HomeMy WebLinkAboutGW Assessment PlanGroundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
TABLE OF CONTENTS
SECTION PAGE
Executive Summary
1.0 Introduction ......................................................................................................................1
2.0 Site History and Source Characterization ...................................................................3
2.1 Plant Description .........................................................................................................3
2.2 Ash Basin ......................................................................................................................3
2.3 Groundwater Monitoring System ............................................................................3
3.0 Receptor Information ......................................................................................................5
4.0 Regional Geology and Hydrogeology .........................................................................7
5.0 Site Geology and Hydrogeology ...................................................................................9
6.0 Groundwater Monitoring Results ..............................................................................10
6.1 Groundwater Analytical Results ............................................................................10
6.2 Preliminary Statistical Evaluation Results ............................................................10
7.0 Assessment Work Plan..................................................................................................12
7.1 Anticipated Ash Basin Boring Locations ...............................................................12
7.2 Anticipated Soil Boring Locations ..........................................................................13
7.2.1 Inside Ash Basin ..................................................................................................13
7.2.2 Outside Ash Basin ...............................................................................................13
7.3 Anticipated Sediment and Surface Water Locations ...........................................14
7.4 Anticipated Groundwater Monitoring Wells .......................................................14
7.4.1 General Construction, Development, Aquifer Testing ..................................14
7.4.2 Background Wells ...............................................................................................16
7.4.3 Ash Basin ..............................................................................................................16
7.4.4 Downgradient Assessment Areas ....................................................................16
7.4.5 Groundwater Sampling .....................................................................................16
7.5 Influence of Pumping Wells on Groundwater System ........................................17
7.6 Site Conceptual Model .............................................................................................17
7.7 Development of Groundwater Computer Model ................................................17
8.0 Implementation Schedule and Report Submittal ....................................................19
9.0 References ........................................................................................................................21
Page i
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
List of Figures
Figure 1 - Site Location Map
Figure 2 - Site Layout
Figure 3 - Geology Map
Figure 4 - Anticipated Sample Locations
List of Tables
Table 1 - Summary of Concentration Ranges for Constituents Detected Greater Than
2L Standards
Table 2 - Groundwater Assessment Parameter List
Table 3 - Assessment Sampling Plan
List of Appendices
Appendix A - NCDENR Letter of August 13, 2014
Page ii
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
EXECUTIVE SUMMARY
Duke Energy Progress, Inc. (Duke Energy), owns and operates the W.H. Weatherspoon
Power plant (Weatherspoon Plant), located near Lumberton, in Robeson County, North
Carolina. The coal ash residue from the coal combustion process was placed in the
Plant’s ash basin, which is permitted by the North Carolina Department of
Environment and Natural Resources (NCDENR) Division of Water Resources (DWR)
under the National Pollution Discharge Elimination System.
In a letter dated August 13, 2014, the DWR requested that Duke Energy prepare a
Groundwater Assessment Plan to identify the source and cause of contamination, any
imminent hazards to public health and safety and actions taken to mitigate them, and
all receptors and significant exposure pathways. In addition, the plan should determine
the horizontal and vertical extent of soil and groundwater contamination and all
significant factors affecting contaminant transport and the geological and
hydrogeological features influencing the movement, chemical, and physical character of
the contaminants.
The following plan includes;
• Implementation of a receptor survey to identify water supply wells, public water
supplies, surface water bodies, and wellhead protection areas (if present) within a
0.5 mile radius of the Sutton Plant waste compliance boundary;
• Installation of borings within the ash basins for chemical and geotechnical analysis
of residuals and in-place soils;
• Installation of background soil borings;
• Installation of monitoring wells and piezometers;
• Collection and analysis of groundwater samples from existing site wells and newly
installed monitoring wells;
• Statistical evaluation of groundwater analytical data; and
• Development of a groundwater model to evaluate the long term fate and transport
of constituents of concern in groundwater associated with the ash management
units.
The information obtained through this Work Plan will be utilized to prepare a
Comprehensive Site Assessment (CSA) report in accordance with the Notice of
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
Regulatory Requirements (NORR). In addition to the components listed above, a
human health and ecological risk assessment will be conducted. This assessment will
include the preparation of a conceptual site model illustrating potential pathways from
the source to possible receptors.
During the CSA process if additional investigations are required NCDENR, will be
notified.
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
1.0 INTRODUCTION
Duke Energy Progress, Inc. (Duke Energy), owns and operates the W.H. Weatherspoon
Power plant (Weatherspoon Plant), located near Lumberton, in Robeson County, North
Carolina (Figure 1). The operations included coal-fired electricity-generating units until
they were retired in October 2011. The coal ash residue from the coal combustion
process was placed in the Plant’s ash basin. The discharge from the ash basin is
permitted by the North Carolina Department of Environment and Natural Resources
(NCDENR) Division of Water Resources (DWR) under the National Pollution Discharge
Elimination System.
Groundwater monitoring has been performed in accordance with the conditions stated
in NPDES Permit #NC0005363 beginning in November 2010. Elevated concentrations of
iron, cadmium, thallium, and manganese have been measured in groundwater samples
collected at monitoring wells BW-1, CW-1, CW-2, and CW-3, when compared to the
North Carolina Administrative Code (NCAC) Title 15A Chapter 02L.0202 groundwater
quality Standards (2L Standards).
The compliance boundary for groundwater quality for the Weatherspoon ash basin is
defined in accordance with NCAC Title 15A Chapter 02L.0107(a) (T15 A NCAC 02L
.0107(a)) as being established at either 500 feet from the waste boundary or at the
property boundary, whichever is closest to the waste. Monitoring wells CW-1, CW-2,
and CW-3 are located at or near the downgradient compliance boundary. The location
of the monitoring wells is shown on Figure 2. Well BW-1 is located northwest of the
ash basin and is considered the upgradient background well. Analytical results from
sampling these wells are submitted to NCDENR no later than the last working day of
the month following the sampling month.
In a Notice of Regulatory Requirements (NORR) letter dated August 13, 2014, the DWR
of the NCDENR requested that Duke Energy prepare a Groundwater Assessment Plan
to conduct a Comprehensive Site Assessment (CSA) in accordance with 15A NCAC 02L
.0106(g) to address groundwater constituents detected at concentrations greater than 2L
Standards at the compliance boundary. A summary of these concentrations is provided
in Table 1 and a copy of the DWR letter is provided in Appendix A.
SynTerra has prepared this Groundwater Assessment Plan on behalf of Duke Energy to
fulfill the DWR letter request and to satisfy the requirements of NC Senate Bill 729 as
ratified August 2014.
Page 1
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
Specifically, this document describes the plans to meet the requirements of 15A NCAC
02L .0106(g) including;
• Identify the source and cause of contamination;
• Identify any imminent hazards to public health and safety and actions taken to
mitigate them in accordance to 15A NCAC 02L .0106(f);
• Identify receptors and significant exposure pathways;
• Determine the horizontal and vertical extent of soil and groundwater
contamination and all significant factors affecting contaminant transport; and
• Determine geological and hydrogeological features influencing the movement,
chemical, and physical character of the contaminants.
The information obtained through this Work Plan will be utilized to prepare a CSA
report in accordance with the requirements of the NORR. In addition to the
components listed above, a human health and ecological risk assessment will be
conducted. This assessment will include the preparation of a conceptual site model
illustrating potential pathways from the source to possible receptors.
During the CSA process if additional investigations are required NCDENR, will be
notified.
Page 2
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
2.0 SITE HISTORY AND SOURCE CHARACTERIZATION
2.1 Plant Description
The Weatherspoon Plant is a former coal-fired electricity-generating facility located in
Robeson County, North Carolina, near the city of Lumberton. The location of the plant
is shown on Figure 1. The Weatherspoon Plant started operations in 1949. Two
additional units were added in the 1950s. Four oil and natural gas fueled combustion
turbines were added in the 1970s.
As of October 2011, all of the coal-fired units were retired. The four oil and natural gas
fueled units continue to operate to meet peak demand. The facility is located southeast
of Lumberton on the east side of North Carolina Highway 72. The topography around
the property generally slopes downward toward the Lumber River.
The Weatherspoon Plant utilizes an approximate 225-acre cooling pond located adjacent
to the Lumber River. The ash basin is located north of the cooling pond, northeast of
the plant.
2.2 Ash Basin
The plant, cooling pond, and ash basin are located on the east side of the Lumber River.
The ash basin is located north of the cooling pond, northeast of the plant, as shown on
Figure 2. The ash basin consists of approximately 65 acres. The 500 foot compliance
boundary circles the ash basin.
The ash basin is impounded by an earthen dike. Ash generated from coal combustion
was stored on-site in the ash basin. Overflow from the ash basin drains to the northeast
corner of the cooling pond. The Weatherspoon Plant NPDES permit (NC005363)
authorizes the discharge of recirculated cooling water, ash sluice water, domestic
wastewater, chemical metal cleaning water, and low volume wastewater including
reject water from a reverse osmosis water treatment unit from the cooling pond via
Outfall 001 to the Lumber River under severe weather conditions and cooling pond
maintenance.
2.3 Groundwater Monitoring System
Four (4) wells comprise the compliance monitoring well network at the Weatherspoon
Plant. These wells include one (1) background well and three (3) downgradient wells.
The locations of the monitoring wells, the waste boundary, and the compliance
boundary are shown on Figure 2.
Monitoring well BW-1 represents background groundwater quality, north of the ash
basin. The compliance boundary well for the east side of the ash basin is CW-3.
Page 3
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
Monitoring well CW-1 is the compliance boundary well for the south side of the ash
basin, and monitoring well CW-2 is the downgradient compliance boundary well to the
southeast of the ash basin.
In accordance with the current NPDES permit, the monitoring wells are sampled three
times per year in March, June, and October for the parameters listed below. The
analytical results for the monitoring program are compared to the 2L Standards or the
site-specific background concentrations.
NPDES Groundwater Monitoring Requirements
Well
Nomenclature Parameter Description Frequency
Monitoring
Wells BW-1,
CW-1, CW-2,
CW-3
Antimony Chromium Nickel Thallium
March, June,
and October
Arsenic Copper Nitrate Water Level
Barium Iron pH Zinc
Boron Lead Selenium
Cadmium Manganese Sulfate
Chloride Mercury TDS
Page 4
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
3.0 RECEPTOR INFORMATION
The August 13, 2014 NORR states:
No later than October 14th, 2014 as authorized pursuant to 15A NCAC 02L.0106(g),
the DWR is requesting that Duke perform a receptor survey at each of the subject
facilities and submitted to the DWR. The receptor survey is required by 15A NCAC 02L
.0106(g) and shall include identification of all receptors within a radius of 2,640 feet
(one-half mile) from the established compliance boundary identified in the respective
National Pollutant Discharge Elimination System (NPDES) permits. Receptors shall
include, but shall not be limited to, public and private water supply wells (including
irrigation wells and unused or abandoned wells) and surface water features within one-
half mile of the facility compliance boundary. For those facilities for which Duke has
already submitted a receptor survey, please update your submittals to ensure they meet
the requirements stated in this letter and referenced attachments and submit them with
the others. If they do not meet these requirements, you must modify and resubmit the
plans.
The results of the receptor survey shall be presented on a sufficiently scaled map. The
map shall show the coal ash facility location, the facility property boundary, the waste
and compliance boundaries, and all monitoring wells listed in the respective NPDES
permits. Any identified water supply wells shall be located on the map and shall have the
well owner's name and location address listed on a separate table that can be matched to
its location on the map.
In accordance with the requirements of the NORR, SynTerra is in the process of
conducting a receptor survey to identify water supply wells, public water supplies,
surface water bodies, and wellhead protection areas (if present) within a 0.5 mile radius
of the Weatherspoon Plant compliance boundary. The compliance boundary for
groundwater quality, in relation to the ash basin, is defined in accordance with 15A
NCAC 02L .0107(a) as being established at either 500 feet from the waste boundary or at
the property boundary, whichever is closer to the source. The receptors include public
and private water supply wells (including irrigation wells and unused or abandoned
wells) and surface water features within a 0.5-mile radius of the Weatherspoon Plant
compliance boundary.
The survey consists of a review of publicly available data from NCDENR Department
of Environmental Health (DEH), NC OneMap GeoSpatial Portal, DWR Source Water
Assessment Program (SWAP) online database, Robeson County GIS, Environmental
Data Resources, Inc. (EDR) Records Review, the USGS National Hydrography Dataset
Page 5
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
(NHD), as well as a vehicular survey along public roads located within 0.5 mile radius
of the compliance boundary.
Additional receptor information will be collected as part of the anticipated assessment
to comply with the CSA guidelines (NCDENR August 2014).
Page 6
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
4.0 REGIONAL GEOLOGY AND HYDROGEOLOGY
Geographically, the Weatherspoon Plant lies within the Coastal Plain Physiographic
Province (North Carolina Department of Natural Resources and Community
Development, 1985).
The North Carolina Coastal Plain is approximately 90 to 150 miles wide from the
Atlantic Ocean westward to its boundary with the Piedmont province (Winner, Jr. and
Coble, 1989). Two natural subdivisions of the Coastal Plain were described by Stuckey
(1965): the Tidewater region and the Inner Coastal Plain. The Weatherspoon Plant is
located within the Inner Coastal Plain, which consists of the gently rolling land surface
between the Tidewater region and the Fall Line (Winner, Jr. and Coble, 1989). The
Weatherspoon Plant is located within a subdivision of the Inner Coastal Plain that is
typified by swampy areas in the flat uplands between major river systems. The
Weatherspoon Plant is located on the east side of the Lumber River.
The Coastal Plain comprises a wedge shaped sequence of stratified marine and non-
marine sedimentary rocks deposited on crystalline basement. The sedimentary
sequences range in age from recent to lower Cretaceous (Winner, Jr. and Coble, 1989).
In this region, units of confined aquifers divided by confining layers overlay the
crystalline bedrock. These confined aquifers consist of laterally continuous silt and clay
rich layers. The Lower Cape Fear and Upper Cape Fear aquifers are depicted as the
lower-most marine sediment units in the Robeson County area (USGS 1989). The Upper
Cape Fear aquifer is overlain by a semi-confining unit that separates the Upper Cape
Fear aquifer from the overlying Black Creek aquifer. A semi-confining unit over the
Black Creek aquifer separates the Black Creek aquifer from the overlying Peedee
aquifer. In this region, the semi-confining unit between the Peedee aquifer and the
overlying Yorktown and/or Coastal Plain deposits that comprise the surficial aquifer is
discontinuous. A geologic map for the Weatherspoon site is provided as Figure 3.
The surficial aquifer is Quaternary in age and primarily composed of sands with inter-
bedded silts and clays. The Yorktown Formation is of the Tertiary Era and generally
consists of fine-grained sands, shell material, and bluish gray silts and clays. The contact
between the Yorktown and the underlying Peedee may represent an erosion
unconformity. Cretaceous in age, the Peedee formation generally consists of gray or
light brown, silty, fine to very fine grained quartz sand with traces of glauconite,
phosphorite, oyster shells, and pyrite. The Black Creek Formation is also considered
Cretaceous in age and generally consists of clay, gray to black, lignitic; contains thin
beds and laminae of fine-grained micaceous sand and thick lenses of cross-bedded
sand. Glauconitic, fossiliferous clayey sand lenses are also reported to exist in the upper
Page 7
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
part of the Black Creek Formation. The surficial aquifer is the saturated zone that
underlies the land surface and is generally shallow in the region. It is the first aquifer to
receive recharge from precipitation. This recharge water is stored in the surface aquifer
as the groundwater migrates toward local discharge points (lakes, rivers, streams, etc.).
A portion of the groundwater in the surficial aquifer migrates vertically to recharge
deeper, confined to semi-confined aquifers. On average, only a fraction of the surficial
aquifer recharge reaches the deeper aquifers (Giese et al., 1997). This finding is thought
to reflect the influence of confining and semi-confining layers and the substantial
amount of time it takes for groundwater to reach these deeper units.
Underlying the surficial aquifer, which has an average thickness of 60 feet in the area, is
the Peedee confining unit, with an average thickness of 25 feet (Giese et al., 1997). The
Peedee aquifer is composed of fine to medium grained sand interbedded with gray to
black marine clay and silt (Giese et al., 1997). Shells are common throughout the
aquifer. The thickness of the aquifer ranges from 10 feet at its eastern edge to greater
than 300 feet thick (Giese et al., 1997).
In the Robeson County part of the North Carolina Coastal Plain, groundwater is
obtained from the surficial, Peedee, Yorktown, and Black Creek aquifers. The Coastal
Plain groundwater system consists of aquifers comprised of permeable sands, gravels,
and limestone separated by confining units of less permeable sediment.
According to Winner, Jr. and Coble (1989), the surficial aquifer consists primarily of fine
sands, clays, shells, peat beds, and scattered deposits of coarse-grained material in the
form of relic beach ridges and floodplain alluvium. The areal extent of the surficial
aquifer in the Coastal Plain is approximately 25,000 square miles with an average
thickness of 35 feet. Average recharge to the surficial aquifer is between 12 and 20
inches per year. The average estimated hydraulic conductivity is 29 feet per day
(Winner, Jr. and Coble, 1989).
Page 8
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
5.0 SITE GEOLOGY AND HYDROGEOLOGY
Based on previous activities at the site, subsurface lithology is comprised of thin
isolated deposits of sub-angular to well-rounded gravel alluvium or Coastal Plain
Surficial Deposits that consist of black, gray, brown, light red tan or white silty fine
sand, sandy silt, clayey silt or sandy clay. These deposits vary in thickness from
approximately 3 to 30 feet. Yorktown Formation deposits (identified based on the
characteristic color and content described for the formation) approximately 14 to 35 feet
thick underlie the surficial deposits. The Yorktown Formation deposits at the
Weatherspoon Plant consist of blue, green, gray, and white fossiliferous sand and sandy
silty clay. The Yorktown Formation occurs unconformably on the eroded surface of the
Peedee Formation. Peedee sediments at Weatherspoon are gray, dark green, olive,
brown, and light gray silty clay, sandy clay and silty fine to medium sand. The
thickness of the Peedee Formation ranges from approximately 22 to 42 feet. Sediments
identified as the Black Creek Formation with characteristic dark gray to black
micaceous clay and sand seams with abundant mica were encountered below the
Peedee Formation.
The first occurrence of groundwater at the Weatherspoon Plant is in the surficial aquifer
at depths ranging from three to ten feet below land surface. The most recent water level
measurements and corresponding elevations from the June 2014 routine groundwater
monitoring event indicated the groundwater flow direction in the surficial aquifer is to
the southeast towards the cooling pond, following the site topography. Water level
maps that have been generated from data collected in the intermediate and deep
aquifers during additional investigations indicate similar a flow direction for those
aquifers.
Shallow groundwater gradients measured vary from 0.005 feet per foot (ft/ft) (northeast
of and exterior to the ash basin) to 0.125 ft/ft (across the southern dike). In a very broad
sense, overall groundwater gradients averaged 0.012 ft/ft west of the ash basin; 0.012
ft/ft in the ash basin; 0.006 ft/ft east of the ash basin; and, 0.05 ft/ft across the southern
dike to the cooling pond.
The surface of groundwater at the Weatherspoon Plant is typically located at depths of
4 to 8 feet below ground surface, depending on antecedent precipitation and
topography. An average transmissivity value of 3,000 square feet per day (ft2/day) was
estimated by Giese et al. (1997) for the surficial sand aquifer in the region. Based on
preliminary work by others, the transmissivity for the surficial aquifer, calculated from
pump tests ranges between approximately 400 and 1,750 ft2/day.
Page 9
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
6.0 GROUNDWATER MONITORING RESULTS
6.1 Groundwater Analytical Results
In June 2014 SynTerra conducted the twelfth groundwater sampling event as part of the
NPDES Permit. The analytical data indicates that cadmium and thallium have only
been detected above the 2L Standard at the background well (BW-1). Cadmium has
only been detected above the 2L Standard once, during the March 2013 sampling event
and thallium has only been detected above the 2L Standard during the June 2012 event.
A summary of the detected concentration ranges for constituents detected at
concentrations greater than the 2L Standards is provided in Table 1.
Iron has been detected above the 2L Standard in the background and in the three
compliance wells during multiple sampling events. The highest concentration of iron
detected in background well was detected during the most recent (June 2014) sampling
event.
Manganese has been detected at concentrations slightly greater than the 2L Standard at
compliance wells CW-1 and CW-3. The elevated concentrations of manganese at well
CW-1 occurred in November 2011 and June of 2012. The only elevated concentration of
manganese at well CW-3 occurred in March 2013.
The groundwater pH tends to be lower than the 2L Standard range in the background
and compliance boundary wells.
A preliminary assessment of the available groundwater data indicates the regional
background groundwater pH is less than the 2L Standard range. The elevated
concentrations of cadmium and thallium detected in background well BW-1 appear to
be data outliers. The regional aquifer also tends to have iron concentrations greater
than the 2L Standard. An alternate 2L Standard for iron of 2,040 µg/L has been
suggested by the NCDENR based upon data available through March 2013.
6.2 Preliminary Statistical Evaluation Results
As a preliminary evaluation tool, statistical analysis was conducted on the groundwater
analytical data collected between November 2010 and June 2014 at the Weatherspoon
Plant. The statistical analysis was conducted in accordance with US EPA, Statistical
Training Course for Ground Water Monitoring Data Analysis, EPA530-R-93-003, 1992 and
US EPA’s Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities; Unified
Guidance EPA 530/R-09-007, March 2009.
An inter-well prediction interval statistical analysis was utilized to evaluate the
groundwater data from the Weatherspoon Plant. The inter-well prediction interval
Page 10
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
statistical evaluation involves comparing background well data to the results for the
most recent sample date from compliance wells. As discussed in Section 2.0,
monitoring well BW-1 is considered the upgradient background well for the ash basin
and monitoring wells CW-1, CW-2, and CW-3 are considered downgradient compliance
wells. Statistical analysis was performed on inorganic constituents in samples from
wells with detectable concentrations in the most recent routine sampling event (June
2014).
Samples with detected inorganic constituents in compliance monitoring wells during
the June 2014 sampling event were analyzed, using the appropriate prediction interval
procedure. Preliminary results indicated that there were no confirmed statistically
significant increases (SSIs) identified in the June 2014 data set. A more robust statistical
analysis will be completed as part of the CSA.
Page 11
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
7.0 ASSESSMENT WORK PLAN
The scope of work discussed in this plan is designed to fulfill the DWR letter request
and to satisfy the requirements of NC Senate Bill 729 as ratified August 2014.
Specifically, this document describes the plans to meet the requirements of 15A NCAC
02L .0106(g) and to;
• Identify the source and cause of contamination;
• Identify any imminent hazards to public health and safety and actions taken to
mitigate them in accordance to 15A NCAC 02L .0106(f);
• Identify all receptors and significant exposure pathways;
• Determine the horizontal and vertical extent of soil and groundwater
contamination and all significant factors affecting contaminant transport; and
• Determine geological and hydrogeological features influencing the movement,
chemical, and physical character of the contaminants.
The following sections generally describe anticipated assessment activities to fill data
gaps associated with the source, vertical and horizontal extent, in soil and groundwater,
for those constituents discussed in Section 1.0 that have been detected at concentrations
greater than the 2L Standards. The assessment may to be iterative with possible
additional assessment activities prior to the preparation of the CSA. The following are
the activities anticipated at this time.
7.1 Anticipated Ash Basin Boring Locations
Borings are anticipated within the ash basin to determine the thickness of ash present in
the basin as well as to determine the current residual saturation of the ash. Four
borings are anticipated in the ash basin at the locations shown on Figure 4.
The borings may be conducted using Direct Push Technology (DPT) or Roto-Sonic
drilling (or similar methods), to provide continuous soil cores through ash and into the
underlying native soil. Drilling will be extended to approximately 20 feet below the
bottom of the ash to allow for characterization of the underlying native soil.
Ash samples will be collected for laboratory analysis of total metals and SPLP metals.
To characterize the variation in ash composition, two samples, a shallow and a deep, are
anticipated at each location, if the ash thickness is less than 20 feet. If the thickness is
Page 12
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
greater than 20 feet, three samples (shallow, intermediate, and deep), may be collected.
A summary of the boring details is provided in Table 3. The depths at which the
samples are collected will be noted on sample IDs.
7.2 Anticipated Soil Boring Locations
7.2.1 Inside Ash Basin
As discussed above, Roto-Sonic drilling (or similar technology) may be used to
conduct borings within the ash basin. These borings are anticipated to extend to
a depth of approximately 20 feet below the bottom of the ash to characterize the
native soil below the ash basin.
Soil samples are anticipated at each of the boring locations immediately below
the ash and at the bottom of the borings to provide information on the vertical
distribution of metals beneath the basin. The soil samples will be analyzed for
total metals, SPLP metals, and geotechnical parameters. A summary of the
anticipated boring details is provided in Table 3.
Following collection of the soil samples, the borings will be abandoned by filling
with a bentonite-grout mixture.
7.2.2 Outside Ash Basin
To characterize the vertical and horizontal extent of metals in soil beyond the ash
basin, four soil borings are anticipated at the locations shown on Figure 4.
Hollow stem auger drilling (or similar technology) will be conducted along with
Standard Penetration Test (SPT) to complete the soil borings. Hollow stem auger
methods use continuous flight augers with a bit on the bottom that drives
cuttings to the surface during the drilling process. SPTs are generally performed
at five-foot intervals in the borings. Soil samples are obtained with a standard
1.4-inch ID/2-inch outside diameter (OD) split-tube sampler. In conjunction with
the SPTs, split-spoon soil samples can be examined for visual soil classification
and laboratory testing.
Along with split-spoon samples, relatively undisturbed samples are anticipated
for potential laboratory testing. Samples will be collected using a Shelby Tube
sampler to obtain the undisturbed samples per ASTM D1587 (2008).
Shallow and deep soil samples are anticipated at each of the four boring
locations. The shallow soil samples would be collected from the 1-2 foot interval
and the deep soil samples would be collected from immediately above the water
table to provide information on the vertical distribution of metals beyond the ash
Page 13
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
basin and to be used as comparison with those soil samples collected below the
ash basin. The collected soil samples would be analyzed for total metals, SPLP
metals, and geotechnical parameters (Table 3).
Following collection of the soil samples, the borings will be abandoned by filling
with a bentonite-grout mixture.
7.3 Anticipated Sediment and Surface Water Locations
Surface water and sediment samples are not anticipated at this time. Data associated
with recent seep sampling will be used to infer preferential pathways and migration
from groundwater to surface water in various areas of the plant. Seep data analysis
may be used to guide the collection of additional sediment or surface water data in the
future.
7.4 Anticipated Groundwater Monitoring Wells
A number of monitoring wells, piezometers, and observation wells are present at the
site to monitor conditions within the aquifer horizontally and vertically. These existing
wells will be supplemented with additional wells to complete the CSA.
7.4.1 General Construction, Development, Aquifer Testing
Monitoring wells and piezometers will be constructed by North Carolina-
licensed well drillers. Drilling equipment will be decontaminated prior to use at
each location using a high pressure steam cleaner.
Monitoring wells will be constructed of 2-inch ID, National Sanitation
Foundation (NSF) grade polyvinyl chloride (PVC) (ASTM 2012a,b) schedule 40
flush-joint threaded casing and 0.010-inch machine-slotted screen.
Monitoring wells will be installed as nested Type II wells at each location. A
shallow well will be installed with the top of the well screen approximately 5 feet
below the water table. The deeper well will be installed to a depth just above the
first apparent confining layer. This will provide information on the vertical
distribution of aquifer characteristics above any confining layers (chemistry and
aquifer parameters) as well was determining the magnitude of vertical hydraulic
gradients.
For nested Type II wells, the well screen intervals will typically be a 10 foot
length for the shallow well and a 5 foot length for the deeper well. The deeper of
the nested wells will be installed first. The annular space between the borehole
wall and the well screens will be filled with clean, well-rounded, washed, high
grade No. 2 silica sand. The sand pack will be placed to approximately 2 feet
Page 14
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
above the top of the slotted screen, and then a pelletized bentonite seal will be
placed above the filter pack to just below the elevation of the anticipated bottom
of the shallow well. The sand pack for the shallow well will then be placed to
approximately 2 feet above the slotted screen. At a minimum, a 2-foot pelletized
bentonite seal will be placed above the filter pack of the shallow screen. The
remainder of the annular space will be filled with a neat cement grout from the
top of the upper bentonite seal to near ground surface.
The monitoring wells will be completed with either steel above ground
protective casings with locking caps or steel flush-mount manholes with locking
expansion caps, and well tags. The protective covers will be secured and
completed in a concrete collar and 2-foot square concrete pad.
Following installation, the monitoring wells will be developed in order to
remove drill fluids, clay, silt, sand, and other fines which may have been
introduced into the formation or sand pack during drilling and well installation,
and to establish communication of the well with the aquifer. Well development
will be performed using a portable submersible pump, which will be repeatedly
moved up and down the well screen interval until the water obtained is
relatively clear. Development will be continued by sustained pumping until
monitoring parameters (e.g., conductivity, pH, temperature) are generally
stabilized; estimated quantities of drilling fluids, if used, are removed; and,
turbidity decreases to acceptable levels.
After the wells have been developed, hydraulic conductivity tests (rising head
slug tests) will be conducted on each of the wells. The slug tests will be
performed in general accordance with ASTM D4044-96 Standard Test Method
(Field Procedure) for Instantaneous Change in Head (Slug) Tests for Determining
Hydraulic Properties of Aquifers.
Prior to performing each slug test, the static water level will be determined and
recorded and a Solinst Model 3001 Levelogger® Edge electronic pressure
transducer/data logger, or equivalent, will be placed in the well at a depth of
approximately six-inches above the bottom of the well. The Levelogger® will be
connected to a field laptop and programmed with the well identification,
approximate elevation of the well, date, and time.
The slug tests will be conducted by lowering a PVC “slug” into the well casing.
The water level within the well is then allowed to equilibrate to a static level.
After equilibrium, the slug is rapidly withdrawn from the well, thereby
Page 15
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
decreasing the water level in the well instantaneously. During the recovery of
the well, the water level is measured and recorded electronically using the
pressure transducer/data logger. Two separate slug tests will be conducted for
each well.
The data obtained during the slug tests will be reduced and analyzed using
AQTESOLV™ for Windows, version 4.5, software to determine the hydraulic
conductivity of the soils in the vicinity of wells.
7.4.2 Background Wells
Existing background well BW-1 is located adjacent to and downgradient from a
used auto parts junkyard. Based on the proximity to the junk yard and possible
metals that may be migrating into the groundwater from this yard, BW-1 may
not be representative of actual background conditions. Therefore, two new
background wells will be installed beyond the compliance boundary at the
locations shown on Figure 4. A summary of the boring details is provided in
Table 3.
7.4.3 Ash Basin
During previous assessment activities conducted at the Weatherspoon Plant,
monitoring wells and piezometers have been installed within the ash basin
(Figure 4). Therefore, no additional monitoring wells or piezometers are
anticipated to be installed within the ash basin as part of the CSA.
7.4.4 Downgradient Assessment Areas
A preliminary review of site data and existing monitoring well/piezometer
locations indicate that there is sufficient horizontal and vertical coverage of the
ash basin and compliance boundary to complete a CSA of the Weatherspoon site,
with the exception of the area southwest of the ash basin, between the ash basin
and the Lumber River. Therefore, it is anticipated that two monitoring well nests
will be installed in this area as shown on Figure 4 for the purpose of providing
additional hydrogeologic and chemical information in this area. A summary of
the boring details is provided in Table 3.
7.4.5 Groundwater Sampling
It is anticipated that groundwater samples will be collected using a low-flow
sampling technique consistent with compliance monitoring wells sampling
protocol. The groundwater samples will be analyzed for the parameters listed in
Table 2. Total and dissolved metals analysis will be conducted. In addition to
the groundwater samples collected from the new monitoring wells, it is
anticipated that groundwater samples will be collected from one or more of the
Page 16
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
existing site monitoring wells, as well as from the two existing site water supply
wells. A summary of the anticipated groundwater samples are included in
Table 3. The data will be used to develop a range of naturally occurring
background concentrations in different geologic settings around the site.
During groundwater sampling activities, water level measurements will be made
at the existing site monitoring wells, observation wells, and piezometers, along
with the new wells. The data will be used to generate water table and
potentiometric maps of the upper and lower portions of the surficial aquifer
zones, above the first confining unit, as well as to determine the degree of
residual saturation beneath the ash basin.
7.5 Influence of Pumping Wells on Groundwater System
There are two water supply wells owned and operated by Duke Energy (DEP-1 and
DEP-2) located approximately 1,000 feet southwest of the ash basin.
In addition to the Duke Energy wells, seven potential water supply wells may be
located within 0.5 mile of the compliance boundary. However, all are located greater
than 0.25 miles from the ash basin. Based on the established distances, possible limited
withdrawal rates, and relatively high transmissivity values discussed in Section 5.0, the
area of influence of the off-site wells is not expected to be large enough to substantially
affect the groundwater system near the ash basin.
7.6 Site Conceptual Model
Using existing hydrogeological site data along with data that will be generated during
the CSA activities, a Site Conceptual Model (SCM) will be prepared. The SCM will be
prepared in accordance with “Evaluating Metals in Groundwater at DWR Permitted
Facilities” (July 2012). The SCM will define the groundwater flow systems at the site,
horizontally and vertically, and provide a better understanding of the fate and transport
of constituents of concern in groundwater. This information will be critical in
developing a groundwater computer model for Weatherspoon that can be used to
evaluate the potential impacts of the ash basin to the surrounding environment. Figure
4 shows the proposed locations for Geologic Cross Sections.
7.7 Development of Groundwater Computer Model
Using data from existing site monitoring wells and compliance monitoring events,
along with data collected during the assessment activities discussed above, and the
conceptual site model for Weatherspoon, a groundwater computer model will be
developed.
Page 17
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
At this time, it is anticipated that a numerical groundwater flow model will be
developed using the MODFLOW finite difference model that was developed by the
USGS and is one of the most widely accepted and widely used groundwater flow
models. The MODFLOW model will be created as a multi-layer flow model to better
determine the vertical flow component of the aquifer system which will allow for more
accurate fate and transport modeling. Once the model is created, it will be calibrated to
site conditions by modifying model inputs, such as hydraulic conductivity, within
established limits based on actual site data, until a reasonable match between the model
and actual site conditions is accomplished.
After the MODFLOW model is calibrated, the modeled flow data will be imported into
MT3D or RT3D and a fate and transport model will be created. MT3D and RT3D are
three-dimensional numerical solute fate and transport model, which will be used to
predict the short and long-term movement of the constituents of interest in
groundwater at the site and under the various predictive scenarios discussed above.
Due to the data requirements of the computer modelling, the computer model will be
completed after the majority of the groundwater assessment activities. The results of
the groundwater modelling are anticipated as an appendix to the CSA Report.
Page 18
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
8.0 IMPLEMENTATION SCHEDULE AND REPORT SUBMITTAL
Implementation will take place immediately following approval of this Groundwater
Assessment Plan by DWR. The anticipated schedule of activities and project
completion once the plan is approved is provided below.
• 10 days to begin field activities upon approval of plan
(Including, but not limited to, notification of public utility locate services,
road access clearing, container requests from laboratories for the soil and
groundwater samples, assemble information on existing site wells and
piezometers in addition to compliance boundary well information)
• 60 days to complete field activities
• Complete drilling activities
• Conduct slug tests
• Survey soil borings, wells, and other assessment locations
• Collect groundwater and other assessment samples
• Collect site-wide water levels
• Setup groundwater computer model
• 30 days after completion of field activities receive analytical data
• 60 days after receipt of analytical data evaluate results, conduct statistical
evaluation, prepare summary tables, develop CSM, and calibrate computer
model.
• 20 days to complete Assessment Report, per NC Senate Bill 729, August 2014.
• 90 days (up to 180 days) to complete computer modeling and Corrective Action
Plan.
• Conduct additional work as may be required to complete the CSA.
• 90 days to complete CSA preparation, review, and submittal, in accordance with
NCDENR guidance (August 2014).
Project Assumptions Include:
• No more than one iterative assessment step will be required;
• No off-site assessment or access agreements are anticipated;
Page 19
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
• Duke Energy will make a diligent effort to collect all receptor information in
accordance with DENR guidance (August 2014); however, it is anticipated that
all such information may not be available;
• If off-site water supply wells sampling is deemed necessary, DENR staff may be
requested to assist with access;
• No special permitting is anticipated;
• Data may not reflect all seasonal or extreme hydrologic conditions;
• During the CSA process if additional investigations are required NCDENR, will
be notified;
• In addition to the components listed above, a human health and ecological risk
assessment will be conducted.
Page 20
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
Groundwater Assessment Work Plan September 2014
W.H. Weatherspoon Power Plant SynTerra
9.0 REFERENCES
ASTM D4044-96 Standard Test Method (Field Procedure) for Instantaneous Change in
Head (Slug) Tests for Determining Hydraulic Properties of Aquifers.
Giese, G.L. Eimers, J.L., and Coble, R.W., 1997 Simulation of Ground-Water Flow in the
Coastal Plain Aquifer System of North Carolina, United States Geological Survey
Professional Paper 1404-M.
Horton, J. W. and Zullo, V. A., 1991, The Geology of the Carolinas, Carolina Geological
Society Fiftieth Anniversary Volume, 406 pp.
Narkunas, J., 1980, Groundwater Evaluation in the Central Coastal Plain of North
Carolina, North Carolina Department of Natural Resources and Community
Development, 119 pp.
NCDENR Document, “Hydrogeologic Investigation and Reporting Policy
Memorandum”, dated May 31, 2007.
NCDENR Document, “Groundwater Modeling Policy Memorandum”, dated May 31,
2007.
NCDENR Document, “Performance and Analysis of Aquifer Slug Tests and Pumping
Test Policy”, dated May 31, 2007.
North Carolina Department of Natural Resources and Community Development, 1985,
Geologic Map of North Carolina.
Stuckey, J.L., 1965, North Carolina: Its Geology and Mineral Resources, Raleigh, North
Carolina Department of Conservation and Development, 550p.
Winner, M.D., Jr., and Coble, R.W., 1989, Hydrogeologic Framework of the North
Carolina Coastal Plain Aquifer System: U.S. Geological Survey Open-File
Report.
Page 21
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment
Plans\Weatherspoon\Weatherspoon GW Assessment Plan.docx
FIGURES
PROJECT MANAGER:
LAYOUT:
DRAWN BY:
KATHY WEBB
DATE:S. ARLEDGE
FIG 1 (USGS SITE LOCATION)
2014-09-25
FIGURE 1
SITE LOCATION MAP
WEATHERSPOON POWER PLANT
491 POWER PLANT RD
LUMBERTON, NORTH CAROLINA
SOUTH EAST LUMBERTON, NC QUADRANGLE
2000
GRAPHIC SCALE
1000
IN FEET
10000CONTOUR INTERVAL:
MAP DATE:
10 FEET
1993
148 RIVER STREET, SUITE 220
GREENVILLE, SOUTH CAROLINA
PHONE 864-421-9999
www.synterracorp.com
SOURCE:
USGS TOPOGRAPHIC MAP OBTAINED FROM THE NRCS GEOSPATIAL DATA
GATEWAY AT http://datagateway.nrcs.usda.gov/
RALEIGH
WILMINGTON
GREENVILLE
GREENSBORO
PROPERTY BOUNDARY
500' COMPLIANCE
BOUNDARY
WASTE
BOUNDARY
WEATHERSPOON
POWER PLANT
ROBESON
COUNTY
4000 400 800GRAPHIC SCALEIN FEETFIG 2 (SITE LAYOUT)2014-09-25H. FRANKS. ARLEDGEPROJECT MANAGER:LAYOUT NAME:DRAWN BY:CHECKED BY:K. WEBBDATE:DATE:FIGURE 2SITE LAYOUTwww.synterracorp.com148 River Street, Suite 220Greenville, South Carolina 29601864-421-9999LEGEND2014-09-25500 ft COMPLIANCE BOUNDARYDUKE ENERGY PROGRESS WEATHERSPOONPLANTWASTE BOUNDARYBACKGROUND MONITORING WELL (SURVEYED)COMPLIANCE MONITORING WELL (SURVEYED)CW-1BW-1SOURCES:1. 2010 HIGH RESOLUTION AERIAL PHOTOGRAPHS AND 1997WATER LINES OBTAINED FROM NC ONE MAP AThttp://data.nconemap.com/geoportal/catalog/raster/download.page2. 2014 AERIAL PHOTOGRAPH WAS OBTAINED FROM WSPFLOWN ON APRIL 17, 2014.3. DRAWING HAS BEEN SET WITH A PROJECTION OF NORTHCAROLINA STATE PLANE COORDINATE SYSTEM FIPS 3200(NAD 83).WEATHERSPOON POWER PLANT491 POWER PLANT RDLUMBERTON, NORTH CAROLINAB
E
U
L
A
H
C
H
U
R
C
H
R
DBERRY STTOMMY DRB
E
U
L
A
H
C
H
U
R
C
H
R
D
OLD WHITEVILLE RDOLD WHITEVILLE RDOLD WHITEVILLE RDRAI
LROAD
R
A
I
L
R
O
A
D
ASH BASINLUMBER RIVERCOOLING PONDLUMBER RIVERPOWER PLANT RDS ROBERTS AVES ROBERTS AVE (NC HWY 72)RAILROADTP
R
D
PHILLIPS DRTP
RDLUMBER RIVERHAVALIH DRCREEKWOOD RDTA
Y
L
O
R
R
DLEXIE LOOPRYAN STBW-1CW-3CW-2CW-1
WEATHERSPOON POWER PLANT
491 POWER PLANT RD
ROBESON COUNTY
LUMBERTON, NC
148 RIVER STREET, SUITE 220
GREENVILLE, SOUTH CAROLINA 29601
PHONE 864-421-9999
www.synterracorp.com
PROJECT MANAGER:
LAYOUT:
DRAWN BY:
KATHY WEBB
DATE:S. ARLEDGE
FIG 3 (GEOLOGY MAP)
2014-09-25
FIGURE 3
GEOLOGY MAP
DUKE ENERGY PROGRESS
WEATHERSPOON POWER PLANT
491 POWER PLANT RD
LUMBERTON, NORTH CAROLINA
LUMBER RIVER
DISCLAIMER AND SOURCE NOTE:
The information on this map was derived from digital databases at the NC Department of Transportation Website. Care was
taken in the creation of this map. SYNTERRA cannot accept any responsibility for errors, omissions, or positional accuracy.
There are no warranties, expressed or implied, including the warranty of merchantability or fitness for a particular purpose,
accompanying this product. However, notification of any errors will be appreciated.
LEGEND - UNIT NAME
Kb BLACK CREEK FORMATION
Tpy YORKTOWN FORMATION & DUPLIN FORMATION, UNDIVIDED
GEOLOGY SOURCE NOTE:
GEOLOGY SHAPEFILES OBTAINED FROM THE USGS Preliminary integrated geologic map databases for the United
States - Alabama, Florida, Georgia, Mississippi, North Carolina, and South Carolina, DATED 2007 AT
http://pubs.usgs.gov/of/2005/1323/
Kb
Kb
Tpy
Tpy
CW-1
CW-2
CW-3
BW-1
OLD
W
H
I
T
E
V
I
L
L
E
R
D
BEULAH CHURCH RDTpy
S ROBERTS AVE1000 0 1000 2000
GRAPHIC SCALE
IN FEET
CW-3 COMPLIANCE WELL
LEGEND
500 ft COMPLIANCE BOUNDARY
DUKE ENERGY PROGRESS LEE PLANT
WASTE BOUNDARY
5000 500 1000GRAPHIC SCALEIN FEETFIG 4 (CROSS SECTIONS) (11X17)2014-09-25H. FRANKS. ARLEDGEPROJECT MANAGER:LAYOUT NAME:DRAWN BY:CHECKED BY:K. WEBBDATE:DATE:FIGURE 4ANTICIPATED SAMPLELOCATIONSwww.synterracorp.com148 River Street, Suite 220Greenville, South Carolina 29601864-421-99992014-09-25SOURCES:1. 2010 HIGH RESOLUTION AERIAL PHOTOGRAPHS AND1997 WATER LINES OBTAINED FROM NC ONE MAP AThttp://data.nconemap.com/geoportal/catalog/raster/download.page2. 2014 AERIAL PHOTOGRAPH WAS OBTAINED FROM WSPFLOWN ON APRIL 17, 2014.3. DRAWING HAS BEEN SET WITH A PROJECTION OFNORTH CAROLINA STATE PLANE COORDINATE SYSTEMFIPS 3200 (NAD 83).4. 2ft CONTOUR INTERVALS FROM NCDOT LIDAR DATED2007https://connect.ncdot.gov/resources/gis/pages/cont-elev_v2.aspxNOTE:1. CONTOUR LINES ARE USED FOR REPRESENTATIVEPURPOSES ONLY AND ARE NOT TO BE USED FORDESIGN OR CONSTRUCTION PURPOSES.WEATHERSPOON POWER PLANT491 POWER PLANT RDLUMBERTON, NORTH CAROLINALEGENDBACKGROUND MONITORING WELL (SURVEYED)COMPLIANCE MONITORING WELL (SURVEYED)500 ft COMPLIANCE BOUNDARYDUKE ENERGY PROGRESS WEATHERSPOONPLANTWASTE BOUNDARYCW-1GENERALIZED GROUNDWATER FLOWDIRECTION•SUPPORTED BY GROUNDWATER ELEVATION DATAOR TOPOGRAPHIC DATAFLOW DIRECTIONBW-1DUKE ENERGY PROGRESSPRODUCTION WELL (APPROXIMATE)DEP 1MONITORING WELL OR PIEZOMETER(SURVEYED)MW-82007 LiDAR CONTOUR MAJOR2007 LiDAR CONTOUR MINOR120BW-3ANTICIPATED MONITORING WELL LOCATIONANTICIPATED SOIL BORING LOCATIONANTICIPATED ASH/SOIL BORING LOCATIONANTICIPATED GEOLOGIC CROSS SECTIONDEP 1B
E
U
L
A
H
C
H
U
R
C
H
R
DBERRY STTOMMY DRB
E
U
L
A
H
C
H
U
R
C
H
R
D
OLD WHITEVILLE RDOLD WHITEVILLE RDOLD WHITEVILLE RDRAI
LROAD
R
A
I
L
R
O
A
D
ASH BASINLUMBER RIVERCOOLING PONDLUMBER RIVERPOWER PLANT RDS ROBERTS AVES ROBERTS AVE (NC HWY 72)RAILROADRAILROADTP
R
D
PHILLIPS DRTP
RDLUMBER RIVERHAVALIH DRCREEKWOOD RDTAY
L
O
R
R
D
MOSES RDLEXIE LOOPR
Y
A
N
S
T
SN
A
K
E
R
DPEACOCK RDNC HWY 211J
A
C
O
B
C
R
E
E
KDEP 2BW-1CW-3CW-2CW-1MW-1PZ-1OW-3OW-1MW-8MW-8IMW-8DOW-8MW-44SMW-44SAMW-44IOW-44DOW-9MW-33SMW-33IMW-33DPZ-2PZ-3OW-17MW-49IMW-49DMW-2MW-3MW-53IMW-53DMW-6MW-7MW-54DMW-5MW-4OB-2MW-52OB-1MW-55DMW-41IMW-41DBW-3DBW-2DAW-1DAW-2DBB'AA'BW-2SBW-3SAW-1SAW-2S
TABLES
TABLE 1SUMMARY OF CONCENTRATION RANGES FOR CONSTITUENTS DETECTED GREATER THAN 2L STANDARDSW.H. WEATHERSPOON POWER PLANT DUKE ENERGY PROGRESS, INC., LUMBERTON, NORTH CAROLINAPARAMETER CADMIUM IRON MANGANESE THALLIUM pH2L STANDARD (eff. 4/1/2013)2300500.2 6.5 - 8.5Units(ug/l)(ug/l)(ug/l)(ug/l)SUBW-1 Background 0.22 - 5.2 43 - 2140 <2L 0.1 - 0.66 3.9 - 4.6CW-1 CB <2L 2060 - 4140 29.7 - 53.5 <2L 5.2 - 6.3CW-2 CB <2L 150 - 453 <2L <2L <2LCW-3 CB <2L 551 - 3740 17.8 - 55 <2L 5.5 - 6.8Notes:Prepared by: RBI Checked by: MCM CB - Compliance Boundary< 2L - Constituent has not been detected above the 2L Standard or beyond range for pHShown concentration ranges only include concentrations detected above the laboratory's reporting limit.Well IDWell Location Relative to Compliance BoundaryConcentration RangePage 1 of 1P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment Plans\Weatherspoon\Tables\Table 1-Summary Concentration Ranges Weatherspoon.xlsx
TABLE 2
GROUNDWATER ASSESSMENT PARAMETER LIST
W.H. WEATHERSPOON POWER PLANT
DUKE ENERGY PROGRESS, INC., LUMBERTON, NORTH CAROLINA
PARAMETER UNITS FIELD EQUIPMENT/
LAB METHOD
pH SU YSI Professional Plus or YSI 556 MPS
Specific Conductance S/cm YSI Professional Plus or YSI 556 MPS
Temperature CYSI Professional Plus or YSI 556 MPS
ORP mV YSI Professional Plus or YSI 556 MPS
Dissolved Oxygen mg/L YSI Professional Plus or YSI 556 MPS
Turbidity NTU Hach 2100Q
Antimony g/L EPA 200.8
Arsenic g/L EPA 200.8
Barium mg/L EPA 200.7
Boron mg/L EPA 200.7
Cadmium g/L EPA 200.8
Chromium g/L EPA 200.8
Copper mg/L EPA 200.7
Iron mg/L EPA 200.7
Lead g/L EPA 200.8
Manganese mg/L EPA 200.7
Mercury g/L EPA 245.1
Molydbenum g/L EPA 200.8
Nickel g/L EPA 200.8
Selenium g/L EPA 200.8
Thallium (low level)g/L EPA 200.8
Zinc mg/L EPA 200.7
Nitrate as Nitrogen mg-N/L EPA 300.0
Ferrous Iron mg/L (Field Test Kit)
Sulfate mg/L EPA 300.0
Sulfide mg/L SM 4500 Sd
Methane mg/L RSK 175
Chloride mg/L EPA 300.0
Calcium mg/L EPA 200.7
Magnesium mg/L EPA 200.7
Sodium mg/L EPA 200.7
Potassium mg/L EPA 200.7
Bromide mg/L EPA 300.1
Total Organic Carbon mg/l EPA 5310
Alkalinity (as CaCO3)mg/L SM 2320B
Total Dissolved Solids mg/L SM 2540C
Prepared by: RBI Checked by: BER
Notes:
SU - Standard Units mg/L - milligrams per liter
S/cm - microsiemens per centimeter NTU - Nephelometric Turbidity Units
C - degrees Celsius g/L - micrograms per liter
mV - millivolts mg-N/L - milligrams nitrate (as nitrogen) per liter
Field Parameters
Lab Parameters - Inorganics (Total & Dissolved)
Lab Parameters - Anions/Cations
Page 1 of 1
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment Plans\Weatherspoon\Tables\Table 2-
Assessment Parameter List Weatherspoon.xlsx
TABLE 3
ASSESSMENT SAMPLING PLAN
W.H. WEATHERSPOON POWER PLANT
DUKE ENERGY PROGRESS, INC., LUMBERTON, NORTH CAROLINA
ASH
MANAGEMENT
AREA
BORING /
WELL ID
ESTIMATED
BORING
DEPTH
(ft bgs)
ESTIMATED
NO. OF
SAMPLES
SAMPLE
MEDIA
SAMPLE
DEPTHS/INTERVALS/
TARGET ZONES
LAB ANALYSIS PURPOSE/NOTES
AB-1 40 4 - 5
Ash
Ash
Ash
Soil
Soil
1-2'
Intermediate (if >20' thick)
Above ash/soil contact
2' Below ash/soil contact
Bottom of boring
Total metals + SPLP
Total metals + SPLP
Total metals + SPLP
Total metals + Geotech
Total metals + Geotech
Refine ash thickness, determine
residual saturation of ash, characterize
ash chemistry and leachability,
characterize soil chemistry beneath ash,
geologic cross section, groundwater
modeling
AB-2 40 4 - 5
Ash
Ash
Ash
Soil
Soil
1-2'
Intermediate (if >20' thick)
Above ash/soil contact
2' Below ash/soil contact
Bottom of boring
Total metals + SPLP
Total metals + SPLP
Total metals + SPLP
Total metals + Geotech
Total metals + Geotech
Refine ash thickness, determine
residual saturation of ash, characterize
ash chemistry and leachability,
characterize soil chemistry beneath ash,
geologic cross section, groundwater
modeling
AB-3 40 4 - 5
Ash
Ash
Ash
Soil
Soil
1-2'
Intermediate (if >20' thick)
Above ash/soil contact
2' Below ash/soil contact
Bottom of boring
Total metals + SPLP
Total metals + SPLP
Total metals + SPLP
Total metals + Geotech
Total metals + Geotech
Refine ash thickness, determine
residual saturation of ash, characterize
ash chemistry and leachability,
characterize soil chemistry beneath ash,
geologic cross section, groundwater
modeling
AB-4 40 4 - 5
Ash
Ash
Ash
Soil
Soil
1-2'
Intermediate (if >20' thick)
Above ash/soil contact
2' Below ash/soil contact
Bottom of boring
Total metals + SPLP
Total metals + SPLP
Total metals + SPLP
Total metals + Geotech
Total metals + Geotech
Refine ash thickness, determine
residual saturation of ash, characterize
ash chemistry and leachability,
characterize soil chemistry beneath ash,
geologic cross section, groundwater
modeling
SB-1 20 2 Soil
Soil
1-2'
Just above the water table
Total metals + Geotech
Total metals + Geotech
Background soil quality and
groundwater modeling data
SB-2 20 2 Soil
Soil
1-2'
Just above the water table
Total metals + Geotech
Total metals + Geotech
Background soil quality and
groundwater modeling data
SB-3 20 2 Soil
Soil
1-2'
Just above the water table
Total metals + Geotech
Total metals + Geotech
Background soil quality and
groundwater modeling data
SB-4 20 2 Soil
Soil
1-2'
Just above the water table
Total metals + Geotech
Total metals + Geotech
Background soil quality and
groundwater modeling data
BW-2S/D 20
50 4
Soil
Soil
Water
Water
Just above the water table
Within lower screen interval
15 feet
45 feet
Total metals
Total metals
Table 2 List
Table 2 List
Groundwater modeling and statistical
evaluation
BW-3S/D 20
50 4
Soil
Soil
Water
Water
Just above the water table
Within lower screen interval
15 feet
45 feet
Total metals
Total metals
Table 2 List
Table 2 List
Groundwater modeling and statistical
evaluation
AW-1S/D 20
50 4
Soil
Soil
Water
Water
Just above the water table
Within lower screen interval
15 feet
45 feet
Total metals
Total metals
Table 2 List
Table 2 List
Groundwater modeling and statistical
evaluation
AW-2S/D 20
50 4
Soil
Soil
Water
Water
Just above the water table
Within lower screen interval
15 feet
45 feet
Total metals
Total metals
Table 2 List
Table 2 List
Groundwater modeling and statistical
evaluation
DEP-1 220 1 Water Screened interval Table 2 List Confirm no influence in Black Creek
Formation, groundwater modeling
DEP-2 193 1 Water Screened interval Table 2 List Confirm no influence in Black Creek
Formation, groundwater modeling
Existing
Monitoring Wells TBD Variable TBD Water
Well Screen Interval
(variable)Table 2 List Groundwater modeling and statistical
evaluation
Notes:
SPLP (Synthetic Preciptation Leaching Procedure) Metals - As, B, Ba, Cd, Cr, Cu, Fe, Hg, Mn,Mo, Ni, Pb, Sb, Se, Tl, and Zn.
Table 2 List - Parameter list presented in Table 2 of this document.
ft bgs - Feet below ground surface.
TBD - To be determined.
Geotech - Geotechnical parameters include moisture content, particle size distribution, Atterberg limits, specific gravity, and permeability.
Total Metals - As, B, Ba, Cd, Cr, Cu, Fe, Hg, Mn,Mo, Ni, Pb, Sb, Se, Tl, and Zn.
Ash Basin
Background
New Monitoring
Wells
Site Production
Wells
Prepared by: HJF Checked by: KWW
P:\Duke Energy Progress.1026\ALL NC SITES\DENR Letter Deliverables\GW Assessment Plans\Weatherspoon\Tables\Table 3-Assessment Sampling Plan Weatherspoon.xlsx Page 1 of 1
APPENDIX A
NCDENR LETTER OF AUGUST 13, 2014