Attach. 7, 20160329 Roxboro Hutson Report Final

GEO-HYDRO, INC
Consulting in Geology and Hydrogeology
1928 E. 14th Avenue
Denver, Colorado 80206
[phone]
EXPERT REPORT OF
MARK A. HUTSON, PG
Roxboro Steam Electric Plant
S emora, NC
Prepared for:
Southern Environmental Law Center
601 West Rosemary Street
Suite 220
Chapel Hill, NC 27516-2356
March 2016

GEO-HYDRO, INC
1. Summary of Opinions Formed
Based upon my review of the available information I have formed the following opinions on closure
of the coal ash basins at the Roxboro Steam Electric Plant (Roxboro).
1. Coal ash stored in the Roxboro ash basins is the source of contamination detected in
groundwater.
2. Capping coal ash located within the Roxboro ash basins will not protect groundwater quality
downgradient of the basins
Monitored Natural Attenuation (MNA) is not an acceptable groundwater remediation
strategy at Roxboro.
4. Capping coal ash located within the Roxboro ash basins will not be protective of surface
water quality.
5. Removal of the coal ash will remove the source and reduce the concentration and extent of
groundwater contaminants.
6. The coal combustion residual impoundment risk classification proposed by the North
Carolina Department of Environmental Quality (NCDEQ) improperly minimizes protection
of environmental quality.
The background and rationale behind each of these opinions are described in this report.

GEO-HYDRO, INC
2. Introduction
Duke Energy (Duke) reportedly stores approximately 33,390,000 tons of coal ash in various areas
around the Roxboro facility, including ash stored in two unlined ash basins (East and West), lined
and unlined landfills, and other ash filled areas'. An additional poorly identified and
uncharacterized Unnamed Eastern Extension impoundment was recently reported to NCDEQ. The
location and volume of additional coal ash contained in the Unnamed Eastern Extension
impoundment was not identified in any of the documents reviewed. Pollution caused by the coal ash
at this site is currently the subject of an enforcement action brought by the NCDEQ. Organizations
represented by the Southern Environmental Law Center are also parties to this litigation.
North Carolina General Assembly Session Law 2014-122, the Coal Ash Management Act (LAMA)
of 2014, required the owner of coal combustion waste surface impoundments to conduct
groundwater monitoring, assessment and remedial activities at coal ash basins across the state, as
necessary. The owner of the coal ash surface impoundments was required to submit a Groundwater
Assessment Plan (GAP) to NCDEQ by December 31, 2014. Comprehensive Site Assessment (CSA)
reports that reported the results of site characterization activities were required to be submitted
within 180 days of approval of the GAP. Information developed under the CSA provided the data to
be used to prepare Corrective Action Plans (CAP) that were to be submitted to NCDEQ within 90
days of submittal of the CSA. An agreement between Duke Energy and NCDEQ resulted in
breaking the CAP into Parts I and 2. As of this date only the CAP Part I has been produced for the
Roxboro site.
Further, CAMA specifies that any impoundments classified by NCDEQ as high-risk be closed no
later than December 31, 2019 by dewatering the waste and either, a) excavating the ash and
converting the impoundment to an industrial landfill, or b) excavating and transporting the waste off-
site for disposal in an appropriately licensed landfill. Intermediate -risk impoundments are required
to be closed similarly to high-risk impoundments, but under a relaxed closure deadline of December
31, 2024. Impoundments classified as low-risk by NCDEQ must be closed by December 31, 2029
either similarly to the high and intermediate -risk sites, or by dewatering to the extent practicable and
capping the waste in place.
In January 2016 the NCDEQ issued Draft Proposed Risk Classifications (NCDEQ, 2016) for 10 ash
impoundment sites, including Roxboro. NCDEQ assigned separate proposed risk classifications for
the West, East, and Unnamed Eastern Extension ash ponds. The East Ash Basin (EAB) was rated
low to intermediate risk and the West Ash Basin (WAB) was rated low risk, thus allowing for
closure of these impoundments by capping waste in place. The Unnamed Eastern Extension (UEE)
' Synterra, 2015a
2

GEO-HYDRO, INC
impoundment was rated intermediate risk pending further assessment. On behalf of the Southern
Environmental Law Center, I have reviewed the Groundwater Assessment Plan (SynTerra, 2014),
Comprehensive Site Assessment (SynTerra, 2015a), the Corrective Action Plan Part 1 (SynTerra,
2015b), the Draft Proposed Risk Classifications (NCDEQ, 2016), and three National Pollutant
Discharge Elimination System (NPDES) discharge monitoring reports (DMR's) for Roxboro (Duke
Energy, 2014).
This report details my opinions regarding: the source of groundwater and surface water pollution at
Roxboro, potential remedies for that pollution discussed in the Corrective Action Plan, and the
proposed risk classification for the Roxboro site.

GEO-HYDRO, INC
3. Qualifications
The opinions expressed in this document have been formulated based upon my formal education in
geology and over thirty-five years of experience on a wide range of environmental characterization
and remediation sites. My education includes B.S. and M.S. degrees in geology from Northern
Illinois University and the University of Illinois at Chicago, respectively. I am a registered
Professional Geologist (PG) in Kansas, Nebraska, Indiana, and Wisconsin, a Certified Professional
Geologist by the American Institute of Professional Geologists, and am currently serving as Past
President of the Colorado Ground Water Association.
My entire professional career has been focused on regulatory, site characterization, and remediation
issues related to waste handling and disposal practices and facilities. I have worked on contaminated
sites in over 35 states and the Caribbean. My site characterization and remediation experience
includes activities at sites located in a full range of geologic conditions, involving soil and
groundwater contamination in both unconsolidated and consolidated geologic media, and a wide
range of contaminants. I have served in various technical and managerial roles in conducting all
aspects of site characterization and remediation including definition of the nature and extent of
contamination, directing human health and ecological risk assessments, conducting feasibility
studies for selection of appropriate remedies to meet remediation goals, and implementing remedial
strategies. For the last ten years much of my consulting activity has been related to groundwater
contamination and permitting issues at coal ash storage and disposal sites.
2

GEO-HYDRO, INC
4. Site Background
The Roxboro plant is a coal-fired electricity -generating facility located near Semora, in Person County
North Carolina. Hyco Reservoir borders the Roxboro plant to the north and west. Coal ash generated
at the plant has been sluiced to the ash basins and hauled to landfill overlying the ash basins since
operations commenced in 1966. The EAB was constructed in 1966 by constructing an earthen dam
across two unnamed creeks located southeast of the power station (Figure 1). An unlined landfill was
constructed over the top of the sluiced ash in the EAB in the late 1980s and a lined landfill was
constructed over the unlined landfill in 20042.
The ground surface elevation below the EAB dam was reported to be between 390 and 400 feet mean
sea level (MSI) 3. Groundwater elevations in EAB monitoring wells are reported to be between 464 and
469 ft ms14. The difference between the reported ash basin groundwater elevations and the natural
ground surface elevations underlying the EAB indicates that from 64 to 79 feet of saturated coal ash is
present within the EAB.
The WAB was constructed in 1973 by installing a dam across Sargents Creek, located south of the
power station. Coal combustion waste was historically sluiced into the WAB. A Flue Gas
Desulfurization (FGD) System, including a lined gypsum settling pond was constructed over a portion
of the WAB. The WAB currently remains in operation, receiving sluiced bottom ash from the power
station and surface waters discharged from the EAB and overlying lined landfill.
The ground surface elevation along the buried Sargents Creek was reported to be between 390 and 410
feet msl prior to construction of the WAB 5 Groundwater elevations in WAB monitoring wells are
reported to be between 448 and 463 ft ms16. The difference between the reported ash basin
groundwater elevations and the natural ground surface elevations underlying the basin indicates that
from 38 to 73 feet of saturated coal ash is present within the WAB.
The CSA describes three natural hydrogeologic units or zones of groundwater flow at the Roxboro
Plant. Coal ash is considered as its own hydrogeologic unit that is localized to the ash basins. The
zone closest to the surface is the shallow or surficial flow zone encompassing saturated conditions,
where present, in the saprolite and alluvium beneath the Site. A transition zone is encountered below
the shallow zone and is characterized primarily by partially weathered rock of variable thickness. The
bedrock flow zone occurs below the transition zone and is characterized by the storage and
2 SynTerra, 2015b, p. 1-2.
3 SynTerra, 2015b, Appendix E, p.3.
4 SynTerra, 2015a, Figure 6-5.
5 SynTerra, 2015b, Appendix E, p.4.
6 SynTerra, 2015a, Figure 6-5.
5

GEO-HYDRO, INC
transmission of groundwater in water -bearing fractures. Due to its limited occurrence and extent, the
shallow zone is considered part of the transition zone. Where present, groundwater exists under
unconfined conditions in each of the hydrogeologic units. The surficial/transition zone and bedrock
aquifers are interconnected.
On a regional scale groundwater appears to flow from highland areas in the south and southeast, to the
northwest toward Hyco Lake. On a local scale groundwater flow directions are poorly defined. Large
areas of the Bedrock Water Level Map included with both the CSA and CAP (Figure 2) show neither
groundwater elevation data nor contours. Due to the scarcity of head data the description of the
groundwater flow system included in the Groundwater Modeling Reports describes groundwater flow
in terms of inferred flows. The groundwater flow system beneath the eastern lobe of the EAB is
inferred to receive recharge from uplands to the south and east9, and discharge from the eastern lobe
by flowing toward the water intake canal, or northeast to a stream that drains the lake (now identified
as the unnamed eastern extension) that flows along the eastern side of the EAB and discharges into the
water intake canal10. Groundwater flow into the western lobe of the EAB is inferred to occur from the
west, south and east' 1. Groundwater discharges from the western lobe of the EAB are inferred to
occur to the north toward the plant. Further, the modeling report infers that groundwater beneath the
EAB flows toward discharge areas in wetlands and/or ponds located north of the EAB dam.
Groundwater flow into the WAB is inferred to flow into the basin from upland areas to the east.
Groundwater appears to discharge from the WAB to the north, west and south. Groundwater is
inferred to discharge from the WAB by flow to the north through and around the dam, through and
beneath the dam on the south end of the WAB, and to discharge into the canal located west of the
WAB.
Surface waters from the EAB, including groundwater that has discharged to surface water, are routed
to the west where it enters the northern end of the WAB. Sluice water used to transport bottom ash to
the WAB also discharges into the northern end of the WAB. Surface water from these sources, along
with precipitation and groundwater that discharges from the WAB, discharges through the filter dam at
the south end of the WAB and into the discharge canal. The discharge canal wraps around the west
side of the WAB, ultimately discharging into Hyco Lake. The CAP indicates 12 that seeps and surface
7 SynTerra, 2015a, p.26.
8 SynTerra, 2015b, Appendix E
9 The discussion of groundwater flow included in Appendix E (p. 4) erroneously indicates that flow toward the EAB is from
uplands to the north and west. Examination of head distribution maps included with the modeling report make it clear that
this statement in the text is in error.
10 SynTerra, 2015b, Appendix E, Section 2.2.
11 The Groundwater Modeling Report actually says recharge is from the north rather than the south. It appears that this was
a mistake as the limited groundwater head data shows higher heads located south of the west lobe.
12 SynTerra, 2015b, Section 2.2.3.
M

GEO-HYDRO, INC
water drain into NPDES-permitted surface water bodies, but fails to recognize that the parameters
required for testing under the NPDES permit are not those that are elevated by coal ash impacts.
Data collected during the CSA show that groundwater is impacted by the ash basins with boron,
strontium, sulfate, total dissolved solids (TDS) and to a lesser extent, cobalt, iron, manganese, and
vanadium. 13 The CSA also determined that Hyco Lake and the plants cooling water intake and
discharge canals are the primary receptors of impacted groundwater and seeps, and that groundwater
flow direction data and surface water data indicate that constituents of interest are migrating to the
reservoir14
Considering the various sources of water that is transferred from the WAB to Hyco Lake through the
discharge canal, it is very likely that the water contains high concentrations of ash -related constituents.
Unfortunately, no samples of discharge canal water were collected during the CSA. The CSA and
CAP each refer to surface water monitoring conducted under NPDES Permit NC0003425 as if that
monitoring augments the CSA surface water characterization. Review of three 2014 Discharge
Monitoring Reports 15 (DMRs) for the Roxboro site showed that NPDES surface water monitoring
requirements do not include the most common analytical parameters that are found in ash impacted
waters. This means that a major discharge of likely ash -impacted water from the Roxboro site into
Hyco Lake was not sampled as part of the CSA and is not being appropriately monitored under
NPDES requirements.
The groundwater flow and transport model of the site was constructed and used in the CAP to evaluate
groundwater flow and investigate three remedial scenarios. The scenarios investigated included the
No Action scenario, a Capping Ash in Place scenario, and a Complete Ash Removal scenario. The
model was used to predict contaminant distributions for the next 5, 15 and 30 years, under each
scenario.
The No Action scenario 16 relies on natural attenuation processes to reduce contaminant concentrations
over time. The ash basin remains in place without modification and "the assumption is made that
current recharge and contaminant loading rates from the ash to the underlying formations are held
constant". "The flow system is assumed to be at steady state with respect to the conditions in 2015."
"Concentrations in the ash were held constant at the measured concentrations." Using these
assumptions the model predicts that the boron plumes will continue to expand laterally and downward,
and increase in concentration over time. The predicted increases in plume size are predicted to be from
on the order of few hundred feet to very small. This result is likely due to constraints on plume size
13 SynTerra, 2015b, p. 3-8
14 SynTerra, 2015a, p.114
15 Duke Energy, 2014
16 The entire description of this scenario is presented in the CAP, Appendix E, Section 6.1.
7

GEO-HYDRO, INC
related to known hydrologic boundaries as were described above. Once a plume reaches a hydrologic
boundary the constituents migrating with groundwater are transferred to the surface water system and
the groundwater plume does not continue to grow in size though contaminants continue to migrate
with surface water.
The Capping Ash in Place scenario 17 involves placing a low permeability liner over the ash basin to
prevent infiltration. The description of this scenario assumes that there is no recharge within the basin
and that contaminant concentrations in the ash were allowed to vary (even though concentrations were
fixed in the No Action scenario). Results of this model predict that zones of boron concentration
increase in size and concentration relative to 2015 conditions, but the magnitude of the increases are
less that those calculated under the No Action scenario. Concerns with the Capping Ash Basin
scenario include the assumption of no recharge within the basin and changing the way that
contaminant concentrations in the source material are handled. The hydrogeology of the Roxboro
impoundments (see description of groundwater flow above) includes recharge into the basins from
higher elevation areas to the south and east. Capping of the ash in the basin will not control influx of
groundwater from upland areas. Discharges of groundwater into the ash basins are likely significant as
groundwater discharges into the basin were sufficient to maintain streams prior to their being buried
under coal waste.
The concentration of contaminants in the ash were held constant in the No Action simulation but were
allowed to vary in the Capping Ash in Place scenario. This change in assumptions allowed the
concentration in the ash to decrease more rapidly in the Capping Ash in Place scenario than in the No
Action simulation. The rationale for changing the method of handling source concentrations between
simulations was not discussed. It is unclear if the noted reduction in plume size and concentration is a
result of cap installation, or if it is an artifact of the change in assumptions.
The Complete Ash Removal 18 scenario represents complete removal of the ash by inactivating the
upper four model layers, adding drain cells to simulate drainages, and setting recharge within the ash
basin to ambient levels. The Complete Ash Removal scenario predicts the largest reduction in ash -
related contaminant concentrations of any of the tested scenarios.
17 The entire description of this scenario is presented in the CAP, Appendix E, Section 6.2
18 The entire description of this scenario is presented in the CAP, Appendix E, Section 6.3
N.

GEO-HYDRO, INC
5. Opinion 1: Coal Ash Stored in the Roxboro Ash Basins is the
Source of Contamination Detected in Groundwater
Coal ash is the source of contaminants detected in groundwater at concentrations above applicable
standards in the vicinity and downgradient of the ash basin. Data collected during the CSA show
that groundwater is impacted by the ash basins with boron, strontium, sulfate, TDS and to a lesser
extent, cobalt, iron, manganese, and vanadium. 19 The lateral extent of groundwater impacts outside
of the ash basins is limited by the presence of water local discharge areas. The contaminated pore
water migrates out of the ash basins and either directly into surface water, or into groundwater that
subsequently discharges to surface water, and eventually into Hyco Lake. This interpretation is
consistent with the CSA which states that:
Hydrologic boundaries are present downgradient of the ash basins in the form of the
intake canal, the discharge canal and the cooling reservoir which discharges to Hyco
Lake. When the CCR constituents reach these hydrologic boundaries, they are
removed from the groundwater system, and they enter the surface water system. At
the Site, boron is the primary constituent that is migrating from the ash basins. 20
19 SynTerra, 2015b, p. 3-8
20 SynTerra 2015b, p.3-8
0

GEO-HYDRO, INC
6. Opinion 2: Capping Coal Ash Located Within the Roxboro Ash
Basin Will Not Protect Groundwater Quality Downgradient of the
Basins
The CAMA process proposed designation of the Roxboro Site as low-risk creates the possibility that
Duke could pursue closure of the Roxboro impoundment by capping the disposed ash in place.
Capping the waste within the footprint of the ash basin will not be protective of groundwater quality
downgradient of the basin.
Environmental contaminants contained in coal ash are leached into groundwater when precipitation
infiltrates through the waste or, when groundwater flows through waste that has been placed below
the water table. In the case of the Roxboro ash basins, both of these processes are currently acting to
create the contaminated ash porewater, groundwater, and surface water that discharge into local
surface waters and eventually into Hyco Lake. The cap -in-place remedy would likely reduce the
amount of water that enters the waste from precipitation. This remedy would however do nothing to
reduce the amount of groundwater that flows laterally into the basin from surrounding geologic
units, through the capped waste, into downgradient groundwater, and eventually into Hyco Lake.
The lined landfill that was constructed over a portion of the EAB should function as a cap over the
ash disposed in the unlined landfill and ash basin. The CSA 21 indicates that construction of a lined
landfill has resulted in decreasing concentrations of iron, manganese and chromium in three
monitoring wells (GMW-06, GMW-10 and GMW-11). The available data set does not show a clear
pattern of decreasing contaminant concentrations related to construction of the lined landfill.
Review of the comprehensive analytical results from Roxboro 22 shows that large decreases in
several parameters were observed in some monitoring wells during the first few sampling events and
prior to construction of the lined landfill. Figures 3 and 4 show graphs of boron, sulfate, selenium
and TDS concentrations measured in samples from wells in the immediate vicinity of the lined
landfill. Sulfate, TDS, and selenium23 concentrations in some wells were very high initially and
show rapid declines in concentration between the initial sampling event in 2002 and 2004 when the
lined landfill was constructed. This is an indication that decreased contaminant concentrations in
wells since their early sampling events appear to have been due to improper well development or
sampling techniques rather than improving water quality resulting from landfill construction.
Even if it is assumed that construction of the lined landfill has had a positive effect on groundwater
quality, the graphs show that concentrations of ash -related parameters in some monitoring wells has
21 SynTerra, 2015b, p.1-8
22 SynTerra, 2015a, Attachment 3
23 Note that boron was not included in the tested parameters until 2002, so the early concentrations of boron are
unknown.
10

GEO-HYDRO, INC
remained at or above water quality standards in wells GMW-06, GMW-08 and GMW-11 despite the
presence of the lined landfill. In fact, boron, sulfate, and TDS concentrations have been increasing
rapidly in monitoring well GMW-8 since 2013. Continued detections of elevated concentrations24
of ash -related contaminants at in groundwater around the lined landfill indicates that ash underlying
the lined landfill continues to release contaminants to groundwater, even though most infiltration
from above has presumably been eliminated by the landfill liner. This result is to be expected at any
location where ash remains submerged below the local water table. Continued generation and
downgradient migration of leachate will occur in the Roxboro Ash basins unless all of the ash in the
basin is dewatered and remains above the high water table, a scenario that is unlikely to occur at
Roxboro.
Groundwater modeling performed for the CAP provided no estimation of the amount of saturated
ash that would remain at Roxboro should the capping in place remediation scenario be implemented.
An estimate of the thickness of the remaining thickness of saturated ash can be obtained by
comparing the elevation of the natural ground surface beneath the basins to the groundwater
elevation in wells just outside of the basins 25. The ground surface elevation below the EAB dam
was reported to be between 390 and 400 feet ms126. Groundwater elevations in EAB monitoring
wells located just outside of the basin are reported to be between 462 and 513 ft ms127. The
difference between the lowest measured groundwater elevation in wells located just outside the ash
basin and the highest natural ground surface elevations underlying the EAB indicates that at least 62
feet of saturated coal should be expected to be present beneath the EAB were the cap in place
remediation scenario implemented.
The natural ground surface elevation beneath the WAB was reported to be between 390 and 410 feet
ms128. Groundwater elevations in WAB monitoring wells located just outside the ash basin are
reported to be between 452 and 456 ft ms129. The difference between the lowest measured
groundwater elevation in wells located just outside the ash basin and the highest natural ground
surface elevations underlying the EAB indicates that at least 42 feet of saturated coal should be
expected to be present beneath the EAB were the cap in place remediation scenario implemented.
The relative effects of the cap in place and removal of the ash scenarios on groundwater quality were
evaluated as part of the groundwater modeling exercise. The modeling report indicates that removal
24 above 2L standards
25 Estimates of the thickness of saturated ash that would likely remain were the capping ash in place scenario
implemented are provided since the groundwater modeling report did not provide an estimation. Further modeling, or
better model reporting, should be conducted to refine these estimates.
26 SynTerra, 2015b, Appendix E, p.3.
27 SynTerra, 2015a, Figure 6-5.
28 SynTerra, 2015b, Appendix E, p.4.
29 SynTerra, 2015a, Figure 6-5.
11

GEO-HYDRO, INC
of the ash reduces the concentration of boron in groundwater more than either the No Action or
Capping Ash in Place scenarios. This indicates that removal of the Roxboro coal ash is the most
effective option for improving groundwater quality and minimizing future discharges to Hyco Lake.
This is as would be expected considering that the cap in place scenario would leave a significant
thickness of saturated ash in place that would continue to leach ash constituents into the groundwater
far into the future.
12

GEO-HYDRO, INC
7. Opinion 3: Monitored Natural Attenuation Is Not An Acceptable
Groundwater Remediation Strategy at Roxboro
The CAp30 indicates that Duke may evaluate Monitored Natural attenuation as a potential
groundwater remedy for certain area of the Roxboro site. The CAP attempts to make it appear that
Monitored Natural Attenuation (MNA) is a viable remedial option for impacted groundwater
downgradient of the Roxboro ash basin. From a technical standpoint, MNA remedies typically
require:
• That there are no current receptors, including surface water or wetland discharges and water
supply wells.
• That there is sufficient lateral space between the contaminant source and groundwater
discharge areas to allow natural attenuation to reduce contaminant concentrations prior to
reaching a receptor.
• Evidence that the location of the leading edge of the contaminant plumes be stable (not be
expanding).
• That there is a natural reduction in contaminant concentrations along flow paths.
• That there is sufficient space between the contaminant source and groundwater discharge
areas to allow a monitoring system to be established, including sentry wells located ahead of
the leading edge of the contaminant plume.
None of these technical factors for considering MNA as an appropriate remedial strategy at the
Roxboro site are met. From a scientific standpoint there is no justification for considering MNA.
There are also legal requirements that must be met in North Carolina in order to utilize MNA as a
groundwater remedy, including:
• NCAC 02L .0106 (1)(1) requires a demonstration that all sources of contamination have been
removed or controlled. So far, Duke Energy has not proposed removal of the waste for
disposal in a secure location. Hydrogeologic conditions presented in this document shows
that some of the ash would remain saturated after capping. Saturated ash will continue to
leach metals into groundwater that will flow toward and eventually discharge into Hyco
Lake. As a practical matter, in the absence of removal all sources of contamination cannot be
controlled
• NCAC 02L.0106 (1)(2) requires a demonstration that the contaminant has the capacity to
degrade or attenuate under site-specific conditions. Many of the ash -related constituents in
groundwater at this site neither degrade nor attenuate. The Geochemical Site Conceptual
30 SynTerra, 2015b, p.5-1
13

GEO-HYDRO, INC
Model31 states that boron is an indicator of coal ash impacts to groundwater because it "is
essentially inert, has limited potential for sorption and lacks an affinity to form complexes
with other ions." The characteristics of the contaminant plumes alone are sufficient to render
the Roxboro site ineligible to use MNA as a remediation strategy.
31 SynTerra, 2015b, Section 3.3
14

GEO-HYDRO, INC
8. Opinion 4: Capping Coal Ash Located Within the Roxboro Ash
Basin Will Not Be Protective of Surface Water Quality
The most problematic issues at the Roxboro plant are related to the interaction of groundwater and
surface water bodies on and around the plant site. The CAP indicates in several locations that the
lateral extent of groundwater contamination is generally limited to areas beneath or immediately
downgradient of the ash basins. These statements would often be interpreted as indicating that
contamination has not spread far from the source and the problem should be readily remedied.
However, at the Roxboro site the ash basins are bounded by drainage features on around the
perimeter of the basins that act as groundwater discharge areas. Ash -impacted groundwater plumes
are not restricted to the immediate area of the basins by a lack of migration; their size is restricted
only because the contaminated groundwater discharges to surface water features. This is particularly
problematic since water quality in the channel that carries most of the discharge from this site has
not been characterized. No surface water samples were collected from the outflow channel even
though the combined drainage from the East and West Ash Basins are passed through this channel to
Hyco Reservoir. In addition, surface water monitoring conducted under NPDES Permit NC0003425
does not include the most common analytical parameters that are found in ash impacted waters. This
means that a major discharge of likely ash -impacted water from the Roxboro site into Hyco Lake
was not sampled as part of the CSA and is not being appropriately monitored under NPDES
requirements. The chemistry and volume of water that flows through canals and into Hyco Lake
under current and expected closure conditions must be evaluated to assure that the selected remedy
is protective of water quality in Hyco Lake.
A cap -in-place remedy would not be protective of surface water quality. While a cap would likely
reduce the amount of water that enters the waste from precipitation, this remedy would do nothing to
reduce the amount of groundwater that flows laterally into the basin from surrounding geologic
units, through the capped waste, into downgradient surface water drainages, and eventually into
Hyco Lake. Groundwater would continue to flow into the ash basins from adjacent upland areas.
Groundwater that flows through the ash will continue to leach metals from the ash and transport
those metals down -gradient before discharging into adjacent surface water features.
15

GEO-HYDRO, INC
9. Opinion 5: Removal of the Coal Ash Will Remove the Source and
Reduce the Concentration and Extent of Groundwater
Contaminants
Removal (excavation) of the coal ash from the Roxboro ash basin is the only remediation scenario
that will separate the coal ash source materials from groundwater and eliminate flow of
contaminated groundwater and surface water into Hyco Lake. Excavation of the ash will remove the
source of groundwater and surface water contaminants, and reduce the concentration and extent of
current contaminants. The groundwater flow and transport model of the site was used in the CAP to
evaluate groundwater flow and investigate three remedial scenarios. The scenarios investigated
included the Existing Conditions scenario, a Capping Ash in Place scenario, and a Removal of Ash
scenario. The model was used to predict contaminant distributions for the next 5, 15 and 30 years,
under each scenario. The model showed that the Removal of Ash scenario resulted in the largest
reduction in ash -related contaminant concentrations of any of the modeled scenarios.
16

GEO-HYDRO, INC
10. Opinion 6: The Coal Combustion Residual Impoundment Risk
Classification Proposed by NCDEQ Improperly Minimizes
Protection of Environmental Quality
A risk ranking process was specified in CAMA to determine the type of closure permitted at each
facility. The law specifically requires NCDEQ to classify each impoundment as either high-risk,
intermediate -risk, or low-risk, based on consideration, at a minimum, of all of the following criteria.
(1) Any hazards to public health, safety, or welfare resulting from the impoundment.
(2) The structural condition and hazard potential of the impoundment.
(3) The proximity of surface waters to the impoundment and whether any surface waters are
contaminated or threatened by contamination as a result of the impoundment.
(4) Information concerning the horizontal and vertical extent of soil and groundwater
contamination for all contaminants confirmed to be present in groundwater in exceedance of
groundwater quality standards and all significant factors affecting contaminant transport.
(5) The location and nature of all receptors and significant exposure pathways.
(6) The geological and hydrogeological features influencing the movement and chemical and
physical character of the contaminants.
(7) The amount and characteristics of coal combustion residuals in the impoundment.
(8) Whether the impoundment is located within an area subject to a 100 -year flood.
(9) Any other factor the Department deems relevant to establishment of risk.
In order to evaluate each impoundment on the nine criteria the NCDEW established a risk
classification group32. The Risk Classification Group was broken into three sub -groups of people
based on areas of expertise (Groundwater, Surface Water, and Dam Safety) to develop a set of risk
factors to address each of the nine required criteria. Each subgroup reportedly placed a primary
emphasis on risk as it relates to the public from a groundwater, surface water, and dam safety
perspective and established one key factor that "plays a significant role in assigning an overall
classification" for that group. Other factors not identified as Key Factors were supposedly used to
"refine the risk classification and address the actual or potential risk to the environment and natural
resources."
The result of the risk classification methodology utilized by NCDEQ is that environmental and
ecologic risks posed by the Roxboro site were not fully considered by NCDEQ when establishing
the overall site risk and clean-up priorities. This resulted in the West, East, and Unnamed Eastern
Extension ash ponds being assigned Low, Low to Intermediate, and Intermediate risk ratings,
32 NDEQ, 2016, p. 13, Classification Methodology
17

GEO-HYDRO, INC
respectively, ratings that essentially ignore the known environmental impacts of the Roxboro ash
ponds. For example, Table 1 provides a listing of the groundwater risk classification factors and
associated ratings for each ash pond at Roxboro. Ten groundwater risk factors were established and
received ratings by NDEQ for each ash pond.
Table 1
Groundwater Risk Classifications
Unnamed Eastern
Groundwater Factors
East Ash Pond
West Ash Pond
Extension
Number of downgradient receptors within 1500 feet of
compliance boundary that are potentially or currently
Low Risk
Low Risk
Low Risk
known to be exposed to impacted water. (Key Factor)
Amount of stored CCR reported in an impoundment
High Risk
High Risk
High Risk
Depth of CCR with respect to the water table
High Risk
High Risk
High Risk
Exceedance of 2L or IMAC standards at or beyond the
High Risk
High Risk
High Risk
established CCR compliance boundary
Population served by water supply wells within 1,500 feet
Low /Intermediate
Low /Intermediate
Low /Intermediate
upgradient or side gradient of the compliance boundary
Risk
Risk
Risk
Population served by water supply wells within 1,500 feet
Low Risk
Low Risk
Low Risk
downgradient of the compliance boundary
Proximity of 2L or IMAC exceedances beyond the
High Risk
Intermediate Risk
High Risk
compliance boundary with respect to water supply wells
Groundwater emanating from the impoundment exceeds
High Risk
High Risk
High Risk
2L or IMAC and that discharges to a surface water body
Ingestion of contaminated soil or fugitive emissions
Low Risk
Low Risk
Low Risk
Data Gaps and Uncertainty
High Risk
High Risk
High Risk
The West Ash Pond received High or Intermediate ratings for 6 of the 10 groundwater risk
classification factors, one factor was rated as Low/Intermediate, and only 3 received ratings of Low
Risk. Only 30% of the rated groundwater risk classification factors were rated Low Risk, yet
NCDEQ gave the Roxboro West Pond an overall Low Risk rating for groundwater.
The East Ash Pond received 6 High Risk ratings, one factor was rated as Low/Intermediate, and only
3 received ratings of Low Risk. High risk rankings were assigned to 60% of the rated groundwater
risk classification factors, yet NCDEQ gave the Roxboro East Pond an overall Low to Intermediate
Risk rating for groundwater.

GEO-HYDRO, INC
The Unnamed Eastern Extension received High risk ratings for 6 of the 10 groundwater risk
classification factors, one factor was rated Low/Intermediate, and only 3 received ratings of Low
Risk. High risk rankings were assigned to 60% of the rated groundwater risk classification factors,
yet NCDEQ gave the Roxboro Unnamed Eastern Extension an overall Low Risk Rating for
groundwater.
Table 2 provides a listing of the surface water risk classification factors and associated ratings for
each of the Roxboro ash ponds. A total of eight surface water risk factors were rated by NCDEQ for
each pond. The West Pond received High or Intermediate ratings for 6 of the 8 surface water risk
classification factors and only 2 received ratings of Low Risk. Only 25% of the rated surface water
risk classification factors were rated Low Risk, yet NCDEQ gave the Roxboro West Pond an overall
Low Risk rating for surface water.
Table 2
Surface Water Risk Factors
Unnamed Eastern
Surface Water Factors
East Ash Pond
West Ash Pond
Extension
Landscape Position and Floodplain (Key Factor)
Low Risk
Low Risk
Low Risk
NPDES Wastewater and Ash Disposal Methods
Low/ Intermediate
High Risk
Intermediate / High
Risk
Risk
Impoundments Footprint Siting in Natural Drainage
High Risk
High Risk
High Risk
Way or Stream
Potential to Impact Surface Water Based on Total
High Risk
High Risk
Low Risk
Ash Amount at Facility
Potential to Impact Surface Water Based on Dilution
High Risk
High Risk
High Risk
Development Density of Single -Family Residences
Intermediate Risk
Intermediate Risk
Intermediate Risk
along Lake/Reservoir Shoreline
Classification of the Receiving Waters
Intermediate Risk
Intermediate Risk
Intermediate Risk
Proximity to Water Supply Intake
Low Risk
Low Risk
Low Risk
The East Pond received High or Intermediate ratings for 5 of the 8 surface water risk classification
factors, one factor was rated as Low/Intermediate, and only 2 received ratings of Low Risk. Only
25% of the rated groundwater risk classification factors were rated Low Risk, yet NCDEQ gave the
Roxboro East Pond an overall Low Risk rating for surface water.
The Unnamed East Extension Pond received High or Intermediate ratings for 5 of the 8 surface
water risk classification factors and only 3 received ratings of Low Risk. Only 37.5% of the rated
19

GEO-HYDRO, INC
surface water risk classification factors were rated Low Risk, yet NCDEQ gave the Unnamed
Eastern Extension pond an overall Low Risk rating for surface water.
The preceding analysis uses the risk ratings applied by NCDEQ with no evaluation or judgment
about whether they were or were not appropriately applied. The risk ratings given to the Roxboro
ash basins demonstrate that protection of environmental and natural resources is not being treated as
priority issues by the North Carolina agency entrusted with the responsibility to do just that. The
approach utilized by NCDEQ effectively ignores impacts to the natural environmental and natural
resources, and even ignores future human users of the groundwater and surface water resources. It
appears that in the view of NCDEQ the only way that a site can be rated as Intermediate or High
Risk is if a facility is located within a 100 -year floodplain or if 11 or more people within 1,500 feet
of the compliance boundary are potentially or currently known to be exposed to ash -impacted
groundwater33. It is hard to imagine that exposed persons 1 through 10 would agree with this rating
scheme.
33 NCDEQ, 2016, page 15, Key Factors
20

GEO-HYDRO, INC
References
Duke Energy, 2014, Discharge Monitoring Reports for September, October, and November 2014.
National Pollutant Discharge Elimination System, Permit NC0003425.
NCDEQ, 2016, Coal Combustion Residual Impoundment Risk Classifications, January 2016.
SynTerra, 2014, Groundwater Assessment Work Plan for Roxboro Steam Electric Plant, Semora,
NC, September 2014.
SynTerra, 2015a, Comprehensive Site Assessment Report, Roxboro Steam Electric Plant, Semora,
NC, September 2015.
SynTerra , 2015b, Corrective Action Plan, Part 1, Roxboro Steam Electric Plant, Semora, NC,
December 2015.
United States Geological Survey, Olive Hill, N.C., 7.5 Minute Topographic Map, 1968, revised
1994.
21

GEO-HYDRO, INC
Figures

r ' r:— f
60
_ � — I � � `-•y ' ,� _ _. f_fi - f 7 '.�_��. �`\s�_:.� �-.R �. I ITIS- a tk.�
1445 " �' � f--. L_ '" i � J•- _ - '�Ir 7 �.- ++ I 7 - _
.x
ti i a -y
M _
ZZ
- --.Jh _ 1�'�il �. tl -: -• e'. Ir`� `+li:{ ;IM1 `<ti.tlhJl t=~�ik1, e' t' ^. I� - ti,�4
1
'� .'+r4'c�bdlant# Bch
Image taken from
USGS Olive Hill, N.C.
1968
Photorevised 1994
GEO-HYDRO, INC
Consulting in Geology and Hydrogeology
f'
Figure l
Ash Basin Locations and Site
Topography
Roxboro Steam Electric Plant

1-
` � WWI
Ln
a
_
LOW
1=4
<°�
4.MFFN4u[Y WIfFPf 85
`L .. E'• ' fit. �,� carnrrce�ekN£tildu.4 F
r
I
1
I z
I +
1
1f
l�
j n
s�"Terra
DUNE:.
V ENERGY
j PROGRESS
*'e � � <..eeoaueiFuw sacrnc Pe.wlr
• nu»wxtrna
JUNE MS
GEO-HYDRO, INC
Consulting in Geology and Hydrogeology
Image taken from Figure 2
SynTerra, 2015b Bedrock Water Level Map
Figure 3-1 1 Roxboro Steam Electric Plant

4500
4000
3500
3000
2500
rn 2000
0
o
0° 1500
1000
500
0
1800
1600
1400
1200
1000
800
600
400
200
0
00`L 000 00N 006 006 00k 0 00 009 0^O O^^ °^ry O^9
rye^9�0- ^�,�'1,��'1�ry 1^1 �.\N`6\0"O\0"0"
Sample Date
Boron Concentration
May 2009 - April 2015
t°N —S&Nb, 'N
'k
'k,�0^� Ob�O�'� 1,��0�� Op�Oej\ ^,��� Op�O ^,���.
Sample Date
Sulfate Concentration
December 2002 -April 2015
GEO-HYDRO, INC
Consulting in Geology and Hydrogeology
—6 GMW-06
t GMW-07
GMW-08
--X—GMW-09
eX r GMW-10
+GMW-11
2L Standard (700 ug/1)
Data From:
Syn Terra, 2015a,
Attachment 3
0 GMW-06
f-GMW -07
GMW-08
X GMW-09
—X GMW-10
—41 W-11
2L Standard (250 mg/I)
Data From:
SynTerra, 2015a,
Attachment 3
Figure 3
Boron and Sulfate Concentrations
Lined Landfill area Monitoring Wells
Roxboro Steam Electric Plant

400
350
300
250
rn
E 200
y
150
100
50
0
\ti
O19 O°� OOb
0�\19 \ti
Selenium Concentration
December 2002 - April 2015
2500
2000
£ 1500
Sample Date
TDS Concentration
December 2002 - April 2015
o.�`y 0^3 O1b
500
0
o°o o°� o°�' 0°6 06 o°b o o°° o^d^ oN oN5 o�
AV
Sample Date
GEO-HYDRO, INC
Consulting in Geology and Hydrogeology
$GMW-06
tGMW-07
GMW-08
GMW-09
--*— GMW-10
--0--G MW -11
2L Standard (20 ug/I)
Data From:
Syn Terra, 2015a,
Attachment 3
—4-- GMW-06
t G M W-07
GMW-08
GMW-09
--)K—GMW-10
—e GMW-11
2L Standard (500
mg/I)
Data From:
S ynTe rra, 2015a,
Attachment 3
Figure 4
Selenium and TDS Concentrations
Lined Landfill area Monitoring Wells
Roxboro Steam Electric Plant