pre- packed PVC screen, hung approximately one foot off the bottom of the boring (to allow filter material below the well screen). Packed well screens for each well were filled with clean, well-rounded, washed high grade No. 1 silica sand. The filter pack extended approximately 2-3 feet above the top of the screen. An approximate 2-3 foot pelletized bentonite seal was placed above the filter pack. The pellets were allowed to hydrate in accordance with manufactures specifications before grouting the remainder of the annular space was filled with Agua Guard cement grout from the top of the upper bentonite seal to near ground surface. Well construction details are summarized on Table 1. These ash observation wells are planned to be abandoned at the conclusion of the pumping test activities. 3.1.4 Saprolite Observation Well Installation One saprolite observation well was installed at the AB-18 well cluster. This well was installed similar to the saprolite pumping well, using temporary steel drill- string casing as a precautionary measure to prevent potential migration from overlying material along annular space of the borehole and beneath the ash-soil interface. Multiple drill string rods/casings were used to construct the saprolite observation well. The largest diameter casing was a nominal 8-inch casing that was advanced a few feet into saprolite, beyond the base of the ash. This casing was left in-place for the remainder of well construction activities. After removing material within the 8-inch casing, drilling resumed to the targeted depth using smaller diameter casing (nominal 6-inch) to install the well into saprolite. A 2-inch diameter PVC well was then installed in a similar approach as ash observation wells as described above. After the bentonite seal was hydrated, the remainder of the annular space was filled with Agua Guard cement grout from the top of the upper bentonite seal to near ground surface and the 8-inch steel casing was removed. Well construction details are summarized on Table 1. The saprolite observation well is planned to remain in place at the conclusion of the pumping test to be used for monitoring as part of the CAMA interim mon itoring program. Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 3-4 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx Well Development 3.2 The newly installed wells were developed until discharge was clear and stable. The main objective of the well development was to improve near-well permeability and stability. Removal of the fine particles from the near-well area would help create a more permeable zone and minimize the effect of well smear or caking. Improper well development can cause significant impact to the results of both the step test and the constant rate pumping test. This could result in the need to stop the test (step test or constant rate test) and redevelop the wells (primarily pumping wells). Development included surging and high volume water removal. Completion of development was determined when turbidity remained below 10 Nephelometric Turbidity Units (NTUs) after surging the well or at least 10 borehole volumes were purged. Turbidity remained greater than 100 NTUs throughout development at several observation wells, even after several tens of well volumes were removed and extensive hours of pumping/surging efforts. Observation of cores from these wells indicated the material was primarily fine-grained (silt), characteristic of fly ash. Well yield was reasonable, similar to other wells installed in ash, indicating the hydraulic interconnectivity of these wells may be uninhibited. Therefore, development was considered complete at these locations. After development (if any additional development is necessary), the wells would be allowed to equilibrate for at least five days prior to the collection of baseline water level data. Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 4-1 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx PUMPING TESTS 4.0 Static Water Level Collection 4.1 Static water level (baseline data) collection may commence once the pumping wells and observation wells have been installed, developed, and allowed to equilibrate (for approximately five days). Baseline water-level readings would be used to determine long-term data trends or potential interferences from other pumping/discharge source(s). Water levels would be monitored in selected wells using pressure transducers. A summary of the wells to be monitored for each test is included as Table 2. Prior to the installation of transducers, an initial round of water levels would be manually collected from the wells listed in Table 2. Transducers would then be installed and programmed to collect water level data every minute for a minimum of 72 hours before the start of any active pumping (step test). At the end of the 72-hour period, baseline measurements would be stopped and downloaded for review. Pumping System Installation 4.2 Once baseline conditions have been established, a submersible pump would be installed in the selected pumping well by the Duke well installation contractor. Two pumping test would be conducted simultaneously. The initial test would be conducted in the saprolite pumping well at the AB-18 cluster and the ash pumping well at the AB-12 well cluster. The second test group would be conducted in the ash pumping well at the AB- 15 cluster and the ash pumping well at the AB-18 cluster. The Duke well installation contractor would provide and install a flow meter capable of continuously-logging discharge rates and total flow in-line with the pump discharge line. The flow meter would need to be installed in such a way as to allow it to be full of water at all times. This can be done by the installation of a six-inch drop in the discharge line prior to the flow meter and a subsequent 6 inch rise in the discharge line past the flow meter. A minimum of one foot of straight piping would also need to be installed after the drop and before the rise to ensure laminar flow through the transducer. Two ball valves should be installed in the discharge line. One should be located prior to the drop and one should be located post rise. A photograph showing the general proposed configuration for the flow meter is presented on Figure 6. A small diameter sampling port should also be installed somewhere near the flow meter to allow for taking field water quality measurements and samples. The remaining discharge line should be extended away from the test area (300-500 feet) to minimize potential influence of the discharged groundwater. Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 4-2 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx After the completion of the initial set of 72-hour pumping tests, the pump at both locations would be decontaminated and moved to the second set of test locations (AB- 18 ash pumping well and AB-15 ash pumping well). Step-Drawdown Tests 4.3 After the pumping system has been installed the well would be allowed to fully recover (assumed to be 12 hours). Once the pumping wells have fully recovered, SynTerra in conjunction with the drilling contractor, would conduct a step-drawdown test (initial test in AB-18 saprolite pumping well and AB-12 ash pumping well). A step-drawdown test (or step test) is a single-well pumping test designed to investigate the performance of a pumping well under controlled variable discharge conditions. During the step-drawdown test, an initial rate of one gallon per minute (gpm) would be used. The discharge rate would be increased approximately 0.5 gpm per step period (subject to change based on field observations). Each step would be approximately 2 hours (subject to change based on field observations). This duration should allow wellbore storage effects to dissipate. This process would continue until the well can no longer sustain the selected flow rate (curve does not flatten out) or a maximum of 20 gpm flow rate is reached. A typical step test drawdown curve is presented in Figure 7. After completion of the step test, the pumping well would be allowed to return to static conditions (recovery tests). Data from the step test would be used to determine an appropriately conservative initial pumping rate (Qmax) for the constant rate pumping tests. A Qmax should be calculated that would result in a drawdown after 72 hours that is approximately 25 percent of the water column. At the end of the test the flow would be adjusted to the selected Qmax using one of the ball valves prior to shutting down the pump. As the pump is shut down the remaining ball valve would be closed to prevent the discharge line from draining into the well (which would affect recovery data). After the completion of the initial set of 72-hour pumping tests and recoveries, the pump at both locations would be decontaminated and moved to the second set of test locations (AB-18 ash pumping well and AB-15 ash pumping well). A second set of step test would be conducted at these new locations following the same procedure. Step-Drawdown Test Recovery 4.4 Once the step test is complete, the pump would be shut off and the flow meter would be isolated (using ball valves upstream and downstream of the flow meter). The well would be allowed to fully recover prior to the start of the constant discharge test. It is Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 4-3 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx anticipated that recovery would take less than 12 hours. Water levels would continue to be monitored at the same frequency during recovery. Once recovery is complete, the transducers water-level readings would be stopped and the data downloaded and analyzed. Constant-Rate Pumping Test 4.5 Once the step-drawdown test has been completed and water levels in the pumping well and affected observation wells have returned to static conditions and transducers have been stopped and reprogramed, a constant-rate pumping test would be conducted at each location (initial two locations AB-18 saprolite pumping well and AB-12 ash pumping followed by AB-18 ash pumping well and AB-15 ash pumping well). Prior to the start of any active pumping a round of manual water levels would be collected in the monitored wells for each test location (Table 2). A constant-rate pumping test involves a control well that is pumped at a constant rate while water-level response (drawdown) is measured in one or more surrounding observation wells and in the pumping well. The goals of a constant-rate pumping test are to estimate hydraulic properties of a saturated porous media such as T, K, and S and to identify potential boundary conditions that may exist. Discharge rates would be measured approximately every 15 minutes during the initial portion of the test (first four hours). If discharge rate is stable, flow readings may be conducted at longer intervals (based on field observations). Water level transducers would be set to record measurements every minute for the duration of the 72-hour test and recovery period. Once pumping has started, the test would run uninterrupted for up to 72 hours. During that period, water-levels would be continuously monitored with data logging pressure transducers and flow measurements continuously recorded (24 hours per day) with an electronic flow meter that averages measurements at five minute intervals. Manual water-level readings would be collected every two hours at each selected well during active pumping to provide automated data backup (Table 2). Manual flow measurements may be conducted based on field observations, as described earlier in this section. Ground water quality field readings and laboratory samples would be collected from the discharge at selected intervals during active pumping (see Section 4.0). Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 5-1 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx WATER QUALITY MEASUREMENTS AND SAMPLING 5.0 In order to help identify the potential geochemical changes that may accrue in the water during the active pumping, water quality data would be collected during each pumping test. Water quality data would include the collection of both field reading and laboratory samples. Particular emphasis would be placed on collection of conductivity and pH data. Changes in water chemistry (conductivity and pH) may indicate contact with a recharge boundary. Groundwater samples would be collected from the pumping well discharge and analyzed for IMP constituent list. Water quality measurements would be collected from the discharge throughout the constant rate discharge test. Readings of pH, specific conductance, temperature, dissolved oxygen, oxidation reduction potential, Eh, and turbidity would be collected once every hour during the test. To facilitate this, a YSI Pro Plus water-quality meter would be plumbed into the discharge line. Flow through the meter would be regulated with both upstream and downstream valves. Water quality samples for laboratory analysis would be collected once per day during the constant rate discharge tests. Each sample would be collected from a sampling port plumbed into the discharge line. Water would be collected in laboratory-prepared sample bottles and immediately placed on ice under strict chain -of-custody. Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 6-1 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx ANALYSIS OF WATER LEVEL DATA 6.0 Analysis of water level fluctuations in monitoring wells would be initially conducted using Aqtesolv® Version 4.5. Baseline data, step-drawdown test data, constant rate discharge data (pumping test), drawdown data, and analytical results would be summarized and included as part of a technical memorandum on the results of pumping tests. Baseline Analysis 6.1 Baseline data would be evaluated to determine whether any long-term trends or interference from nearby production wells are observable. If long-term data trends are observed, the baseline data would be used to adjust the pumping test drawdown data to compensate for the observed trend. Step-Drawdown Test Analysis 6.2 Step-drawdown test analysis would be conducted in the field. The Theis (1935) step- drawdown procedure would be used to analyze data. Additional analytical methods (Dougherty-Badu, 1984; Hantush-Jacob, 1955; Theis, 1935; and Hantush, 1961) may be used depending on results of the step test drawdown data. Step test results would be used to calculate a flow rate that would result in a drawdown of approximately 25 percent of the saturated thickness after 72 hours (and excel spread sheet would be provided for making these calculations). Constant Discharge Rate Test Analysis 6.3 Final analysis methods of drawdown data are dependent on actual results of the tests. Initially, it is assumed that the proposed ash pumping wells are unconfined and the saprolite pumping well may be unconfined, semi-confined or confined. Additionally, drawdown may be observed only in the pumping well. This will result in analysis of the data as a single-well pumping test. If data indicates drawdown in one or more observation wells, the test will be analyzed as a multiple-well pump test. Suggested analytical methodologies for data analysis of both single-well and multiple-well pump tests are outlined in the Technical Guidance Manual for Hydrogeologic Investigations and Groundwater Monitoring, Chapter 4, Slug and Pumping Test, Table 4.2 (single-well pump test) and Table 4.7 (multiple-well pump test) (Clemson, February 1995) at: http://www.clemson.edu/ces/hydro/murdoch/PDF%20 Files/Pumping%20tests,%20EPA%20guidance.pdf Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra Page 7-1 P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Marshall Pumping Test Work Plan.docx REFERENCES 7.0 Theis, C.V., 1935. The relation between the lowering of the piezometric surface and the rate and duration of discharge of a well using groundwater storage, Am. Geophys. Union Trans., vol. 16, pp. 519-524. Dougherty, D.E and D.K. Babu, 1984. Flow to a partially penetrating well in a double porosity reservoir, Water Resources Research, vol. 20, no. 8, pp. 1116-1122. Hantush, M.S. and C.E. Jacob, 1955. Non-steady radial flow in an infinite leaky aquifer, Am. Geophys. Union Trans., vol. 36, pp. 95-100. Hantush, M.S., 1961b. Aquifer tests on partially penetrating wells, Jour. of the Hyd. Div., Proc. of the Am. Soc. of Civil Eng., vol. 87, no. HY5, pp. 171-194. Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra FIGURES 01/18/2018 12:02 PM P:\Duke Energy Carolinas\18. MARSHALL\CSA Update January 2018\DWG\DE MARSHALL FIG 1-1 (SITE LOC MAP).dwg FIGURE 1 SITE LOCATION MAP MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC 8320 NC HIGHWAY 150 E TERRELL, NORTH CAROLINA LAKE NORMAN SURFACE IMPOUNDMENT BOUNDARY GRAPHIC SCALE1000 IN FEET 0 1000 2000 MARSHALL STEAM STATION PARCEL LINE SOURCE:USGS TOPOGRAPHIC MAP OBTAINED FROM THE USGS STORE AThttp://store.usgs.gov/b2c_usgs/b2c/start/%%%28xcm=r3standardpitrex_prd%%%29/.do ASH BASIN 148 RIVER STREET, SUITE 220GREENVILLE, SOUTH CAROLINA 29601PHONE 864-421-9999www.synterracorp.com DATE:DRAWN BY: JOHN CHASTAIN PROJECT MANAGER: BRIAN WILKER LAYOUT: FIG 1 SITE LOCATION 01/18/2018 MARSHALL STEAM STATION FGD LANDFILL PERMIT NO. 1809 DRY ASH LANDFILL (PHASE I) PERMIT NO. 1804 DRY ASH LANDFILL (PHASE II) PERMIT NO. 1804 PV STRUCTURAL FILL INDUSTRIAL LANDFILL NO. 1 PERMIT NO. 1812 ASH BASIN LAKE NORMAN ASH BASIN FGDRESIDUELANDFILL PV STRUCTURALFILL INDUSTRIALLANDFILL #1 C&DLANDFILL ASH LANDFILL(PHASE II) ASHLANDFILL(PHASE I) ASBESTOSLANDFILL ACCESS ROADSTRUCTURAL FILLBEATTY RDMARSHALL RD GR E E N W O O D R D S H E R R I L L S F O R D R D NOTES: 1. IT IS HEREIN NOTED THAT DUKE ENERGY IS NOT WAIVING THE RIGHT TO A COMPLIANCE BOUNDARY(S) TO THE FULL EXTENT SET OUT IN THE LAW OR ATTEMPT TO IMPAIR THE DEPARTMENT'S ABILITY TO CHANGE THE COMPLIANCE BOUNDARY(S) IN THE FUTURE, IF CIRCUMSTANCES WARRANT. 2. PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS. 3. AERIAL PHOTOGRAPHY OBTAINED FROM GOOGLE EARTH PRO ON SEPTEMBER 12, 2017. AERIAL WAS COLLECTED ON OCTOBER 8, 2016. 4. DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE SYSTEM FIPS 3200 (NAD83). FIGURE 2MARSHALL PLANT VICINITY MAPMARSHALL STEAM STATIONDUKE ENERGY CAROLINAS LLC,TERRELL NORTH CAROLINA, DRAWN BY: B. YOUNGPROJECT MANAGER: B. WILKER CHECKED BY: B. WILKER DATE: 01/03/2018 148 RIVER STREET, SUITE 220 GREENVILLE, SOUTH CAROLINA 29601 PHONE 864-421-9999 www.synterracorp.com P:\Duke Energy Progress.1026\00 GIS BASE DATA\Marshall\Mapdocs\CSA_Supplement_2\Fig02-01 - Plant Vicinity Map.mxd 600 0 600 1,200300 GRAPHIC SCALE IN FEET ASH BASIN WASTE BOUNDARY ASH BASIN COMPLIANCE BOUNDARY LANDFILL BOUNDARY STRUCTURAL FILL BOUNDARY LANDFILL COMPLIANCE BOUNDARY DUKE ENERGY CAROLINAS MARSHALL PLANT SITE BOUNDARY <STREAM (AMEC NRTR 2015) WETLAND (MCKIM AND CREED 2016) LEGEND AB-12GROUNDSURFACE10 BGS10020020 BGS30 BGS40 BGS50 BGS60 BGSGROUNDSURFACE10 BGS20 BGS30 BGS40 BGS50 BGS60 BGSSAPROLITEASHTRANSITION ZONE300ROCKAB-10SAB-10SLAB-12DMW-205/04/2018 1:11 PM P:\Duke Energy Carolinas\18. MARSHALL\CAP Update 2018\Aquifer Pumping Test\DWG\DE MARSHALL Ash Dewatering_1.dwg148 RIVER STREET, SUITE 220GREENVILLE, SOUTH CAROLINA 29601PHONE 864-421-9999www.synterracorp.comFIGURE 3 LOCATION FOR AB-12 WELL CLUSTER PUMPING TEST MARSHALL STEAM STATIONDUKE ENERGY CAROLINAS, LLCTERRELL, NORTH CAROLINADUKEENERGYCAROLINASPROJECT MANAGER:LAYOUT:DRAWN BY:DATE:CHRIS BRUCEAB-12 Cluster02/19/18500`100GRAPHIC SCALEIN FEETCONCEPTUAL PROPOSED PUMPING TESTWELL SCHEMATICCONCEPTUAL LAYOUT, ACTUAL LOCATIONS FORWELLS HAVE NOT BEEN SURVEYEDLEGENDMARSHALL STEAM STATION8320 NC HIGHWAY 150 ETERRELL, NORTH CAROLINAEXISTING AB-12SEXISTING AB-12SLBRIAN WILKERAB-15BRWELL IN BEDROCKAB-15SLWELL IN ASH PORE WATERASH BASIN WASTE BOUNDARY (APPROXIMATE)BGSBELOW GROUND SURFACEAB-15DWELL IN TRANSITION ZONEWELL IN SAPROLITECCR-15SPROPOSED PUMPING WELL (ASH PORE WATER)PROPOSED OBSERVATION WELL (LOWER ASH PORE WATER)PROPOSED OBSERVATION WELL (UPPER ASH PORE WATER)PROPOSED PUMPING WELL (SAPROLITE)PROPOSED OBSERVATION WELL (MEDIUM ASH PORE WATER)PROPOSED OBSERVATION WELL (SAPROLITE)AB-12SM (15)AB-12PAB-12SLAB-12SUAB-12BRAB-12SAB-12SLAB-12SM (30)AB-12PAB-12SM (15)AB-12SUAB-12SLAB-12SM (30)AQUIFER TEST DISCHARGE LINE AND DIRECTION OF FLOWDISCHARGE LINE SAPROLITEASHAB-15GROUNDSURFACE10 BGS10020020 BGS30 BGS40 BGS50 BGS60 BGSGROUNDSURFACE10 BGS20 BGS30 BGS40 BGS50 BGS60 BGS300TRANSITION ZONEROCK05/04/2018 1:00 PM P:\Duke Energy Carolinas\18. MARSHALL\CAP Update 2018\Aquifer Pumping Test\DWG\DE MARSHALL Ash Dewatering_1.dwg148 RIVER STREET, SUITE 220GREENVILLE, SOUTH CAROLINA 29601PHONE 864-421-9999www.synterracorp.comFIGURE 4LOCATION FOR AB-15 WELL CLUSTER PUMPING TEST MARSHALL STEAM STATIONDUKE ENERGY CAROLINAS, LLCTERRELL, NORTH CAROLINADUKEENERGYCAROLINASPROJECT MANAGER:LAYOUT:DRAWN BY:DATE:CHRIS BRUCEAB-15 Cluster02/19/18CONCEPTUAL PROPOSED PUMPING TESTWELL SCHEMATICMARSHALL STEAM STATION8320 NC HIGHWAY 150 ETERRELL, NORTH CAROLINA500`100GRAPHIC SCALEIN FEETEXISTING AB-15SEXISTING AB-15SLAB-15SLAB-15DAB-15SAB-15BRBRIAN WILKERLEGENDAB-15BRWELL IN BEDROCKAB-15SLWELL IN ASH PORE WATERASH BASIN WASTE BOUNDARY (APPROXIMATE)BGSBELOW GROUND SURFACEAB-15DWELL IN TRANSITION ZONEWELL IN SAPROLITECCR-15SPROPOSED PUMPING WELL (ASH PORE WATER)PROPOSED OBSERVATION WELL (LOWER ASH PORE WATER)PROPOSED OBSERVATION WELL (UPPER ASH PORE WATER)PROPOSED PUMPING WELL (SAPROLITE)PROPOSED OBSERVATION WELL (MEDIUM ASH PORE WATER)PROPOSED OBSERVATION WELL (SAPROLITE)AB-15PAB-15SLAB-15SUDISCHARGE LINEAB-15PAB-15SLAB-15SUCONCEPTUAL LAYOUT, ACTUAL LOCATIONS FORWELLS HAVE NOT BEEN SURVEYEDAQUIFER TEST DISCHARGE LINE AND DIRECTION OF FLOW SAPROLITEASHGROUNDSURFACE10 BGS10020020 BGS30 BGS40 BGS50 BGS60 BGSGROUNDSURFACE10 BGS20 BGS30 BGS40 BGS50 BGS60 BGS300TRANSITION ZONEROCKAB-18AB-18DAB-18S05/04/2018 1:23 PM P:\Duke Energy Carolinas\18. MARSHALL\CAP Update 2018\Aquifer Pumping Test\DWG\DE MARSHALL Ash Dewatering_1.dwg148 RIVER STREET, SUITE 220GREENVILLE, SOUTH CAROLINA 29601PHONE 864-421-9999www.synterracorp.comFIGURE 5LOCATIONS FOR AB-18 WELL CLUSTER PUMPING TEST MARSHALL STEAM STATIONDUKE ENERGY CAROLINAS, LLCTERRELL, NORTH CAROLINADUKEENERGYCAROLINASPROJECT MANAGER:LAYOUT:DRAWN BY:DATE:CHRIS BRUCEFigure 102/09/18CONCEPTUAL PROPOSED PUMPING TESTWELL SCHEMATICMARSHALL STEAM STATION8320 NC HIGHWAY 150 ETERRELL, NORTH CAROLINA500`100GRAPHIC SCALEIN FEETEXISTING AB-18SA TOTAL OF TWO PUMPING TEST WILL BE CONDUCTED AT THIS LOCATION.ONE WILL BE IN THE ASH AND A SECOND WILL BE IN THE UNDERLYINGSAPROLITE.BRIAN WILKERAB-15BRWELL IN BEDROCKAB-15SLWELL IN ASH PORE WATERASH BASIN WASTE BOUNDARY (APPROXIMATE)LEGENDBGSBELOW GROUND SURFACEAB-15DWELL IN TRANSITION ZONEWELL IN SAPROLITECCR-15SPROPOSED PUMPING WELL (ASH PORE WATER)PROPOSED OBSERVATION WELL (LOWER ASH PORE WATER)PROPOSED OBSERVATION WELL (UPPER ASH PORE WATER)PROPOSED PUMPING WELL (SAPROLITE)PROPOSED OBSERVATION WELL (MEDIUM ASH PORE WATER)PROPOSED OBSERVATION WELL (SAPROLITE)AB-18APAB-18SL (15)AB-18SUAB-18SPAB-18SL (30)AB-18DUAB-18SPAB-18DUAB-18APAB-18SL (15)AB-18SUAB-18SL (30)CONCEPTUAL LAYOUT, ACTUAL LOCATIONS FORWELLS HAVE NOT BEEN SURVEYEDAQUIFER TEST DISCHARGE LINE AND DIRECTION OF FLOWDISCHARGE LINE FLOW METER CONFIGURATION THIS SHOWS THE GENERAL CONFI GURATION OF THE DISCHARGE LINE AND FlLOW METER. FLOW METER TYPE MAY VERY BUT SHOULD =oLLOW THIS GENERAL CONFIGUJRATION. "' synTerra 148 RIVER STREET. SUITE 220 GREENVILLc, SOUTH CAROLIN/\ 29601 PHONE 864-421-9999 www.synt.eracorp.com DRAWN BY·CHRIS BRUCE DATE; 04/01/18 PROJECT MANAGER: BRIAN WILKER LAYOUT: Flgul"8 3 FIGURE 6 TYPICAL FLOW METER CONFIGURATION MARSHALL STEAM STATIONDUKE ENERGY CAROLINAS, LLCTERRELL, NORTH CAROLINA SOURCE: 25 20 £ 15 C: :-0 -0 10 s 0 0 ' . STEP DRAWDOWN TEST •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• .......... , ........................ . t t t "STEP" PORTION OF CURVE-----····-············ ···············�·-·············· .•........ � ......•......•.....•..... RECOVERY PORTION OF CURVE "FLAT" PORTION OF CURVE ............. "' ........... :• ......... .·····t .................................... �-··············· .............. �························· ••...•...•.... . • • • t ......................................................... �················ ··········�························· • • • 5 10 15 Time [h] "' 20 148 RIVER STREET. SUITE 220 GREENVILLc, SOUTH CAROLIN/\ 29601 PHONE 864-421-9999 www.synt.eracorp.com MLU (Multi-Layer Unsteady state) http://www.microfem.1tl/products/mlu.html synTerra DRAWN BY: CHRIS BRUCE PROJECT MANAGER: BRIAN WILKER LAYOl/T: Figure 4 CATE; 04/0'\,1 18 or;: 04/2018 1:29 PM � Duke E:ner 25 • ■ • ■ • Pumping Period 1, Layer: 1 Pumping Period 2, Layer: 1 Pumping Period 3, Layer: 1 Pumping Period 4, Layer: 1 Pumping Period 5, Layer: 1 Pumping Period 6, Layer: Pumping Period 7, Layer: Pumping Period 1 Pumping Period 1 Pumping Period 1 Pumping Period 1 Pumping Period 1 Pumping Period 1 Recovery Period FIGURE 7 TYPICAL STEP TEST DRAWDOWN CURVE MARSHALL STEAM STATIONDUKE ENERGY CAROLINAS, LLC TERRELL, NORTH CAROLINA Pumping Test Work Plan May 2018 Duke Energy Carolinas, LLC, Marshall Steam Station SynTerra TABLES TABLE 1 WELL CONSTRUCTION DETAILS FOR PUMPING TESTS MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Identification Well Purpose Approximate Distance from Pumping Well (Feet) Monitoring Zone Base of Ash (ft bgs) Borehole Diameter (Inches) Well Diameter (inches) Total Well Depth1 (Feet BGS) Screen Length (Feet) Top of Filter Sand Pack (Feet BGS) Top of Bentonite Seal (Feet BGS) AB-12 LOCATION AB-12S (Existing)Observation TBD Upper Ash 49 NA 2 13 10 2 1 AB-12SL (Existing)Observation TBD Lower Ash 49 NA 2 50 10 38 36 AB-12D (Existing)Observation TBD Transition Zone 49 NA 2 73.69 5 60 58 AB-12P Pumping NA Lower Ash 45 13 10 6 45 10 32 29 AB-12SU Observation 15 Upper Ash 45 6 2 15 5 8 5 AB-12SM(15)Observation 15 Medium Ash 45 6 2 28 5 21 18 AB-12SL Observation 15 Lower Ash 45 6 2 50 5 42.6 39.6 AB-12SM(30)Observation 30 Medium Ash 49 6 2 27.5 5 20 18 AB-15S (Existing)Observation TBD Upper Ash 46 NA 2 20 10 37 35 AB-15SL (Existing)Observation TBD Lower Ash 46 NA 2 50 10 3 2 AB-15D (Existing)Observation TBD Transition Zone 46 NA 2 77.78 5 62 60 AB-15P Pumping NA Lower Ash 50 13 10 6 50 10 37 34 AB-15SU Observation 15 Upper Ash 50 6 2 25 5 17.5 14 AB-15SL Observation 15 Lower Ash 50 6 2 48 5 41 36 AB-18S (Existing)Observation TBD Upper Ash 29.5 NA 2 14 10 2 1 AB-18AP Pumping NA Lower Ash 35 13 10 6 35 10 22 19 AB-18SU Observation 15 Upper Ash 29.5 6 2 13 5 6 4 AB-18SL(15)Observation 15 Lower Ash 29.5 6 2 32.5 5 25 21 AB-18SL(30)Observation 30 Lower Ash 35 6 2 36 5 25 22 AB-18SP Pumping NA Saprolite 35 13 10 6 53 10 40 35 AB-18DU Observation 30 Saprolite 34 6 2 53 10 41 38.6 AB-10S (Existing)Observation TBD Upper Ash 51 NA 2 27.87 15 7 5 AB-10SL (Existing)Observation TBD Lower Ash 51 NA 2 56.00 10 38 36 AB-13S (Existing)Observation TBD Upper Ash 62 NA 2 33.52 15 13 11 Prepared by: CHB Checked by: BDW Notes: Total depths and well construction details were determined based on field observations Bold - Indicates recently installed wells 1 "Total Well Depth" is the depth to the bottom of the screened interval, as measured during well installation. BGS - Below ground surface NA - Not applicable TBD - to be determined AB-18 LOCATION AB-15 LOCATION OBSERVATION WELLS (BEYOND TEST LOCATION) P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Tables\Table 1 Well Construction - Marshall Ash Basin Pumping Tests Page 1 of 1 TABLE 2 SUMMARY OF PUMPING AND OBSERVATION WELLS MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Step Test Pumping Test Step Test Pumping Test Step Test (Ash) Pumping Test (Ash) Step Test (Saprolite) Pumping Test (Saprolite) AB-12S X AB-12SL X AB-12D X AB-12P (Ash Pumping Well)X X AB-12SU (Upper Ash)X AB-12SM(15') (Medium Ash) X AB-12SL (Lower Ash)X AB-12SM(30') (Medium Ash)X AB-15S X AB-15SL X AB-15D X AB-15P (Ash Pumping Well)X X AB-15SU (Upper Ash)X X X AB-15SL (Lower Ash) X X X AB-18S X X X AB-18AP (Ash Pumping Well)X X X AB-18SU (Upper Ash)X X AB-18SL(15') (Lower Ash) X X AB-18SL(30') (Lower Ash)X X AB-18SP (Saprolite Pumping Well)X X X AB-18DU (Saprolite Observation Well)X X AB-10S X AB-10SL X AB-13S X X Notes:Prepared by: CHB Checked by: BDW Refer to Work Plan for frequency of manual water level measurements Well ID AB-12 CLUSTER AB-15 CLUSTER AB-18 CLUSTER P:\Duke Energy Carolinas\18. MARSHALL\08.CCP Ash Basin Pumping Test\Work Plan\Tables\Table 2 Summary of Pumping and Observation WellsTable 2 Summary of Pumping and Observation Wells Page 1 of 1