NC0005088_Powell Expert Report - Cliffside_20160630

Expert Report of
Robert L. Powell Ph.D., P.E.
Cliffside Steam Station
Mooresboro, NC
In the matter of
State of North Carolina ex. rel. North
Carolina Department of Environmental
Quality vs. Duke Energy Carolinas,
LLC.
Prepared for:
Hunton & Williams, LLP
Charlotte, NC
Prepared by:
Ramboll Environ US Corporation
Tampa, Florida
Date:
June 30, 2016
Project Number:
25-39485A
ENVIRON

Contents
Page
1 Introduction and Summary of Opinions 1
2 Qualifications and Experience
3 Materials Considered
4 Explanation and Basis for Opinions
4.1 Opinion 1
4.2 Opinion 2
4.3 Opinion 3
4.4 Opinion 4
4.5 Opinion 5
3
4
6
6
6
8
11
13
5 Signature 16
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1 Introduction and Summary of Opinions
I have been retained by Hunton & Williams, LLP on behalf of its client, Duke Energy Carolinas,
LLC ("Duke Energy") to conduct an independent evaluation and provide certain expert opinions
in response to a lawsuit filed by the state of North Carolina in the matter of State of North
Carolina ex. rel. North Carolina Department of Environment and Natural Resources vs. Duke
Energy Carolinas, LLC. The opinions I have formed and offer herein are related to
hydrologic/hydrogeologic conditions at Duke Energy's Cliffside Steam Station in Mooresboro,
North Carolina (the "Cliffside Station" or "Site") and the appropriateness of measures to manage
and close certain ash management facilities on the property in compliance with the
requirements of the state Coal Ash Management Act of 2014 (CAMA), and to remedy alleged
violations of state laws related to discharges to ground water and surface water systems.
In order to comply in part with the requirements of the CAMA, Duke Energy completed and filed
a Comprehensive Site Assessment Report (CSA) with the North Carolina Department of
Environment and Natural Resources (NCDENR) on August 18, 2015 (HDR; 2015a). This CSA
reported on the findings of an assessment of environmental conditions on the Cliffside Station
property, focusing specifically on the impacts, if any, from the past and current onsite
management of coal ash on underlying soil, ground water and surface water resources.' The
scope of this CSA included extensive subsurface investigations of soil and ground water
conditions, and water quality testing of ground water and surface waters on the Cliffside Station
property. This CSA report, and subsequent monitoring data, form the primary body of
information that describes onsite environmental conditions of the Cliffside Station property that I
have considered.
Subsequently Duke Energy also prepared and filed a Corrective Action Plan, Part 1 with the NC
Department of Environmental Qualityz dated November 16, 2015 (HDR; 2015b) and a
Corrective Action Plan, Part 2 dated February 12, 2016 (HDR; 2016) in which it reported on its
initial evaluation of potential remedial alternatives to address releases of constituents of coal
ash to underlying ground water systems as found and reported in the CSA. These remedial
measures ranged from No- Action (essentially leaving current ash management units in place
under then -current conditions) to in-place capping, and/or removal of the current ash
management units, with reburial of the ash in a new lined landfill. The supporting analyses in
these CAP reports form the primary basis for my review of remedial alternatives for closure of
ash facilities and the mitigation of seepage.
Based on my review of documents and related information in this case I have reached the
following general opinions:
Opinion 1: The environmental investigations performed by Duke Energy at the Cliffside Station
pursuant to the CAMA and the prior compliance monitoring programs conducted pursuant to its
state operating permits provide a sufficient volume of scientific knowledge to define the general
nature of the hydrogeologic systems that underlie the Cliffside Station property, the impacts of
Coal ash is a waste byproduct from Duke Energy's onsite combustion of coal to generate electrical power.
2 Prior to September 18, 2015, the NCDEQ was referred to as the North Carolina Department of Environment and
Natural Resources (NCDENR).
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seepage from onsite ash management units on ground water and surface water quality, and to
support the closure planning of prior and current ash management units.
Opinion 2: Ground water beneath the Cliffside Station property originates primarily from the
local, onsite infiltration of rain water into native soil and process water that infiltrates thru the
current ash management units and storm water storage ponds. Ground water beneath the site
ultimately discharges into a surface channel (Suck Creek) that crosses the property from the
south to north, or as a broad area of seepage along the boundary of the Broad River, which
borders the property to the north.
Opinion 3: Seepage of water from the prior and current ash management units has caused the
release of certain Constituents of Interest (COls) to the shallow ground water at concentrations
that exceed the NCDENR 2L water quality standards in localized areas around and immediately
beneath the ash management units. Some of these COls have migrated downgradient generally
to the north towards adjoining surface water features, and have in limited areas reached
compliance boundaries established for individual ash management units. Ultimately, the
migration of these COls (if not mitigated by geochemical processes in the aquifer) will cause
their discharge into adjoining surface water features. Such discharges should not cause any
exceedance of applicable surface water standards in the Broad River.
Opinion 4: The presence of COls in ground water beneath the Cliffside Station property and the
migration of Cols in ground water to the north into the Broad River poses no risk to on-site or
neighboring drinking water supplies.
Opinion 5: A substantial level of control of COI release/migration from the closed and active
ash management units can be achieved by the use of appropriate and conventional engineering
controls, including the placement of multi -media caps over closed ash management units and
the collection and treatment of seepage that has been found to be discharging from the toe
drains at the base of the earthen dams that form the ash impoundments, or otherwise from
natural, discrete seeps that have formed in low areas along the base of the impoundments or
bordering Suck Creek. Such controls should substantially reduce the overall release of COls
into ground water and ultimately to Suck Creek and the Broad River over the long term,
providing additional assurance of continued achievement of surface water quality standards.
My qualifications as an expert in this case are provided in Section 2 of this report. The materials
I have relied on in formulating my opinions are identified in Section 3. The bases for and
detailed explanation of my opinions are presented in Section 4.
I am compensated by my employer, Ramboll-Environ US Corporation (Ramboll-ENVIRON), for
my services and expenses on this matter at my normal hourly compensation rate. Ramboll-
ENVIRON bills Duke Energy at a rate of $300/hour for these services.
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2 Qualifications and Experience
I am a Principal of Ramboll-Environ in Tampa, Florida. Ramboll-Environ (formerly ENVIRON
International Corporation ("ENVIRON")) is an international consulting firm that provides
scientific, engineering and strategic risk management services to clients in the public and
private sectors. ENVIRON was formed in 1982, and in December 2014, merged with Ramboll.
The combined, Ramboll-Environ has nearly 300 offices and over 12,000 employees worldwide.
I am a practicing professional engineer, 3 hydrologist and hydrogeologist. I received a Ph.D. in
Civil Engineering (Groundwater Hydrology) in 1983. 1 received an M.S. in Civil Engineering
(Water Resources) in 1977. 1 received a B.S. in Civil Engineering (Environmental Engineering)
in 1973. All degrees were received from the University of Maryland, College Park.
I have approximately 40 years of experience as a practicing consultant in the fields of
environmental engineering, surface and ground water hydrology, hazardous waste
management, contaminated site investigation/remediation, risk assessment, and environmental
risk management. This experience includes professional consulting services at many of the
largest solid waste management facilities throughout the United States that are regulated under
federal and state environmental statutes. My recent work as an expert included consulting
services at two large coal ash management facilities in the state of Maryland, focusing on issues
of the impacts to underlying and adjoining ground water/surface water systems and the efficacy
of closure alternatives that had been implemented at the sites. I have also conducted
environmental investigation, and evaluated corrective action requirements at numerous
industrial and commercial facilities that generate solid/hazardous wastes and other regulated
materials for federal, state and private clients. These have included facilities that have
undergone closure under RCRA, TSCA, CERCLA, and related state regulatory programs.
have previously been qualified as an expert and testified in United States federal and state
courts in the fields of ground water hydrology, environmental investigations and remediation
planning, environmental risk management, and cost allocation/National Contingency Plan (NCP)
consistency under CERCLA regulations.
3 My currently active PE license is in the state of Florida (No. 64379) where I currently reside and work.
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3 Materials Considered
The opinions set forth in this report are based on my approximately 40 years of experience in
consulting engineering as well as my formal academic training as an environmental engineer
and hydrologist/hydrogeologist. In forming my opinions I considered observations I made during
my visit to the Site on June 6, 2016 and information concurrently provided by Duke personnel. I
also considered information from certain documents that describe the conditions of the Cliffside
Station property, as identified below, which documents were provided to me at my request by
counsel. I also reviewed and considered the reports and opinions of the opposing experts in this
matter (Drs. Douglas Cosler, Phillip Bedient and Robert Parette). Specifically, I reviewed and
considered the following Site and case related documents:
Comprehensive Site Assessment Report, Cliffside Steam Station Ash Basin; HDR Engineering
Inc. of the Carolinas; August 18, 2015[a].
Corrective Action Plan, Part 1, Cliffside Steam Station Ash Basin; HDR Engineering Inc. of the
Carolinas; November 16, 2015[b].
Corrective Action Plan, Part 2, Cliffside Steam Station Ash Basin; HDR Engineering Inc. of the
Carolinas; February 12, 2016.
Ground water level data from Rounds 2 (August 2015) and 3 (April 2016) at the CSS.
Expert Report of Douglas J. Cosler, PhD, P.E.; Cliffside Steam Station Ash Basins, Mooresboro,
North Carolina; February 29, 2016.
Amended Expert Report of Douglas J. Cosler, PhD, P.E.; Cliffside Steam Station Ash Basins,
Mooresboro, North Carolina; April 13, 2016.
Remediation of Soil and Groundwater at the Cliffside Steam Station Operated by Duke Energy
Carolinas, LLC Mooresboro, North Carolina; Expert Opinion of: Philip B. Bedient, PhD, P.E.;
February 29, 2016.
Remediation of Soil and Groundwater at the Cliffside Steam Station Operated by Duke Energy
Carolinas, LLC Mooresboro, North Carolina; Expert Opinion of: Philip B. Bedient, PhD, P.E.;
Amended 13 April 2016.
Opinions on the Appropriateness of Monitored Natural Attenuation in Conjunction with Partial
Excavation and Cap -in -Place at the Cliffside Steam Station, Mooresboro, NC; Robert Parette,
PHD, PE; May 13, 2016.
NPDES Permit No. NC0005088 (Exhibit 12 to the Complaint)
Surface water quality monitoring records for the Cliffside Station site.
Emergency Action Plan (EAP) Duke Energy, Cliffside/Rogers Energy Complex, May 16, 2016.
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Letter to Duke Energy Corporation from NCDEQ Re: Notice of Deficiency Issued March 5, 2014
and June 13, 2014, Cliffside Steam Station Inactive Basin #5 Main Dam; August 11, 2014.
Letter to Duke Energy Corporation from NCDEQ Re: Notice of Deficiency Issued June 13, 2014,
Cliffside Active Ash Basin Downstream Dam; August 11, 2014.
Notice of Deficiency Re: Cliffside Inactive Ash Basin #5 Main Dam; March 5, 2014.
I reserve the right to amend or supplement my opinions if additional information becomes
available.
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4 Explanation and Basis for Opinions
4.1 Opinion 1
The environmental investigations performed by Duke Energy at the Cliffside Station pursuant to
the CAMA and the prior compliance monitoring programs conducted pursuant to its state
operating permits provide a sufficient volume of scientific knowledge to define the general
nature of the hydrogeologic systems that underlie the Cliffside Station property, the impacts of
seepage from onsite ash management units on ground water and surface water quality, and to
support the closure planning of prior and current ash management units.
During the 2015 CSA investigation, extensive numbers of soil boring and monitoring wells were
drilled and/or constructed on the Cliffside Station property to investigate subsurface
hydrogeologic conditions. Samples of soil cutting were collected for physical/chemical
examination/testing, ground water and surface water samples were collected and chemically
tested, aquifer hydraulic tests were performed on multiple wells from each of the identified
ground water zones (i.e. the saprolite, transition and the bedrock units), and multiple rounds
(three to date) of water level measurements were performed in onsite wells. Collectively this
body of field investigations has provided a comprehensive database that describes the natural
geology and hydrology of the Cliffside Station property and from which a Conceptual Site Model
of the underlying ground water system, and its interaction with overlying surface waters, can be
formed. The level of investigation in this instance is on par, in my nearly 40 years of experience,
with comparable investigations I have performed at some of the most complex waste sites
under similar environmental programs (e.g. CERCLA or RCRA). The resulting knowledge that
has been gained is sufficient to perform the initial screening and evaluation of options for future
management of ash management units on the property pursuant to the CAMA. To the extent
that additional data needs are identified in the course of these remedial evaluations, focused
data collection programs are likely to occur as these analyses progress to remedial design. This
is a normal course for such evaluations and does not diminish the comprehensive nature of the
work already performed under such a short time -frame.
4.2 Opinion 2
Ground water beneath the Cliffside Station property originates primarily from the local, onsite
infiltration of rain water into native soil and process water that infiltrates thru the current ash
management units and storm water storage ponds. Ground water beneath the Site ultimately
discharges into a surface channel (Suck Creek) that crosses the property from the south to
north, or as a broad area of seepage along the boundary of the Broad River, which borders the
property to the north (see Figure 2-2 of the CSA report; HDR, 2015a).
The extensive geologic and hydrologic data that has been derived from the onsite drilling
program and documented in the CSA report demonstrates that the Cliffside Station property is
underlain by the typical saprolitic soils and fractured bedrock that are characteristic of the mid-
Atlantic Piedmont region. Shallow soils are formed by the in-place weathering of native rocks
into a relatively fine-grained matrix of clayey material with varying amounts of intermixed silts,
sand and rock fragments. Beneath this soil is a transitional zone of less weathered but typically
highly fractured rock at the base level of the saprolite zone, with varying amounts of infilled soils
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in the fractures. Deeper still is native fractured bedrock, 4 where the degree of fracturing typically
diminishes with greater depth.
In this type of geology, and on the Cliffside Station property, subsurface water principally
derives from the local infiltration of rainwater at the ground surface and the subsequent
percolation of this infiltration into successive deeper soil and rock layers. The amount of natural
recharge in unpaved areas of the Site is in the range of 6-8 inches/year. As water percolates
through the subsurface, it generally follows a downward pathway through the soil and rock
fractures towards lower elevations. This pattern of flow is readily apparent in the comparison of
water levels in monitoring well nests constructed in the upper hillside areas, where water levels
generally diminish with depth creating a downward gradient (see for example the water levels in
well nest GWA-5S/BRU reported in Table 11-13 of the CSA report; HDR 2015a).6 Water has
also historically been added to the Site in the form of infiltration and seepage of rain and
process water from ash management units, where ash has been historically deposited as a wet
slurry, and storm water has accumulated in shallow impoundments inside the ash management
units 1-4.
As ground water and artificial infiltration flows deeper into the ground, there is also a tendency
to flow laterally down slope along bedding planes in the soil, or fractures in the transition zone or
bedrock towards surface drainage features. Most prominent in this regard is Suck Creek, which
crosses the Cliffside Station property from the south to north, more or less bifurcating the
property, and the Broad River, which flows west to east and forms the northern property
boundary. The emergence of ground water by drainage into these surface water features may
be in the form of discrete seeps (or springs), or as a much broader and diffuse inflow as base -
flow along the streambed. The flow of ground water from the higher recharge areas into the
lower discharge areas along Suck Creek and the Broad River is readily apparent in the ground
water level maps presented in the CSA report and in the reported seeps that have formed along
these discharge boundaries (see for example Figures 6-6, 6-7 and 6-8 from the CSA report;
HDR 2015a).
As ground water approaches the Broad River to the north, the higher pressures found in deeper
wells in the bedrock zone will tend to force water to the surface, causing it to discharge through
the fractured bedrock in the river -bed and thus become part of the surface base -flow in the river.
Ground water level data reported in the CSA and in particular in subsequent rounds of ground
water monitoring are consistent with this generalized interpretation of the ground water flow
system.6 Similar patterns of ground water flow from the higher ground to the north of the river
4 Rock types reported in this bedrock zone are primarily metamorphic in origin with varying degrees of fracturing.
6 Some limited amount of ground water also likely flows onto the Cliffside Station property from the south from the
upper portions of the Suck Creek basin. The majority of the water entering the property from this area, however,
has probably already reached the surface and is reflected in the seasonal base flow of water in the creek -bed that
crosses onto the property from the south.
6 Care must be taken, however, when interpreting such data to consider also the immediate construction and
monitoring history of individual wells, particularly when they exhibit abnormal or unusually low water levels in
comparison to the general site conceptual model. In this instance, the well construction and development records
in Appendix G of the CSA (HDR, 2015a) indicate the unusually low bedrock water levels along the river reported in
the first round of well testing from June 2015 were the result of insufficient time between when the wells were
developed and when the water level measurements were made, during which time the water levels in the wells
had not yet fully recovered. Water level data in such wells under this circumstance are of no value in interpreting
the interaction of ground water with the river. A further discussion of this issue is presented in Opinion 4 below.
7 Ramboll Environ

will cause a convergence of flow along the riverbed and prevents the movement of ground water
and any dissolved COls beneath the Site into the areas north of the river.
The specific local interaction of the ground water that flows across the property to the north and
ultimately into the river bed in this case can be bifurcated into two regions, being: that area
upstream of the low -head dam that crosses the river in the central portion of the property, and
the area downstream of the dam. Upstream of the dam, surface water levels are higher and the
gradient of the river surface is relatively flatter (due to the impoundment of water behind the
dam). In addition, the riverbed in this area likely contains an accumulated layer of finer grained
sediment which will tend to inhibit the free-flow of ground water across the riverbed. These
conditions will tend to raise the water levels in the ground water zone on the Cliffside Station
property near the river, as can be seen for instance in the water level records for wells MW36
and MW38. Ground water will discharge into the river in this area as a broad region of diffuse
seepage through the riverbed sediments rather than along discrete pathways (e.g. from discrete
fractures).
In the immediate area of the dam there is an abrupt drop in surface water levels by
approximately 8-10 feet; and the river bed below the dam is well scoured to native bedrock by
the turbulence created by the overflow (see Figure 1). Ground water beneath the river
immediately above the dam will tend to drain along the riverbed towards the dam, where it will
ultimately discharge through the riverbed immediately downstream. Further downstream of the
dam the gradient of the water surface in the river is steeper, generally following the slope of the
riverbed; and the resulting velocity of water flowing in the river will be greater, as compared to
the area above the dam (see Figure 2 and 3). In this area there is much less accumulation of
sediment on the riverbed, which is primarily founded on fractured bedrock. Ground water will
tend to readily flow into the river directly through fractures that intercept the riverbed following
the dominant northerly trending fracture patterns in the region of the Site (see Figure 6-4 of the
CSA report). This drainage through fractures into the river limits the downstream movement of
ground water to the east beneath the river bed, in favor of more direct discharge to surface
water along the Site boundary directly into the river. Contrary to the views of downstream
subsurface migration expressed by Dr. Cosler in his expert report, any COls in the groundwater
downstream of the ash management units near the river (e.g. near units 1-4 and 6) discharge
fully into the river along the Site property boundary and do not migrate further downstream in
ground water.
4.3 Opinion 3
Seepage of water from the prior and current ash management units has caused the release of
certain Constituents of Interest (COls) to the shallow ground water at concentrations that
exceed the NCDENR 2L water quality standards in localized areas around and immediately
beneath the ash management units. Some of these COls have migrated downgradient generally
to the north towards adjoining surface water features, and have in limited areas reached
compliance boundaries established for individual ash management units. Ultimately, the
migration of these Cols (if not mitigated by geochemical processes in the aquifer) will cause
their discharge into adjoining surface water features. Such discharges should not cause any
exceedance of applicable surface water standards in the Broad River.
8 Ramboll Environ

The extensive testing of ground water and surface water chemistry as part of the CSA
investigations has established that COls have dissolved into water that naturally percolates
through the closed and active ash disposal units, and have since migrated deeper into the
saprolite soils and bedrock beneath and immediately downgradient of these units, causing
exceedance of NCDEQ 2L ground water quality standards. COls currently identified in the
CSA/CAP1/CAP2 reports as exceeding the 2L standards include 17 metals and mineral -related
constituents (see Table 2-2 and 2-3 of the CAP2 report). Many of these same COls have only
been detected in very limited instances above standards. Many are also found naturally in
ground water on the Site (e.g. antimony, cobalt, chromium, iron, manganese, vanadium) at
concentrations that exceed state 2L or IMAC standards. These latter COls are part of the
minerals that form the underlying bedrock. 7 The more mobile of the COls (e.g. boron and
sulfate) have migrated downgradient generally to the north towards adjoining surface water
features, and have in limited areas reached compliance boundaries established for individual
ash management units. Of these two, boron provides the most definite tracer to identify the
migration of COls from the ash management units.
The interpretation of the precise extent of COI migration from the ash management units is
complicated by their natural occurrence in ground water and the relatively limited number of
tests of water samples from each well that could be performed under the tight project schedules
mandated by the CAMA regulations, the results of which are not entirely consistent when
comparing the first and later rounds of water quality testing. Several cautions are in order in this
regard. First, a number of the monitoring wells are reported to be very low producers of water
(some can reportedly even be pumped dry) and continue to exhibit elevated turbidity when
pumped and sampled. COls that sorb to particulates in the well (the source of the turbidity) can
create a false (high) impression of the amount of COls that are actually present in the
groundwater as a dissolved, and potentially mobile, constituent plume.
Second, water samples from a number of the new monitoring wells constructed during the CSA
continue to exhibit elevated pH in the range of 9 to 12 pH units (e.g. wells GWA-22S and BRU,
located along the Broad River at the downgradient property boundary). Based on my review of
data from wells constructed in the ash deposits, it is unlikely that such high pH values result
from ash leachate migration. Rather, it is far more likely that cement used to grout the well
casings is sufficiently close to the screened interval and/or gravel pack of the well to cause a
local rise in the measured pH. A shift in pH to such a strong base range has the potential to
cause an unnatural change in the speciation of COls and their concentrations reported in the
chemical tests of water reported in the CSA. Water chemistry from such wells likely does not
accurately reflect the true condition of ground water in these areas. I note that Dr. Cosler failed
to identify and discuss this concern in his otherwise broad citation of COI exceedances in his
expert report.
Third, a number of the COls that are present in the ash are also natural constituents of the
soil/rocks that form the aquifer system beneath the Site (see Table 10-9 of the CSA report;
HDR, 2015a). These COls, therefore, are naturally present in ground water sampled from
background monitoring wells, and in some instances (e.g. antimony, chromium, cobalt, iron,
The elevated iron content of the native rocks is particularly apparent in the red -rust staining that is visible when
soil/rocks are exposed at the surface in graded areas and road cuts.
9 Ramboll Environ

manganese, vanadium) have been reported in these background wells in excess of NCDEQ 2L
or IMAC standards. Given the limited number of tests of ground water performed to date, there
remain significant uncertainty as to the range of these COls that naturally occur and could be
expected to be found in ground water extracted from monitoring wells drilled into this aquifer
system. The current ground water quality data are insufficient to establish a reliable statistical
"model" of background water quality that could be used to identify the extent of ash migration
with any accuracy and confidence, particularly when compared to wells that only exhibit COI
concentrations in the same range as have also been found in background areas. Further
analysis of this issue is warranted, as additional rounds of ground water are sampled and
tested.
In the interim, boron serves as the most reliable, conservative "tracer" to interpret the presence
of ash -derived COls in ground water. Boron is a soluble and mobile constituent of the ash that
has not been generally detected 8 in background monitoring wells located upgradient of the ash
management units on the Cliffside Station property. Simply stated, if boron is not concurrently
found in monitoring wells that otherwise have reported COI exceedances of NCDEQ 2L
standards, it is unlikely such exceedance derive from seepage/migration from the ash
management areas.
Lastly, I note that a number of the COls reported in the CSA as exceeding NCDEQ 2L
standards are very inconsistent in the reported concentrations, with values dramatically rising or
falling from one round to the next. Such variability, although not uncommon when testing for the
types of metal COls at issue in this case, confounds any meaningful interpretation that can be
drawn as to whether contamination in excess of a particular standard is actually present in the
ground water surrounding the well.
These cautions notwithstanding, it is clear from my review of the ground water and seep data
that Cols have migrated and will continue to migrate from the former and active ash
management units at levels that are causing localized exceedances of NCDEQ 2L standards in
ground water beneath the units and in some immediately downgradient areas. This migration is
facilitated by a permanent water table within the ash deposits that is caused by the discharge of
water from the slurried ash, local infiltration of rainwater falling inside the unit boundaries, and to
a lesser extent the lateral inflow of ground water from adjoining higher areas.
The extent of the COI migration can best be considered by the consistent presence of elevated
concentrations9 of COls such as boron in monitoring wells along the river downgradient of the
ash management units. Migration has been particularly apparent by the presence of boron at
elevated levels (albeit at less that the NCDEQ 2L standards) in wells screened in the shallow
overburden and transition zones along the river north of closed Units 1-4 (e.g. GWA-11s/BRU)
and the active unit 6 (e.g. MW-20D/DR) bordering the river, and the increasing elevation of
boron, sulfate, and TDS in MW38D along the Point of Compliance north of former Unit 5 near
the Broad River (see Figures 10-59, 10-60 and 10-61 of the CSA report; HDR 2015a). Much
a The typical detection limit for boron is 50 ug/L, which is sufficiently sensitive to serve as a reliable tracer for COI
migration from ash management areas.
9 Although present in ground water in these areas, the concentration of boron has not typically exceeded the NCDEQ
2L standard along the boundary of the river.
10 Ramboll Environ

more limited migration of boron into the deeper bedrock unit is indicated in these same areas.
Boron is not readily attenuated other than by dilution as it migrates in ground water, and in the
absence of remedial actions to prevent such migration, a slow progressive movement towards
the river is expected. Upon reaching the river boundary, it will slowly seep through the river bed
sediments and combine to form the surface water flowing in the river to the east past the Site.
Other more geochemically reactive COls such as arsenic have migrated to a much lesser
degree.
The conservative mixing zone analyses presented in the CAP1 and 2 reports indicate that
seepage and/or COI migration via ground water into the river is unlikely to ever cause a violation
of NCDEQ 2B surface water standards. This analysis modeled the rate of mass inflow of
identified COls to the river and Suck Creek and estimated the amount of dilution that would
occur under drought and normal base -flow conditions. This analysis was conservative in that it
assumed that the rate of groundwater and COI inflow would be the same under drought vs non -
drought conditions. It is likely, however, that local ground water inflow to the river would diminish
under the same drought conditions that would produce the lower base -flow in the river, so the
amount of dilution for the drought scenarios is likely understated in the modeling analysis. In any
case, no violation of the water quality standards in the Broad River was predicted, and current
monitoring in the river demonstrate NCDEQ 2B surface water quality standards are currently
being met (HDR 2015a).
4.4 Opinion 4
The presence of COls in ground water beneath the Cliffside Station property and the migration
of COls in ground water to the north into the Broad River poses no risk to on-site or neighboring
drinking water supplies.
Information provided in the CSA (HDR; 2015a) indicate there is no onsite use of ground water
for drinking water supply on the Cliffside Station property. All potable water used by onsite
employees is supplied by a local municipality. There are some private water supply wells
located on adjoining or neighboring properties to the south, southeast, east and across the
Broad River to the north that supply water for individual homes or businesses (see Figure 4-1
from the CSA report, HDR, 2015a). Although no direct measurements of the daily volumes of
water individually extracted by these private wells has been made, the assumed pumping rate
used in the ground water model documented in the CAP2 (HDR, 2016) report of 400 gpm is
reasonable in my experience. At this rate of supply, the source area for the ground water
pumped from these wells should involve approximately one to two acres of surrounding
property, lying generally in an uphill direction. Although information on the depth and
construction of these private wells is not available, based on my experience in the Piedmont
region, most are likely screened or drilled into the bedrock. I am not aware of any other larger
10 Boron is not a COI that is monitored under the Site's NPDES permit and does not have a current surface water
quality (2B) standard.
11 Ramboll Environ

industrial or municipal ground water supply wells within the immediate vicinity of the Site (i.e.
within one-half mile).
Those private water supply wells located to the south and southeast are generally located in
areas that are hydraulically upgradient from the Cliffside Station property, based on my review
of regional topography and ground water level maps included in the CSA reports cited above.
The water that supplies these wells derives from local infiltration of rainwater in the immediate
surrounding area. This is graphically demonstrated in the particle traces shown on Figure 18,
Appendix B of the CAP2 report (HDR; 2016), which was prepared using the onsite ground water
flow model, for 13 nearby private wells that are located within the model domain. Other private
wells located farther to the east, outside the model domain, are positioned so as to be side -
gradient from the Cliffside Station. Water pumped from these wells would also primarily derive
from local infiltration on nearby properties and to the south. None of the ground water produced
by wells located south, southeast or east of the Cliffside Station property originates in the onsite
areas previously used by Duke Energy for management of ash.
Other private water supply wells located to the north across the Broad River are too distant and
pump too little water to draw COls in onsite ground water across the river and uphill, onto higher
ground. As discussed above in Opinion 2, the hydrogeologic investigations on the Cliffside
Station property clearly demonstrate that onsite groundwater in the shallow, transitional and
bedrock zones flows to the north, if it is not first intercepted by local drainages such as Suck
Creek, and ultimately discharge through the riverbed into the Broad River consistent with the
hillslope patterns of ground water flow found throughout the Piedmont region along the mid-
Atlantic basin. The natural drainage of ground water into the river cuts off, and thereby
prevents, the flow of ground water from the Cliffside Station property farther to the north of the
river, where these private supply wells are located. This interpretation is further supported by
the absence of boron (a mobile, conservative tracer of ash -derived COIs) in water
sampled/tested from compliance well MW -25D located across the Broad River from the former
Unit 1-4 and the active Unit 6 (see Figure 10-60 from the CSA report; HDR 2015a).
In his expert report, Dr. Cosler (an expert witness retained by the intervenor -plaintiffs in this
case) disputes this latter conclusion and has stated that low water levels (below the local water
level in the river) in certain bedrock monitoring wells along the river reported in the CSA (HDR;
2015a) demonstrate that pumping from the private wells to the north is causing sufficient
drawdown to risk the migration of COIs into their water supplies. His conclusion in this regard is
incorrect and is based on faulty data. The low water levels reported in the CSA near the river in
certain bedrock wells (e.g. wells) in late June, 2015 were caused by the incomplete recovery of
water levels to normal ranges following the construction and purging/development of the wells.
Based on my review of the purge records in Appendix G of the CSA (HDR, 2015a), all of the
wells in question in this area had been purged of water (some to a completely dry condition)
within the few days to week before the first round of water level measurement was performed in
late June, 2015." The water levels at the time of this first round of measurements were in many
" Over -pumping and purging a new well of water is a normal procedure in the latter stages of well construction to
remove sediment and particulates that remain in the borehole. This cleaning procedure is used to ensure the water
later pumped from the well and tested is representative of the natural ground water condition in the area of the
12 Ramboll Environ

cases well below what is reported as the pre -purge level on the individual well development
logs. Two subsequent rounds of water level measurements in these same wells in August 2015
and April 2016 demonstrate that the artificially low water levels in round 1 have since recovered
and are now consistently higher than the river. There is no drawdown of the water levels in the
bedrock along the river in this area caused by pumping from private wells to the north. Water
level data in these latter rounds of measurements are consistent with the discharge of ground
water along the Cliffside Station property boundary into the Broad River.
4.5 Opinion 5
A substantial level of control of COI releases/migration from the closed and active ash
management units can be achieved by the use of appropriate and conventional engineering
controls, including the placement of multi -media caps over closed ash management units and
the collection and treatment of seepage that has been found to be discharging from the toe
drains at the base of the earthen dams that form the ash impoundments, or otherwise from
natural, discrete seeps that have formed in low areas along the base of the impoundments or
bordering Suck Creek. Such controls should substantially reduce the overall release of COls
into ground water (and ultimately into Suck Creek and the Broad River) over the long term,
providing additional assurance of continued achievement of surface water quality standards.
Following a comprehensive review of the stability and security of the current onsite ash
management units, I understand Duke Energy has decided to close former management units
1-4 by removing the ash and reburying it in a lined landfill. I understand this decision was
primarily driven by a concern with the current condition of the downstream storm -water piping
and the outlet spillway through the earthen dam that forms the north wall of the unit. In my
opinion, this decision is justified and prudent under the circumstances. The removal of ash from
the units 1-4 is currently ongoing.
Water has historically entered the former and active ash management units from the natural
accumulation of rainfall and local runoff on the surface of the unit, the application of water from
the slurried ash pumped to the unit for disposal, and by the lateral subsurface movement of
shallow ground water from surrounding higher ground towards the topographically lower valleys
that were filled to form the ash management units. Estimates in the CAP 1 and 2 reports of the
net rate of infiltration range from 6-8 inches per year in closed units such as No.5, to 11 inches
per year in active units such as No. 6, rates which I find to be reasonable. As the units have
been closed, the artificial application of water with the ash in a slurry no longer occurs, but
rainfall infiltration and lateral ground water inflow have continued to occur. The former issue
(infiltration) is the largest source of water entering the now -closed units (e.g. Unit 5) and can be
effectively controlled by the placement of a multi -media cap (e.g. a clay and synthetic geotextile
such as HDPE composite cap) over the unit. Such a cap represents the current state of the art
in moisture control and would virtually eliminate infiltration as a source of future water entering
the closed ash management unit. In the CAP2 report (HDR, 2016) Duke Energy is proposing to
close the inactive unit 5 and the active unit 6 in-place by placing a multi -media cap, potentially
well. Following this purging, a sufficient period of time (which may be days, weeks or even a few months in the
tightest formations) must be allowed for the water level to recover before meaningful and accurate measurements
of ground water levels can be performed.
13 Ramboll Environ

along with downgradient seepage controls and MNA, to control the rate of migration of COls into
adjoining surface waters.
Modeling analyses in the CAP 1 and 2 reports (HDR 2015b and 2016) show that the net effect
of such a cap would be to lower the water table in the ash. Nevertheless, some saturated ash
would likely remain in the deepest part of the units due to the continued lateral inflow of water.
Such inflow could prove difficult to control upstream of the unit given its size and the
surrounding topography, and additional measures to intercept/treat/recycle seepage and toe
drain discharge below the reconfigured dam may prove to be necessary if such discharges are
not otherwise permitted under the Site NPDES perm it. 12 Measures that could be particularly
effective in preventing COls from reaching the Broad River include the interception of water
flowing from seeps in the shallow and transitions zones downgradient of the units. This water
could then be treated before discharge or recycled in the dry ash before it is landfilled. In other
onsite areas such as Suck Creek, supplementation of base flow during drought conditions with
clean water pumped from the Broad River could also prove to be a cost-effective water quality
management strategy. Such measures working in concert with the capping system and the
natural attenuation of Cols in the underlying saprolite and transition zone by adsorption and co-
precipitation, would add to the level of protection of the surface water systems that are receiving
discharges of COls that have migrated, and would likely continue to migrate, from the ash
management units in the future under a Cap -in -Place closure strategy.
It is my understanding that NCDEQ has recently classified ash management units 5 and 6 as an
intermediate risk under the CAMA regulations. This classification would require the excavation
and removal of these units by 2024. Once historic ash management units were closed (e.g. unit
5) and covered with a soil cap, the net rate of rainfall recharge from infiltration would be about 6-
8 inches/year with a natural soil cover; this infiltration would be further reduced to near zero with
a multimedia cap. In the event these units are reopened to remove the ash, rainfall would
accumulate in the unit at a rate of approximately 48-51 inches/year,13 a significant portion of
which would likely eventually percolate from the base of the unit into ground water. The removal
of the ash from otherwise closed units (e.g. unit 5) in the near term therefore would likely
accelerate the rate of release of water -borne COls to the underlying ground water system, and
ultimately to the river. Substantial control of this rainwater infiltration during removal of the ash
to prevent its eventual release into the river would be very difficult, given the heterogeneous
landscape in an excavated unit and the flow of seepage along discrete fractures in the transition
and bedrock unit beneath the Site.
In his expert report, Dr. Parette opines that the placement of a cap over units 5 and 6 would
cause the underlying ground water to become anoxic, creating a reducing environment that
would cause even greater amounts of Cols to be released into ground water. This conclusion is
speculative and unsupported by the Site data. If the units are covered with a multi -media cap,
shallow ground water would continue to flow slowly beneath and through the ash beneath the
cap, albeit at a much slower rate than is currently the case. This water will infiltrate into the
12 1 understand Duke Energy has submitted a modified NPDES permit application to NCDEQ that incorporates the toe
drains and identified seeps below the ash management unit dam as authorized discharges under the permit. As
yet, no final decision on this permit application has been made by the NCDEQ.
13 This is the approximate average rate of annual rainfall in this region (see CSA report, Section 2.5; HDR 2015a).
14 Ramboll Environ

ground in the areas along the immediate perimeter of the unit and would initially be enriched
with oxygen. The subsequent movement of this water beneath the cap would continue to supply
aerobic ground water to the shallowest ash layers. As the water seeps deeper through the ash
and hence into deeper ground water layers, this oxygen is consumed by biotic and abiotic
reactions, such that a more reducing environment will then predominate in these deeper ground
water zones. My review of the current ground water monitoring data for the Site from the CSA
demonstrates such reactions and conditions are already occurring, and much of the deeper
ground water beneath the units already exhibit a reducing environment. The solubility of COls in
this ground water have adjusted accordingly. I am not aware of any evidence in this case, and it
is mere speculation Dr. Parette's part, that the placement of caps over the ash will cause this
condition to deteriorate significantly toward an even stronger reducing condition. What is
indisputable is that the cessation of the placement of slurried ash, and the construction of a
multimedia cap will substantially reduce the volumes of water that flow through the ash as
compared to current conditions, and thereby substantially lessen the rate of release of COls to
ground water and ultimately the river.
The other remedial alternative considered by Duke Energy in the CAP1 and 2 reports (removal
of Units 5 and 6) was not adopted, in part because the units were evaluated and found to be
structurally stable 14, and capping and MNA is effective in controlling the migration of COls to the
degree necessary to meet water quality standards in the Broad River at far less cost as
compared to excavation. I agree with this conclusion. The engineering controls described
above should be more than adequate to protect surface water resources below the ash
management unit dams, and there are no serviceable ground water resources in the area that
would be threatened by the continued presence of the closed ash management unit with an
effective cap and seepage control system. In my nearly 40 years of practice, working on
projects to close land-based waste management units under a range of federal and state
environmental regulations, I have never seen an example whereby the complete removal of a
large solid waste unit was ordered by the supervising regulatory agency in the absence of
irreparable concerns with its structural stability, particularly when effective containment
measures can otherwise be readily employed to protect the environment, as is the case in this
instance. The complete removal of Units 5 and 6 is unwarranted and unnecessary to protect the
environment.
14 Some maintenance and repair issues related to the spillways of Units 5 and 6 were noted in NCDEQ's 2014 NODs
which Duke Energy is currently working with the state to correct.
15 Ramboll Environ

5 Signature
The opinions in this expert report are based on my education and training, my more than
40 years of experience in environmental consulting, and the materials listed in Section 3.
1 may revise these opinions as additional information, documents, testimony, or
discovery responses become available.
Robert L. Powell, PHD, P. E.
June 30, 2016
16 Ramboll Environ

Ramboll Environ

ENVIRON
Robert L. Powell, PhD, PE Principal
Tampa, Florida
[phone] [e-mail]
Dr. Robert Powell has over 40 years of experience in environmental engineering and hydrogeology, with special
emphasis on the investigation and management of risks related to the release of chemical contaminants into soil,
surface water and groundwater systems. Specific areas of expertise include the evaluation of fate and transport of
chemicals in the natural environment; investigation and remediation of chemical releases; and the development of
complex models of chemical migration in natural hydrologic systems. He has provided litigation support and acted as
an expert witness in state and federal courts on a range of matters related to property damage and personal injury
claims from chemical releases and migration into the natural environment, cost contribution and recovery under the
National Contingency Plan and environment -related bankruptcy claims and insurance recovery.
"�LLIWOL
1983 PhD, Civil Engineering (Groundwater Hydrology), University of Maryland
1977 MS, Civil Engineering (Water Resources), University of Maryland
1973 BS, Civil Engineering (Environmental), University of Maryland
EXPERIENCE
CERCLA Remedial Investigations and Remediation Planning
Dr. Powell has conducted numerous Remedial Investigations and Feasibility Studies and related remedial planning
projects for private and public -sector clients under the federal Superfund and related state programs for the
investigation and remediation of contaminants released into the natural environment. Representative projects
include:
— Completed an RI/FS of soil and groundwater conditions for a former refinery -waste disposal site in Fullerton,
California, that was regulated under CERCLA by the USEPA. This work focused on the investigation and control
of waste migration in shallow, perched groundwater zones and the mitigation of impacts on regional water
supply aquifers. Contaminants of concern at the site included hydrocarbons, aromatics, thiophenes and metals.
The RI/FS lead to the issuance of final ROD by the USEPA to close the site and restore the overlying property to
beneficial use as a community golf course. Groundwater impacts were addressed by a Monitored Natural
Attenuation remedy.
— Served as the principal technical advisor to the PRP steering committee, composed of a number of major
international oil companies, during a negotiation with the USEPA for the development of a Scope of Work to
implement the final remedy for closure of the OII NPL site near Los Angeles, California. This project focused on
the development of specific performance metrics and verification measures to evaluate the effectiveness of
identified remedial actions in meeting specific performance goals prescribed in the final ROD for the OII site,
the development of work plans for the implementation of additional investigations to facilitate remedial design,
and in the negotiation of a final scope of work with the USEPA to implement closure of the site.
— Directed the completion of a supplemental feasibility study for the California EPA for closure of the primary
disposal area at the Stringfellow NPL site in Glen Avon, California. This project also included conducting pilot
tests for the evaluation of technologies for removal of VOC and other contaminants through the use of high -
vacuum extraction, and a performance review of the remedial systems in the downstream areas to control the
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Rob L. Powell, PhD, PE
migration of contamination. Prior to this work, Rob served for nearly ten years as the technical advisor to the
Stringfellow Advisory Community, a group representing various community and local government interests.
- Prepared an analysis of the human health risks associated with emission of chemicals during the remediation of
the Royal Hardage hazardous waste disposal facility in Criner, Oklahoma. The facility had served as a
regional site for the disposal of hazardous liquids, sludge and solids in bulk and in drums. Waste management
unit that were constructed at the facility included a hazardous waste landfill, a waste lagoon (filled with sludge
and other bulk solids) and a large burial mound of liquid and solid waste in steel drums. This facility was
closed under the oversight of the USEPA under the Superfund program.
- Prepared an analysis of the human health risks associated with the excavation of wastes from the Hyde Park
Landfill NPL Site near Niagara Falls, New York. This landfill had been used for the disposal of a wide range of
hazardous liquids and sludge from the manufacturing of pesticides, solvents and other chemical intermediaries
into an open pit in fractured bedrock. The site was believed to be leaking DNAPLs and other liquids into
groundwater and the nearby Niagara River. The risk analysis was prepared for the USEPA and the US
Department of Justice to support the negotiation with the landfill owner for the closure of the site.
- Managed the completion of a major regional groundwater Remedial Investigation/Feasibility Study to address
VOC contamination over a 30 square mile multi -layer aquifer system in New Brighton, Minnesota associated
with releases from the Twin Cities Army Ammunition Plant. This project was completed for the Minnesota
Pollution Control Agency under a cooperative agreement with the USEPA under CERCLA.
- Provided regulatory support and expert reports to three major corporations in a series of negotiations with
USEPA regarding CERCLA liability for groundwater contamination in the Baldwin Park Operable Unit of the
San Gabriel Valley NPL site near Los Angeles.
- Prepared a remedial action plan and supported negotiation with the USEPA on behalf of a PRPs group for the
closure of Atlas Mine NPI -site near Coalinga, California. This site was formerly an asbestos mine and ore
processing facility that was a major source of asbestos -contaminated sediments discharging into the Central
Valley of California.
- On behalf of a PRP group, prepared pilot treatment tests and a remedial action plan to address releases of
sulfuric acid and toxic metals in soil and groundwater, and supported negotiation with the SCDHEC, for the
closure of the Stoller Chemical site, a former fertilizer manufacturing facility near Charleston, Sout Carolina,
listed on the NPL.
- Provided consulting services to Fairfax County, Virginia to oversee the investigation and cleanup of a large
gasoline release from a ruptured pipeline into a new residential community. Services focused on the evaluation
of applicable remedial strategies and the quantification of potential pathways for exposure from gasoline that
accumulated on the underlying water table.
RCRA Facility Permitting, Compliance and Corrective Action
Dr. Powell maintains an active practice of permitting, compliance support, and corrective action services,
including RCRA facility investigations and remedial planning projects, to companies regulated under RCRA for the
treatment, storage and disposal of hazardous wastes and under the RCRA UST program. Representative projects
include:
- Directed the completion of a remedial investigation and remediation planning project in Culvert City, California
to evaluate alternatives for the cleanup of MTBE and other gasoline constituents from the Charnock Sub -basin
and to restore the use of municipal well field owned by the city of Santa Monica and the Southern California
Water Company to productive use. This project involved extensive field investigations to define the nature
/extent of contamination, development of regional groundwater and water quality databases, computer
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Rob L. Powell, PhD, PE
modeling of groundwater flow and contaminant transport, evaluation of technologies to treat groundwater for
gasoline, MTBE and tBA, and the development and evaluation of detailed remedial alternatives to restore
regional groundwater quality and the use of well fields for municipal supply. The project was completed under
the oversight of the USEPA under RCRA and the LARWQCB under the state water code.
- Completed detailed hydrogeologic studies and analyses, designed final groundwater monitoring systems, and
prepared a final groundwater monitoring program for the Laidlaw Environmental hazardous waste landfill in
Pinewood, South Carolina, as part of a RCRA Part B permit application. Also completed investigation of
shallow groundwater contamination and developed a control strategy to limit the migration of contamination in
accordance with applicable permit requirements. During the adjudicatory hearings for the Part B permit, served
as the primary expert witness for the permit applicant on hydrogeologic characterization, groundwater
monitoring and landfill integrity issues.
- Served as a member in an expert international (US and Canadian) panel to develop an environmental
management strategy and remediation plans for Laidlaw Environmental for the control of soil and groundwater
contamination at a former waste oil and solvent disposal site near Montreal, Canada. The site was used for the
disposal of a range of bulk organic liquids into a former gravel -mining pit. Liquid organic wastes migrated as a
DNAPL into underlying fractured bedrock zones and contaminated regional groundwater supplies. The site
closure was being conducted under the supervision of the Quebec Ministry of the Environment.
- Completed investigations of soil and groundwater contamination at the BKK landfill in West Covina,
California, as part of a program for closure of a former hazardous waste co -disposal landfill under a RCRA
Corrective Action program. The site was former used for the disposal of liquid hazardous wastes into an
unlined municipal landfill area. This project was performed under the oversight of the USEPA.
- Prepared hydrogeologic investigations, developed statistically based environmental sampling programs,
designed and constructed groundwater monitoring systems, conducted RCRA facility investigations, developed
statistically based closure plans for former hazardous waste lagoons, and provided regulatory support for
negotiation of federal, state, and local permits for two major RCRA hazardous waste landfills (near Bakersfield
and in the Imperial Valley) operated by Laidlaw Environmental in California. During later public and zoning
hearings for the operating permits, provided testimony on the site hydrogeology and environmental monitoring
programs. Also, provided turnkey groundwater compliance monitoring programs for a period of five years at
both facilities.
- Directed a RCRA facility investigation report and stabilization measures evaluation for soil/surface
water/sediment and groundwater contamination at a precious metals manufacturing facility in Massachusetts
under a consent agreement with USEPA (Region 1). This project has included extensive hydrogeologic and
aquatic investigations, environmental monitoring, risk assessment and environmental fate & transport modeling
to support the identification of site -related risks and developed focused stabilization measures for soil,
groundwater and storm water runoff. Contaminants of concern at the site that have been the focus of this work
include VOCs, metals, PCBs and radionuclides.
- Prepared a RCRA facility investigation, a corrective measures study and remedial plans and specifications for
the investigation of soil and groundwater contamination to support the closure of several unlined waste disposal
pits at an operating hazardous waste disposal facility in central Louisiana. The facility had been used for the
storage, treatment, and recovery of fuel products from waste oils and related organic liquids. Sludge from the
thermal treatment (distillation) units was disposed into two unlined pits. Contamination (oil and solvents)
migrated into underlying soils and groundwater. The facility was required to remove the wastes and install a
groundwater remediation system as part of the implementation of a new master plan to develop a regional
waste management facility. ENVIRON's services were provided to the facility owner, the largest commercial
hazardous waste management facility operator in North America.
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Rob L. Powell, PhD, PE
- Developed an environmental risk management program and statistical sampling design to evaluate waste
classification and direct the reuse/disposal strategies for certain combustion co -product materials (gypsum and
fly -ash) under federal and California state hazardous waste criteria in accordance with procedures prescribed
in CCR Title 22 and 40CFR Part 261.
- Completed an analysis of the performance of natural -clay liner for a wastewater storage lagoon near Barstow,
California on behalf of Southern California Edison Co. to demonstrate compliance with regulations under the
California Water Code. The project resulted in an agreement by the RWQCB that the pond liner systems meet
the functional requirements of the liner standards under CCR Title 26.
- Provided supervision and oversight of a RCRA facility assessment at a facility in Roebuck, South Carolina on
behalf of the owner.
Litigation/Mediation Services and Expert Testimony
Dr. Powell provides litigation/mediation consulting, negotiation, and expert testimony services in cases involving
the recovery of damages to property and personal injury from contaminants in the natural environment; the
consistency of remedial investigations and remedial/removal actions with the requirements of the NCP, insurance
cost recovery, and cost allocation. He has also testified in administrative and zoning hearings regarding
environmental permitting of commercial hazardous waste facilities. Representative projects include:
- Provided expert services and trial testimony in defense of Tampa Electric in a property damage/cost recovery
claim related to the alleged past disposal of MGP wastes on a property in N. Miami, FL.
- Provided expert services and testimony to a major oil company in defense of a NRDA claim filed by the state of
NJ related to the releases of gasoline from a service station in southern NJ.
- Provided expert services and testimony on behalf of a major utility in an insurance cost recovery claim related
to contaminantion at numerous former MGPs on Long Island, NY.
- Provided expert hydrologic services in defense of a Clean Water Act criminal investigation by the US Attorney
related to the discharge of storm water and solid wastes from an operating MSW landfill in Hawaii.
- Provided expert services and testimony to a major pipeline/terminal operator in defense of a claim filed by the
state of NJ related to alleged releases of gasoline and MTBE at an operating terminal in Cherry Hill, NJ.
- Provided expert services to a pipeline operator in defense of claims filed by a nearby landowner related to
historic releases of hydrocarbons from a pump station in Danielsville, GA.
- Provided expert services and testimony in a property damage case involving the release of gasoline/MTBE to
groundwater in Hartford County, Maryland.
- Provided expert services and testimony in an arbitration hearing related to indemnity claims for past and future
costs for investigation and remediation of soil and groundwater contamination at a petroleum refinery in
Louisiana.
- Provided an expert report and testimony in a property damage and personal injury claim related to the release
of gasoline/kerosene from a convenience store and gasoline station in northern Indiana. Subsequently
provided expert reports and testimony in a mediation of claims against a past owner for contribution to site
cleanup costs at five gasoline stations in northern Indiana. This work included an analysis of forensic data to
quantify the relative amounts of petroleum (principally gasoline) releases that occurred prior to the sale of the
properties to the current owner.
- Provided an expert report and testimony on a RCRA claim and enforcement action by the USEPA related to the
future closure of waste management units at a magnesium extraction facility in central Utah.
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Rob L. Powell, PhD, PE
- Provided expert testimony in a series of bankruptcy estimation hearings related to the value of CERCLA claims
by the USEPA against the estate of a large international mining and smelting/refining company.
- Provided expert testimony in an international arbitration case involving the recovery of environmental response
costs for soil and groundwater contamination, environmental compliance, and worker Health & Safety pursuant
to a contract indemnity. The principal environmental issues in the cases related to the release of chlorinated
solvents from degreasing operation at former and operating aircraft fastener manufacturing facilities in the US
and Europe.
- Provided expert testimony in Louisiana state court on behalf of Clean Harbors in a citizen's lawsuit related to
the closure of former waste management lagoons on a hazardous waste management facility near Baton
Rogue, LA. Testimony related to the nature of current contamination in the vicinity of the closed lagoons and the
potential for migration into groundwater and nearby surface waters.
- Provided expert and negotiation services to Lockheed -Martin in the settlement of claims by the city of San
Francisco to recovery the costs for the investigation and remediation of jet fuel releases discovered during the
redevelopment of the new international terminal at the San Francisco International Airport.
- Provided expert testimony services on behalf of a semiconductor client in support of settlement mediation
negotiations for claims related to the release of chlorinated solvents into shallow aquifers in Santa Clara
County, California. These claims were successfully mediated under the supervision of a federal District Court
judge in San Jose, California.
- Provided deposition and trial testimony in federal district court regarding the nature, extent and source of
contamination, the allocation of future remedial costs among PRPs, and the consistency of the RI/FS and past
removal actions with the National Contingency Plan at a former wood -treating plant in Charleston, South
Carolina.
- Prepared a cost allocation and NCP consistency analysis for a multiparty NPL site in Utica, NY involving a
former manufactured gas plant, tar recovery plant, gas oil refinery, petroleum storage terminals, chemical plant,
municipal harbor and dredge spoil areas. The allocation analysis formed the basis for opinions that were
presented in an expert report in a cost recovery lawsuit filed in federal District Court. Subsequently provided
deposition testimony in support of the allocation analysis.
- Prepared an analysis of the relative contribution by various PRP sectors (industrial, commercial, municipal, small
quantity generation) of hazardous substances to five municipal landfills in the New York City area as part of
litigation support to various PRPs in a Superfund cost recovery action. Also analyzed the associated
environmental impacts of leachate discharges from the landfills into adjoining tidal and marine estuaries.
Subsequently, Dr. Powell was retained by a special master to the federal district court in New York to provide
expert scientific services in support of the court's mediation of a lawsuit by private citizens against the city of
New York regarding the extent of engineering controls that should be installed to control the migration of
leachate into adjoining tidally controlled estuaries from a particular landfill.
- Provided litigation support to a South Carolina electric and gas company in a negotiation with the city of
Charleston related to the former operation of an MGP and the alleged damages to nearby properties owned
by the city. This project also included an analysis of the potential increase in construction costs for a new city
aquarium and marina, and a stormwater protection project, from manufactured gas plant -related contaminants
in shallow soil and groundwater.
- Provided litigation support and deposition testimony on allocation and NCP consistency in a CERCLA cost
recovery case in Newark, California, related to the remediation of a facility undergoing redevelopment as a
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Rob L. Powell, PhD, PE
brownfield site, following over 100 years of operation of metals manufacturing. The case was won in summary
judgment in favor of ENVIRON's client on NCP consistency issues.
- Provided expert litigation support services to a major international oil company in a negotiation with the Port of
San Diego related to the allocation of costs for cleanup of hydrocarbon jgasoline and diesel fuel) and coal tar
releases completed by the Port as part of a Brownfields redevelopment project.
- Provided expert litigation support on issues of NCP consistency for the recovery of costs related to the closure of
waste lagoons at a facility manufacturing PCP -based wood treating chemicals in Newark, California.
- Prepared a cost allocation analysis of former owner/operators and generators of wastes disposed of in a
municipal landfill in central California. This analysis was used to provide information to the California EPA for
its consideration in preparing an NBAR for this state Superfund site.
- Provided litigation support to a PRP to examine cost allocation among former owner/operators of two wood -
treating plants in Missouri and Louisiana.
- Provided litigation support and deposition testimony on behalf of an industrial client, related to environmental
insurance claims for soil and groundwater contamination at multiple facilities throughout the US.
- Prepared an expert report and provided deposition testimony for an insurance claim related to environmental
releases from multiple aerospace test/manufacturing facilities in California.
- Prepared an expert report and provided deposition testimony on behalf of a major international oil company
for an insurance claim related to environmental releases from multiple petroleum refineries and tank farm
facilities throughout the US.
- Prepared an expert report and provided deposition testimony for an insurance claim related to environmental
releases from a former manufacturing facility in Wilmington, North Carolina. A central issue in the case was
the allocation of future remediation costs among potentially divisible sources of onsite DNAPL-VOC
contamination.
- Prepared an expert settlement report and participated in settlement negotiations for the recovery of insurance
related to environmental conditions at 45 MGP sites in the mid -western US on behalf of a major gas production
and transmission company.
- Prepared an expert report and provided deposition testimony in support of litigation by the Southern California
Gas Company for the recovery of insurance for environmental conditions at 29 former MGP sites in southern
California.
- Prepared an expert report and presented deposition testimony on behalf of DOW Chemical Company in a
case seeking recovery of past and future costs for environmental corrective action at DOW's chemical
manufacturing plants in Freeport, Texas.
- Prepared an expert report and provided deposition testimony on behalf of Union Pacific Corporation in an
insurance cost recovery case related to soil and groundwater contamination from its former operation of a
major locomotive and rail -car manufacturing facility in Sacramento, California.
- Provided deposition and trial testimony in federal District Court regarding the extent of contamination, costs to
remediate, and the potential for community exposure in a property damage case related to a gasoline release
in a residential area in Columbia, South Carolina.
- Provided expert consulting services in a cost recovery suit related to the rupture of a regional pipeline
transporting gasoline near Davis, California. Services focused on an evaluation of the reasonableness of
environcorp.com 6

Rob L. Powell, PhD, PE
response costs and the forensic reconstruction of the mechanisms/actions that contributed to the initial release
and subsequent spread of gasoline in nearby irrigation canals.
- Provided expert and deposition services to the owner of a large former "truck stop" near Sacramento, California
that was an ongoing Brownfields redevelopment project related to the recovery of costs from former
owner/operators for the remediation of soil and groundwater for gasoline and diesel -range hydrocarbons.
- Provided litigation consulting support and presented trial testimony in state court regarding the source and
extent of groundwater contamination and future remedial costs in a trespass/property damage case in
Greenville, South Carolina.
- Testified before the California State Water Resources Control Board regarding proposed regulations on vadose
zone monitoring at waste disposal sites.
- Provided expert testimony at administrative hearings on the environmental setting, groundwater conditions, and
monitoring programs for hazardous waste landfills in South Carolina and California.
- Provided deposition and trial testimony in state court for a public water utility in Florida regarding the source
and extent of groundwater contamination in a major county -owned well field near Tampa, Florida.
Other General Engineering and Hydrology Practice
Designed and supervised the installation and operation of a system to recover PCB- contaminated oil and VOCs
from a shallow water table at a chemical manufacturing facility in northern NewJersey for compliance with the
state ECRA statute.
Provided expert consulting support to Hillsboro County, Florida, for the permitting of a major waster disposal
landfill at a facility near Tampa. The waste disposal facility was proposed to be used for the disposal of acidic
gypsum wastes from the manufacturing of phosphate -based fertilizers by extraction with sulfuric acid.
Evaluated the hydrologic impacts of land application of wastewater effluent on water resources in Orange
County, Florida, to demonstrate compliance with operating state permits.
Conducted a flood protection analysis and developed a management strategy for the South Florida Water
Management District to control agricultural discharges of storm water into drainage canals in St. Lucie County,
Florida.
Evaluated the feasibility of groundwater and surface water supply development on behalf of a municipal water
utility in western Florida.
Prepared a real-time flood forecasting system to optimize flood protection and water supply objectives for a major
municipal reservoir in Manatee County, Florida.
Evaluated the hydrologic impact of major municipal well field pumping on lake levels and wetlands near Ft.
Lauderdale and Tampa, Florida.
Prepared numerous due diligence Phase I reviews for acquisition of industrial and hazardous waste treatment and
disposal facilities.
Conducted an in-depth due diligence review of environmental issues on behalf of an investor group as part of an
acquisition/reorganization of an airline, following their bankruptcy.
Managed multidisciplinary projects including flood hazard analysis, flood protection, sediment and erosion
control, dam and reservoir analysis and design, lake restoration, surface mining impact evaluations, combined
sewer overflow conveyance and storage systems, and solid waste disposal facilities in the mid-Atlantic and
southeast regions of the US.
environcorp.com 7

Rob L. Powell, PhD, PE
Designed remedial measures for surface drainage and leachate control; directed restoration and closure; and
performed water quality data analysis for a hazardous waste landfill, Glen Burnie, Maryland.
Prior to joining ENVIRON, Rob held the following positions:
Manager of Water Resources Engineering Services, Gulf Coast Area; Camp Dresser & McKee, Inc., Tampa,
Florida
Faculty Research Associate; University of Maryland, Department of Civil Engineering, College Park, Maryland
Department Head/Senior Engineer; Water Resources Division, Greenhorne & O'Mara, Inc, Riverdale, Maryland
Graduate Research Assistant; Department of Civil Engineering, University of Maryland, College Park, Maryland
Project Engineer; Water Resources Division, Greenhorne & O'Mara, Inc., Riverdale, Maryland
Design Engineer; Dewberry, Nealon & Davis, Fairfax, Virginia
CREDENTIALS
Registrations and Certifications
Registered Professional Engineer, State of Maryland, 1977
Registered Professional Engineer, State of Florida, 2006
Professional Activities
Member, American Society of Civil Engineers
SELECTED PUBLICATIONS & PRESENTATIONS
Calise, SJ., and R.L. Powell. 1984. Microcomputer based management of land disposal systems. Paper presented at
the ASCE Annual Meeting (Florida Section), September.
Powell, R.L., and Y.M. Sternberg. 1983. Deterministic models of uncertainty for regional contaminant transport systems.
Paper presented at the National Water Well Association -Eastern Regional Conference on Groundwater
Management, October.
Onasch, C., R.L. Powell, and R.M. Ragan. 1982. Near surface regional groundwater systems modeling and potential
applications for remote sensing. AGRISTARS Report CP -G2-04361. NASA-GSFC, October.
Hawley, M.E., and R.L. Powell. 1982. Risk analysis in groundwater quality testing at hazardous waste landfills. Paper
presented at the 14th Mid -Atlantic Industrial Waste Conference, June.
Cook, D.E., R.H. McCuen, and R.L. Powell. 1980. Water quality projections: A preimpoundment case study. Water
Resource Bulletin 16(1).
Dew, F.W., R.H. McCuen, and R.L. Powell. 1978. A programming approach to planning for agricultural resource
allocation and irrigation system design. Journal of the Washington Academy of Science 68(4).
Fisher, G.T., R.H. McCuen, R.L. Powell, and WJ. Rawls. 1977. Flooding flow frequency for ungaged watersheds: A
literature evaluation. ARS -NE -86. Agriculture Research Service, USDA, November.
McCuen, R.H., R.L. Powell, and R.C. Sutherland. 1976. Relative importance of factors affecting pollutant loadings in
runoff from urban stream. In Utility of Urban Modeling. ASCE Technical Memorandum No. 31, July.
environcorp.com

TRIAL/DEPOSITION TESTIMONY SUMMARY
Robert L. Powell, Ph.D.
YEAR
CASE NAME
VENUE
CASE NO.
(Trial/De o)
1993
Johnson, et al. v. Hoechst Celanese and Daniel Construction
State of South Carolina, Court of Common Pleas
90 -CP -23-2180
(D/T)
1994
The Alpine Forrest Partners v. Crown Central Petroleum Corporation
U.S. District Court of South Carolina, Columbia Division
3:90-2730-0
(T)
1994
Braswell Shipyard, Inc. v. Beazer East, Inc.
U.S. District Court, District of South Carolina, Charleston Division
2:89-455-8
(D/T)
1994
City of West Covina v. BKK Corporation
Superior Court of California, County of Los Angeles
KC 013713
(D)
BC 083729
1994
Snyder General v. Century Indemnity
U.S. District Court, Northern District of Texas,
3:93 -CV -0832-D
(D)
Dallas Division
1995
Angelo K. Tsakopoulos v. Phillips Petroleum Company, et al.
Superior Court of California, County of Sacramento
526157
(D)
1995
James R. Thomason, Jr. v. Ortho Pharmaceutical Corporation
U.S. District Court, District of South Carolina, Greenville Division
6:94-2851-3
(D)
1996
Union Oil Company of California v. The Aetna Casualty & Surety
Superior Court of California, County of Los Angeles
BC 028271
(D)
Company
1996
Atlantic Richfield Company v. Aetna Casualty & Surety Company of
Superior Court of California, County of Los Angeles
BC 015575
(D)
America, et al.
1997
Employers Insurance of Wausau v. McGraw -Edison Company, et al.
Circuit Court of the 18th Judicial Circuit, Dupage County, Illinois
91 MR 0256
(D)
1997
AMOCO Chemical Company, et al. v. Certain Underwriters at Lloyd's
Circuit Court of Cook County, Illinois
93L8484
(D)
of London, et al.
1998
Southern Pacific, et al. v. Certain Underwriters at Lloyd's of London,
Superior Court of California, County of Los Angeles
BC 154722
(D)
et al.
1999
Niagara Mohawk Power Corporation v. Jones Chemical et. al.
U.S. District Court, Northern District of New York
95 -CV -717
(D)
1999
A.O. Smith Corporation v. Rheem Manufacturing Corporation
U.S. District Court, Northern District of California.
C 94 03887 CW
(D)
1999
Olin Corporation v. Fisons Corporation, et al.
U.S. District Court for the District of Massachusetts
CA93-11166-WGY
(D)
2000
Raytheon Company v. Certain Underwriters at Lloyd's London, et al.
Superior Court of California, County of San Francisco
950755
(D)
2002
Associated Indemnity Corporation and The American Insurance
U.S. District Court, Eastern District of Michigan, Northern Division
No. 99 CV 10426
(D)
Company v. The Dow Chemical Company
The Dow Chemical Company v. Fireman's Fund Insurance Company,
No. 99 CV 10427
et al.
6/28/16

TRIAL/DEPOSITION TESTIMONY SUMMARY
Robert L. Powell, Ph.D.
YEAR CASE NAME VENUE CASE NO.
(Trial/Depo)
2005/2010
Merco Group at Aventura landings et.al. v. Tampa Electric Company,
Circuit Court for Miami -Dade County, Florida
04-22909
(D/T)
et.al.
2006
Terry Giauque et.al. v. Clean Harbors Plaquimine, LLC et al.
18' Judicial District Court, Parrish of Iberville, Louisiana
60195
(D/T)
2007
Keystone Consolidated Industries, Inc. and Valhi v. Employers Mutual
US District Court for the Central District of Illinois
03-1201
(D)
Liability Insurance Company of Wisconsin
2007
City of Rialto, et.al. v. US Department of Defense et al.
US District Court, Central District of California
ED CV 04-00079 PSG
(D)
2007-8
Official Committee of Unsecured Creditors v. ASARCO LLC
US Bankruptcy Court, Southern District of Texas
05-21207
(D/T)
2007
Larry Bowens et al. v. 7 -Eleven, Inc. et al.
Elkhart (IN) Superior Court III
20D03 -0209 -CT -48
(D)
2007
United States vs. U. S. Magnesium Corporation
US District Court for the District of Utah, Central Division
2:01CV004013
(D)
2007
Occidental Petroleum Corporation and Oxy USA, Inc. v.
Private Arbitration
NA
(D/T)
CITGO Petroleum Corporation
2007
Kurt Petersen, et al. v. D.R. Horton, Inc.
Circuit Court for Montgomery County, Maryland
268778-V
(D/T)
2007
ALCOA v. Fairchild Industries
Private Arbitration
NA
(T)
2009-10
USF&G et al. v. SOCO West, Inc.
US District Court for the District of Montana
CV-04-29-BLG-RFC
(D/T)
CV-08-29-BLG-RFC
2010
State of Alabama et al v. Alabama Wood Treating Corporation, et al.
US District Court for the Southern District of Alabama
1:85 CV -0642 -CG -C
(D)
2010-2015
BASF Catalyst v. Allstate Insurance Co. et al.
Superior Court of New Jersey
MID -L-2061-05
(D/T)
2010
St. Croix Renaissance Group v. St. Croix Alumina
District Court of the Virgin Islands, St. Croix Division
CV -04-067
(D/T)
2010
U.S. Virgin Islands, Department of Planning and Natural Resources v.
District Court of the Virgin Islands, St. Croix Division
CV 2007/0114
(D)
St. Croix Renaissance Group, LLLP et al.
6/28/16

TRIAL/DEPOSITION TESTIMONY SUMMARY
Robert L. Powell, Ph.D.
6/28/16
2012
(D/T)
Lee E. Buchwald vs. The Renco Group, Inc.
U S Bankruptcy Court, Southern District of New York
Civil Action No: 2:012-
CV -0040B
2012
(D)
The Bank of NY Mellon Trust Co. vs. Morgan Stanley Mortgage
Capital
U S District Court, Southern District of New York
Case No: 11 CV 0505
(CM)(GWG)
2012
(D/T)
Angelo's Aggregate Materials LTD v. state of Florida DEP
FDEP hearing before FL Administrative Law Judge
Case No. 09-1543
2013
(D/T)
Long Island Lighting, Keyspan Corp. v. Alliance Underwriters
Insurance Co. et al.
Supreme Court, County of New York
Index No. 604715/97
2013
(D)
NJ Department of Environmental Protection vs. Atlantic Richfield et al.
US District Court, Southern District of New York
No. 08 CIV. 00312
2014
(D)
Richard Bennett v. Colonial Pipeline Company
Superior Court of Gwinnette County, Georgia
No.13A03746-3
6/28/16