Attachments

Expert Report of Douglas Cosler, P.E.

Amended Expert Report of
Douglas J. Cosler, Ph.D., P.E.
Chemical Hydrogeologist
Adaptive Groundwater Solutions LLC
Charlotte, North Carolina

Cliffside Steam Station Ash Basins
Mooresboro, North Carolina

April 13, 2016

 Introduction
Site Background
The Cliffside Steam Station (CSS) is a coal-fired generating station owned by Duke Energy and located
on a 1,000-acre site in Mooresboro, Rutherford and Cleveland Counties, North Carolina, adjacent to the
Broad River. CSS began operations 1940 with Units 1-4, followed later by Unit 5 (1972) and Unit 6
(2013). Units 5 and 6 are currently operating, but Units 1-4 were retired from service in 2011. An ash
basin system has been historically used to dispose of coal combustion residuals ("coal ash") and other
liquid discharges from the CSS coal combustion process. The ash basin system consists of an active ash
basin (constructed in 1975 and expanded in 1980; used by Units 5 and 6), the Units 1-4 inactive ash
basin (retired in 1977 upon reaching its capacity), and the Unit 5 inactive ash basin (retired at capacity in
1980, but local stormwater collects and infiltrates within its footprint). The active ash basin also contains
an unlined dry ash storage area.

Duke Energy performed voluntary groundwater monitoring around the active ash basin from August 2008
to August 2010 using wells installed in 1995/1996, 2005, and 2007. Compliance groundwater monitoring,
required by a NPDES permit, has been performed by Duke starting in April 2011. Recent groundwater
sampling results at Cliffside have indicated exceedances of 15A NCAC 02L.0202 Groundwater Quality
Standards (2L Standards). In response to this, the North Carolina Department of Environmental Quality
(NC DEQ) required Duke Energy to perform a groundwater assessment at the site and prepare a
Comprehensive Site Assessment (CSA) report. The Coal Ash Management Act of 2014 (CAMA) also
required owners of surface impoundments containing coal combustion residuals (CCR) to conduct
groundwater monitoring and assessment and prepare a CSA report. The recently-completed CSA
(August 2015) prepared by HDR Engineering, Inc. of the Carolinas (HDR) determined that the source and
cause of certain constituent regulatory exceedances at the CSS site is leaching from coal ash contained
in the active and inactive ash basins and the ash storage area into underlying soil and groundwater. The
Cliffside CSA report defined Constituents of Interest (COI) in soil, groundwater, and seeps that are
attributable to coal ash handling and storage.

CAMA also requires the submittal of a Corrective Action Plan (CAP); the CAP for the Cliffside site
consists of two parts. CAP Part 1 (submitted to DEQ in November 2015) provides a summary of CSA
findings, further evaluation and selection of COI, a site conceptual model (SCM), the development of
groundwater flow and chemical transport models of the site, presentation and analysis of the results of
the modeling, and a quantitative analysis of groundwater and surface water interactions. The CAP Part 2
contains proposed remedial methods for achieving groundwater quality restoration, conceptual plans for
recommended corrective action, proposed future monitoring plans, and a risk assessment.

2

 Information Reviewed
My opinions are based upon an analysis and technical review of (i) hydrogeologic and chemical data
collected at the Cliffside site; (ii) the analyses, interpretations, and conclusions presented in site-related
technical documents and reports; (iii) the groundwater flow and chemical transport models constructed
for the site (including model development, calibration, and simulations of remedial alternatives); (iv) the
effectiveness of proposed remedial alternatives to achieve groundwater quality restoration; and (v)
proposed future site monitoring. This amended report contains additional opinions based on my review of
the recently-issued CAP Part 2 report. These opinions are subject to change as new information
becomes available.

As a basis for forming my opinions I reviewed the following documents and associated appendices:
(1) Comprehensive Site Assessment Report, Cliffside Steam Station Ash Basin (August 18, 2015);
(2) Corrective Action Plan, Part 1, Cliffside Steam Station Ash Basin (November 16, 2015);
(3) Corrective Action Plan, Part 2, Cliffside Steam Station Ash Basin (February 12, 2016);
(4) Miscellaneous historical groundwater and soil concentration data for the Cliffside site collected
prior to the CSA; and
(5) Specific references cited in and listed at the end of this report.

Professional Qualifications
I have advanced graduate degrees in Hydrogeology (Ph.D. Degree from The Ohio State University) and
Civil and Environmental Engineering (Civil Engineer Degree from the Massachusetts Institute of
Technology), and M.S. and B.S. degrees from Ohio State in Civil and Environmental Engineering. I have
36 years of experience as a chemical hydrogeologist and environmental engineer investigating and
performing data analyses and computer modeling for a wide variety of projects. These projects include:
investigation, remediation, and regulation of Superfund, RCRA, and other hazardous waste sites involving
overburden and bedrock aquifers; ground water flow and chemical transport model development; natural
attenuation/biodegradation assessments for chlorinated solvent and petroleum contamination sites;
volatile organic compound vapor migration and exposure assessment; exposure modeling for health risk
assessments; hydrologic impact assessment for minerals and coal mining; leachate collection system
modeling and design for mine tailings disposal impoundments; and expert witness testimony and
litigation support. I also develop commercial groundwater flow and chemical transport modeling software
for the environmental industry.

The types of sites I have investigated include: landfills, mining operations, manufactured gas plants,
wood-treating facilities, chemical plants, water supply well fields, gasoline and fuel oil storage/delivery
facilities, nuclear waste disposal sites, hazardous waste incinerators, and various industrial facilities. I
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 have investigated the following dissolved, nonaqueous-phase (LNAPL/DNAPL), and vapor-phase
contaminants: chlorinated solvents, various metals, gasoline and fuel oil constituents, wood-treating
products, coal tars, polychlorinated biphenyls, pesticides, dioxins and furans, phenolic compounds, flame
retardants (PBDE), phthalates, radionuclides, and biological constituents.

Summary of Opinions
The following is a brief summary of the opinions developed in my report:
•

A total of 62 Compliance Boundary groundwater samples exceeded North Carolina groundwater
standards for these COI: antimony, boron, chromium, cobalt, iron, manganese, sulfate, total
dissolved solids, and vanadium. Of these 62 exceedances, 36 were greater than the proposed
provisional background concentrations by HDR;

•

The statistical analyses of shallow background groundwater concentrations at the Cliffside site
(well MW-24D) are invalid due to the characteristically slow rate of COI migration in groundwater;

•

There is a significant risk of chemical migration from the ash basin to neighboring private water
supply wells in fractured bedrock;

•

Major limitations of the CAP groundwater flow and chemical transport models prevent simulation
and analysis of off-site migration;

•

The CAP Closure Scenario simulations greatly underestimate (by factors of 10 or more) the time
frames required to achieve meaningful groundwater concentration reductions in response to
remedial actions;

•

For either the Existing Condition or Cap-in-Place Model Scenario groundwater concentrations of
coal-ash constituents much higher than background levels will continue to exceed North Carolina
groundwater standards at the Compliance Boundary because saturated coal-ash material and
secondary sources will remain in place;

•

Source-area mass removal included in the Excavation Scenario results in COI concentration
reductions at the Compliance Boundary that are generally two to ten (2 - 10x) times greater
compared to Cap-in-Place, best reduces impacts to surface water, and reduces cleanup times by
factors of two to five (2 - 5x). Additional excavation of secondary sources would further
accelerate concentration reductions;

•

The CAP simulations show that source excavation reduces groundwater concentrations for many
COI below North Carolina groundwater standards (antimony, arsenic, chromium, hexavalent
chromium, cobalt, nickel, thallium, vanadium), but cap-in-place closure does not;

•

CSA data show multiple exceedances of groundwater standards in bedrock not only at the
compliance boundary but also inside the CB. However, the CAP Closure Scenarios do not
address either concentration reduction or off-site chemical migration control in the fractured
bedrock aquifer;
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 •

Due to an incorrect boundary-condition representation of the active ash basin, the CAP models
underestimate by a factor of two or more both the mass loading of COI into the Broad River and
the corresponding Broad River water concentrations (attributable to coal ash ponds) estimated by
the groundwater/surface-water mixing model;

•

The CAP Part 2 geochemical modeling and monitored natural attenuation (MNA) evaluations do
not provide the required quantitative analyses of COI attenuation rates necessary to support MNA
as a viable corrective action. The CAP 2 chemical transport modeling, which included attenuation
by sorption, demonstrated that MNA is not an effective remedial option for several COI (e.g.,
antimony, arsenic, beryllium, boron, chromium, hexavalent chromium, cobalt, lead, sulfate,
thallium, and vanadium);

•

Future Compliance Monitoring at the Cliffside site should include much more closely-spaced
Compliance Wells to provide more accurate detection, and groundwater sampling frequency
should be re-evaluated to allow valid statistical analyses of concentration variations.

Hydrogeology of the Cliffside Site
Introduction
The groundwater system at the Cliffside site is an unconfined, connected system consisting of three basic
flow layers: shallow, deep, and fractured bedrock. The shallow and deep layers consist of residual soil,
saprolite (clay and coarser granular material formed by chemical weathering of bedrock), and weathered
fractured rock (regolith). A transition zone at the base of the regolith is also present and consists of
partially-weathered/fractured bedrock and lesser amounts of saprolite. The ash basin system overlies
native soil and was constructed in historical drainage features formed from tributaries that flowed toward
the Broad River using earthen embankment dams and dikes. As described in the CSA report, the active
ash basin was formed by construction of two dams across natural drainages. At the upstream dam, Suck
Creek was diverted through a canal and away from the ash basin to the Broad River, at its present-day
configuration. The active ash basin downstream dam is located near the historical discharge point of
Suck Creek into the Broad River. A large percentage of the coal ash lies below the groundwater table
and is saturated. Groundwater flow through saturated coal ash and downward infiltration of rainwater
through unsaturated coal ash leach COI into the subsurface beneath the basin and via seeps through the
embankments.

As described by HDR, groundwater flow in all three layers within the site boundary is generally from south
to north toward the Broad River. Vertical groundwater flow between the three layers also occurs, and
surface water ponding in the active ash basin effects flow directions locally. The CSA and CAP
investigations assumed that all groundwater north of the ash basin system (overburden and bedrock
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 aquifers) discharges into the Broad River. However, these studies did not collect hydrogeologic data or
perform data analyses or groundwater flow modeling to support this assumption. The CSA and CAP
Parts 1 and 2 also did not analyze potential changes to site groundwater flow directions, or the risk of offsite migration of COI in the overburden or bedrock aquifers, caused by groundwater extraction from
numerous private and public water supply wells located close to the site boundaries and near the Broad
River.

My report begins with a discussion of significant errors in CSA data analysis and conceptual model
development that contradict HDR's interpretation of three-dimensional groundwater flow patterns at the
Cliffside site. This is followed by a presentation and discussion of measured exceedances of North
Carolina groundwater standards at multiple locations on the ash basin compliance boundary. I then
address several limitations of the CAP Parts 1 and 2 groundwater flow and chemical transport models
and identify various model input data errors. Finally, I present my evaluations of the CAP Closure
Scenario simulations and provide my opinions regarding the effectiveness of various remedial alternatives
for restoring groundwater quality to North Carolina standards.
Errors in Hydraulic Conductivity Test Analyses
Background
Throughout the CSA and CAP reports HDR provides interpretations and conclusions regarding the
horizontal and vertical variations of groundwater flow directions and rates, and the fate and transport of
COI dissolved in groundwater. The most important site-specific parameter that controls these timedependent flow and transport mechanisms is the hydraulic conductivity (also referred to as "permeability")
of the underlying soils and fractured bedrock (Bear, 1979). Hydraulic conductivity (length/time) is a
media-specific measure of the rate at which water can flow through a porous (soil) or fractured (bedrock)
porous medium. Groundwater flow and chemical transport rates are directly proportional to the product of
hydraulic conductivity and the hydraulic gradient (hydraulic head difference between two points divided by
the separation distance; e.g., the water table elevation slope at the Cliffside site). Therefore, accurate
measurement of hydraulic conductivity is critical for understanding the current and future distributions of
COI in soil and groundwater and for evaluating the effectiveness (e.g., cleanup times) of alternative
remedial measures.

In addition, the contrast in hydraulic conductivity between adjacent hydrogeologic units is the key factor in
determining three-dimensional groundwater flow directions and the ultimate fate of dissolved COI. For
example, at the Cliffside site accurate measurement of hydraulic conductivity is critical in evaluating the
potential for: downward chemical migration into the fractured bedrock unit, off-site COI migration in the

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 overburden (soil) or fractured bedrock aquifers, groundwater flow and COI transport into or beneath the
Broad River.

A slug test is one of the standard field methods for measuring hydraulic conductivity (K) using a soil
boring or installed monitoring well. Slug tests were performed in most of the overburden and bedrock
wells at the Cliffside site. In this test the static water level in the open hole (boring) or well casing is
suddenly increased or decreased and the resulting transient change in water level is recorded. Two
commonly-used techniques for quickly changing the water level are the introduction (increases the water
level) and removal (decreases the water level) of a solid rod, or "slug" into the boring or well casing.
These tests are called "falling-head" and "rising-head" tests, respectively. Higher rates of water-level
recovery correspond to higher values of K. The measurements of water level versus time are analyzed
using mathematical models of the groundwater flow hydraulics and information regarding the well
installation (e.g., length of the slotted monitoring well screen and well casing diameter) to compute an
estimate of K.

As discussed below, HDR made significant errors in all of their analyses of field slug test data. Their
analysis errors caused the reported (CSA report) slug test hydraulic conductivity values to be as large as
a factor of two (almost 100 percent) smaller than the correct K values. I discuss the impacts of these
analysis errors on HDR's groundwater flow and chemical transport assessments and the CAP modeling
later in my report.

Overburden Slug Tests
HDR analyzed all of the CSA overburden slug tests in shallow and deep wells with the Bouwer-Rice
(1976) method using a vertical anisotropy, Av = Khorizontal / Kvertical , that is as large as a factor of 100 lower
than the values presented in the CSA report (e.g., compare geometric mean values in CSA Tables 11-10
and 11-11) and used in the CAP modeling (e.g., CAP 1 report Appendix C, Table 2), where K is hydraulic
conductivity. Comparing CSA Tables 11-10 and 11-11, the measured Av for overburden soil units ranges
from 4 to 50. In the calibrated CAP flow model Av is on the order of 100 for overburden soil. However,
the Bouwer-Rice slug test analyses assumed Av = 1 for every monitoring well (CSA Appendix H). If the
CAP 1 flow model results (Av ~ 100) are used in the Bouwer-Rice analyses all of the measured
overburden hydraulic conductivity values increase by about 70 percent (factor of 1.7), depending on how
the slug-test radius of influence was computed. Using the Tables 11-10/11-11 measured vertical
anisotropies (Av = 4 to 50) increases all of the measured overburden hydraulic conductivity values (CSA
Table 11-4) by about 20-60 percent.

Since every reported overburden K value in the CSA report (at least for new shallow and deep wells) is
up to 70 percent too low, the actual average chemical transport rates in overburden soils are up to 70
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 percent greater than reported. This site-wide data reduction error also affects the CAP flow and transport
model calibrations. For example, the transport model developers significantly reduced laboratory
measurements of the soil-water partition coefficient, Kd, for various COI during the transport model
calibration based on comparisons of observed and simulated chemical migration rates. However, if the
correct (i.e., higher) overburden K values had been used in the model calibration the Kd values would not
have been reduced as much (compared to laboratory values). The reason for this is, assuming linear
equilibrium partitioning of COI with soil, the chemical migration rate is proportional to K / Kd (except for Kd
<< 1). The CAP 1 and 2 transport model history matching indicated that the simulated transport rate was
too low, so the model developers reduced the model Kd. In other words, the reductions in calibrated Kd
values would not have been as great if the correct (higher) K values were used in the first place. As
discussed below, the CAP Part 2 transport modeling used Kd values that are generally a factor of about
10 larger than the CAP 1 values; however, the CAP 2 Kd 's are still on the order of 10 times smaller than
the measured site-specific Kd 's reported in CAP 1 Appendix D and CAP 2 Appendix C. COI sorption to
soil is important because, as discussed below, aquifer cleanup times (i.e., chemical flushing rates) are
generally proportional to the chemical retardation factor, which is directly proportional to Kd , except when
Kd << 1 (Zheng et al., 1991).
Groundwater Flow
Throughout the CSA and CAP reports HDR made several critical assumptions, not supported by data,
regarding the horizontal and vertical groundwater flow directions near the boundaries of the Cliffside site
which impacted their conclusions regarding the ultimate discharge locations for site groundwater and
dissolved COI. Two examples discussed in this section are (i) the relationship between site groundwater
and the Broad River and (ii) groundwater flow directions and the potential for offsite migration of COI.
Broad River and the LeGrand Conceptual Model
Most of the groundwater at the Cliffside site was apparently assumed to discharge into the Broad River
(other than groundwater discharges to small streams such as Suck Creek) according to a generalized
conceptual model (LeGrand, 2004) before actual site-specific hydrogeologic data were analyzed.
Statements to this effect were made at numerous points in the CSA and CAP reports. However, HDR did
not present any site-specific data analyses or groundwater flow modeling that would support this
assumption in either report. In fact, as discussed below, the boundary conditions for the CAP Parts 1 and
2 flow models effectively forced site groundwater to discharge into the river at the downgradient model
boundary.

HDR continued to state this assumption in the CAP 2 report (e.g., Section 3.3.2) even though strong
measured downward groundwater flow components exist next to the Broad River. In CAP 2 Section
3.3.2, HDR also states that "The Broad River serves as a hydrologic boundary for groundwater within the
8

 shallow, deep, and bedrock flow layers at the site." However, the river cannot be a "hydrologic boundary"
for the deep and bedrock layers when the measured vertical flow direction in these layers is consistently
downward at many locations next to the river (see discussion below), which demonstrates that HDR has
not delineated this inferred "lower boundary" used in the CAP models. HDR further states in CAP 2
Section 3.3.2 that "the approximate vertical extent of the groundwater impacts is generally limited to the
shallow and deep flow layers, and vertical migration of COIs is limited by the underlying bedrock." This
statement ignores that fact that groundwater flow across the site is consistently downward from the
impacted deep flow layer to the highly-fractured bedrock aquifer at many locations and that, as discussed
below, 35 exceedances of North Carolina 2L and/or IMAC groundwater standards (and greater than
background concentrations) were measured in samples collected from bedrock wells located inside the
Compliance Boundary.

The LeGrand (2004) guidance document presents a general discussion of groundwater flow patterns that
may occur near streams in the Piedmont and Mountain Region of North Carolina based on ground
surface elevations (i.e., site topography and surface watershed boundaries). However, surface water and
groundwater watersheds commonly do not coincide (Winter et al., 2003). Further, groundwater flow
patterns and rates in bedrock have been found to be poorly related to topographic characteristics (Yin
and Brook, 1992). LeGrand does not present or derive any mathematical equations or quantitative
relationships for groundwater flow near rivers or streams. The author emphasizes that site-specific data
must be collected in order to correctly evaluate river inflow or outflow. In strong contrast to the LeGrand
generalizations, numerous detailed and sophisticated mathematical (analytical and numerical) riveraquifer models and highly-monitored field studies have been published in the scientific and engineering
literature in the past several decades. What these investigations and applied hydraulic models show is
that the water flow rate into or out of a river or stream and the depth of hydraulic influence within an
underlying aquifer are highly sensitive to several factors, including: the transient river water surface
elevation and slope; river bed topography; bed permeability and thickness; horizontal and vertical
permeability (and thickness) of the different hydrogeologic units underlying the river; transient horizontal
and vertical hydraulic head variations in groundwater beneath and near the river; and groundwater
extraction rates and screen elevations for neighboring pumping wells (e.g., Simon et al. 2015; McDonald
and Harbaugh, 1988; Bear, 1979; Hantush, 1964).

The CSA investigation did not: measure river bed permeability or thickness; characterize the river
bathymetry; monitor transient water surface elevation variations at more than one location (one average
value was used); collect river bed hydraulic gradient data; measure horizontal or vertical overburden or
bedrock permeability beneath or on the northern side of the river; characterize the geology beneath or
north of the river; measure hydraulic heads in the overburden or bedrock beneath or north of the river; or
consider the hydraulic effects of groundwater extraction from nearby private water supply wells, as
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 discussed in the following section. With regard to the Cliffside site, much of the data that were collected
in the CSA contradict the LeGrand hypothesis. A strong downward flow component (~ 10 feet head
difference) from deep overburden to bedrock was measured at the following locations next to the Broad
River: GWA-21 (near several private bedrock supply wells), GWA-29, IB-3D/GWA-11BRU, MW38D/MW-36BRU, and the entire area between the river and northern portion of the Active Ash Basin as
generally bounded by the 650- to 725-foot bedrock head contours (compare CSA Figures 6-6 and 6-7).
The vertical flow direction from shallow to deep overburden is also downward in this area located
between the Broad River and the Active Ash Basin (compare CSA Figures 6-5 and 6-6). In addition,
downward groundwater flow was measured at several other locations across the site (CSA Table 11-13).
A similar trend of downward groundwater flow from deep overburden to bedrock in these areas next to
the river was measured in the CAP 2 investigation. Contour maps of vertical hydraulic gradient variations
were not generated for the CSA or CAP Part 2, and HDR did not discuss the significance of downward
hydraulic gradients next to the Broad River and at many other deep/bedrock monitoring well clusters.
These downward groundwater flow measurements are consistent with the hydraulic conductivities of the
bedrock and overburden being of similar magnitude, as discussed above.

The strong and consistent measured downward groundwater flow components immediately adjacent to
the Broad River and at other well clusters indicate that site groundwater is entering the deep fractured
bedrock unit in these areas and that not all of the site groundwater discharges into the river as the site
Conceptual Model and the CAP flow and transport models assume. The downward flow into bedrock
may also be due in part to groundwater extraction from private bedrock water supply wells located near
the eastern property boundary, but in the CSA and CAP investigations HDR assumed these factors
related to the potential for off-site COI migration beneath the river were not important and did not evaluate
them.

Groundwater Flow Directions
The CSA assumptions and analysis errors discussed above have had a strong effect on: the Conceptual
Model development; the site hydrogeologic and COI transport assessment; the construction/calibration
of the CAP flow and transport models; and the simulations of CAP Close Scenarios. The hydrogeologic
assumptions should have been carefully evaluated and tested during the performance of the CSA and as
part of the CAP groundwater flow model construction and calibration to determine whether they were
valid. Instead, the hypotheses appear to have effectively guided the model development and led to
inaccurate interpretations.

As an illustration, because the permeability of the weathered bedrock is similar to the overlying soils at
the Cliffside site the CSA and CAP interpretation that the bedrock acts as a lower confining layer for
groundwater flow and chemical transport is incorrect. In addition, the similarity of the overburden and
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 bedrock aquifer permeability values increases the potential for off-site COI migration toward private water
supply wells. Therefore, the CSA and CAP conclusions that (i) all site groundwater discharges into the
Broad River and (ii) groundwater and dissolved coal-ash constituents are restricted from migrating to
residential water supply wells are not consistent with the data.

The CSA and CAP reports also did not adequately evaluate the three-dimensional groundwater flow field
near and beneath the Broad River. Numerous private water supply wells are located in the following
areas (CSA Figure 4-2): a few hundred feet north of the Broad River and immediately east of the
Compliance Boundary for the Active Ash Basin, less than 1,500 feet from the Active and Unit 5 Inactive
Ash Basins, and less than 1,500 feet from the Active Ash Basin and on the southern shore of the Broad
River (close to the northeastern portion of the Compliance Boundary). Bedrock hydraulic head
measurements (CSA Figure 6-8) for monitoring wells located next to the river (e.g., Wells GWA-32BR,
GWA-11BRU, GWA-29BR, and GWA-21BR) indicate a strong easterly bedrock aquifer flow component
from downgradient areas of the site toward these private wells on the southern shoreline. However, CSA
Figure 6-8 does not show these head contours, and the CAP flow model boundary conditions artificially
prevent groundwater from either flowing east or northeast beneath the Broad River (as underflow), or
flowing toward the private wells near the northeast Compliance Boundary. The CSA and CAP reports
also do not address the large measured downward hydraulic gradients in the northern portion of the
Active Ash Basin and near the river, and their potential relationship to offsite groundwater extraction from
the bedrock aquifer. The CAP flow models were not properly constructed to allow evaluation of these
observed three-dimensional flow patterns due to: the model no-flow boundary condition on the eastern
and western sides of the grid; the uniform specified head boundary condition in grid cells underlying the
river (i.e., the sloping, west-to-east water surface elevation in the river was not represented in the model);
and the fact that the CAP flow models did not include the effects of groundwater extraction from off-site
water supply wells.

Exceedances of Groundwater Standards
In this section I compare measured groundwater concentrations in shallow, deep, and bedrock
groundwater samples to North Carolina 2L and IMAC standards and show the following: (i) 60 measured
exceedances for several COI at multiple locations on the Compliance Boundary (CB); (ii) an additional
two CB exceedances based on chemical transport modeling I performed; (iii) 36 of the 62 Compliance
Boundary exceedances were greater than the proposed provisional background concentrations (PPBC)
by HDR; (iv) 37 of the 62 Compliance Boundary exceedances were greater than the maximum
concentration at any background well from the same hydrogeologic unit (e.g., shallow, deep, or bedrock)
for a particular constituent; (v) 12 more exceedances were measured in wells located on the Broad River;
11

 (vi) 54 additional exceedances were observed in wells screened in the highly-permeable fractured
bedrock unit underlying the ash basin system and located inside the CB; and (vii) the statistical analyses
of groundwater concentrations at shallow monitoring well MW-24D for purposes of defining background
levels were performed incorrectly.

Throughout this report I reference the ash basin compliance boundary and the Duke Energy property
boundary for the Cliffside site as drawn on maps developed by HDR (e.g., CSA Figure 6-2). My reference
to the "compliance boundary" is only for identification purposes and not an opinion that this boundary as
drawn by HDR is accurate or legally correct.

Summary of Exceedances
Table 1 summarizes exceedances of 2L or IMAC standards in shallow, deep, and bedrock groundwater
samples obtained from monitoring wells located: (i) on the Ash Basin Compliance Boundary (CB) as
drawn by HDR; (ii) on the southern shore of the Broad River (RV), which is the downgradient boundary of
the CAP groundwater flow and chemical transport models; (iii) bedrock wells (BR) located inside the CB;
and (iv) modeled Compliance Boundary concentrations (CBM), using modeling techniques described
below. The proposed provisional background concentrations (PPBC) by HDR are also listed in Table 1.

A total of 33 Compliance Boundary groundwater samples exceeded North Carolina 2L standards, and
IMAC standards were exceeded in an additional 27 samples for these COI: antimony, boron, chromium,
cobalt, iron, manganese, sulfate, total dissolved solids, and vanadium. I estimated an additional two CB
exceedances dowgradient from wells MW-11S and GWA-27D for boron based on chemical transport
modeling and measured upgradient concentrations (designated CBM in Table 1). In addition, 39
exceedances of 2L regulatory limits were observed in wells screened in the highly fractured bedrock unit
located inside the CB. An additional 15 bedrock sample concentrations were greater than IMAC limits.
Ten more 2L (plus two IMAC) exceedances were measured in wells located on the Broad River.

A total of 29 of the 35 Compliance Boundary 2L (and 9 of 25 IMAC) exceedances were greater than the
maximum concentration at any background well (from the same hydrogeologic unit; e.g., shallow or
deep) for a particular constituent. All of the Broad River shoreline "RV" exceedances were greater than
background levels. A total of 27 of the 39 bedrock 2L (and 8 of 15 IMAC) exceedances were greater than
the maximum background concentration.

A total of 36 of the 62 Compliance Boundary exceedances were greater than the proposed provisional
background concentrations (PPBC) by HDR.

12

 Note that the iso-concentration contours in all of the CSA Section 10 figures are not consistent, and are in
many cases misleading, with regard to chemical transport mechanisms in the subsurface. For example,
the iso-concentration contours in Section 10 generally closely encircle a monitoring well and infer no
subsequent transport downgradient from the well location. This contouring problem is especially
prevalent near the southern shore of the Broad River. Figure 10-65 (cobalt) is a good example of this
practice. These closed contours at the downgradient property boundary suggest that COI transport
beyond the farthest downgradient line of monitoring wells does not occur and that no COI migrate north of
the southern shore of the river. However, the simulated (CAP model) "existing conditions" cobalt
concentration contours in CAP Appendix C are "open" at the Broad River, indicating transport beneath the
river.

Modeled Compliance Boundary Exceedances
I computed Compliance Boundary (CB) concentrations labeled "CBM" with footnote "e" in Table 1 (MW11S and GWA-27D) using a calibrated one-dimensional, analytical chemical transport model (van
Genuchten and Alves, 1982; Equation C5) because the CB at these locations was up to 400 feet
downgradient from the wells and boron is highly mobile in the subsurface. I calibrated the analytical
model to chemical-specific site conditions (i.e., determined model input parameter values) using CAP
transport model simulated concentration versus time curves for "Existing Conditions" (CAP report
Appendix C). The analytical model input parameters in my model were: groundwater pore velocity,
chemical retardation factor, and longitudinal dispersivity. For each constituent, I used the calibrated
analytical model to compute the concentration versus time curve immediately downgradient at the
Compliance Boundary.

Exceedances of Groundwater and Surface Water Standards in Seep Samples
Concentrations in seeps discharging from the active ash basin (upstream toe, adjacent to Suck Creek)
have exceeded North Carolina surface water standards (2B) and 2L and/or IMAC groundwater standards
(e.g., arsenic, chromium, iron, lead, manganese, nickel, selenium, and vanadium; CAP Figures 2-2 and
2-3, CSA Table 7-9). Groundwater discharges to Suck Creek were confirmed by the CAP flow modeling.
Elevated concentrations of boron, calcium, chloride, sulfate, and total dissolved solids were detected in a
surface water sample from Suck Creek (SW-3) collected downgradient from the toe of the active ash
basin upstream dam (page 90 of the CSA report).

The CSA also identified other continuously-flowing seeps as tributaries of the Broad River [e.g., S-1, S-3,
S-6, and S-8; refer to Table 1 in the Topographic Map and Discharge Assessment Plan(DAP)]. Seep S-3
is apparently part of a stream discharging to the Broad River north of inactive units 1-4 (DAP Figure 2).
Seep S-6 is located downgradient from the downstream dam of the active ash basin and coincides with
historical Suck Creek discharge (CSA Appendix I, Figure 1). Concentrations in samples from seep S-6
13

 have exceeded relevant surface water 2B standards, and 2L and/or IMAC groundwater standards for
boron, cobalt, iron, manganese, and vanadium. Concentrations in samples from seep S-3 have
exceeded relevant surface water 2B standards for cobalt, iron, manganese, sulfate, thallium and total
dissolved solids. For the CAP 2 sampling round (September 2015) the 2B standard for mercury was also
exceeded at Seep S-1.

Referring to my Table 1, 122 of the seep samples exceeded North Carolina groundwater standards (84
2L exceedances and 38 IMAC exceedances; CSA Table 7-11) for these COI: arsenic, barium, beryllium,
boron, chromium, cobalt, iron, lead, manganese, nickel, sulfate, total dissolved solids, thallium, and
vanadium. These samples were collected at the active ash basin; inactive ash basins 1-4 and 5; and
the ash storage area.

Statistical Analyses of Background Concentrations
Appendix G of the CSA report presents statistical analyses of historical concentrations from Monitoring
Wells MW-24D and MW-24DR, which HDR described as following methods specified by the U.S.
Environmental Protection Agency (EPA, 2009), in an attempt to establish background groundwater
concentrations for the Cliffside site. As outlined in Sections 3.2.1 and 5.5.2 of the EPA guidance
document these data must be checked to ensure that they are statistically independent and exhibit no
pairwise correlation. Groundwater sampling data can be non-independent (i.e., autocorrelated) if the
sampling frequency is too high (i.e., time interval between sampling events is too small) compared to the
chemical migration rate in the aquifer (groundwater pore velocity divided by chemical retardation factor).
Section 14 of the EPA guidance presents methods for ensuring that the Wells MW-24D and MW-24DR
background data are not autocorrelated, but the analyses in CSA Appendix G did not include evaluations
for statistical independence.

As an illustration, "slow-moving" groundwater combined with high chemical retardation (i.e., large soilwater partition coefficients, Kd), which is the case at the Cliffside site, can lead to the same general
volume of the chemical plume being repeatedly sampled when the monitoring events are closely spaced.
Examining shallow wells at the Cliffside site, the shallow groundwater pore velocity (Vp) is in the order of
70 ft/yr (CSA Table 11-14), which is representative of the pore velocity near well MW-24D. Note that
shallow pore velocities are as much as a factor of 100 greater in many areas downgradient of the ash
basin system (e.g., the active ash basin) due to much greater hydraulic gradients (~ 10x larger) and larger
hydraulic conductivity (~ 10x greater) in these areas. In addition, groundwater pore velocities in deep
overburden and in fractured bedrock are generally more than a factor of 1,000 greater than velocities in
the shallow overburden (CSA Table 11-14).

14

 3

The retardation factors, Rd, based on laboratory Kd measurements (Kd ~ 10 cm /g, or greater) are on the
order of 100 (or greater) for many of the COI (except conservative parameters such as sulfate and
boron). Therefore, the average shallow chemical migration rate at Cliffside (Vp / Rd) is on the order of 0.7
ft/yr many of the non-conservative COI near well MW-24D, assuming linear equilibrium sorption (refer to
discussion below). For quarterly sampling, the chemical migration distance between sampling rounds is
about 0.2 feet for several COI, which is smaller than the sand pack diameter for the monitoring wells.

Therefore, based on either quarterly or annual monitoring the shallow groundwater samples at Cliffside
are basically representative of the same volume of the plume (i.e., the sandpack, depending on the well
purge volume) for many COI, and any measured sample concentration changes are not due to real
chemical transport effects in the aquifer. In this case, this means that the groundwater samples are nonindependent and that the statistical analyses of background concentrations at Wells MW-24D do not
satisfy the key requirements of the analysis method.

CAP Groundwater Flow Model Underestimates Potential for Off-Site Chemical Migration
My discussions in this section focus on limitations of the CAP groundwater flow model. I focus specifically
on model boundary conditions representing the Broad River; the overall size of the model grid and noflow boundary conditions on the western, southern, and eastern grid boundaries; groundwater flow in the
fractured bedrock aquifer; and the potential for off-site groundwater flow in relation to groundwater
extraction from numerous private and public water supply wells located close to the model boundaries,
but not incorporated into the flow model
Broad River Boundary Condition
The CAP Parts 1 and 2 groundwater flow models force all Cliffside site groundwater along the northern
model boundary to discharge directly into the Broad River and underestimate the potential for off-site flow
and chemical migration in fractured bedrock. No-flow boundary conditions defined along the entire
western, eastern, and southern model boundaries prevent any off-site groundwater flow and chemical
transport in these areas (refer to Figures 1 and 5 in Appendix C of the CAP 1 Report). The bottom
surface (bedrock) of the flow model is also assumed to be a no-flow boundary even though the hydraulic
conductivity data and measured downward hydraulic gradients at several monitoring well clusters do not
support this assumption. The only locations where groundwater and dissolved constituents are allowed
to leave the CAP models are streams (e.g., Suck Creek and unnamed tributaries to the west), top-layer
flood plain cells next to the Broad River, and the vertical array of cells underlying Broad River along the
northern grid boundary; these cells are specified as constant-head boundary conditions in which the
head is uniform with depth.
15

 This hydraulic representation of the Broad River in the flow model is inaccurate for several reasons. First,
the river bottom is assumed to extend all the way through the unconsolidated deposits and the fractured
bedrock unit, which is not the case. Second, groundwater flow beneath and adjacent to the river is
assumed to be horizontal with zero vertical flow component. Because this boundary condition does not
allow groundwater to flow vertically in areas that underlie the river, the CAP models do not represent
actual site hydrologic conditions. Further, groundwater flow at the Cliffside site is not strictly horizontal
and, as discussed above, many of the vertical hydraulic gradient measurements (including next to the
river) are downward. Third, as represented in the CAP models, neither the lower-permeability river bed
sediments nor the smaller vertically hydraulic conductivity of underlying soils restricts the potential flow
rate into or out of the river (i.e., a perfect hydraulic connection exists between the aquifer and the Broad
River). The actual degree of aquifer-river hydraulic connection was not evaluated in the CSA. In
summary, due to all of these factors the potential for site groundwater and dissolved constituents to
migrate off-site northward beyond the Broad River or eastward as underflow beneath the river cannot be
evaluated with the model.

The CAP models should have represented the Broad River using a "leaky-type" (i.e., river) boundary
condition in the top model layer (McDonald and Harbaugh, 1988), and the model grid should have
extended farther north so that the above factors could have been evaluated during model calibration and
sensitivity analyses. In their reviews of both the CAP 1 and 2 models (submitted with the CAP modeling
appendices), the Electric Power Research Institute third-party peer review team also concluded that the
Broad River should be modeled as a leaky boundary condition instead of using constant heads. The
models also should have included groundwater extraction from the private water supply wells installed at
many points close to the river bank. A river boundary condition incorporates the bed permeability and
thickness, the river water surface elevation, and the simulated hydraulic head in the aquifer (at the base
of the river bed) to dynamically specify a flux (flow rate per unit bed area) into or out of the groundwater
model depending on the head difference between the river and aquifer. Typically, permeability and
vertical hydraulic gradient measurements for the river bed (not collected in the CSA) and flow model
calibration (three-dimensional matching of simulated and measured hydraulic head measurements in the
aquifer) are used to determine a best-fit estimate of river bed conductance (permeability divided by
thickness) in the model. HDR did not perform this routine analysis.

Limitations of No-Flow Boundary Conditions and Small Model Domain Size
The limited areal extent and depth of the CAP Parts 1 and 2 flow and transport model grids prevent the
use of the models as unbiased computational tools that can be used to evaluate off-site migration of coalash constituents. For example, the model grids should have extended farther north and east to
incorporate groundwater extraction from off-site private water-supply wells and allow three-dimensional
16

 groundwater flow patterns to naturally develop. The eastern and western no-flow boundaries in the
current CAP models artificially prevent any off-site flow or transport in either the bedrock or overburden
aquifers. The same is true for the entire northern and southern model boundaries despite the fact that
several private homes are located north and east of the Active Ash Basin, and the bedrock hydraulic head
map (CSA Figure 6-7) exhibits a strong easterly flow component in this area. Some additional private
water supply wells are also located close to the northern shore of the Broad River (CSA Figure 4-2).
Artificial limitations created by the northern Broad River boundary condition are outlined above.

The bottom boundaries of the CAP models should extend much deeper because the hydraulic
conductivity of the fractured bedrock zone is of the same order of magnitude as the overburden soils
based on slug test results. In the present configuration the lower boundaries of the CAP Parts 1 and 2
model grids are only about 50 feet below the bedrock surface (Figure 2 in both the CAP 1 & 2 modeling
appendices). Because several bedrock wells were screened to this depth the bedrock hydraulic
conductivity data collected for the CSA demonstrate that imposing an impermeable model boundary at
this depth is incorrect (compare similarities of mean overburden and bedrock aquifer permeabilities in
CSA Table 11-10). As discussed above, the strong downward hydraulic gradients between deep and
bedrock wells in the northern portion of the Active Ash Basin also demonstrate that vertical and horizontal
groundwater flow in bedrock is important, and these transport mechanisms need to be accurately
simulated in the CAP models in order to accurately assess the potential for off-site chemical migration.

Off-Site Groundwater Extraction Ignored
The CSA and CAP Parts 1 and 2 failed to examine the strong potential for coal-ash constituents from the
Cliffside site to migrate with groundwater to private water supply wells located immediately east and
northeast of the Active Ash Basin. COI may also potentially migrate to private wells located close to the
northern Duke Energy property boundary on the northern side of the Broad River. CSA Figure 4-2 shows
the locations of water supply wells near the site. The basis of my opinion includes the following:
hydraulic conductivity measurements for the overburden and bedrock formations; three-dimensional
variations in measured hydraulic head in the bedrock and overburden units; groundwater concentration
data; and calculations of potential hydraulic head reductions (i.e., drawdown) that could be caused by offsite groundwater extraction. As discussed throughout my report, neither the CSA nor CAP Parts 1 or 2
investigations addressed the potential for off-site migration.

COI's were detected in several water supply well samples (CSA Appendix B), but the CSA report did not
plot these detections on a map and did not discuss their possible relationship to the Cliffside site.
Appendix B also did not present the well construction details (e.g., well diameter and elevation range of
the well screen or open bedrock interval) so that well dilution effects and potential chemical transport
pathways in the bedrock unit could be evaluated. In addition, the CSA investigations and CAP Part 1
17

 modeling did not include these areas east and north of the Cliffside site. The CAP Part 2 flow model did
include a small number of residential wells (13 of the 100 neighboring private wells) located inside the
undersized model domain (east of the active ash basin), but the CAP 2 modeling report (CAP 2, Appendix
B) did not show simulated hydraulic head maps with these residential wells pumping and did not provide
any discussion or analyses of the potential for these wells to capture COI dissolved in groundwater. The
CAP Part 2 also did not increase the model grid size to incorporate the large number of residential water
supply wells located immediately north of the Broad River and downgradient from the active ash basin in
the northeastern portion of the site (CAP 2 Figure 3-3); fix the boundary condition problems; or correct
the model input data errors I have outlined so that the flow and transport models could be used to more
accurately analyze the potential for off-site chemical transport.

Another important model input data error is the bedrock hydraulic conductivity, which is assumed in the
CAP 1 and 2 flow models to be about a factor of ten (10x) lower than the overburden aquifer in different
areas (Tables 2 in CAP 1 Appendix C and CAP 2 Appendix B). The bedrock slug test results show that
the mean bedrock permeability is approximately the same as the overburden permeability. Also, in the
CAP 1 model HDR assumed that the vertical bedrock permeability [ (KBR)vert ] was the same as the
horizontal value (i.e., vertical anisotropy, Av = 1). Without justification or any field measurement of
(KBR)vert the CAP 2 model assumed Av = 10-1,000 in bedrock; at several locations the model assumes
the vertical bedrock permeability is 100 to 1,000 times smaller than the horizontal permeability. These
vertical anisotropy values are extremely large, are highly variable across the site, and do not appear to be
supported by data. By comparison, HDR assumed Av = 2 in their hydraulic modeling of bedrock slug
tests (CSA Appendix H). In an extensive hydrogeologic study and groundwater model of the Indian
Creek Basin in the southwestern Piedmont of North Carolina by the U.S. Geological Survey (Daniel et al.,
1989) a value of Av = 1 in bedrock was used by the USGS. This study is especially relevant because the
146-square-mile Indian Creek model area lies in parts of Catawba, Lincoln, and Gaston Counties, North
Carolina and is located in the general vicinity of the Cliffside site. Therefore, the CAP 1 and 2 flow
models significantly restrict (incorrectly) groundwater from flowing from the overburden aquifer into the
fractured bedrock unit, which causes the CAP transport models to underestimate the potential for off-site
chemical migration.

Model Significantly Underestimates Leakage Rate from Active Ash Basin
The CAP Part 2 flow model underestimates leachate discharge from the active ash basin by as much as
a factor of 180 in areas of ponded surface water (e.g., refer to CSA Figures 4-5 and 8-2). The CAP 1
model underestimates active basin leakage by as much as a factor of 330. As shown in Figure 5 of CAP
1, Appendix C, the CAP 1 flow model assumes a constant groundwater recharge rate (i.e., leakage rate)
equal to 6.0 inches/year in the active ash basin and all other unlined areas of the site. In the CAP 2 flow
model the active basin leakage rate is assumed to be 11 inches/year (Figure 5 of CAP 2, Appendix B).
18

 '

However, CSA Figure 8-2 (cross-section A-A ) shows that the vertical hydraulic gradient through the coal
ash in the downgradient portion of the active ash basin is on the order of unity. Using Darcy's law and the
mean vertical coal-ash permeability of 1.6E-4 cm/sec in CSA Table 11-11, the approximate vertical
leakage rate out of the active basin is about 2,000 inches/year near the Broad River (i.e., ~ 180 times
greater than the specified CAP 2 recharge rate of 11 inches/year; and ~ 330 times greater than the
specified CAP 1 recharge rate of 6 inches/year).

The CAP flow models should have represented ponded areas of the active ash basin as either constanthead or leaky-type boundary conditions, which would have allowed the model to simulate a realistic
leakage rate for the active ash basin. The major discrepancies between the measured shallow hydraulic
head maps (CSA Figure 6-5 and CAP 2 Figure 2-2) and the CAP 1 and 2 simulated shallow head maps
(Figure 14 in CAP 1, Appendix C; Figure 15 in CAP 2, Appendix B) clearly show that the CAP flow
models significantly underestimate the hydraulic head beneath the active ash basin due to the fact that
the modeled leakage rate from the active basin is much too low.

Three related impacts of this incorrect active basin boundary condition are that the CAP models
significantly underestimate: (i) vertical groundwater flow rates (by on the order of a factor of 200) through
coal-ash source material in the vicinity of the downgradient portion of the active ash basin; (ii) horizontal
groundwater flow and chemical transport rates downgradient from the active ash basin; and (iii) vertical
flow rates from the overburden aquifer into the fractured bedrock unit beneath ponded areas. This
incorrect boundary condition representation of the active ash basin also causes the CAP models to
significantly underestimate (by on the order of a factor of two or more) both the mass loading of COI into
the Broad River and the corresponding Broad River surface water concentrations (attributable to coal ash
ponds) that HDR estimated with their mixing model (e.g., CAP 2 report Table 4-2 and Appendix D).

CAP Chemical Transport Modeling
Due to model calibration, model construction, and boundary-condition and input-data errors the CAP
models significantly underestimate remediation time frames. As discussed in this section, reasons for this
include significant underestimation of the chemical mass sorbed to soil, failure to account for slow
chemical desorption rates, inaccurate analyses of water-table lowering due to capping, and flaws in the
transport model calibration.
Soil-Water Partition Coefficients and Model Calibration
The fraction of chemical mass sorbed to soil can be represented by the soil-water partition coefficient, Kd
(Lyman et al., 1982). Kd is an especially important parameter at the Cliffside site because for most of the
19

 COI the bulk of the chemical mass in the soil is associated with the solid phase (i.e., sorbed to soil grains
rather than dissolved in pore water). In effect, the solid fraction of the soil matrix acts as a large "storage
reservoir" for chemical mass when Kd is large [e.g., metals, many chlorinated solvents, and highlychlorinated polycyclic aromatic hydrocarbon (PAH) compounds associated with coal tars and woodtreating fluids]. Kd is also a very important chemical transport parameter which is used to compute the
chemical retardation factor, Rd, assuming linear equilibrium partitioning of mass between the soil (solid)
and pore-water phases (Hemond and Fechner, 1994):

Rd = 1 + ρb K d / ne
where

ρb

is the soil matrix bulk dry density and ne is the effective soil porosity. For example, the

chemical migration rate is directly proportional to hydraulic conductivity and inversely proportional to Rd .
The total contaminant mass in an aquifer is also directly proportional to Rd , as well as aquifer cleanup
times once the source is removed (e.g., Zheng et al., 1991).

Accordingly, it is very important to use accurate Kd values in the CAP Closure Scenario modeling.
Specifically, the CAP Part 1 transport modeling used Kd values that were typically factors of 10 - 100 (i.e.,
one to two orders of magnitude) smaller than the measured site-specific Kd 's reported in CAP Appendix
D. In contrast, the CAP Part 2 transport modeling used Kd values that are generally a factor of about 10
larger than the CAP 1 values; however, the CAP 2 Kd 's are still on the order of 10 times smaller than the
measured site-specific Kd 's reported in CAP 1 Appendix D and CAP 2 Appendix C. Further, soil-water
partition coefficients for the CAP Parts 1 and 2 models are much smaller than most values presented in
the literature for the COI (e.g., EPRI, 1984; Baes and Sharp, 1983). This means that, using the actual
measured Kd 's for the Cliffside site, the times required to reach North Carolina water quality standards at
the Compliance Boundary are at least a factor of 10 longer (see additional discussion below) than
cleanup times predicted by the CAP Parts 1 and 2 transport models for many COI.

The CAP 1 modeling report (CAP 1 Appendix C; Section 4.8) argues that the major Kd reductions were
needed due to the following:
"The conceptual transport model specifies that COis enter the model from the shallow saturated source
zones in the ash basins. When the measured Kd values are applied in the numerical model to COIs
migrating from the source zones, some COIs do not reach the downgradient observation wells where they
were observed in June/July 2015 at the end of the simulation period. The most appropriate method to
calibrate the transport model in this case is to lower the Kd values until an acceptable agreement
between measured and modeled concentrations is achieved. Thus, an effective Kd value results that
likely represents the combined result of intermittent activities over the service life of the ash basin. These
may include pond dredging, dewatering for dike construction, and ash grading and placement. This
approach is expected to produce conservative results, as sorbed constituent mass is released and
transported downgradient."
20

 First, considering the approach that was used to develop the chemical transport model (history matching),
it is not true that "the most appropriate method to calibrate the transport model is to lower the Kd values."
3

The CAP Parts 1 and 2 transport models used an incorrect value (2.65 g/cm ) for the bulk density of
overburden materials; this value is the density of a solid mass of mineral (e.g., quartz) with zero porosity.
The bulk density should have been computed using the total porosity (n) values in CSA Table 11-1 using
the following formula (e.g., Baes and Sharp, 1983):

=
ρb 2.65(1 − n)
Based on the Table 11-1 values

ρb ~ 1.0 - 1.9 g/cm3, which means that the Rd values for the CAP 1 and

2 models were as much as a factor of 2.65 (2.65/1.0) too high before HDR adjusted the Kd values during
calibration. Also, as discussed earlier, the overburden slug test values were about 70 percent too low
due to HDR's data analysis errors. Both of these errors (sorption rate and hydraulic conductivity) resulted
in a modeled transport rate that was up to five times (5x) too low before calibration simply due to data
input errors.

At least two other important factors were not considered during the transport model calibration. At least
two other important factors were not considered during the CAP 1 and 2 transport model calibrations.
First, the groundwater flow models are based on average hydraulic conductivity (K) values within a
material zone, but K distributions in aquifers are highly variable (e.g., varying by factors of 3-10, or more,
over distances as small as a few feet: Gelhar, 1984, 1986, 1987; Gelhar and Axness, 1983; Rehfeldt et
al., 1992; Rehfeldt and Gelhar, 1992; Molz, 2015). The Cliffside site hydrogeology certainly qualifies as
"heterogeneous". This is very important to consider for the CAP transport model calibrations because it is
the high-permeability zones and/or layers that control the time required (Ttravel ) for a constituent to reach
a downgradient observation point, and HDR used differences in observed versus simulated Ttravel (i.e.,
time to travel from sources zones to downgradient monitoring wells) as the justification for lowering
measured Kd values.
Second, the history matching that HDR performed is very sensitive to the assumed time at which the
source (i.e., coal ash) is "turned on" and to the assumed distribution of source concentrations (fixed pore
water concentrations) in source area cells. Section 5.3 of CAP 1 Appendix C explains that the source
was activated 58 years ago in the model:
"The model assumed an initial concentration of 0 within the groundwater system for all COIs at the
beginning of operations approximately 58 years ago. A source term matching the pore water
concentrations for each COI was applied within the Units 1-4 inactive ash basin, Unit 5 inactive ash basin,
active ash basin and the ash storage area at the start of the calibration period. The source concentrations

21

 were adjusted to match measured values in the downgradient monitoring wells that had exceedances of
the 2L Standard for each COI in June 2015."
For several reasons it is a major simplification (and generally inaccurate) to use 2015 ash pore water
concentrations to define year-1957 source zone (fixed concentration) boundary conditions. These
reasons include: coal ash was gradually and nonuniformly distributed (spatially and temporally) in ash
basins throughout the 58-year simulation period (not instantaneously in 1957); it is very difficult (or not
possible) to accurately extrapolate geochemical or ash-water leaching conditions (i.e., predict COI porewater concentrations) that existed during the 2015 sampling round to conditions that may have existed in
1957 and thereafter; the actual source-area concentration distributions are highly nonuniform, but it is not
clear from the CAP modeling reports how "... source concentrations were adjusted to match measured
values ... ", or if the source area concentrations were nonuniform. All of these uncertainties are further
magnified when using history matching to calibrate a chemical transport model.

Based on the above model input errors and major uncertainties in hydraulic-conductivity variations and
source-term modeling, it is incorrect to simply reduce Kd values by factors of 10 to 100 below site
measurements (and the large database of literature Kd values) based only on the transport model "history
matching" exercises that HDR performed. My additional comments on the CAP Parts 1 and 2 transport
modeling of Closure Scenarios are listed in the following section.

Geochemical Modeling and Evaluation of Monitored Natural Attenuation
The CAP Part 2 geochemical modeling results do not include quantitative analyses of COI attenuation
rates at the Cliffside site and are only qualitative in nature. In addition, HDR did not incorporate any
source/sink (e.g., precipitation/dissolution) terms representing geochemical reaction mechanisms in the
CAP 2 chemical transport model to evaluate whether such reactions are important compared to
groundwater concentration changes caused by advection, dispersion, and soil-water partitioning. In this
regard, HDR states in Section 2.10 of CAP 2 Appendix B : "A physical-type modeling approach was
used, as site-specific geochemical conditions are not understood or characterized at the scale and extent
required for inclusion in the model." Indeed, the Electric Power Research Institute (e.g., EPRI, 1984;
page S-8) has extensively reviewed subsurface chemical attenuation mechanisms applicable to the "utility
waste environment" and concluded: (i) precipitation/dissolution has not been adequately studied; and (ii)
"Quantitative predictions of chemical attenuation rates based upon mineralogy and groundwater
composition cannot be made because only descriptive and qualitative information are available for
adsorption/desorption mechanisms."

Nonetheless, HDR performed the geochemical modeling to evaluate the technical basis for its MNA
analysis; however, any quantitative MNA analysis must compare mass transport rates and changes (e.g.,
22

 grams/year per unit area normal to a groundwater pathline) in the aquifer for the various active transport
mechanisms in order to determine whether MNA is a viable alternative (e.g., produces meaningful
groundwater concentration reductions) at the Cliffside site. In Section 6.3.2 of the CAP 2 report HDR
acknowledges that these quantitative evaluations were not performed in CAP 2 and indicated that they
would need to be completed as part of a Tier III MNA assessment. Nevertheless, HDR suggested in the
CAP 2 report that COI concentrations "will" or "may" attenuate over time without completing the
necessary evaluations to reach these conclusions. HDR also states in CAP 2 Section 6.3.4 that "MNA is
an effective correction action because COIs will attenuate over time to restore groundwater quality at the
CSS site...." and in CAP 2 Section 6.3.3 that "the groundwater model did not allow for removal of COI via
co-precipitation with iron oxides, which likely resulted in an over-prediction of COI transport. Completion
of the Tier II assessment described in Appendix H has addressed this issue." I saw no quantitative
analysis or evidence in the CAP 2 report or related appendices to support these claims. In fact, the CAP
2 Appendix H emphasizes that much more geochemical data need to be collected and chemical transport
modeling with a source/sink term must be performed in a Tier III assessment to further assess whether
MNA is a viable remedial alternative.

Therefore, the CAP 2 report fails to provide any quantitative evidence supporting COI attenuation due to
co-precipitation with iron or manganese. The second component of COI attenuation evaluated in
Appendix H is chemical sorption to soil. It is important to note that, although the CAP models did not
incorporate a mechanism for co-precipitation with iron or manganese (or any COI sink term), the CAP
models did simulate attenuation due to sorption. Even with the sorption attenuation mechanism included,
CAP 2 Table 4-1 shows that for both the "existing conditions" and "cap-in-place" scenarios the following
COI will exceed North Carolina groundwater standards at the Compliance Boundary 100 years into the
future: antimony, arsenic, beryllium, boron, chromium, hexavalent chromium, cobalt, lead, sulfate,
thallium, and vanadium. Further, my Table 1 shows that groundwater standards are currently exceeded
at the Compliance Boundary for barium, cobalt, iron, manganese, nickel, and total dissolved solids (i.e.,
barium, cobalt, iron, manganese, nickel, and TDS contaminant plumes originating in the source areas
have already reached the Compliance Boundary). The conclusions of the MNA Tier I analyses (CAP 2
Appendix H, page 18) were that arsenic, barium, beryllium, boron, chromium, cobalt, lead, thallium, and
vanadium showed some evidence of attenuation and should be evaluated further in a Tier II evaluation.
However, the CAP 2 modeling results in Table 4-1 (which included a significant amount of sorption
attenuation) show that all of these COI currently exceed North Carolina groundwater standards at the
Compliance Boundary and are expected to exceed those standard 100 years into the future. All of these
data and CAP 2 modeling results strongly contradict the CAP 2 conclusion that MNA is a viable corrective
action at the Cliffside site.

23

 Simulation of Closure Scenarios
As discussed below, CAP 1 Closure Scenario simulations greatly underestimate (by factors of 10 or
more) the time frames required to achieve meaningful groundwater concentration reductions in response
to remedial actions. Compared to the Cap-in-Place (CIP) remedial alternative evaluated in the CAP Part
1, the Excavation Scenario results in COI concentration reductions at the Compliance Boundary that are
generally two to ten times greater compared to Cap-in-Place and best reduces impacts to surface water.
In addition, the time frames to achieve equivalent concentration reductions are at least factors of 2 to 5 (2
- 5x) shorter for excavation compared to cap-in-place for most of the COI; further, several COI
concentrations reduce below 2L or IMAC standards with excavation but remain significantly higher than
the groundwater standards with cap-in-place.

Although the CAP 1 modeling showed that Source Excavation outperforms CIP, the CAP 2 modeling did
not simulate an Excavation closure scenario. Nonetheless, the following comparisons between CIP and
Excavation impacts on groundwater concentrations are valid for both the CAP 1 and 2 model results.
This is because the main difference with the CAP 2 transport model (compared to CAP 1) is that
concentration changes resulting from either CIP or Excavation (if it was evaluated in CAP 2) occur much
more slowly (i.e., ~ 10x slower) in the CAP 2 model due to the much larger Kd (and Rd ) values. The CAP
2 transport model also assumed uniform initial COI concentrations equal to HDR's proposed provisional
background concentrations (PPBC), even though the PPBC exaggerate background levels (see above
discussion) and there are no data to suggest that background concentrations should be spatially uniform.
Despite these changes in the CAP 1 and 2 models, the relative differences in groundwater concentrations
between the two closure scenarios remain about the same if the uniform starting (PPBC) COI
concentrations are subtracted from the simulated concentration versus time curves. For these reasons
the following discussions focus on the CAP 1 modeling results.

Source Concentrations for Cap-in-Place Scenario
In this scenario the CAP 1 flow model predicts cap-induced water-table declines equal to approximately 5
feet (relative to the Existing Conditions simulation) within the Units 1-4 inactive ash basins, 12 feet within
the Unit 5 inactive ash basin (11 feet in the CAP 2 flow modeling), and 10 feet within the active ash basin
(10 feet in CAP 2). However, the geologic cross-sections presented in the CSA show that the saturated
coal ash thickness at several borings is as great as 30-60 feet. This means that under the simulated
Cap-In-Place Scenario most of the coal ash, which is the source of dissolved COI, would remain
saturated and continue to leach constituents into groundwater in several parts of the ash basin system.
The CAP 1 simulations ignored this fact and set all source concentrations equal to zero (i.e., assumed all
coal ash was dewatered). Therefore, the simulated Cap-in-Place concentrations should be much higher
than the values presented in the CAP Part 1.

24

 The groundwater flow model simulations also exaggerate the hydraulic effects of the cap (i.e., overstates
water table lowering) because the no-flow boundary conditions along the entire western, southern, and
eastern grid boundaries prevent flow into the Ash Basin System when the laterally inward hydraulic
gradients are created by capping. In addition, the base of the flow model is assumed to be impervious
even though the bedrock aquifer hydraulic conductivity is about the same as the overburden aquifer; this
artificially restricts upward flow from bedrock into the capped area and exaggerates predicted water table
lowering.

In addition, a site-specific distribution of groundwater recharge values should have been developed for
this and the other simulation scenarios to take into account site-specific topography and soil types (e.g.,
runoff estimation) and climate data (precipitation, evapotranspiration, etc.; e.g., using the U.S. Army
Corps of Engineers HELP Model; Schroeder et al., 1994). The CAP 1 flow model uses an assumed
value of 6 inches year uniformly throughout the model domain even though the actual value is highly
variable across the Ash Basin System and site land surface. Further, as discussed above, HDR should
have used a leaky-type boundary condition to model ponded areas of the active ash basin. The predicted
water table lowering due to capping is very sensitive to the model recharge value, so more effort should
have been made to develop a site-specific recharge-rate distribution.

Slow and Multirate Nonequilibrium Desorption of COI
Since the 1980's the groundwater industry has learned how difficult it is to achieve water quality
standards at remediation sites without using robust corrective actions such as source removal (Hadley
and Newell, 2012, 2014; Siegel, 2014). Two of the key reasons for this in aqueous-phase contaminated
soil are inherently low groundwater or remediation fluid flushing rates in low-permeability zones and slow,
nonequilibrium chemical desorption from the soil matrix (Culver et al., 1997, 2000; Zheng et al., 2010). A
good example of this is the "tailing effect" (i.e., very slow concentration reduction with time) that is
commonly observed with pump-and-treat, hydraulic containment systems. These factors are also related
to the "rebound effect" in which groundwater concentrations sometimes increase shortly after a
remediation system is turned off (Sudicky and Illman, 2011; Hadley and Newell, 2014; Culver et al.,
1997).

The CAP 1 and 2 flow models use different permeability (K) zones, but the scale of these zones is very
large and within each zone K is homogeneous even though large hydraulic conductivity variations (e.g.,
lognormal distribution) are known to exist at any field site over relatively small length scales (Molz, 2015).
Moreover, the CAP transport models assume linear, equilibrium soil-water partitioning which corresponds
to instantaneous COI release into flowing groundwater. The transport code (MT3D) has the capability of
simulating single-rate nonequilibrium sorption, but the Close Scenario simulations did not utilize this
modeling feature. Slow desorption of COI can also be expected at the Allen site because sorption rates
25

 are generally highly variable, and multi-rate (Culver et al., 1997, 2000; Zheng et al., 2010), and Kd
values are nonuniform spatially (Baes and Sharp, 1983; EPRI, 1984; De Wit et al., 1995). The CAP flow
and transport models can be expected to significantly underestimate cleanup times required to meet
groundwater standards at the compliance boundary because they do not incorporate these important
physical mechanisms.

Adequacy of the Kd Model for Transport Simulation
The laboratory column experiment effluent data (e.g., CAP 1 Appendix D) generally gave very poor
matches with the analytical (one-dimensional) transport model used to compute Kd values. Since the
CAP transport model solves the same governing equations in three dimensions, the adequacy of the Kd
modeling approach for long-term remedial simulations should have been evaluated in much more detail in
the modeling appendix.

The transport modeling also did not evaluate alternative nonlinear sorption models such as the Freundlich
and Langmuir isotherms (Hemond and Fechner, 1994), which are input options in the MT3D transport
code. Several of the batch equilibrium sorption experiments (CAP 1 Appendix D) exhibited nonlinear
behavior, and such behavior is commonly observed in other studies (e.g., EPRI, 1984). However, HDR
only computed linear sorption coefficients (i.e., Kd) for the Cliffside site in CAP Part 1. In CAP Part 2 HDR
did fit Freundlich isotherms to the batch sorption data for selected COI (CAP 2 Appendix C, Tables 1-8)
but did not use these Freundlich isotherm results in the CAP 2 transport modeling. De Wit et al. (1995)
showed that the nonlinear sorption mechanism is similar in importance to aquifer heterogeneities in
extending remediation time frames.

Closure Scenario Time Frames
As outlined in my report, the CAP Part 1 chemical transport model underestimates the time intervals
required to achieve groundwater concentration reductions (i.e., achieve groundwater quality restoration)
by factors that are at least on the order of 10 to 100. In other words, the CAP 1 transport model
significantly overestimates the rate at which concentrations may reduce in response to remedial actions
such as capping or source removal. This is due to several factors, including major errors in model input
data, model calibration mistakes, field data analysis errors, and oversimplified model representation of
field conditions (e.g., hydraulic conductivity) and transport mechanisms (e.g., chemical
sorption/desorption). These limitations of transport models for realistically predicting cleanup times have
been recognized by the groundwater industry for the past few decades based on hands-on experience at
hundreds of extensively-monitored remediation sites.

Even if we ignore the factors of 10 or more errors in cleanup time predictions with the CAP 1 model, the
remediation time frames for the Excavation Scenarios are still more than two centuries for several
26

 constituents due to slow groundwater flushing rates from secondary sources (surrounding residual soil)
left in place after excavation and due to high chemical retardation factors for most of the COI. However,
excavation of secondary-source material would further accelerate cleanup rates under this alternative.
The CAP 1 simulated Cap-In-Place concentration reduction rates are much slower, compared to
excavation, but are also incorrect (i.e., overestimated) because the cap-induced water-table lowering is
insufficient to dewater all of the source-area coal ash, as discussed above, and the CAP 1 and 2 flow
models overestimate cap-induced water-table lowering due to boundary condition errors. Furthermore,
these simulation times are well beyond the prediction capabilities of any chemical transport model for a
complex field site (especially one that is as geochemically complex as the Cliffside site). The historical
model-calibration dataset (1957-2015) is also significantly smaller than the predictive (remediation) time
frames. In addition, the "history matching" technique used to calibrate the transport model (e.g., major
reduction in measured Kd values) was not performed correctly by HDR.
Cap-In-Place versus Excavation Closure Scenarios
Although the the CAP 1 model underestimates remediation time frames, the CAP 1 Closure Scenario
simulations demonstrate several significant advantages of excavation for restoring site groundwater
quality versus cap-in-place. First, predicted COI concentration reductions in groundwater downgradient
from the ash basin system are generally factors of 2-10 greater with excavation compared to cap-in-place
(e.g., refer to most of the simulated concentration versus time curves in CAP 1 Appendix C). Further, if
HDR had correctly performed the CAP 1 cap-in-place simulations the predicted CIP concentrations would
be much higher because predicted water-table lowering due to the cap would be insufficient to dewater all
of the coal ash. Second, North Carolina 2L or IMAC standards for many COI (antimony, arsenic,
chromium, hexavalent chromium, cobalt, nickel, thallium, vanadium) are not achieved by cap-in-place but
are achieved by excavation (e.g., CAP 1 Appendix C Figures 13, 20, 21, 26, 27, 28, 29, 30, 31, 33, 34,
36, 37, and 39). Third, the time frames to achieve equivalent concentration reductions are at least factors
of 2 to 5 shorter for excavation compared to cap-in-place; further, several COI concentrations reduce
below 2L or IMAC standards with excavation but remain significantly higher than the groundwater
standards with cap-in-place.

Even though the CAP 1 modeling demonstrated that the CIP closure alternative would be much less
effective than excavation, and that CIP would only dewater about 20-40 percent of the saturated coal-ash
thickness in many areas, HDR eliminated excavation from consideration in CAP 2. In Section 7.1 of the
CAP 2 report HDR assumes that "Evaluation of the geochemical modeling indicated COIs are attenuated
by a combination of sorption and/or precipitation" and that "Based on review of the groundwater modeling
results, COIs with sorption coefficients similar to or greater than arsenic are immobilized by sorption
and/or precipitation .....". As discussed above, HDR provided no quantitative analysis or evidence in the
CAP 2 report or related appendices to support this claim. Further, sorption is not a mechanism that
27

 "immobilizes" a dissolved consituent; sorption only slows down the rate of transport proportional the
chemical retardation factor. Considering that up to 80 percent of the coal-ash source material would
remain saturated with CIP and that multiple exceedances of groundwater standards at the Compliance
Boundary currently exist (with no historical data to indicate that these Compliance Boundary
concentrations are decreasing with time), it is not reasonable to make sweeping assumptions about future
concentration changes. Tier III MNA analyses require rigorous quantitative evaluations using the CAP
transport model with a source/sink term that incorporates geochemical reactions to support MNA as a
viable corrective action. CAP 2 did not provide this information.

As discussed above, the CAP Part 2 flow model did include a small number of residential wells (13 of the
100 neighboring private wells), but the CAP 2 modeling report (CAP 2, Appendix B) did not show
simulated hydraulic head maps with these residential wells pumping and did not provide any discussion
or analyses of the long-term potential for these wells to capture COI dissolved in groundwater. Further,
the private bedrock wells that HDR chose to include in the CAP 2 model appear to be located upgradient
from the active ash basin; HDR should have included all of the private wells located near the northern
bank of the Broad River (in a downgradient direction from the ash basin system) and near the
northeastern site boundary which is downgradient from the active ash basin, as I describe above. In CAP
2 section 4.1.5 HDR discusses that fact that the CAP 2 flow model was used to compute 1-year, reverse
particle pathlines for these bedrock residential wells (Figure 18 in CAP 2 Appendix B) to determine their
short-term groundwater capture zones. However, the residential well reverse pathline tracing should
have been performed for a much longer time period (e.g., from the beginning of coal ash disposal to the
present) to evaluate whether COI may have migrated from source areas to these wells. In addition, if
HDR had extended the CAP 2 model grid much farther to the north and east the capture zones for the
remaining 87 private water supply wells could have been determined, as I discuss earlier in my report.

The CAP Closure Scenarios do not include hydraulic containment remedial alternatives (e.g., gradient
reversal) for the bedrock aquifer that would address the risk of off-site COI transport. As discussed
above, the CSA data show many exceedances of groundwater standards in bedrock not only at the
compliance boundary but also inside the CB. In addition, strong downward groundwater flow components
from the deep overburden to bedrock aquifers were measured during the CSA at multiple locations
across the site, including the southern shoreline of the Broad River. The cap-in-place alternative does not
address either concentration reduction or off-site chemical migration control in the fractured bedrock
aquifer.

The CAP Parts 1 and 2 do not assess whether water quality standards will be achieved in the tributaries
and wetlands between the ash basins and the Broad River [e.g., seep locations S-3 or S-6 (Broad River
tributaries) or the wetland located along Suck Creek downgradient from the upstream dam of the active
28

 ash basin] under any closure scenario. As discussed above, for the cap-in-place scenario a significant
fraction of the source material will remain saturated and dissolved COI will continue to migrate with
groundwater toward these seep locations. Although unaddressed by the model, COI concentration
decreases in groundwater and unsaturated zone pore water due to source removal would also reduce
impacts to tributaries and wetlands that are influenced by the ash basins.

Conclusions
Based on my technical review and analyses of the referenced information for the Cliffside site I have
reached the following conclusions:
•

A total of 62 Compliance Boundary groundwater samples exceeded North Carolina groundwater
standards for these COI: antimony, boron, chromium, cobalt, iron, manganese, sulfate, total
dissolved solids, and vanadium. Of these 62 exceedances, 36 were greater than the proposed
provisional background concentrations by HDR;

•

The statistical analyses of shallow background groundwater concentrations at the Cliffside site
(well MW-24D) are invalid. The time periods between groundwater sample collection from this
well are too small and the concentration data are not independent;

•

There is a significant risk of chemical migration from the ash basin to neighboring private water
supply wells in fractured bedrock. The design of the CAP flow and transport models prevents the
potential for off-site migration from being evaluated;

•

The limited CAP model domain size; the no-flow boundary conditions along the western,
southern, and eastern boundaries; and incorrect hydraulic boundary condition representations of
the Broad River and the active ash basin prevent simulation and analysis of off-site COI
migration;

•

The CAP Closure Scenario simulations greatly underestimate (by factors of 10 or more) the time
frames required to achieve meaningful groundwater concentration reductions in response to
remedial actions. This is due to oversimplification of field fate and transport mechanisms in the
CAP model and several model input errors;

•

The simulated water table lowering for the Cap-in-Place Scenario is more than a factor of five too
small at several locations in the ash basin system in order to dewater all source material; and the
actual cap-induced water table elevation reduction would be much less than predicted due to the
incorrect no-flow boundary conditions. Therefore, the remediation time frames for this scenario
would be much greater because a large percentage of the source zone would still be active with
the cap installed;

29

 •

For either the Existing Condition or Cap-in-Place Model Scenario groundwater concentrations of
coal-ash constituents much higher than background levels will continue to exceed North Carolina
groundwater standards at the Compliance Boundary because saturated coal-ash material and
secondary sources will remain in place;

•

Due to an incorrect boundary-condition representation of the active ash basin, the CAP models
underestimate by a factor of two or more both the mass loading of COI into the Broad River and
the corresponding Broad River water concentrations (attributable to coal ash ponds) estimated by
the groundwater/surface-water mixing model;

•

Source-area mass removal included in the Excavation Scenario results in COI concentration
reductions at the Compliance Boundary that are generally two to ten (2 - 10x) times greater
compared to Cap-in-Place and best reduces impacts to surface water. In addition, the time
frames to achieve equivalent concentration reductions are factors of two to five (2 - 5x) shorter for
excavation compared to cap-in-place, and source removal reduces the number of COI that will
exceed North Carolina groundwater standards in the future. Additional excavation of secondary
sources would further accelerate concentration reductions;

•

The CAP simulations show that source excavation reduces groundwater concentrations for many
COI below North Carolina groundwater standards (antimony, arsenic, chromium, hexavalent
chromium, cobalt, nickel, thallium, vanadium), but cap-in-place closure does not;

•

The CAP Part 2 geochemical modeling and monitored natural attenuation (MNA) evaluations do
not provide the required quantitative analyses (e.g., numerical transport modeling) of COI
attenuation rates necessary to support MNA as a viable corrective action and are only qualitative
in nature. The CAP 2 chemical transport modeling, which included attenuation by sorption,
demonstrated that MNA is not an effective remedial option for several COI (e.g., antimony,
arsenic, beryllium, boron, chromium, hexavalent chromium, cobalt, lead, sulfate, thallium, and
vanadium);

•

The CAP Closure Scenarios do not include hydraulic containment remedial alternatives for the
bedrock aquifer and do not address the risk of off-site COI transport. CSA data show multiple
exceedances of groundwater standards in bedrock not only at the compliance boundary but also
inside the CB. The cap-in-place alternative does not address either concentration reduction or
off-site chemical migration control in the fractured bedrock aquifer; and

•

Future Compliance Monitoring at the site should include much more closely-spaced Compliance
Wells to provide more accurate detection, and the time intervals between sample collection
should be large enough to ensure that the groundwater sample data are statistically independent
to allow accurate interpretation of concentration trends.

30

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33

 DOUGLAS J. COSLER, Ph.D., P.E.
10240 Stonemede Lane
Matthews, NC 28105

704-246-7702
dcosler@adaptivegroundwater.com

EDUCATION
Ph.D.

Chemical Hydrogeology

The Ohio State University

2006

C.E.D.

Civil Engineer Degree

Massachusetts Institute of Technology 1987

M.S.

Civil & Environmental Engineering

The Ohio State University

1979

B.S.

Civil & Environmental Engineering
Summa Cum Laude

The Ohio State University

1977

PROFESSIONAL HISTORY
20092007-2009
2006-2007
2003-2006
1987-2003
1984-1987
1979-1984
1977-1979

Principal Hydrogeologist and Commercial Software Developer,
Adaptive Groundwater Solutions LLC, Charlotte, NC
Environmental Consultant, Hart Crowser, Portland, OR
Research Scientist and Instructor, School of Earth Sciences, The Ohio State University,
Columbus, OH
Research Assistant, School of Earth Sciences, The Ohio State University, Columbus, OH
Environmental Consultant, MACTEC (now AMEC), Nashua, NH
Research Assistant, Department of Civil & Environmental Engineering,
Massachusetts Institute of Technology, Cambridge, MA
Environmental Consultant, D'Appolonia Consulting Engineers, Pittsburgh, PA
Research Assistant, Department of Civil & Environmental Engineering,
The Ohio State University, Columbus, OH

REGISTRATION
Registered Professional Engineer: Pennsylvania and Vermont
HONORS AND AWARDS
Member of Tau Beta Pi
University Graduate Fellowship, The Ohio State University, 1979
The Brown Scholarship (top undergraduate in Civil Engineering), The Ohio State University, 1977
PROFESSIONAL EXPERIENCE
Environmental Consulting
•

1979-1984, 1987-2003, 2007-present

Areas of Specialization: Groundwater flow and chemical transport analyses and computer modeling,
contaminant fate and transport in the environment, numerical code development, ground water and
surface water hydraulics and hydrology, contaminant fate and transport, expert witness testimony and
litigation support, hydrogeologic investigation, nonaqueous phase liquid (LNAPL/DNAPL)

 Douglas J. Cosler, Ph.D., P.E. - Page 2 of 15

investigation, subsurface remediation and remedial design, natural attenuation and risk assessment, and
hydrologic and wetlands impact evaluation.
•

Responsibilities: Principal Hydrogeologist/Hydrologist responsible for technical aspects of a wide
variety of projects, including: investigation, remediation, and regulation of Superfund, RCRA, and
other hazardous waste sites; ground water flow and chemical transport model development for
numerous projects; expert witness testimony and litigation support for several clients and hazardous
waste sites; natural attenuation/biodegradation assessments for chlorinated solvent and petroleum
contamination sites; volatile organic compound vapor (soil gas) migration and exposure assessment;
exposure modeling for health risk assessments; hydraulic and hydrologic modeling of impoundments
and spillways for U.S. Army Corps of Engineers dam safety assessments; stream hydraulics and solute
transport modeling; hydrologic impact assessment for minerals and coal mining; leachate collection
system modeling and design for waste disposal impoundments; and design of runoff, sedimentation,
and erosion control plans.

•

Types of Sites and Contaminants: Sites investigated include: landfills, manufactured gas plants, woodtreating facilities, chemical plants, water supply well fields, gasoline and fuel oil storage/delivery
facilities, nuclear waste disposal sites, hazardous waste incinerators, mining operations, and various
industrial facilities. Investigated dissolved, nonaqueous-phase (LNAPL/DNAPL), and vapor-phase
contaminants: chlorinated solvents, gasoline and fuel oil constituents, wood-treating products (e.g.,
creosote and pentachlorophenol), coal tars, polychlorinated biphenyls, pesticides, dioxins and furans,
phenolic compounds, flame retardants (PBDE), phthalates, radionuclides, biological constituents, and
various metals.

•

Representative Project Experience:
Expert Witness Testimony and Litigation Support

Litigation and Expert Witness Support, Wells G&H Superfund Site, Woburn, MA (MACTEC). Doug
provided technical support for property owners involved in litigation related to economic damages
associated with groundwater contamination in a fractured bedrock aquifer resulting from upgradient sources
of chlorinated solvents (DNAPL and aqueous-phase). He completed a thorough review of RI/FS technical
reports (including groundwater pumping tests) and performed modeling of chemical transport in the
fractured bedrock aquifer that accounted for the effects of horizontal anisotropy on transport directions.
Based on the evaluations, Doug developed an alternative site conceptual model that incorporated the effects
of bedrock fractures on solute transport in order to define probable contaminant migration pathways in
overburden and bedrock aquifers that were not identified in historical documents. He demonstrated the
existence of these pathways using two-dimensional models of groundwater flow and contaminant advection
(particle pathlines) that established a connection between DNAPL sources areas and groundwater
contamination beneath the subject properties.
Expert Witness Testimony and Litigation Support, Gasoline Remediation Site and Sewer/House Explosion
Case, Winneconne, WI (MACTEC). Doug provided expert witness testimony and investigated the potential
causes of and chemical fate and transport mechanisms responsible for a house explosion case. Plaintiffs
alleged that vadose and saturated zone petroleum remediation activities at a service station located a few
blocks from the residence and subsequent transport of gasoline vapors through a sewer line/backfill were
the fuel source for the explosion. He analyzed gasoline vapor transport rates and concentrations in the

 Douglas J. Cosler, Ph.D., P.E. - Page 3 of 15

subsurface at the service station site, in the 12-inch sewer pipe, and within the sewer backfill. Doug
demonstrated that gasoline vapors could not have migrated to the residence between the time that
remediation stopped and the house exploded. He also demonstrated that gasoline vapors at explosive levels
could not have migrated up the sewer lateral and into the house. His analyses showed that sewer gas
(methane) was the likely cause of the explosion because a methane source was present in the sewer line
near the residence (sewage blockage due to tree root growth through pipe joints) and lighter-than-air
methane naturally migrates upslope along sewer lines and laterals.
Remedial Investigation and Feasibility Study (RI/FS) and Expert Witness Testimony for the Old
Southington Landfill Superfund Project, Southington, CT (MACTEC). Doug developed a threedimensional groundwater flow model (MODFLOW) to evaluate source control alternatives for a municipal
landfill that received solid and semi-solid waste materials (primarily VOC). In the vicinity of the landfill,
high-permeability deposits in the bottom portion of the aquifer and the presence of a neighboring pond
caused large downward groundwater flow components that complicated contaminant transport analysis. He
directed the site investigation that focused on the landfill and underlying and downgradient portions of the
regional aquifer. He prepared an expert report and provided expert witness testimony for insurance
litigation regarding the nature and timing of waste disposal in the landfill.
Expert Witness Testimony, Hydrogeologic Investigations of a Gasoline Station, CT (MACTEC). Doug
provided expert witness testimony regarding the results of a hydrogeologic investigation to determine the
source of petroleum contamination within a telephone company utility conduit. He provided opinions
concerning groundwater flow and chemical transport rates in the surrounding aquifer, age dating of
petroleum products, and the potential relationship of gasoline-related contaminants in a utility manhole to
historical petroleum releases at an upgradient gasoline station.
Remedial Investigation, Site Remediation and Expert Witness Testimony, Former MGP Site, Concord, NH
(MACTEC). Historical discharges of carburetted water gas tar contaminated a 10-acre pond and the
underlying groundwater with aqueous-phase constituents and NAPL. Contaminants included PAHs and
BTEX compounds. Doug designed the hydrogeologic investigation to determine the nature and extent of
groundwater and NAPL contamination. He performed data evaluations to assess the potential for vertical
and horizontal migration of NAPL and the potential for contamination of a river adjacent to the site. He
also prepared two expert reports and provided expert witness testimony for two related insurance litigation
actions regarding the timing and ongoing nature of pond contamination and contamination from the former
MGP, located upgradient from the pond.
Remedial Design Evaluation and Expert Witness Support, Chlorinated Solvent and Petroleum
Contamination Site, MO (MACTEC). Doug served as a company expert for litigation involving a
groundwater extraction system designed to control LNAPL and aqueous-phase contaminants. Plaintiffs
(downgradient property) claimed that the extraction system was not controlling contamination. Doug
developed a hydraulic model of the site, analyzed in detail the groundwater capture zone, and demonstrated
that the system was very effective in controlling LNAPL and aqueous-phase contaminant migration.

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Expert Witness Testimony, Petroleum Contamination Site, Concord, NH (MACTEC). Doug served as a
hydrogeology, coal tar, and petroleum fate and transport expert for property damage litigation involving a
fuel oil distributor and former MGP site. The plaintiff claimed that coal tar contamination from the former
MGP caused environmental damage and increased construction costs for a new hotel being built at the site.
Doug performed petroleum transport and fingerprinting analyses and demonstrated that the fuel oil
distributor located immediately upgradient from the subject property was the likely source of contamination
- not coal tar.
Remedial Investigation, Design, and Expert Witness Testimony, Former MGP Site, Laconia, NH
(MACTEC). Doug reviewed site investigation reports and evaluated hydrogeologic conditions, contaminant
sources, and NAPL mobility at a former MGP site. Historical MGP waste releases (coal tar) had
contaminated soil and groundwater and dissolved-phase constituents, and NAPL had migrated into adjacent
surface water bodies. He developed conceptual remedial alternatives for the site and evaluated NAPL
containment and collection designs. He prepared an expert report and provided expert witness testimony
for insurance litigation regarding the timing and ongoing nature of pond contamination.
Expert Witness Report, Former MGP Site, Goshen, IN (MACTEC). Provided litigation support and expert
report preparation for a case involving a former MGP site. Technical aspects of the project involved
hydrogeology, coal tar, and petroleum fate and transport.
Remedial Alternatives Evaluation and Expert Witness Report Preparation, Former Electronics
Manufacturing Facility, Manchester, NH (MACTEC). Historical releases of tetrachloroethene (PCE) and
PCE dissolved in fuel oil caused soil and groundwater contamination at the site. Contaminants were
present as dissolved-phase constituents and DNAPL. Doug evaluated data regarding site hydrogeology and
contaminant fate and transport to assess the relative contributions of the PCE sources. He evaluated the
feasibility and costs of potential remedial alternatives and prepared an expert report assessing the relative
contributions of the two different sources of contamination.
Groundwater Flow and Aqueous-Phase Chemical Fate and Transport
Developed Adaptive Groundwater, a Three-Dimensional Groundwater Flow and Chemical Transport
Code based on the Adaptive Mesh Refinement Method (Adaptive Groundwater Solutions LLC). Adaptive
Groundwater is a highly-scalable, three-dimensional numerical code for high-resolution simulation of
groundwater flow and solute transport problems. Dynamic adaptive mesh refinement (AMR) and multithreading are used to automatically generate unstructured grids to handle multiple scales of flow and
transport processes. This is done by translating and adding/ removing telescoping levels of progressively
finer subgrids during simulation (https://www.rockware.com/product/overview.php?id=329).
Groundwater Flow, Contaminant Transport, and Biodegradation Model, Feasibility Study and Natural
Attenuation Assessment, Estes Landfill Site, Phoenix, AZ (MACTEC). Doug developed three-dimensional
groundwater flow and contaminant transport models to simulate current and future, long-term TCE, cis 1,2DCE, and vinyl chloride (VC) concentrations in the sand and gravel, overburden aquifer at the Estes
Landfill site. He used MODFLOW and MT3D99 to simulate chemical transport and fate mechanisms,

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including advection, dispersion, dilution by surface water, sorption to soil, and TCE>DCE>VC
biotransformation modeled as a sequential, first-order decay-chain process. He computed site
biotransformation rates from historical chemical data and transport model calibration. He demonstrated
that natural attenuation was a viable remedial alternative, primarily due to significant source-area VOC
depletion and high biodegradation rates (reductive dechlorination and direct oxidation of DCE and VC).
Combined MTCA RI/FS and RCRA RFI/CMS Plus Independent Cleanup Actions, Confidential Metals
Manufacturing Facility, WA (Hart Crowser). As the Hydrogeologist and Technical Lead for PCB fate and
transport issues during work on this large metals manufacturing facility, Doug developed a threedimensional transport model of the PCB plume that incorporated the variation in mobility and mass fraction
of each of the 209 congeners in the PCB mixture. He constructed a three-dimensional groundwater
flow/transport model (MODFLOW/MT3D99) to analyze the capture zones and effluent concentration
variations for multiple extraction wells with various screened-interval depths. He investigated PCB
contamination sources at the site, including industrial wastewater transfer line leaks and
unsaturated/saturated zone water contact with contaminated soils.
Doug also developed an innovative two-dimensional, rate-limited PCB congener and colloid transport
model to evaluate fate and transport mechanisms at the site. The model simulates the transport of all 209
PCB congeners simultaneously, both as aqueous-phase (i.e., dissolved in groundwater) and colloidal
(sorbed to mobile colloids flowing with the groundwater) fractions. Colloid filtration due to interactions
with the porous media is included. Because of the high groundwater velocities at the site, the model also
incorporates rate-limited soil to groundwater chemical partitioning (nonequilibrium chemical sorption) and
nonequilibrium groundwater to colloid PCB sorption mechanisms.
Remedial Design and Natural Attenuation Modeling, Savage Municipal Water Supply Superfund Site,
Milford, NH (MACTEC). Doug developed three-dimensional groundwater flow and solute transport
models of this extensive drinking water aquifer using MODFLOW and MT3D. DNAPL releases (PCE and
TCA) caused groundwater contamination. Doug directed evaluation of data collected during field
permeability testing, monitoring well sampling, and extensive vertical groundwater profiling using
microwells. He modeled the effectiveness of various remedial design alternatives that included soil
excavation and hydraulic containment in the source area, hydraulic control of downgradient portions of the
PCE and TCA plumes, and natural attenuation due to biodegradation, natural groundwater flushing, and
dilution by rainwater and river recharge. Doug estimated biodegradation rates using 1) long-term
measurements of VOC concentration reductions along the plume centerline, 2) comparisons of parent to
daughter compound concentrations, and 3) computations of total VOC mass reductions in the aquifer. In
addition, the natural attenuation evaluation used other analytical parameters (e.g., electron acceptor
concentrations) to assess the strength of the biodegradation evidence based on the Technical Protocol for
Natural Attenuation of Chlorinated Aliphatic Hydrocarbons in Ground Water. He used the MODFLOW
model and the AQTESOLV software to analyze the pumping test data. He used AQTESOLV and the
Hantush solution for partially-penetrating wells to analyze the single-well tests.
Natural Attenuation Software Development, Risk-Based Correction Action (RBCA) Tier 2 Analyzer
(MACTEC). Doug authored the commercial software package RBCA Tier 2 Analyzer, a two-dimensional

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groundwater flow and biodegradation (transport) model. The software provides five different transport
simulation capabilities: 1) single constituent; 2) the PCE>TCE>DCE>VC sequential-decay sequence that
occurs during reductive dechlorination; 3) instantaneous BTEX biodegradation with a single electron
acceptor (oxygen); 4) instantaneous BTEX biodegradation with multiple electron acceptors (oxygen,
nitrate, iron(III), sulfate, carbon dioxide); and 5) kinetics-limited BTEX biodegradation with multiple
electron acceptors. The transport model can simulate either equilibrium or non-equilibrium (one-, two-, or
multi-site sorption) partitioning between water and soil. The software provides a design tool that can be
used for a wide variety of problems, including the analysis of remedial alternatives such as groundwater
pump and treat systems (including extraction well concentration “tailing” effects caused by slow
contaminant desorption from soil), natural attenuation evaluation, and source remediation level
determination.
Remedial Investigation and Feasibility Study (RI/FS) for the Gallups Quarry Superfund Site, Plainfield, CT
(MACTEC). Designed investigations of this former waste disposal site to evaluate the nature and extent of
groundwater and residual soil (source area) contamination. The initial field program included geophysical
surveys, a source-area soil vapor survey, installation and sampling of 50 microwells, wetlands delineation,
and surface water/sediment sampling. Doug performed three-dimensional computer visualization of the
contaminant plume based on microwell results to direct monitoring well installation. He performed twodimensional flow modeling to identify an off-site source of groundwater contamination and developed a
three-dimensional groundwater flow and chemical transport model (MODFLOW/MT3D) of the site to
facilitate the evaluation of remedial alternatives during the FS process.
Darling Hill Superfund Site Remedial Investigation and Feasibility Study (RI/FS), Lyndonville, VT
(MACTEC). As Technical Leader during the RI/FS for a municipal well field contaminated with VOCs,
Doug directed the site investigation, which focused on a disposal area upgradient of the well field and a
highly permeable sand and gravel aquifer. The investigation included geophysical investigations, a soil gas
survey, boring and well installations, groundwater sampling and analysis, air sampling, surface water and
sediment sampling, and pumping and slug tests. Doug developed a three-dimensional analytical
groundwater flow model to evaluate potential plume control at the disposal area and the municipal well
field. He also constructed a one-dimensional, numerical contaminant transport model, coupled with a
chemical leaching model of the waste disposal area, to estimate cleanup times in the regional aquifer in
response to various source control alternatives.
Evaluation of New Monitoring Well Design and Sampling Techniques to Determine Vertical Concentration
Variations in an Aquifer, Independent Research Project (MACTEC). Performed independent research to
determine new monitoring well designs and sampling techniques that can provide the necessary data to
evaluate vertical concentration variations in an aquifer. Doug developed two-dimensional, numerical
axisymmetric groundwater flow and chemical transport models to analyze time-dependent monitoring well
concentrations during sampling as a function of various vertical concentration distributions in the aquifer
and different well designs. The results of this research demonstrated that discrete intervals of monitoring
wells with long screens (e.g., 10 to 20 feet or more) can be sampled in a manner that allows both the
vertical plume location and concentration variation in the aquifer to be determined. The research also
showed that the time vs. concentration responses of a well during a sampling event lasting a few days

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exhibit characteristic shapes that can be directly related to aquifer properties and well design parameters
and the vertical concentration distribution. He computed a series of concentration vs. time "type curves,"
analogous to time-drawdown type curves for aquifer permeability tests, that can be matched with measured
time-concentration responses.
Evaluation and Recommendation of Hydrologic Models for the Department of Natural Resources,
Commonwealth of Kentucky (D’Appolonia). Doug performed an extensive analysis of hydraulic/hydrologic
simulation models for the Department of Natural Resources, Commonwealth of Kentucky. He evaluated
more than 60 hydrologic (i.e., watershed), surface water, and groundwater computer models for simulating
flow and contaminant transport that could be used in determining the potential hydrologic and
environmental impacts of coal mining operations at various locations in Kentucky. He made several code
modifications to the USACE’s STORM, Stream Hydraulics Package (SHP), and Water Quality for
River/Reservoir Systems (WQRRS) models.
Mine Inflow Evaluation for the Shell Minerals Company, IN (D’Appolonia). To evaluate groundwater
inflow rates into a 30-square mile underground coal mine in southwestern Indiana during a 30-year mine
life, Doug developed a three-dimensional computer model to simulate groundwater flow into various mine
panels from an overlying sandstone aquifer by three processes: (1) artesian flow from portions of the
aquifer outside of the mine plan area, (2) gravity drainage of water from the voids in the overlying
sandstone, and (3) infiltration through a shale layer separating the aquifer and coal seam.
Site Investigation and Hydrogeologic Study, Massachusetts Contingency Plan (MCP), Manufacturing
Facility (MACTEC). Designed an investigation to characterize the nature and extent of VOC contamination
in a shallow overburden-bedrock aquifer system underlying a manufacturing facility. The investigation
included soil vapor analysis, overburden and bedrock monitoring well installation, and permeability testing.
Doug designed an interim pump and treat system to control contaminant migration from a source area
containing PCE in the form of a NAPL.
Hydrogeologic Study and Groundwater Remediation for an Industrial Facility, NH (MACTEC). Served as
the Technical Leader during the Phase I investigation and performed data evaluation for this 70-acre
salvage yard site. The investigation included evaluation of VOC contamination in the groundwater and the
design, installation, and operation of a pump and treat system. Doug developed a two-dimensional,
axisymmetric groundwater flow model to evaluate the data from a pumping test involving a large-diameter,
partially penetrating water supply well. He performed groundwater flow modeling for the final engineering
design of the pump and treat system.
Design of Waste Disposal Facility for the U.S. Department of Energy, WV (D’Appolonia). Doug designed
the leachate collection system for a waste disposal facility that contained process waste from a proposed
solvent-refined coal preparation plant near Morgantown, West Virginia. The 800-acre-foot impoundment
consisted of two embankments approximately 60 feet in height constructed from coarse refuse, a primary
spillway system, a 5-foot clay liner beneath the impoundment, and an underdrain system directly above the
liner to reduce the liquid content of the waste and thereby decrease seepage of contaminants through the
clay blanket. He performed a detailed computer simulation of the underdrain system performance to

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determine the hydrostatic pressure reduction above the clay liner as a function of waste permeability, drain
spacing, ground slope, saturated waste depth, and drain dimensions.
Remedial Investigation/Feasibility Study (RI/FS) for Allied Chemical Company, OH (D’Appolonia). Doug
performed a groundwater contamination evaluation and remedial design study for a chemical plant
bordering the Ohio River. He developed two-dimensional groundwater flow and chemical transport models
to evaluate migration beneath a stream to a local municipal well field and computed a groundwater mass
balance to determine the percentage of site groundwater flow reaching the well field, the Ohio River, a
neighboring stream, and an adjacent property. He used the calibrated model to screen remedial alternatives
and determine cleanup levels.
Vadose Zone Flow and Transport
Vadose Zone and Hydrogeologic Modeling of Storm Water Detention Facilities, Vancouver, WA (Hart
Crowser). Doug developed a three-dimensional saturated/unsaturated groundwater flow model of a storm
water detention facility using the USGS computer program SUTRA (Saturated-Unsaturated Transport). He
dynamically linked the SUTRA code with watershed hydrology (i.e., runoff hydrograph) and detention
basin (storage and discharge rate vs. elevation) models. He modified the SUTRA code to incorporate the
hydrologic and hydraulic models as subroutines, which provided storm water runoff inflow rates and timedependent water elevations in the detention basins. Water elevations were converted to time-dependent
specified pressure node values in SUTRA. He added transient discharge rates through the porous
boundaries of the detention facilities (computed by SUTRA) to the outflow hydrographs. Doug used the
models to evaluate the impacts of several factors on the storm water detention facility performance and
design, including groundwater table mounding, hydraulic conductivity (K) heterogeneity, the ratio of
vertical to horizontal K, detention basin storage capacity, and storm event recurrence interval.
Hydrologic Impact Assessment at a Waste Isolation Pilot Plant for the U.S. Department of Energy, NM
(D’Appolonia). Evaluated potential salt removal from beneath a radioactive waste disposal facility
enclosed in a 2,000-foot-thick salt formation in southeastern New Mexico. The objective was to determine
the size and geometry of a dissolution cavity that could form beneath the facility in the next 10,000 years
due to hydraulic interaction with a water-bearing unit located 1,000 feet below. Doug evaluated potential
mechanisms for salt dissolution and migration to the underlying unit (e.g., diffusion or advection currents
produced by density differences), derived analytical equations to quantify the salt removal rate and cavity
geometries, and developed a computer model of salt transport in the water-bearing unit.
Hydrologic Impact Assessment and Vadose Zone Modeling for the Exxon Minerals Company, WI
(D’Appolonia). Evaluated potential hydrologic impacts on the groundwater and surface water regimes due
to minerals mining and the related disposal of inorganic wastes at a 400-acre site. Doug developed
site-specific computer models of saturated/unsaturated flow and transport to predict changes in groundwater
flow rates, water quality, and water levels in hydraulically-connected lakes. He used predictions
encompassing an estimated 100-year mine life to negotiate a work plan with the Wisconsin DNR.

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Remedial Investigation/Feasibility Study, Vadose Zone Modeling, and Remedial Design for a Former
Wood-Treating Facility, Olympia, WA (MACTEC). Doug directed the hydrogeologic investigation and
remedial design for this wood-treating site. The site involved tidally influenced groundwater contaminated
with polynuclear aromatic hydrocarbons (PAH), chlorinated dibenzo-p-dioxins, pentachlorophenol (PCP),
LNAPL (PCP carrier oil), and DNAPL (creosote). The investigation consisted of installation of monitoring
wells specifically designed to detect LNAPL and DNAPL, aquifer tests, long-term tidal monitoring, salt
water intrusion evaluation, aquifer water budget (infiltration) modeling, and treatability studies for
bioremediation of soil and groundwater. Doug designed a NAPL and groundwater extraction system and
developed a two-dimensional, numerical groundwater flow model as part of the groundwater extraction
system design. He performed one-dimensional unsaturated zone vapor transport modeling to estimate
leachate and soil gas flux loadings to groundwater. He used the AquiferTest software to analyze the
pumping test data and analyzed tidal variations in water-level amplitude and phase lag to evaluate hydraulic
conductivity variations.
Vapor-Phase Transport Modeling, Lipari Landfill Superfund Site, NJ (MACTEC). Doug constructed a
vertical, one-dimensional vapor (soil gas) flux model to calculate VOC emission rates from contaminated
soil downgradient of the landfill. He used the emission estimates as source terms in an atmospheric
dispersion model to compute air concentrations in the immediate vicinity of the contaminated soil and at
several downgradient receptors and used the results to estimate health risks caused by inhalation exposure.
These modeling results and health risk estimates provided the necessary data to determine excavation
depths for contaminated soil and the thickness of a soil cap that would reduce future exposures to
acceptable levels.
Health Risk Assessment, Massachusetts Contingency Plan (MCP), Auto Auction Facility (MACTEC).
Doug performed the exposure assessment for potential exposure to VOC contamination resulting from a
leaking underground fuel tank. He developed a one-dimensional, unsaturated zone, soil gas flux model for
estimating indoor air concentrations in domestic buildings overlying subsurface areas contaminated by the
spill. He also developed a two-dimensional groundwater transport model for estimating downgradient
concentrations beyond the existing monitoring network.
Development of Performance Goals for Remedial Measures, a Risk-Based Approach for a Manufacturing
Facility, OH (MACTEC). Computed exposure point concentrations for a health risk assessment to
determine performance goals for soil and groundwater remediation at a 2-acre site contaminated with
several organic chemicals. Doug was responsible for the exposure assessment that involved the
development of a groundwater transport model to perform two basic calculations: 1) rate of chemical
removal from the contaminated areas of the unsaturated zone soil, and 2) two-dimensional chemical
advection and dispersion in the shallow groundwater unit downgradient from the source area. The
computation of contaminant removal from the unsaturated zone involved a one-dimensional (vertical)
analysis of advection due to infiltration and molecular diffusion through the water and air phases of the soil.
He also calculated contaminant dilution in the sand layer using a calibrated two-dimensional (horizontal)
transport model.

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NAPL Characterization and Modeling
Petroleum Extraction System Optimization, Former Manufacturing Facility, MA (MACTEC). Developed
and calibrated a two-dimensional fuel oil flow model using the SPILLCAD software to evaluate historical
free product recovery volumes and optimize extraction well locations and oil and groundwater pumping
rates. He used the calibrated oil flow model to (i) demonstrate the effectiveness of the recovery system in
minimizing the future risk of off-site free product transport and (ii) estimate the time period required to
obtain the remedial goals for the site.
Remedial Design and Investigation, Former Manufactured Gas Plant (MGP) Site, Fort Wayne, IN
(MACTEC). Doug designed a groundwater and NAPL (coal tar) containment and collection system for this
former MGP site adjacent to a river. A sheet pile wall provided containment along the perimeter of the site,
and a trench system with collection pipes and wells collected groundwater and NAPL. Doug developed a
three-dimensional groundwater model (MODFLOW) to determine the required water levels in the various
collection trench segments to provide hydraulic control of the groundwater plume and optimize NAPL
recovery.
Remedial Design and Investigation, Former MGP Site, Hammond, IN (MACTEC). Doug designed a
NAPL (coal tar) containment system at this former MGP site to prevent NAPL migration into a river that
formed the downgradient site boundary. Doug evaluated slurry wall and sheet piling designs. He
developed a three-dimensional groundwater model (MODFLOW) of the site to evaluate optimal
containment wall designs (e.g., wing wall orientation and length) for minimizing off-site groundwater
transport of contaminants. In addition, he used the model to evaluate water level increases on the
upgradient side of the wall and potential design options (e.g., gates) to mitigate this effect.
Surface Water Modeling
Evaporation Prediction for Heated Water Bodies, Research Project for the Electric Power Research
Institute, GA (Massachusetts Institute of Technology). Evaluated the evaporative heat loss from a series of
heated (70 degrees Celsius) cooling ponds (1 to 5 acres) and canals. Doug developed a one-dimensional
hydrothermal model to evaluate the temperature distribution and the energy budgets for the system of water
bodies. He performed a literature review of evaporation prediction methods, emphasizing methods capable
of predicting combined free (thermally induced) and forced (wind) evaporative heat loss. The research
resulted in the formulation of a new evaporation equation that more accurately predicts heat loss from water
bodies for conditions, such as high water temperature, where both free and forced evaporation are
important.
Site Evaluation of Two Nuclear Power Plants for Northeast Utilities, New England (Massachusetts
Institute of Technology). Doug evaluated waste heat transport from two nuclear power generation facilities
located along the coast of New England. He developed two-dimensional numerical tidal hydrodynamic and

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thermal transport models to evaluate temperature increases in adjacent estuaries. He used the temperature
simulations to locate new water intakes and to determine heat effects on sediment biota.
Sewage Disposal Outfall Siting Study for the Massachusetts Water Resources Authority, Boston, MA
(Massachusetts Institute of Technology). Doug evaluated tidal hydrodynamics and contaminant transport in
Boston Harbor as part of the design of the new Deer Island sewage treatment plant. He used mass loading
data at the existing Deer and Nut Island treatment plants in conjunction with measured concentration
distributions for six chlorinated VOCs to calibrate dispersion coefficients and first order surface
volatilization rates for the compounds. He used current meter measurements for calibration of the twodimensional, harmonic hydrodynamic model. He simulated harbor concentrations for several planned
diffuser outfall locations using a two-dimensional, transient contaminant transport model that was linked
with the hydrodynamic model.
Estimate of Toxic Chemical Loadings to Puget Sound, Washington State Department of Ecology Toxics
Cleanup Program, WA (Hart Crowser). Doug was the Technical Director assisting Ecology with a multiyear effort to develop strategies, remedial actions, and performance measures to protect and restore the
overall health of the Puget Sound ecosystem. He identified toxic chemicals of concern and characterized
contaminant sources and pathways (e.g., stormwater runoff, municipal/industrial wastewater effluents,
groundwater discharge, chemical spills, and atmospheric deposition). For each of the 17 chemicals of
concern, Doug estimated average annual rates of mass loading (runoff rates and stormwater concentrations)
to Puget Sound via each pathway. He developed a probabilistic approach to characterizing data uncertainty
that involved computing cumulative probability distributions for each mass loading pathway.
Surface Water Quality Impact of Treatment System Effluent, Industri-Plex Trust, Superfund Site, Woburn,
MA (MACTEC). Developed two-dimensional hydrodynamic and contaminant transport models of a 10-acre
impoundment to evaluate water quality impacts of the treatment system effluent from a series of
groundwater extraction wells. Both organic (VOC) and inorganic contaminants were present in the waste
stream. Steady-state hydrodynamic simulations, qualitatively verified by field observations, provided an
understanding of the velocity distribution in the impoundment that was a function of both tributary and
treatment system inflows and large water depth variations of 5 to 20 feet. Doug incorporated depthaveraged contaminant concentration distributions computed using the transport model in an aquatic impact
assessment designed to determine preferred effluent discharge locations and rates.
Surface Water Quality Impact of Dam Breach, Bangor Hydroelectric, ME (MACTEC). Doug developed a
numerical, one-dimensional dissolved oxygen transport model to evaluate receiving water quality impacts
from hydrodynamic changes caused by the breaching of a dam in a large river system. He used the
USACE’s stream hydraulics model HEC-1 to simulate river stage and velocity for a range of breach
elevations and stream flow rates. For each flow field the transport model provided estimates of dissolved
oxygen changes in the river system. These results demonstrated the beneficial effects of leaving the dam in
place.
Sedimentation and Erosion Control Plan Design for DuPont, SC (D’Appolonia). Designed the
sedimentation and erosion control plan for a 200-acre site disturbed during construction of a waste

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processing facility. Evaluations included calculation of storm runoff hydrographs, the design of three
sedimentation basins with heights ranging from 10 to 20 feet and storage capacities of 3 to 5 acre-feet,
hydraulic design of primary and emergency spillways for the basins, specification of diversion ditch
locations and sizes, and design of various other erosion control measures.

Research
Research Assistant, School of Earth Sciences, The Ohio State University, Columbus, OH, 2003 – 2006.
• Dissertation: Numerical Investigation of Field-Scale Convective Mixing Processes in Heterogeneous,
Variable-Density Flow Systems Using High-Resolution Adaptive Mesh Refinement Methods.
Advisor: Motomu Ibaraki.
• Ph.D. Research: Developed new adaptive simulation software for high-resolution, field-scale modeling
of non-linear, variable-density ground water flow systems. Examined practical problems such as in situ
chemical oxidation of contaminants by dense treatment fluids, water supply applications such as
freshwater storage and recovery in coastal aquifers, and saltwater intrusion assessments. The software
automatically adjusts to multiple scales of convective mixing processes by translating and
adding/removing telescoping levels of progressively finer subgrids to maintain a specified numerical
accuracy throughout the global simulation domain. Adaptive mesh refinement methods and higherorder Eulerian-Lagrangian discretization schemes were used to construct a three-dimensional flow and
transport code capable of simulating fine-scale (~1-10 cm) instability development and resulting
convective mixing in field-scale variable-density ground water flow systems. Because the flow and
transport solutions for each subgrid are computed independently, field-scale simulations are broken into
multiple smaller problems that can be modeled more efficiently and with finer detail.
Convective mixing in heterogeneous porous media is shown to be more amenable to prediction than
previously concluded. Convective mixing rates are related to the geostatistical properties of the aquifer
(variance and mean of the log permeability distribution, horizontal and vertical correlation scales), the
fluid density difference, the magnitude of local small-scale dispersion, the effects of different
permeability field realizations, the injection well size and orientation, hydraulic parameters such as
injection rate and regional hydraulic gradient, and the spatial resolution. Further, three-dimensional
fluid mixing rates are related to mathematical expressions for density-dependent macrodispersivity that
are based on stochastic flow and solute transport theory.
•

Colloid transport modeling: Simulated colloid and radionuclide injection experiments for fracturedrock test site in Switzerland. Used two-dimensional finite element code COLFRAC (flow and transport
of colloids and contaminants in discretely-fractured porous media) to perform sensitivity analyses
involving: fracture aperture, spacing, connectivity; secondary permeability and diffusion rate in rock
matrix; equilibrium and kinetic radionuclide sorption parameters for colloids and fracture walls;
longitudinal dispersivity; colloid filtration coefficient; and radionuclide decay rate.

Research Assistant, Department of Civil & Environmental Engineering, Massachusetts Institute of
Technology, Cambridge, MA, 1984 – 1987.
• Areas of Specialization: Hydraulics/hydrology, surface water heat transport mechanisms, heat transfer
in unstable atmospheric boundary layers, tidally- and density-driven flow/transport, chemical
fate/transport, numerical methods (finite element, finite difference, Eulerian-Lagrangian).
• Thesis: Evaporation from Heated Water Bodies, Predicting Combined Forced Plus Free Convection.
Advisor: Eric Adams. Constructed hydrothermal model to compute evaporative heat loss from 70o C
cooling ponds and canals based on simulated temperature distributions and energy budgets.

 Douglas J. Cosler, Ph.D., P.E. - Page 13 of 15

•

•

Formulated new evaporation equation that more accurately predicts heat loss from heated water bodies
for conditions where both free and forced evaporation are important.
Surface water modeling: Analyzed tidal hydrodynamics and contaminant transport in Boston Harbor
and Massachusetts Bay for design of new Deer Island sewage treatment plant. Constructed twodimensional, finite element hydrodynamic (harmonic) flow and Eulerian-Lagrangian transport models
to evaluate mixing of treatment plant effluent for alternative multi-port diffuser designs and locations.
Hydrothermal modeling: Developed two-dimensional finite element, tidal hydrodynamic and thermal
transport models to evaluate waste heat transport in estuaries for two nuclear power generation
facilities.

Research Assistant, Department of Civil & Environmental Engineering, The Ohio State University,
Columbus, OH, 1977 – 1979.
• Areas of Specialization: Turbulent transport processes, hydraulics/hydrology, numerical methods.
• Thesis: Numerical Simulation of Turbulence in a Wind-Driven, Shallow Water Lake. Advisor: Keith
Bedford. Developed three-dimensional hydrodynamics code (finite difference) using large-eddy
simulation techniques. Evaluated energy cascade process for turbulent flows in lakes through spectral
analysis of velocity fluctuation time series.
Independent Research, 1990 – 2002.
• Effects of Rate-Limited Mass Transfer, Vertical Concentration Distribution, and Well Design on
Ground-Water Sampling and Remediation: Constructed numerical axisymmetric flow and
nonequilibrium (multi-rate) transport models to simulate monitoring/extraction well concentrations as a
function of plume shape and well design. Showed how sample concentration variations with time can
be used to determine vertical concentration distributions in plumes and aquifer properties such as
vertical anisotropy ratio, porosity, retardation factor, and soil-water mass transfer parameters.
• Commercial Contaminant Transport and Biodegradation Modeling Software: Author of the RiskBased Correction Action (RBCA) Tier 2 Analyzer, a two-dimensional ground water flow,
nonequilibrium (multi-rate) transport, and biodegradation model. Software is based on EulerianLagrangian solution of transport equation with alternating direction implict (ADI) technique for
dispersion, and fourth-order Runge-Kutta scheme for PCE decay chain and BTEX biodegradation
terms.

Teaching
Instructor, School of Earth Sciences, The Ohio State University, Columbus, OH, 2006.
• Instructor for graduate-level courses in hydrogeology and environmental risk assessment, and
undergraduate courses in hydrology and water resources.
Teaching Assistant, School of Earth Sciences, The Ohio State University, Columbus, OH, 2003-2006.
• Taught several class sessions of graduate-level courses in hydrogeology and environmental risk
assessment, and an undergraduate course in water resources. Assisted in the preparation of lecture
materials and homework assignments, developed class projects involving field applications, and guided
group discussions among students during classes.
• Instructor for laboratory sessions of class in earth sciences and water resources. Prepared review
materials and lectured on fundamental concepts, and directed students during laboratory exercises.
Mathematics Tutor, Boston Partners in Education, Boston, MA, 2001.

 Douglas J. Cosler, Ph.D., P.E. - Page 14 of 15

•

Served as volunteer tutor for high school students in Boston Public School system. Taught individual
studies mathematics course in preparation for Massachusetts Comprehensive Assessment System
(MCAS) proficiency tests.

Teaching Assistant, Department of Civil & Environmental Engineering, Massachusetts Institute of
Technology, Cambridge, MA, 1984 – 1987.
• Instructed laboratory sessions of undergraduate fluid mechanics course. Conducted laboratory
demonstrations and directed students during experiments using various fluid mechanics apparatus. Led
field trip to conduct a stream tracer study and evaluate stream hydraulics and dispersion characteristics.
Engineering Tutor and Coordinator, College of Engineering, The Ohio State University, 1974 – 1977.
• Tutored undergraduate engineering students in mathematics, physics, chemistry, and engineering
mechanics. Served as student program coordinator responsible for evaluating undergraduate
educational requirements, and tutor assignments and schedules.
PUBLICATIONS
Cosler, D.J. 2006.
Numerical Investigation of Field-Scale Convective Mixing Processes in
Heterogeneous, Variable-Density Flow Systems Using High-Resolution Adaptive Mesh Refinement
Methods. Ph.D. Dissertation, The Ohio State University, School of Earth Sciences, Columbus, Ohio.
Cosler, D.J. 2004*. Effects of Rate-Limited Mass Transfer on Water Sampling with Partially Penetrating
Wells. Ground Water 42, no. 2: 203-222.
Cosler, D.J. 2000. Risk-Based Correction Action (RBCA) Tier 2 Analyzer, Two-Dimensional
Groundwater Flow and Biodegradation Model, Ref. Manual. Waterloo Hydrogeologic, Inc., Waterloo,
Ontario, Canada.
Cosler, D.J. 1997*. Ground-Water Sampling and Time-Series Evaluation Techniques to Determine
Vertical Concentration Distributions. Ground Water 35, no. 5: 825-841.
Adams, E.E. and Cosler, D.J. 1990*. Evaporation from Heated Water Bodies: Predicting Combined
Forced Plus Free Convection. Water Resources Research 26, no. 3: 425-435.
Adams, E., Kossik, R., Cosler, D., MacFarlane, J., and Gschwend, P. 1990. Calibration of a Transport
Model Using Halocarbons. Estuarine and Coastal Modeling, M.L. Spaulding, ed., ASCE, New York,
N.Y., pp. 380-389.
Andrews, D.E. and Cosler, D.J. 1989*. Preventing and Coping with Water Pollution. Journal of Testing
and Evaluation, ASTM 17, no. 2: 95-105.
Walton, R., Kossik, R., Adams, E., and Cosler, D. 1989. Far-Field Numerical Model Studies for Boston's
New Secondary Treatment Plant Outfall Siting. Third National Conference on Hydraulic Engineering,
New Orleans, Louisiana, August 14-18.
Adams, E.E. and Cosler, D.J. 1988*. Density Exchange Flow Through a Slotted Curtain. Journal of
Hydraulic Research 26, no. 3: 261-273.
Adams, E.E. and Cosler, D.J. 1987. Predicting Circulation and Dispersion Near Coastal Power Plants:
Applications Using Models TEA and ELA. Massachusetts Institute of Technology Energy Laboratory
Report No. MIT-EL 87-008, 113.
Adams, E.E., Cosler, D.J., and Helfrich, K.R. 1987. Evaporation from Heated Water Bodies: Analysis of
Data from the East Mesa and Savannah River Sites. Civil Engineer Degree Thesis, Massachusetts
Institute of Technology, Cambridge, Massachusetts.
Cosler, D.J. and Snow, R.E. 1984*. Leachate Collection System Performance Analysis. Journal of
Geotechnical Engineering, ASCE 110, no. 8: 1025-1041.
Snow, R.E. and Cosler, D.J. 1983. Computer Simulation of Ground Water Inflow to an Underground
Mine. In Proceedings of the First Conference on Use of Computers in the Coal Industry, AIME, (Y.J.
Wang and R.L. Sanford editors), pp. 587-593. W. Virginia University, August 1-3.

 Douglas J. Cosler, Ph.D., P.E. - Page 15 of 15

Cosler, D.J. 1979. Numerical Simulation of Turbulence in a Wind-Driven, Shallow Water Lake. M.S.
Thesis, The Ohio State University, Columbus, Ohio.
*

Denotes peer-reviewed journal.

PRESENTATIONS
Cosler, D.J. 2015. An Intelligent Graphical User Interface for MODFLOW and MT3D based on
Dynamic Adaptive Mesh Refinement Methods. MODFLOW and More 2015 Conference.
Colorado School of Mines, Golden, Colorado, May 31 - June 3.
Cosler, D.J. 2013. Numerical Simulation of Multiscale Transport Processes in Variable-Density Flow
Systems Using High-Resolution Adaptive Mesh Refinement Methods. MODFLOW and More 2013
Conference. Colorado School of Mines, Golden, Colorado, June 2-5.
Cosler, D.J. 2006. Numerical Investigation of Field-Scale Convective Mixing Processes in Heterogeneous,
Variable-Density Flow Systems Using High-Resolution Adaptive Mesh Refinement Methods.
Geological Society of America Annual Meeting, October 22-25, Philadelphia, Pennsylvania.
Cosler, D.J. and Ibaraki, M. 2006. Numerical Investigation of Multiple-, Interacting-Scale VariableDensity Ground Water Flow Systems. American Geophysical Union, Western Pacific Geophysics
Meeting, July 24-27, Beijing, China.
Cosler, D.J. and Ibaraki, M. 2005. Numerical Investigation of Multiple-, Interacting-Scale VariableDensity Ground Water Flow Systems. Geological Society of America Annual Meeting, October 16-19,
Salt Lake City, Utah.
Cosler, D.J. 2003. Modeling the Effects of Multirate Mass Transfer on Water Sampling with PartiallyPenetrating Wells. Geological Society of America Annual Meeting, November 2-5, Seattle,
Washington.

 Expert Report of Philip Bedient, P.E.

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, Ph.D., P.E.
P.B. Bedient and Associates, Inc.
P.O. Box 1892
Houston, Texas 77251
713-303-0266

Amended
13 April 2016

 13 April 2016
REMEDIATION OF SOIL AND GROUNDWATER
AT THE
CLIFFSIDE STEAM STATION
OPERATED BY DUKE ENERGY CAROLINAS, LLC
MOORESBORO, NORTH CAROLINA
TABLE OF CONTENTS

1.0

Introduction ........................................................................................................................ 1
1.1
1.2

2.0

Summary of the HDR CSA ............................................................................................... 2
2.1
2.2
2.3
2.4

3.0

Excavation and Removal .................................................................................................... 5
Cap-In-place........................................................................................................................ 5

Opinions .............................................................................................................................. 5
4.1
4.2

4.3

5.0

Physical Setting................................................................................................................... 2
Hydrogeology ..................................................................................................................... 3
Cliffside Coal Ash Basins and Coal Combustion Products (CCP) Landfill ....................... 3
Contamination..................................................................................................................... 4

Efficacy of Remedial Options for Coal Ash Contaminants Evaluated by HDR .......... 4
3.1
3.2

4.0

Summary of Opinions ......................................................................................................... 1
Qualifications ...................................................................................................................... 2

The groundwater flow and transport model developed by HDR to evaluate
remediation scenarios at the site is fundamentally flawed. ................................................. 5
The remediation scenarios evaluated by HDR will not prevent coal ash
contaminants from migrating across the compliance boundary and into the Broad
River for the foreseeable future. ......................................................................................... 6
Successful remediation of groundwater will require excavation and removal
coupled with hydraulic groundwater containment. ............................................................. 7

References ........................................................................................................................... 7

Remediation of Soil and Groundwater
Cliffside Steam Station, Belmont, NC

i

Expert Opinion of
Philip B. Bedient, Ph.D., P.E.

 13 April 2016

REMEDIATION OF SOIL AND GROUNDWATER
AT THE
CLIFFSIDE STEAM STATION
OPERATED BY DUKE ENERGY CAROLINAS, LLC
BELMONT, NORTH CAROLINA

1.0

Introduction

I was retained on this project for the purpose of evaluating remediation of soil and groundwater
at the Duke Energy Carolinas, LLC (Duke) Cliffside Steam Station (the “site”) coal ash disposal
facilities. In particular, I have focused my analysis on different methods of preventing continued
transport of coal ash contaminants across the compliance boundary in groundwater at
concentrations that exceed relevant groundwater standards. The compliance boundary 1 is the
regulatory boundary established for measuring compliance with applicable water quality
standards by the North Carolina Department of Environmental Quality (NCDEQ). The relevant
standards are:
•

15A NCAC 02L.0202 Groundwater Quality Standards (2L Standards); and,

•

15A NCAC 2L.0202(c) Interim Maximum Allowable Concentrations (IMACs)
established by the NCDEQ, which apply to groundwater locations beyond the limits of
the ash basins.

My opinions are based on my professional experience in hydrogeology, environmental
engineering, hydrology and hydraulics, and review of relevant data, maps, aerials, documentation
to date, and are subject to change if and when additional information becomes available.
1.1

Summary of Opinions

It is my opinion that:
•

The groundwater flow and transport model developed by HDR to evaluate remediation
scenarios at the site is fundamentally flawed.

•

The cap-in-place remediation scenario evaluated by HDR will not cause groundwater
standards to be met inside the compliance boundary, cause groundwater standards to be
met beyond the compliance boundary, prevent coal ash contaminants from migrating
across the compliance boundary, or prevent migration into Suck Creek and the Broad
River for the foreseeable future.

•

Successful remediation of groundwater will require excavation and removal coupled with
additional measures, such as hydraulic groundwater containment.

1

My references to the compliance boundary mean the compliance boundary as drawn by HDR in the CSA (HDR,
2015a). My references do not imply that I believe that the compliance boundary drawn by HDR is correct.

Remediation of Soil and Groundwater
Cliffside Steam Station, Mooresboro, NC

1

Expert Opinion of
Philip B. Bedient, Ph.D., P.E.

 13 April 2016

1.2

Qualifications

My educational background, research and professional experience, and the review of documents
and models provided are the basis of my opinions. I hold the Ph.D. degree from the University of
Florida in Environmental Engineering Sciences, and I have attached a curriculum vita including
a list of peer-reviewed publications. I am the professor of Civil and Environmental Engineering
at Rice University, where I have been on faculty since 1975, and teach courses in hydrology,
floodplain analysis and modeling, and courses in groundwater hydrology, contaminant transport,
and transport modeling. My textbook entitled “Hydrology and Floodplain Analysis” is one of the
top texts used at over 75 universities in the U.S. I have also written a textbook entitled “Ground
Water Contamination Transport and Remediation.” I am currently the Herman Brown Professor
of Engineering, a Fellow of ASCE, and a Diplomat of the American Academy of Water
Resources Engineers. I am a registered professional engineer in Texas.
Groundwater Contamination and Remediation
I have been actively involved in groundwater contamination and remediation studies for many
years. I was principle investigator (PI) on a major EPA-funded study of Hill Air Force base in
the late 1990s where comparison tests for various remediation of Dense Non-Aqueous Phase
Liquids (DNAPLs) were performed. In the 1990s, I was a member of the EPA National Center
for Groundwater Research, and I held the Shell Distinguished Chair in Environmental Science
for my efforts in developing biodegradation models in the subsurface. Between 1999 and 2002, I
had the opportunity to work on the remediation of MTBE spills sites in Texas and California.
From 2000-2003, I worked on chlorinated solvent impacts and remediation strategies through a
study funded by EPA. More recently, I evaluated the impact of ethanol on groundwater and
various remediation methods on an API-funded study from 2003-2007.
I have worked on groundwater contamination and remediation litigation at more than 30 waste
sites nationwide. These sites include DOW Chemical and Vista Chemical in Louisiana; Conroe
Creosote, Brio, Texas Instruments and San Jacinto Waste Pits in Texas; Raytheon in Florida;
coal ash sites in North Carolina; BF Goodrich in California; and an Amoco site in Missouri.
My experience with groundwater contamination and remediation at military sites include Coast
Guard facility in Michigan, Eglin, Hill and Kelly Air Force Bases.

2.0

Summary of the HDR CSA

The information related in this summary is derived from the HDR Comprehensive Site
Assessment report and CAP Part 1 and Part 2 report (CSA; HDR, 2015a; HDR, 2016). I have
noted in this section where my interpretation of the CSA data differs from HDR’s, and the basis
for those differing interpretations are provided in my technical opinions.
2.1

Physical Setting

Duke Energy owns and operates the Cliffside Steam Station (CSS) which is located in
Moorseboro, North Carolina. Operation as a coal-fired generating station began at CSS in 1940

Remediation of Soil and Groundwater
Cliffside Steam Station, Mooresboro, NC

2

Expert Opinion of
Philip B. Bedient, Ph.D., P.E.

 13 April 2016

(HDR, 2015). CSS was once a 6-unit operating station. In 2011, Units 1 through 4 were retired
while Units 5 and 6 continue to operate.
2.2

Hydrogeology

The CSS site is located in the Inner Piedmont within the Cat Square terrane, which is one of a
number of tectonostratigraphic terranes that have been defined in the southern and central
Appalachians (HDR, 2015). According to the Corrective Action Plan (CAP) Part I, the Cat
Square Terrane is bounded by the younger-over-older Brindle Creek fault to the west that places
the terrane over the Tugaloo terrane of the Inner Piedmont and the Central Piedmont suture to the
east. The terrane is characterized by gentle dipping structures and low-angle thrust faulting and
sillimanite and higher amphibolite grade metamorphism (HDR, 2015).
The fractured bedrock is overlain by a mantle of unconsolidated material known as regolith
(HDR, 2015). According to the CAP Part I, the regolith includes residual soil and saprolite
zones, and where present, alluvial deposits. Saprolite, the product of chemical weathering of the
underlying bedrock, is typically composed of clay and coarser granular materials (HDR, 2015).
According to the CAP Part I, the groundwater system is a two medium system generally
restricted to the local drainage basin. The groundwater occurs in a system composed of two
interconnected layers: residual soil/saprolite and weather rock overlying fractured metamorphic
rock separated by a transition zone (TZ). Typically, the residual soil/saprolite is partially
saturated and the water table fluctuates within it; water movement is generally preferential
through the weathered/fractured bedrock of the TZ (i.e., zone of higher horizontal permeability)
(HDR, 2015). According to HDR, the character of the system results from the combined effects
of the rock type, fracture system, topography, and weathering. Topography exerts an influence
on both weathering and the opening of fractures, while the weathering of the crystalline rock
modifies both transmissive and storage characteristics (HDR, 2015).
The geologic and hydrogeological features influencing the migration, chemical, and physical
characteristics of contaminants are related to the Piedmont hydrogeologic system present at the
site (HDR, 2015). According to the CSA, the direction of the migration of the contaminants is
towards Suck Creek and the Broad River.
According to HDR, groundwater under CSS site flows horizontally generally toward the north
and discharges to the Broad River. Groundwater flow that is to the west of the active ash basin
and east of Unit 6 flows toward Suck Creek which discharges to the Broad River (HDR, 2015).
2.3

Cliffside Coal Ash Basins and Coal Combustion Products (CCP) Landfill

According to HDR, coal ash residue and other liquid discharges from CSS’s coal combustion
process have been disposed of in the ash basin system located both west and east-southeast from
the station and adjacent to the Broad River.
As referenced in the CAP Part I, coal ash residue is conveyed to the active ash basin system at
the plant and is used to settle and retain ash generated from coal combustion at CSS. The ash
basin system is located adjacent to the Broad River and consists of the active ash basin, the Units
Remediation of Soil and Groundwater
Cliffside Steam Station, Mooresboro, NC

3

Expert Opinion of
Philip B. Bedient, Ph.D., P.E.

 13 April 2016

1-4 inactive ash basin, and the Unit 5 inactive ash basin, all of which are unlined (HDR, 2015).
According to HDR, the Units 1-4 inactive ash basin was converted into holding cells for storm
and plant process water. Two unlined ash storage areas are also located north and adjacent to the
active ash basin (HDR, 2015). During operation of the coal-fired units, the active ash basin
receives variable inflows from the ash removal system and other permitted discharges. Currently,
the active ash basin is permitted to receive variable inflows from the Unit 5 fly ash handling
system, Unit 5 bottom ash handling system, cooling tower blowdown, stormwater runoff from
yard drainage, coal pile runoff, gypsum pile runoff, limestone pile runoff, landfill leachate, and
wastewater streams generated from emission monitoring equipment (HDR, 2015).
Duke Energy also owns and operates the Cliffside Steam Station Coal Combustion Products
(CCP) Landfill (HDR, 2015). The CCP landfill is located nearly a mile southwest of the CSS on
Duke Energy property entirely within Rutherford County (HDR, 2015). According to the CAP
Part I, the CCP landfill is permitted to receive fly ash, bottom ash, boiler slag, mill rejects, flue
gas desulfurization sludge, gypsum, leachate basin sludge, nob-hazardous sandblast material,
limestone, ball mill rejects, coal, carbon, sulfur pellets, cation and anion resins, sediment from
sumps, and cooling tower sludge generated by Duke Energy North Carolina coal-fired facilities,
including from CSS.
2.4

Contamination

The CAP Part I assembled by HDR uses the term COI to describe any parameter that exceeded
its applicable regulatory standard or criteria. Review of laboratory analytical results within the
CAP Part I identified eight COIs including arsenic, barium, boron, cobalt, iron, manganese,
selenium, and vanadium. COIs identified in pore water in the ash basins and ash storage area
included antimony, arsenic, boron, cobalt, iron manganese, pH, sulfate, thallium, vanadium, and
TDS (HDR, 2015).
According to the CAP Part I, upgradient, background monitoring wells contain naturally
occurring metals and other constituents at concentrations that exceeded their respective 2L
Standards or Interim Maximum Allowable Concentration (IMACs). The CAP Part I explains the
that some naturally occurring metals and constituents, including antimony, chromium, cobalt,
iron, manganese, and vanadium were all detected in background groundwater samples at
concentrations greater than 2L Standards or IMACs however, groundwater monitoring data
shows concentrations of several other constituents exceeding their respective 2L Standards or
IMACS in groundwater across the site (HDR, 2015). These specific constituents with
exceedances include arsenic, barium, beryllium, boron, chromium, cobalt, lead, manganese,
nickel, sulfate, TDS, thallium, and vanadium (HDR, 2015).

3.0

Efficacy of Remedial Options for Coal Ash Contaminants Evaluated by
HDR

In its CAP Part I, HDR evaluates the effects of two remedial options on groundwater
concentrations at the compliance boundary: (1) excavation of the coal ash material, and (2) the
use of a cap to reduce leaching of contaminants to groundwater. The efficacy of these two

Remediation of Soil and Groundwater
Cliffside Steam Station, Mooresboro, NC

4

Expert Opinion of
Philip B. Bedient, Ph.D., P.E.

 13 April 2016

remediation options for the COIs present in groundwater at the Cliffside Station site is discussed
below.
3.1

Excavation and Removal

Excavation and removal would remove the source of the contamination (coal ash in all of the
basins) entirely in order to end the contamination of underlying groundwater. This process would
entail excavating coal ash from the site, loading it onto trucks or rail cars, and disposing of in a
secure landfill that is equipped with a proper liner and leachate collection system. This
remediation technique is underway at other contaminated coal ash sites in North Carolina. While
there is precedent for complete removal of the coal ash, additional, temporary protective
measures, such as the construction of sheet piles and coffer dams, would be necessary on this site
to prevent influx of groundwater and river water during excavation.
Ultimately, this remedial approach is feasible and the most effective remediation measure due to
permanent source removal. Even with coal ash removal, however, the current impacted
groundwater will exist as a constant source of contamination within the transmissive zones
beneath and adjacent to the site and to the Broad River. Additional measures will be needed to
address this residual contamination at the site. Nevertheless, excavation and removal stands as
the only remediation measure that completely removes the source of contamination and, in
conjunction with other measures described below, safeguards against future contamination.
3.2

Cap-In-place

A cap-in-place remedy utilizes a cap of low-permeability material, including clay and/or
synthetic liners, to reduce the rate of water infiltration into the underlying coal ash. The cap may
be equipped with an underdrain system to capture even small amounts of water that infiltrates
through the cap material. In systems where contaminants are relatively fast-moving or
biodegradable, capping provides more time for the chemicals to become degraded, protecting
potential receptors downgradient.
Cap-and-treat technology is also limited, however. Where contaminants exist in thick material
that contains substantial water, continued leaching of contaminants to groundwater may occur,
even with reduced infiltration. These materials can serve as a long-term source of groundwater
impacts.

4.0

Opinions

Based on my review of the available reports and analysis of other data received to date, my
opinions are, to a reasonable scientific certainty, the following:
4.1

The groundwater flow and transport model developed by HDR to evaluate
remediation scenarios at the site is fundamentally flawed.

The groundwater flow model developed for Duke has been constructed so that only one pattern
of groundwater flow is possible; flow from the south site boundary northward to the Broad

Remediation of Soil and Groundwater
Cliffside Steam Station, Mooresboro, NC

5

Expert Opinion of
Philip B. Bedient, Ph.D., P.E.

 13 April 2016

River. This effect is the result of the choice of hydraulic boundary conditions in the model,
which can only result in this groundwater flow pattern.
No-flow boundaries to the west and east are not realistic and pre-define the groundwater flow
direction. The flow model developed for Duke allows groundwater to flow only generally
northward, from the coal ash basins into the Broad River. The no-flow boundaries to the west
channel this flow and pre-establish the flow direction. This a priori dictation of flow direction
limits the utility of the model for investigating COI transport, and inaccurate flow paths also lead
to erroneous expectations of contaminant migration pathways and mass loading to the Broad
River.
The southern boundary condition in the flow model is not technically supported. The no-flow
boundary to the south presumes that there is a groundwater divide that follows the east-west
trending ridge south of the site. There is not enough evidence to support this assumption of a
distinct groundwater divide south of the site.
The Duke model does not account for the significant pumping from wells in the vicinity of the
coal ash ponds, which would serve to divert groundwater from the direction calculated by the
flow model. Many groundwater wells near the boundaries of the flow model could affect
groundwater flow patterns, and these are not included in the CAP I model.
4.2

The remediation scenarios evaluated by HDR are inadequate.

The cap-in-place remediation scenario evaluated by HDR will not cause groundwater standards
to be met inside the compliance boundary, cause groundwater standards to be met beyond the
compliance boundary, prevent coal ash contaminants from migrating across the compliance
boundary, or prevent migration into Suck Creek and the Broad River for the foreseeable future.
The CAP I prepared for Duke by HDR (HDR, 2015b) is not effective in addressing or mitigating
the groundwater contamination occurring at this site as a result of the leakage of coal ash
contents from coal ash disposal at the Cliffside Station. In Appendix C of the CAP (HDR,
2015b), Duke acknowledges that under the cap-in-place scenario, many COIs will remain above
groundwater cleanup standards at the Broad River compliance boundary after 250 years. This
conclusion is reached even when the soil-water partitioning coefficient (Kd) values for metals
were significantly reduced during model calibration. Setting the Kd values equal to those
determined in laboratory studies would result in much slower contaminant migration and more
persistent exceedances at all compliance boundaries because of the much slower release of
adsorbed COIs into groundwater. Of course, remediation measures that fail to meet groundwater
standards beyond the compliance boundary will also fail to restore groundwater to the required
standards within the compliance boundary.
In the CAP Part 2 report (HDR, 2016), the cap-in-place scenario does not reduce a single COI
concentration to below the groundwater standards after 100 years.

The excavation and removal option would perform better than the cap-in-place option, as
acknowledge by HDR in the CAP (HDR, 2015b). However, even under the excavation and
removal scenario, several COIs are all projected to remain above cleanup standards at the Broad
Remediation of Soil and Groundwater
Cliffside Steam Station, Mooresboro, NC

6

Expert Opinion of
Philip B. Bedient, Ph.D., P.E.

 13 April 2016

River compliance boundary after many decades. With a more appropriate value of Kd, it is likely
that other constituents would also exceed groundwater cleanup levels at the Broad River
compliance boundary.
4.3

Successful remediation of groundwater will require excavation and removal coupled
with hydraulic groundwater containment.

To eliminate ongoing migration of COIs across the compliance boundary, full excavation and
removal of the ash from the landfill and the underlying unlined coal ash pit is necessary as a first
step. The precedent for this degree of remediation is occurring currently in North Carolina
among several sites. In addition, care will need to be taken with the excavation process due to the
site’s proximity to the Broad River. This can be accomplished by means such as the construction
of sheet piles and coffer dams, or by the installation of hydraulic control wells prior to
excavation.
Excavation alone, however, will not prevent discharges of COIs to the Broad River. Because of
the significant depth of the bedrock unit and the rocky composition of the lower groundwaterbearing zones, barrier walls on the site boundaries are probably not feasible. Thus, the
implementation of additional measures will be needed in order to meet groundwater standards
under the excavation and removal approach. As a result, additional measures would need to be
implemented following coal ash removal, such as hydraulic containment to remove COIimpacted groundwater so that COIs are maintained on Duke property. Ultimately, full excavation
and removal of the ash coupled with the suggested additional measures is the most effective
remedial approach. It is important to note that pairing such additional measures with lesser
source control strategies, such as the cap-in-place option, will still not be sufficient to meet the
groundwater standards.

5.0

References

Bedient, 1997. Ground Water Contamination: Transport and Remediation. Second Addition.
Bedient, Philip B.; Rifai, Hanadi S.; Newell, Charles J. 1997.
HDR, 2015a. “Comprehensive Site Assessment Report, Cliffside Steam Station Ash Basin, HDR
Engineering,” Inc. of the Carolinas, August 23, 2015.
HDR, 2015b. “Corrective Action Plan Part 1, Cliffside Steam Station Ash Basin,” HDR
Engineering, Inc. of the Carolinas, November 20, 2015.
HDR, 2016. “Corrective Action Plan Part 2, Cliffside Steam Station Ash Basin,” HDR
Engineering, Inc. of the Carolinas, February 19, 2016.

Remediation of Soil and Groundwater
Cliffside Steam Station, Mooresboro, NC

7

Expert Opinion of
Philip B. Bedient, Ph.D., P.E.

 November 2, 2015

Philip B. Bedient, Ph.D., P.E.
Curriculum Vitae
ADDRESS:
Herman Brown Professor of Engineering
Department of Civil and Environmental Engineering
Rice University/MS - 317
6100 Main St. / Houston, Texas 77005
(713) 348-4953 or fax (713) 348-5239
Email – bedient@rice.edu
P.B. Bedient and Associates, Inc.
13910 Wilde Forest Court
Sugar Land, TX 77498
(281) 491-3911
EDUCATION:
B.S. Physics, University of Florida, Gainesville, Florida, 1969
M.S. Environmental Engineering, University of Florida, 1972
Ph.D. Environmental Engineering Sciences, University of Florida, 1975
PROFESSIONAL EXPERIENCE:
Herman Brown Professor of Engineering - Civil and Environmental Engineering- Rice
University - July 2001 to present.
Professor - Environmental Engineering - Rice University - 1986 to 2001.
Professor and Chair - Department of Environmental Science and Engineering, Rice University,
Houston, Texas, 1992 - 1999.
Associate Professor - Environmental Engineering – 1980 - 1986.
Assistant Professor - Environmental Engineering – 1975 - 1980.
SCIENTIFIC SOCIETIES:
American Society of Civil Engineers
American Institute of Hydrology
American Water Resources Association
Association of Environmental Engineering Professors
American Academy of Water Resources Engineers
American Geophysical Union

HONORS:
Diplomate - Water Resources Engineer, American Academy of Water Resources Engineers
(2008)
C.V. Theis Award from the American Institute of Hydrology (April 2007)
Fellow – American Society of Civil Engineers (April, 2006)
Endowed Chair – Herman Brown Professor in Engineering (July, 2001)
Shell Distinguished Chair in Environmental Science (1988-93)
Phi Beta Kappa
PROFESSIONAL COMMITTEES:
SSPEED Center Committee 2007-2014
Expert Panel – “Impacts of Climate Change on Transportation Systems and Infrastructure in the
Gulf Coast” USDOT and USGS, 2005 - 2006
TS Allison Recovery Project - Technical Advisory Committee - 2002-2003
Harris County Flood Control District - Brays Bayou Federal Project Com – 1998- 2002

 2

National Academy of Engineers (National Research Council)
Committee on DoE Environmental Management Technologies (CEMT) - 1995-96
Committee on In-Situ Bioremediation - 1992-93
UNIVERSITY COMMITTEES:
Undergraduate Curriculum Committee, 2005-2012
Accreditation (ABET/SACS) Committee, 2005-2012
Events and Reception Committee (Chair) 2012
Mentorship Committee 2012
Space Planning Committee, 2005-2012
CEE Student-Group Advisors 2012
BSCE Advisor 2012
Center for Civic Engagement Committee, 2007-2012
Parking Committee, 1998-2012
Search Committee, Civil and Environmental Engineering, (2001-2002)
Chair, Dean of Engineering Search Committee, (1988)
Computer Committee, Athletics Committee, 1998-2000
Advisory Council, School of Engineering,
LICENSES:
Professional Engineer, State of Texas, Environmental Engineering (45626)
Professional Hydrologist, American Institute of Hydrology
RESEARCH INTERESTS:
Floodplain Management - Analysis of effects of land use changes and development patterns on flood
hydrographs and floodplain boundaries; use of lumped and distributed hydrologic models;
detailed modeling of alternative flood control strategies and dynamic floodplain models.
Analysis of the severe storm impacts in urban watershed areas using radar rainfall data, combined
with GIS techniques for digital terrain and hydraulic modeling in Houston and other coastal areas
in Texas.
Flood Alert Systems with Radar - The development of a real-time flood ALERT system (FAS) for
Brays Bayou and the Texas Medical Center in Houston, TX has been completed. The FAS
currently uses NEXRAD radar for application to flood prediction and real-time flood alert
systems. FAS2 is a second-generation system being implemented with funding from FEMA after
TS Allison. TXDOT funded new FAS for inundated bridge crossings (2008).
Groundwater Contaminant Transport - Monitoring and modeling of groundwater hydrology and
contaminant movement from various waste sources, numerical and analytical methods for
transport with biodegradation. Development and application of tracer studies and models for
groundwater transport with biodegradation in a controlled release tank (ECRS), for studying
degradation of PCE and TCE plumes and for ethanol in fuel spills. Analysis of plume dynamics
at sites in California, Texas and Florida.
Hazardous Waste Site Evaluation - Monitoring and modeling of waste plumes associated with 35
hazardous waste sites nationally. Identification of extent of contamination, transport mechanisms,
and control strategies. MODFLOW and RT3D modeling of transport and aquifer restoration
using withdrawal-treatment and microbial degradation methods. Analysis of hazardous waste
sites in California, Texas and Florida.
COURSES and STUDENTS:
• CEVE 412 - Hydrology and Watershed Analysis
• CEVE 512 - Hydrologic Design Laboratory

 3

•
•

CEVE 101 - Fundamentals of Civil and Environmental Engineering
CEVE 415/515 - Water Resources Planning and Management (50%)

•

13 Ph.D. and 60 M.S. degrees since 1975

RESEARCH STATEMENT:
Dr. Philip B. Bedient is also Herman Brown Professor of Engineering in the Dept of Civil and
Environmental Engineering at Rice University. He teaches and performs research in surface and ground
water hydrology, disaster management, and flood prediction systems. He served as Chair of
Environmental Engineering from 1992 to 1999. He has directed 60 research projects over the past 36
years, has written over 180 articles in journals and conference proceedings. He is lead author on a text on
“Hydrology and Floodplain Analysis” (Prentice Hall, 5th ed., 2012) used in over 75 universities across
the U.S. Dr. Bedient received the Herman Brown endowed Chair of Engineering in 2002 at Rice
University. He was elected to Fellow ASCE in 2006 and received the prestigious C.V. Theis Award from
the American Institute of Hydrology in 2007. He earlier received the Shell Distinguished Chair in
Environmental Science (1988 to 1993).
He is the director of the Severe Storm Prediction Center (SSPEED) at Rice University (since
2007) consisting of a team of seven universities and 15 investigators from Gulf coast universities
dedicated to improving storm prediction, education, and evacuation from disaster. The Center was
approved by the Texas Legislature and is currently funded at over $4.5 million for 5 years from various
sources including the Houston Endowment (Hurricane Ike Lessons Learned and Future Steps). A book
has been developed and published by TAMU press titled “Lessons from Hurricane Ike” published in June
2012. The SSPEED Center has taken a zone approach to developing mitigation strategies and has
identified four zones of interest in the Houston-Galveston region: the Houston Ship Channel, West
Bayshore, Galveston Island and a Coastal Recreation Area.
Dr. Bedient has over 37 years of experience working on flood and flood prediction problems in
the U.S. He has evaluated flood issues in Texas, California, Florida, Louisiana, and Tennessee. He has
worked on some of the largest and most devastating floods to hit the U.S. including the San Jacinto River
flood of 1994, T.S. Frances in 1998, T.S. Allison in 2001, Hurricane Katrina in 2005, Hurricane Rita in
2005, Hurricane Ike in 2008, and the Nashville, TN flood of 2010. He routinely runs computer models
such as HEC-HMS, HEC-RAS, SWMM, and VFLO for advanced hydrologic analysis. He developed one
of the first radar based rainfall flood alert systems (FAS-3) in the U.S. for the Texas Medical Center.
The SSPEED Center has put on a number of conferences, meetings, and training courses since
2007. Prominent national speakers have been invited to these conferences, which include attendees from
academia, industry, consulting, and emergency managers. These conferences provide a forum for public
discussion and response for decision and policy makers, and stakeholders. As a result of this work, we
have received a large number of Rice News stories over the past several years, in the form of both video
interviews with the media as well as newspaper coverage.
Dr. Bedient has been involved in the technology transfer area for more than two decades through the
teaching of short courses for government, university, and private sectors. He has recently organized five
conferences on Severe Storm flooding and recovery projects in 2001, 2003, and 2005, 2006, and 2007 on
the Rice University campus. In 2008 he organized a new major conference on “Severe Storms Prediction
and Global Climate in the Gulf Coast” in October 2008 which hosted speakers who experienced first hand
the impacts of both hurricanes Katrina and Ike this past summer. More than 125 people attended on the
Rice campus and the conference was highlighted with over 60 talks including the keynote from the
director of the National Hurricane Center.

 4

SURFACE WATER PROJECT
“SSPEED Center Proposal to the Houston Endowment Coastal Integrated”, Houston Endowment,
2011-2014, $3,195,451
“FAS3- Operational Support”, Texas Medical Center, 2012, $69,000
“Urban Resilience: Flooding in the Houston-Galveston Area”, Kinder. 2009-2012, $240,003
“White Oak Bayou BMP Demonstration Project – Cottage Grove Subdivision”, City of Houston,
2009-2013, $165,000.
“Residential Storm Surge Damage Assessment for Galveston County”, Texas General Land
(GLO), 2012-2013, $100,000

Office

“Rice University FEMA: Food Analysis”, Rice, 2011-2012, $70,000
“Amendment to Expand Development and Validation of the Online Storm Risk Calculator Tool for
Public Usage”, City of Houston, 2011, $388,030
“Hurricane Ike: Lessons Learned and Steps to the Future”, Houston Endowment, 2009-2012,
$1,250,000
“Libya AEL Training Grant”, AECOM, 2008-2010, $1.7 million over 2 years.
“Texas OEM SSPEED Training” University of Texas, 2008, $90,000
“Watershed Information Sensing and Evaluation System”, Houston Endowment (with UH), 20072010, $400,000.
“Advanced Flood Alert System for the TXDOT for Bridge Control at 288”, HGAC, 2007-2011
$200,000.
“Civil and Environmental Engineering for the 21st Century”, NSF Dept Reform Grant, 2005-2007,
$100,000.
“CASA – Collaborative Adaptive Sensing of the Atmosphere – the Houston Testbed”, NSF, 2003 –
2009, $110,000, ($90,000 for 2006-07).
“FAS2 - Operational Support”, Texas Medical Center, 2003-2012, $69,000
.
“Flood Alert System (FAS2) for the Texas Medical Center and Brays Bayou”, FEMA, 2002-2003,
$300,000.
“Multi-Purpose Water Management Technology for the Texas Mexico Border”, Advanced
Technology Program, 2000-2001, $129,000.
“Analysis of Clear Creek Watershed,” Galveston Bay Preservation Foundation, 1999-2000, $15,000.
“Flood Alert System - Maintenance and Support”, Texas Medical Center, 1998-2002, $271,000.

 5

“Flood Prediction System for the Texas Medical Center”, Texas Medical Center, 1997-1998,
$262,000.
“The Effects of Changing Water Quality and Market Inefficiencies on Water Resource Allocation in
the Lower Rio Grande Valley”, Energy and Environmental Systems Institute, Rice University, 19961997, $12,000.
"Characterization of Laguna Madre Contaminated Sediments", Environmental Protection Agency,
1995, $68,500.
"Role of Particles in Mobilizing Hazardous Chemicals in Urban Runoff", Environmental Protection
Agency, 1992-95, $240,000. (P. B. Bedient, Co-P.I.).
"Galveston Bay Characterization Report", Galveston Bay National Estuary Program, 1991-1992,
$35,000.
"Characterization of Non-Point Sources and Loadings to Galveston Bay", Galveston Bay National
Estuary Program, 1990-1991, $125,000.
"Linkages between Sewage Treatment Plant Discharges, Lake Houston Water Quality, and Potable
Water Supply during Storm Events", City of Houston, 1984-1985, $42,200.
"Plan of Study for Upper Watershed Drainage Improvements and Flood Control - San Jacinto River
Basin", subcontract from R. Wayne Smith, Engineer, 1984-85, $120,260.
"Harris Gully Sub watershed Study", South Main Center Association, 1983-1984. $15,000.
"Sedimentation and Nonpoint Source Study of Lake Houston", Houston-Galveston Area Council,
1981-1982, $55,000.
"Environmental Study of the Lake Houston Watershed - Phase II", Houston-Galveston Area Council,
1980-1981, $30,000.
"Evaluation of Effects of Storm water Detention in Urban Areas", matching grant with City of
Houston Health Department, Office of Water Research and Technology (OWRT), Washington, D.C.,
and City of Houston Public Health Engineering, 1980-81, $116,000.
"Environmental Management of the Lake Houston Watershed", Funded by City of Houston, Dept. of
Public Health, 1978-80, $80,000.
"A Preliminary Feasibility Report for Bear Creek, Texas, Local Protection Project", Grant to
Southwest Center for Urban Research, Funded by U.S. Army Corps of Engineers, 1977-78, $47,000.
"Environmental Study of New Iberia Navigation Port and Channel, Louisiana", Funded to Rice
Center, 1979, $50,000.
"Strategies for Flood Control on Cypress Creek, Texas", Funded by U.S. Corps of Engineers,
Galveston, Texas, 1977, $9,500.
"Water Quality Automatic Monitoring and Data Management Information System", Funded by City
of Houston, Dept. of Public Health, 1977-1978, $62,414.
"Maximum Utilization of Water Resources in a Planned Community", The Woodlands Project, 19751976.

 6

GROUNDWATER PROJECTS
“A Large-Scale Experimental Investigation of the Impact of Ethanol on Groundwater
Contamination”, (P.J.J. Alvarez – Co-P.I.) American Petroleum Institute, 2004-2007, $120,000.
“A Large-Scale Experimental Investigation of the Impact of Ethanol on Groundwater
Contamination”, Gulf Coast Hazardous Substances Research Center, 2004-2005, $45,000.
“A Large-Scale Experimental Investigation of the Impact of Ethanol on Groundwater
Contamination”, Gulf Coast Hazardous Substances Research Center, 2003-2004, $95,000.
"Chlorinated Solvent Impact and Remediation strategies in the Dry Cleaning Industry”, Gulf Coast
Hazardous Substances Research Center, 2000 – 2003, $149,400.
"Design Manual for the Extraction of Contaminants from Subsurface Environments", Environmental
Protection Agency, 1994-2002, $4,500,000.
"Development of Data Evaluation/Decision Support System for Bioremediation of Subsurface
Contamination", Environmental Protection Agency, 1993-1996, $450,000.
Shell Distinguished Chair in Environmental Science, Shell Oil Company Foundation, 1988-1993,
$750,000.
"Evaluation of Nitrate-Based Bioremediation: Eglin Air Force Base", Environmental Protection
Agency, 1992-1993, $120,000.
"Decision Support System for Evaluating Remediation Performance with Interactive Pump-and-Treat
Simulator", Environmental Protection Agency, 1992-1994, $250,000.
"Characterization of Oil and Gas Waste Disposal Practices and Assessment of Treatment Costs",
Department of Energy, 1992-94, $200,000.
"Subsurface Monitoring Data for Assessing In-Situ Biodegradation of Aromatic Hydrocarbons
(BTEX) in Groundwater", American Petroleum Institute, 1991-93, $170,000.
"System 9 GIS System", Prime Computers, 1989-90, $50,000.
"Effects of Various Pumping and Injection Schemes and Variable Source Loading on Biorestoration",
American Petroleum Institute, 1988-90, $186,000.
"Parameter Estimation System for Aquifer Restoration Model", U.S. Environmental Protection
Agency, 1987-89, $400,000.
"Distribution of BIOPLUME II", National Center for Ground Water Research (EPA), 1987-88,
$40,000.
"Development and Application of a Groundwater Modeling Data Base for Hazardous Waste
Regulation", American Petroleum Institute, 1987-88, $40,000.
"Practical Procedures for Evaluating Attenuation of Ground Water Contaminants Due to
Biotransformation Process", National Center for Ground Water Research (EPA), 1986-87, $150,000.

 7

"Modeling and Field Testing of Contaminant Transport with Biodegradation and Enhanced In Situ
Biochemical Reclamation", National Center for Ground Water Research (EPA), 1985-88, $249,000.
"Ground Water Modeling for the Houston Water Plant", City of Houston, subcontracts from Law
Engineering & Testing Co., 1985-86, $127,000.
"Environmental Fate and Attenuation of Gasoline Components in the Subsurface", American
Petroleum Institute, 1984-86, $78,300.
"Simulation of Contaminant Transport Influenced by Oxygen Limited Biodegradation", National
Center for Ground Water Research (EPA), 1984-85, $25,500.
"Ground Water Pollutant Transport along Flow Lines for Hazardous Waste Sites", National Center
for Ground Water Research (EPA), 1983-85, $167,000.
"Math Models for Transport and Transformation of Chemical Substances in the Subsurface",
National Center for Ground Water Research (EPA), Subcontract from Oklahoma State University,
1982-83, $15,000.
"Characterization of Ground Water Contamination from Hazardous Waste Sites", National Center for
Ground Water Research (EPA), 1982-83, $113,000.
"Characterization of Ground Water Contamination from Hazardous Waste Sites". National Center for
Ground Water Research (EPA), 1980-82, $45,000.
PUBLICATIONS AND PRESENTATIONS
A. Books or Related Chapters

1. Fang, Z., Sebastian A., and Bedient, P.B. 2014. “Modern Flood Prediction and Warning
Systems.” Handbook of Engineering Hydrology: Fundamentals and Applications (Chapter 21),
Vol. 1, Taylor & Francis Inc. ISBN-10:1466552417.
2. Bedient, P. B. and W. C. Huber, 2012, “Hydrology and Floodplain Analysis”, 5th Ed.
Prentice-Hall Publishing Co., Upper Saddle River, NJ, February 2012, 800 page textbook.
3. Bedient, P. B., 2012 “Lessons learned from Hurricane Ike” Ed. Philip Bedient. College
Station, TX: Texas A&M University Press, College Station, TX: 2012, 194 Pages
4. Rifai H.S., Borden R.C., Newell C.J. and Bedient P.B., “ Modeling Remediation of
Chlorinated solvent plumes” In Situ Remediation of Chlorinated solvent Plumes, Chapter 6,
H.F. Stroo, C.H. Ward Editors, Springer, N.Y. 2010, 145 pp.
5.

Fang, Z., Safiolea, E., Bedient, P.B. (2006) “Enhanced Flood Alert and Control Systems for
Houston.” In Chapter 16, Coastal Hydrology and Processes, Ed. By Vijay P. Singh and Y. Jun
Xu, Water Resource Publications, LLC, pp. 199-210

6. Capiro, N.L. and Bedient P.B. "Transport of Reactive Solute in Soil and Groundwater" The
Water Encyclopedia (2005): 524-531.
7. Horsak, R.D., Bedient, P.B., Thomas, F.B., and Hamilton, C. "Pesticides”, Environmental
Forensics (2005).

 8

8. Thompson, J.F. and Bedient, P.B. “Urban Storm Water Design and Management,” The
Engineering Handbook, Chapter 94, CRC Press, 2004, 21 pp.
9. Bedient, P. B., Rifai H. S., and Newell C. J., “Ground Water Contamination: Transport and
Remediation”, 2nd Ed. PTR Publ., Upper Saddle River, NJ, 1999, 605 pages.
10. Charbeneau, R. J., Bedient, P. B. and Loehr R. C., “Groundwater Remediation”, Technomic
Publishing Co., Inc., Lancaster, PA 1992, 188 pages.

B. Peer Reviewed Journal Publications

1. Bass, B., Juan, A., Gori, A., Fang, Z., and Bedient, P.B. (2015). 1.
2015 Memorial Day
Storm Flood Impacts for Changing Watershed Conditions in Brays Bayou, Houston, TX. ASCE
Journal of Hydrologic Engineering (in-review).
2. Torres, Jacob M., Benjamin Bass, Nicholas Irza, Zheng Fang, Jennifer Proft, Clint Dawson,
Morteza Kiani, and Philip Bedient. "Characterizing the hydraulic interactions of hurricane storm
surge and rainfall–runoff for the Houston–Galveston region." Coastal Engineering 106 (2015): 719.
3. Juan, A, Fang, Z., and Bedient, P.B. "Developing a Radar-Based Flood Alert System for Sugar
Land, Texas." Journal of Hydrologic Engineering (2015).
4. Brody, S.D., Sebastian, A., Blessing, R., & Bedient, P.B. (2015). Case-study results from
southeast Houston, Texas: Identifying the impacts of residential location on flood risk and loss.
Journal of Flood Risk Management, (accepted for publication). doi: 10.1111/jfr3.12184
5. Fang, N., Dolan G., Sebastian, A., & Bedient, P.B. (2014). Case Study of Flood Mitigation and
Hazard Management at the Texas Medical Center in the Wake of Tropical Storm Allison in 2001.
ASCE Natural Hazards Review, 15(3). doi: 10.1061/(ASCE)NH.1527-6996.0000139.
6. Christian, J, Fang, Z., Torres, J., Deitz, R. and Bedient, P.B. "Modeling the Hydraulic
Effectiveness of a Proposed Storm Surge Barrier System for the Houston Ship Channel during
Hurricane Events." Natural Hazards Review 16, no. 1 (2014): 04014015
7. Burleson, Daniel W., Hanadi S. Rifai, Jennifer K. Proft, Clint N. Dawson, and Philip B. Bedient.
"Vulnerability of an industrial corridor in Texas to storm surge." Natural Hazards 77, no. 2
(2015): 1183-1203.
8. Sebastian, A., Proft, J., Dawson, C., & Bedient, P.B. (2014). Characterizing hurricane storm surge
behavior in Galveston Bay using the SWAN+ADCIRC model. Coastal Engineering, 88, 171-181.
doi: http://dx.doi.org/10.1016/j.coastaleng.2014.03.002.
9. Brody, S.D., Blessing, R., Sebastian, A., & Bedient, P.B. (2014). Examining the impact of land
use/land cover characteristics on flood losses. Journal of Environmental Planning and
Management, 57(8), 1252-1265. doi: 10.1080/09640568.2013.802228.

10. Brody, S.D., Blessing, R., Sebastian, A., and Bedient, P.B. (2013). “Delineating the Reality of
Flood Risk and Loss in Southeast, TX.” ASCE Natural Hazards Review, 14, 89-97.doi:
10.1061/(ASCE) NH.1527-6996.0000091.

 9

11. Fang, Z., Sebastian A., and Bedient, P.B. 2014. “Modern Flood Prediction and Warning
Systems.” Handbook of Engineering Hydrology: Fundamentals and Applications (Chapter 21),
Vol. 1, Taylor & Francis Inc. ISBN-10:1466552417.

12. Teague, A., J. Christian, and P. Bedient. (2013) “Use of Radar Rainfall in an Application of
Distributed Hydrologic Modeling for Cypress Creek Watershed, Texas”. Journal of Hydrologic
Engineering. DOI: 10.1061/(ASCE) HE.1943-5584.000056.
13. Doubleday, G., Sebastian, A., Luttenschlager, T., and Bedient, P.B. (2013). “Modeling
Hydrologic Benefits of Low Impact Development: A Distributed Hydrologic Model of The
Woodlands, TX.” Journal of American Water Resources, 1-13. doi: 10.1111/jawr.12095.
14. Christian, J., A. Teague, L. Dueñas-Osario, Z. Fang, and P. Bedient, (2012). “Uncertainty in
Floodplain Delineation: Expression of Flood Hazard and Risk in a Gulf Coastal Watershed.”
Journal of Hydrological Processes, doi: 10.1002/hyp.9360.
15. Ray, T., Stepinski, E., Sebastian, A., Bedient, P.B. (2011)“Dynamic Modeling of Storm Surge
and Inland Flooding in Texas Coastal Floodplain” ”, Journal of Hydraulic Engineering, ASCE,
Vol. 137, No.10, October 2011, ISSN 0733-9429/2011/10-1103-1110
16. Fang, Z., Bedient, P. B., and Buzcu-Guven, B. (2011). “Long-Term Performance of a Flood Alert
System and Upgrade to FAS3: A Houston Texas Case Study”. Journal of Hydrologic
Engineering, ASCE Vol. 16, No. 10, October 1, 2011, ISSN 1084-0699/2011/10-818-828.
17. Teague, A., Bedient, P. and Guven, B. (2010). “Targeted Application of Seasonal Load Duration
Curves using Multivariate Analysis in Two Watersheds Flowing into Lake Houston” (JAWRA10-0003-P.R1). Journal of American Water Resources Association. Accepted.
18. Fang, Z, Zimmer, A., Bedient, P. B, Robinson, H., Christian, J., and Vieux, B. E. (2010). “Using
a Distributed Hydrologic Model to Evaluate the Location of Urban Development and Flood
Control Storage”. Journal of Water Resources Planning and Management, ASCE, Vol. 136, No.
5, September 2010, ISSN 0733-9496/2010/5-597-601.
19. Fang, Z., Bedient, P. B., Benavides J.A, and Zimmer A. L. (2008). “Enhanced Radar-based Flood
Alert System and Floodplain Map Library”. Journal of Hydrologic Engineering, ASCE, Vol. 13,
No. 10, October 1, 2008, ISSN 1084-0699/2008/10-926-938.
20. Gomez, D. E., De Blanc, P. C., Rixey, W., Bedient, P.B., Alvarez, P. J.J. (2008), “Evaluation of
Benzene Plume Elongation Mechanisms Exerted by Ethanol Using RT3D with a General
Substrate Interaction Module” Water Resource Research Journal, Vol. 44, May.
21. Rifai, H.S., Borden, R. C., Newell, C. J., and Bedient, P.B. “Modeling Dissolved Chlorinated
Solvents in Groundwater and Their Remediation,” in SERDP monograph on Remediation of
Dissolved Phase Chlorinated Solvents in Groundwater, (accepted) 2007.
22. Bedient, P. B., Holder, A., and Thompson, J. F., and Fang, Z. (2007). “Modeling of Storm water
Response under Large Tailwater Conditions – Case Study for the Texas Medical Center”. Journal
of Hydrologic Engineering, Vol. 12, No. 3, May 1, 2007.
23. Capiro, N.L., Stafford, B.P., Rixey, W.G., Alvarez, P.J.J. and Bedient, P.B. "Fuel-Grade Ethanol
Transport at the Water Table Interface in a Pilot-Scale Experimental Tank" Water Research,
41(3), pp. 656-654, 2007.
24. Bedient, P.B., Rifai, H.S., Suarez, M.P., and Hovinga, R.M. “Houston Water Issues” Chapter in
Water for Texas. Jim Norwine and J.R. Giardino, Eds. pp. 107-121, 2005.

 10

25. Characklis, G.W., Griffin, R.C., and Bedient, P.B. "Measuring Long-term Benefits of Salinity
Reduction" Journal of Agricultural and Resource Economics, 30 (1) (2005): 69-93.
26. Bedient, P.B., Horsak, R.D., Schlenk, D., Hovinga, R.M., and Pierson, J.D. "Environmental
Impact on Fipronil to Louisiana Crawfish Industry" Environmental Forensics (2005): 289-299.
27. Characklis, G. W., Griffin, R.C., and Bedient, P.B. "Measuring the Long-term Benefits of
Salinity Reduction" Journal of Agricultural and Resource Economics, 30(1), pp.69-93, 2005.
28. Vieux, B.E. and Bedient, P.B. “Assessing urban hydrologic prediction accuracy through event
reconstruction” Journal of Hydrology, 299(3-4), pp. 217-236. Special Issue on Urban Hydrology,
2004.
29. Thompson, J.F. and Bedient, P.B. “Urban Storm Water Design and Management” The
Engineering Handbook, Chapter 94, CRC Press, 2004, 21 pp.
30. Capiro, N.L. and Bedient P.B. “Transport of Reactive Solute in Soil and Groundwater” The
Encyclopedia of Water, John Wiley and Sons, Inc., New York, NY, USA pp. 524-531, 2005.
31. Bedient, P.B., Holder, A., and Benavides, J. “Advanced Analysis of T.S. Allison’s Impacts”
submitted to Jn. of American Water Resources Assn., 2004.
32. Bedient, P. B., A. Holder, J. Benavides, and B. Vieux “Radar-Based Flood Warning System
applied to TS Allison, ASCE Journal of Hydrologic Engineering, 8(6), pp 308-318, Nov, 2003.
33. Glenn, S., Bedient, P.B., and B. Vieux “Ground Water Recharge Analysis Using NEXRAD in a
GIS Framework” submitted to Ground Water, October 2002.
34. Bedient, P.B., Vieux, B.E., Vieux, J.E., Koehler, E.R., and H.L. Rietz “Mitigating Flood Impacts
of Tropical Storm Allison” accepted by Bulletin of American Meteorological Society, 2002.
35. El-Beshry, M., Gierke, J.S., and P.B. Bedient “Practical Modeling of SVE Performance at a JetFuel Spill Site” ASCE Journal of Environmental Engineering pp. 630-638, (127) 7, July 2001.
36. El-Beshry, M.Z., Gierke, J.S., and P.B. Bedient “Modeling the Performance of an SVE Field
Test” in Chapter 7, Vadose Zone Science and Technology Solutions, Brian B. Looney and
Ronald W. Falta Editors, Vol. II, pp. 1157-1169, (2000).
37. Rifai, H.S., Brock, S.M. Ensor, K.B., and P.B. Bedient "Determination of Low-Flow
Characteristics for Texas Streams" ASCE Journal of Water Resources Planning and Management,
(126)5, pp.310-319, September-October 2000.
38. Bedient, P.B., Hoblit, B.C., Gladwell, D.C., and B.E. Vieux “NEXRAD Radar for Flood
Prediction in Houston” ASCE Journal of Hydrologic Engineering, 5(3), pp. 269-277, July 2000.
39. Hamed, M.M., Nelson, P.D., and P.B. Bedient “A Distributed Site Model for Non-equilibrium
Dissolution of Multicomponent Residually Trapped NAPL” Environmental Modeling and
Software, (15), pp. 443-450, September 2000.
40. Holder, A.W., Bedient, P.B., and C.N. Dawson “FLOTRAN, a Three-dimensional Ground Water
Model, with Comparisons to Analytical Solutions and Other Models” Advances in Water
Resources, pp. 517-530. 2000.
41. Rifai, H.S., Bedient, P.B., and G.L. Shorr “Monitoring Hazardous Waste Sites: Characterization
and Remediation Considerations” Journal of Environmental Monitoring, 2(3), pp. 199-212, June
2000.
42. Hoblit, B.C., Baxter, E.V., Holder, A.W., and P.B. Bedient “Predicting With Precision” ASCE
Civil Engineering Magazine, 69(11), pp. 40-43, November 1999.
43. Bedient, P.B., Holder, A.W., Enfield, C.G., and A.L. Wood “Enhanced Remediation
Demonstrations at Hill Air Force Base: Introduction” Innovative Subsurface Remediation: Field
Testing of Physical, Chemical, and Characterization Technologies, Mark L. Brusseau, et al., eds.,
pp. 36-48, American Chemical Society, Washington, DC, 1999.

 11

44. Holder, A.W., Bedient, P.B., and J.B. Hughes “Modeling the Impact of Oxygen Reaeration on
Natural Attenuation” Bioremediation Journal, 3(2): 137-149, June 1999.
45. Characklis, G.W., Griffin, R.C., and P.B. Bedient “Improving the Ability of a Water Market to
Efficiently Manage Drought” Water Resources Research, (35) 3, 823-831, March 1999.
46. Vieux, B.E. and P.B. Bedient “Estimation of Rainfall for Flood Prediction from WSR-88D
Reflectivity: A Case Study, 17-18 October 1994” Weather and Forecasting, 1998 American
Meteorological Society, 13:2, 407-415, June 1998.
47. Bedient, P.B. “Hydrology and Transport Processes” Subsurface Restoration, C.H. Ward, J.A.
Cherry and M.R. Scalf, editors, Ann Arbor Press, Chelsea, MI, 59-73, 1997.
48. Hamed, M.M. and P.B. Bedient “On the Performance of Computational Methods for the
Assessment of Risk from Ground-Water Contamination” Ground Water, 35(4), 638-646, JulyAugust 1997.
49. Hamed, M.M. and P.B. Bedient “On the Effect of Probability Distributions of Input Variables in
Public Health Risk Assessment” Risk Analysis, 17(1), 97-105, 1997.
50. Hamed, M.M., Bedient, P.B., and J.P. Conte “Numerical Stochastic Analysis of Groundwater
Contaminant Transport and Plume Containment” Journal of Contaminant Hydrology, 1996, 24
pp.
51. Hamed, M.M., Bedient, P.B., and C.N. Dawson “Probabilistic Modeling of Aquifer
Heterogeneity Using Reliability Methods” Advances in Water Resources, 19(5), 277-295, 1996.
52. Sweed, H., Bedient, P.B., and S.R. Hutchins "Surface Application System for In-Situ
Bioremediation: Site Characterization and Modeling" Groundwater Journal, 34(2), 211-222,
1996.
53. Hamed, M.M., Conte, J.P., and P.B. Bedient "Uncertainty Analysis of Subsurface Transport of
Reactive Solute Using Reliability Methods" Groundwater Models for Resources Analysis and
Management, CRC Press, Inc., Chapter 8:123-135 1995.
54. Hamed, M.M., Conte, J.P., and P.B. Bedient "Probabilistic Screening Tool for Groundwater
Contamination Assessment" ASCE Journal of Environmental Engineering, 121(11): 767-775,
(1995).
55. Rifai, H.S. and P.B. Bedient "A Review of Biodegradation Models: Theory and Applications"
Groundwater Models for Resources Analysis and Management, CRC Press, Inc., Chapter 16:295312 (1995).
56. Rifai, H. S., Newell, C. J., Bedient, P.B., Shipley, F.S., and R.W. McFarlane, The State of the
Bay, The Galveston Bay National Estuary Program, Webster, TX, 232 pp. (1994).
57. Rifai, H.S. and P.B. Bedient "Modeling Contaminant Transport and Biodegradation in Ground
Water" Advances in Environmental Science Groundwater Contamination, Volume I:
Methodology and Modeling, Springer-Verlag, New York, NY (1994).
58. Bedient, P.B. and H.S. Rifai "Modeling in Situ Bioremediation" In Situ Bioremediation, When
Does It Work?” National Academy Press, pp. 153-159 (1993).
59. Rifai, H. S., Bedient, P.B., Hendricks, L.A., and K. Kilborn "A Geographical Information System
(GIS) User Interface for Delineating Wellhead Protection" Ground Water, 31:3, pp. 480-488
(1993).
60. H. S. Rifai, Newell, C. J., and P.B. Bedient "Getting to the Nonpoint Source with GIS" Civil
Engineering, June, pp. 44-46 (1993).
61. H. S. Rifai, Newell, C. J., and P.B. Bedient "GIS Enhances Water Quality Modeling" GIS World,
August, pp. 52-55 (1993).
62. Bedient, P.B., Schwartz, F.W., and H.S. Rifai "Hydrologic Design for Groundwater Pollution

 12

Control" Handbook of Hydrology, McGraw Hill, pp. 29.1-29.47 (1993).
63. Wise, W.R., Robinson, G.C., and P.B. Bedient "Chromatographic Evidence for Nonlinear
Partitioning of Aromatic Compounds Between Petroleum and Water" Ground Water, 30(6): 936944. (Nov. - Dec. 1992).
64. Charbeneau, R.J., Bedient, P.B., and R.C. Loehr, Groundwater Remediation, Technomic
Publishing Co., Inc., Lancaster, PA, 188 pages (1992).
65. Bedient, P.B. and H.S. Rifai "Ground Water Contaminant Modeling for Bioremediation: A
Review" Journal of Hazardous Materials, 32:225-243 (1992).
66. Kilborn, K., Rifai, H.S., and P. B. Bedient "Connecting Groundwater Models and GIS" Geo Info
Systems, pp. 26-31, (February 1992).
67. Rifai, H. S. and P. B. Bedient "Modeling Contaminant Transport and Biodegradation in Ground
Water" To be published in Textbook: Advances in Environmental Science Groundwater
Contamination, Volume I: Methodology and Modeling, Springer Verlag, (In Press) (September
1991).
68. Newell, C.J., Rifai, H.S., and P.B. Bedient "Characterization of Non-Point Sources and Loadings
to Galveston Bay" Galveston Bay National Estuary Program, Houston, Texas, 150 pp (October
1991).
69. Rifai, H.S., Long, G.P., and P.B. Bedient "Modeling Bioremediation: Theory and Field
Application" In Situ Bioreclamation Applications and Investigations for Hydrocarbon and
Contaminated Site Remediation, Ed. by R. E. Hinchee and R. F. Olfenbuttel, Battelle Memorial
Institute, Butterworth-Heinemann, Boston, (1991).
70. Kilborn, K., Rifai, H.S., and P.B. Bedient "The Integration of Ground Water Models with
Geographic Information Systems (GIS)" 1991 ACSM/ASPRS 10 Annual Convention, Baltimore,
Maryland, In Technical Papers, vol. 2, pp. 150-159, (March 1991).
71. Wise, W.R., Chang, C.C., Klopp, R.A., and P. B. Bedient "Impact of Recharge Through Residual
Oil Upon Sampling of Underlying Ground Water" Ground Water Monitoring Review, pp. 93-100
(Spring 1991).
72. Rifai, H.S. and P.B. Bedient "Comparison of Biodegradation Kinetics with an Instantaneous
Reaction Model for Ground Water" Water Resource. Res. 26:637-645 (1990).
73. Newell, C.J., Hopkins, L.P., and P.B. Bedient "A Hydrogeologic Database for Ground Water
Modeling" Ground Water 28:703-714 (1990).
74. Newell, C.J., Haasbeek, J.F., and P.B. Bedient "OASIS: A Graphical Decision Support System
for Ground Water Contaminant Modeling" Ground Water 28:224-234 (1990).
75. Chiang, C.Y., Wheeler, M.F., and P.B. Bedient "A Modified Method of Characteristics
Technique and Mixed Finite Elements Method for Simulation of Ground Water Contaminant
Transport" Water Resource. Res. 25:1541-1549 (1989).
76. Todd, D.A., Bedient, P.B., Haasbeek, J.F., and J. Noell "Impact of Land Use and NPS Loads on
Lake Water Quality" ASCE J. Environmental Engr. Div. 115:633-649 (1989).
77. Borden, R.C., Lee, M.D., Thomas, J.M., Bedient, P.B., and C.H. Ward “In Situ Measurement and
Numerical Simulation of Oxygen Limited Biotransformation" Ground Water Monitoring Review.
Rev. 9:83-91 (1989).
78. Rifai, H.S., Bedient, P.B., Wilson, J.T., Miller, K.M., and J.M. Armstrong "Biodegradation
Modeling at an Aviation Spill Site" ASCE J. Environmental Engr. Div. 114:1007-1019 (1988).
79. Satkin, R.L. and P.B. Bedient "Effectiveness of Various Aquifer Restoration Schemes under
Variable Hydrogeologic Conditions" Ground Water Monitoring Review. , 26:488-498 (1988).
80. Todd, D.A. and P B. Bedient "Stream Dissolved Oxygen Analysis and Control" (Closure), ASCE

 13

J. Environmental Engr. Div. 113:927-928 (1987).
81. Freeberg, K.M., Bedient, P.B., and J.A. Connor "Modeling of TCE Contamination and Recovery
in a Shallow Sand Aquifer" Ground Water Monitoring Review. 25:70-80 (1987).
82. Borden, R.C. and P.B. Bedient "In Situ Measurement of Adsorption and Biotransformation at a
Hazardous Waste Site" Water Resources Report. Bull. 23(4): 629-636 (1987).
83. Borden, R.C., Bedient, P.B., Lee, M.D., Ward, C.H., and J.T. Wilson " Transport of Dissolved
Hydrocarbons Influenced by Oxygen Limited Biodegradation: 2. Field Application" Water
Resources Report. Res. 22:1983-1990 (1986).
84. Borden, R.C. and P.B. Bedient "Transport of Dissolved Hydrocarbons Influenced by Reaeration
and Oxygen Limited Biodegradation: 1. Theoretical Development" Water Resources Report.
Res. 22:1973-1982 (1986).
85. C.H. Ward, Tomson, M.B., Bedient, P.B., and M.D. Lee "Transport and Fate Processes in the
Subsurface" In R. C. Loehr, and J.F. Malina, Jr., eds., Land Treatment, A Hazardous Waste
Management Alternative, Center for Research in Water Resources, University of Texas, Austin,
TX, pp. 19-39. (1986).
86. Wilson, J.T., McNabb, J.F., Cochran, J.W., Wang, T.H., Tomson, M.B., and P.B. Bedient
"Influence of Microbial Adaptation on the Fate of Organic Pollutants in Ground Water" Environ.
Toxicol. Chem. 4:721-726 (1985).
87. Bedient, P.B. "Overview of Subsurface Characterization Research" In Ward, C.H., Giger, W., and
P. L. McCarty, eds., Ground Water Quality, John Wiley & Sons, Inc., New York, NY, pp. 345347 (1985).
88. Bedient, P.B., Flores, A., Johnson, S., and P. Pappas "Floodplain Storage and Land Use Analyses
at the Woodlands, Texas" Water Resources Research. Bull. 21:543-551 (1985).
89. Hutchins, S.R., Tomson, M.B., Bedient, P.B., and C.H. Ward "Fate of Trace Organics During
Land Application of Municipal Wastewater" CRC Crit. Rev. Environ. Control 15:355-416
(1985).
90. Todd, D.A. and P.B. Bedient "Stream Dissolved Oxygen Analysis and Control" ASCE J.
Environmental Engr. Div. 111:336-352 (June 1985).
91. Chiang, C.Y. and P.B. Bedient "PIBS Model for Surcharged Pipe Flow" ASCE J. Hydraulics Div.
112:181-192 (1985).
92. Bedient, P.B., Borden, R.C., and D.I. Leib "Basic Concepts for Ground Water Transport
Modeling" In Ward, C.H., Giger, W., and P.L. McCarty, eds., Ground Water Quality, John Wiley
& Sons, Inc., New York, NY, pp. 512-531, (1985).
93. Bedient, P.B., Rodgers, A.C., Bouvette, T.C., and M.B. Tomson "Ground Water Quality at a
Creosote Waste Site" Ground Water 22:318-319 (1984).
94. Bedient, P.B. and P.G. Rowe, eds., Urban Watershed Management: Flooding and Water Quality,
Rice University Studies, 205 pp. (March 1979).
95. Bedient, P.B., Huber, W.C., and J. Heaney “Environmental Model of the Kissimmee River
Basin” ASCE Water Resources Planning and Management, Vol. 103, No. WR2, (1977).
Conference Proceedings and Other Technical Publications
1. Juan, A., Fang, Z., and Bedient, P. B. (2012). “Flood Warning Indicator: Establish a Reliable
Radar-Based Flood Warning System for Sugar Land, Texas”, American Geophysical Union
(AGU) 2012 Fall Meeting, San Francisco, CA, December 3-7.

 14

2. Deitz, R., Christian, J. K., Wright, G., Fang, Z., and Bedient, P. B. (2012). “Linkage of RainfallRunoff and Hurricane Storm Surge in Galveston Bay”, American Geophysical Union (AGU)
2012 Fall Meeting, San Francisco, CA, December 3-7.
3. Bedient, P. B., Doubleday, G., Sebastian, A., and Fang, Z. (2012). “Distributed Hydrologic
Modeling of LID in the Woodlands, Texas”, American Geophysical Union (AGU) 2012 Fall
Meeting, San Francisco, CA, December 3-7.
4.

Burcham, M., Bedient, P. B., McGuire, T., Adamson, D.,. New Ch., (2012) Occurrence of
Sustained Treatment Following Enhanced Anaerobic Bioremediation at Chlorinated Solvent
Sites 

, AGU Fall Meeting, San Francisco, California, December 3-7 2012

5. Fang, Z. and Bedient, P., Performance Evaluation of a NEXRAD-Based Flood Warning during
Recent Events in 2012 

, AGU Fall Meeting, San Francisco, California, December 3-7 2012
6. Juan, A., Fang, Z. and Bedient, P., Radar-based Flood Warning Indicator for the Upper Oyster
Creek Watershed in Sugar Land, Texas 
AGU Fall Meeting, San Francisco, California,
December 3-7 2012
7. Environmental and Water Res. Inst. (EWRI) 2012 Congress, Organized three sessions for
SSPEED research results. Albuquerque, New Mexico, May 20-24 2012.
8. Fang, Z. and Bedient, P. B. (2012). “Creating Flood Alert Systems in Coastal Areas”, SSPEED
Conference – Gulf Coast Hurricanes: Mitigation and Response, Houston, Texas, April 10.
9. Fang, Z. and Bedient, P. B. (2012). “Advanced Radar-Based Flood Warning System for Urban
Areas and its Performance Evaluation”, SSPEED Conference – Gulf Coast Hurricanes:
Mitigation and Response, Houston, Texas, April 11.
10. Teague, A, and Bedient, P. B. (2011). “Visualization of Hydrologic Simulations with Pollutant
Load Estimation for Cypress Creek Watershed, Houston, Texas”. 2011 World Environmental and
Water Resources Congress. Palm Springs California 22-26 May 2011.
11. Christian, J. K., Fang, Z., and Bedient, P. B. (2011). “Probabilistic Floodplain Delineation”,
2011 World Environmental and Water Resources Congress, Palm Springs, California. May 22-26
12. Fang, Z., Juan, A., Bedient, P. B., Kumar, S., and Steubing, C. (2011). “Flood Warning Indicator:
Establishing a Reliable Radar-Based Flood Warning System for the Upper Oyster Creek
Watershed”, ASCE/TFMA, TFMA 2011 Annual Conference, Sugar Land, Texas, April 11- 14.
13. Bedient, P. B. and Fang, Z. (2010). "Advanced Radar-based Flood Warning System for
Hurricane-prone Urban Areas and Performance during Recent Events", 2nd International
Conference on Flood Recovery, Innovation and Response (FRIAR), Milano, Italy, May 26-28.
14. Fang, Z., Juan, A., Bedient, P. B., Kumar, S., and Steubing, C. (2010). "Flood Alert System for
Upper Oyster Creek Watershed in Sugar Land, Texas using NEXRAD, HEC-HMS, HEC-RAS,
and GIS", ASCE/TFMA, TFMA 2010 Annual Conference, Fort Worth, Texas, June 7- 10.
15. Fang, Z. and Bedient, P. B. (2010). "Radar Applications in Flood Warning System for an Urban
Watershed in Houston, Texas", Remote Sensing and Hydrology 2010 Symposium - Special
Session on Flood Forecasting and Management with Remote Sensing and GIS, Jackson Hole,
WO, September 27 -30.
16. Bedient, P. B., Fang, Z., and Vieux, B. E. (2010). "Radar-based Flood Warning System for the
Texas Medical Center and Performance Evaluation", National Flood Workshop, Houston, Texas,
October 24-26.

 15

17. Teague, A. and Bedient, P. 2010. “Distributed Modeling of Water Quality in Cypress Creek
Watershed, Houston, Texas”. 21st Century Watershed Technology: Improving Water Quality and
the Environment, EARTH University, Costa Rica, February 21-24, 2010.
18. Teague, A. and Bedient, P. 2010. “Visualization of Hydrologic Simulations in Support of Water
Quality Applications for Cypress Creek, Houston, Texas”. Conference Proceedings. Annual
Water Resources Conference, American Water Resources Association. November 1-4, 2010,
Philadelphia, PA.
19. Teague, A. and Bedient, P. 2010. “Distributed Water Quality Modeling for a Drinking Water
Source Watershed for the City of Houston, Texas”. Conference Proceedings. World
Environmental and Water Resources Congress. May 16-20, 2010, Providence, RI.
20. Fang, Z. and Bedient, P.B. (2009). “Radar-based Flood Warning System for Houston and Its
Performance Evaluation”. American Geophysical Union (AGU) 2009 Fall Meeting, December
14-18, San Francisco, CA.
21. Fang, Z. and Bedient, P.B. (2009). “Radar-based Flood Alert System for Coastal Area and
Collaborated Efforts for Disaster Prevention and Risk Management”. IRCD 34th Annual Natural
Hazards Research and Applications Workshop – Hazards and the Economy: Challenges and
Opportunity, July 15-18, Boulder, CO.
22. Fang, Z. and Bedient, P.B. (2009). “Flood Inundation Prediction and Performance during
Hurricane Ike”. Proceedings of World Environmental & Water Resources Congress 2008,
Environmental and Water Resources Institute (EWRI), ASCE, Kansas City, Missouri, May 1721.
23. Robinson, H., Fang, Z. and Bedient, P.B. (2009). “Distributed Hydrologic Modeling of the Yuna
River Watershed in the Dominican Republic”. Proceedings of World Environmental & Water
Resources Congress 2008, Environmental and Water Resources Institute (EWRI), ASCE, Kansas
City, Missouri, May 17-21.
24. Ray, T., Fang, Z., and Bedient, P.B. (2009). “Assessment of Flood Risk Due to Storm Surge in
Coastal Bayous Using Dynamic Hydraulic Modeling”. Proceedings of World Environmental &
Water Resources Congress 2008, Environmental and Water Resources Institute (EWRI), ASCE,
Kansas City, Missouri, May 17-21.
25. Fang, Z. and Bedient, P.B. (2009). “Advanced Radar-based Flood Forecasting Systems for a
Highly Urbanized Coastal Area and SSPEED Center”, ASCE/TFMA Flood Awareness and Flood
Response Workshop, April 29, San Marcos, TX.
26. Fang, Z. and Bedient, P.B. (2009). “Flood Warning Systems for Urban Flooding”. Grand
Challenges in Coastal Resiliency I: Transforming Coastal Inundation Modeling to Public
Security, January 20-21, Baton Rouge, LA.
27. Fang, Z. and Bedient, P.B. (2008). “NEXRAD Radar-based Hydraulic Flood Prediction System
for a Major Evacuation Routes in Houston”. American Geophysical Union 2008 Fall Meeting,
December 15-19, San Francisco, CA.
28. Fang, Z. and Bedient, P.B. (2008). “Advanced Flood Alert System with Hydraulic Prediction for
a Major Evacuation Route in Houston”. Proceedings of American Water Resources Association
(AWRA) Annual Conference 2008, New Orleans, Louisianan, November 17-20.

 16

29. Fang, Z. and Bedient, P.B. (2008). “Flood Inundation Prediction and Performance during
Hurricane Ile”. Proceedings of Severe Storm Prediction and Global Climate Impact in the Gulf
Coast Conference 2008, Houston, Texas, October 28-31.
30. Bedient, P.B. and Fang, Z. (2008). “Predicting and Managing Severe Storms in the Gulf Coast
through University Research”. Proceedings of Severe Storm Prediction and Global Climate
Impact in the Gulf Coast Conference 2008, Houston, Texas, October 28-31.
31. Robinson, H., Fang, Z. and Bedient, P.B. (2008). “Distributed Hydrologic Model Development in
the Topographically Challenging Yuna River Watershed, Dominican Republic”. Proceedings of
Severe Storm Prediction and Global Climate Impact in the Gulf Coast Conference 2008, Houston,
Texas, October 28-31.
32. Ray, T., Fang, Z. and Bedient, P.B. (2008). “Assessment of Flood Risk Due to Storm Surge in
Coastal Bayous Using Dynamic Hydraulic Modeling”. Proceedings of Severe Storm Prediction
and Global Climate Impact in the Gulf Coast Conference 2008, Houston, Texas, October 28-31.
33. Fang, Z. and Bedient, P.B. (2008). “Floodplain Map Library (FPML): Innovative Method for
Flood Warning System for Urban Watershed in Houston, TX”. Proceedings of World
Environmental & Water Resources Congress 2008, Environmental and Water Resources Institute
(EWRI), ASCE, Honolulu, Hawaii, May 13-16.
34. Bedient, P.B., “Foresight Panel on Environmental Effects” Houston-Galveston Area Council,
Houston, Texas, February 5, 2008
35. Bedient, P.B., Fang, Z., Hovinga, R, M., “Flood Warning System (FAS2) Rice University
Training, Houston, Texas, January 15, 2008
36. Bedient, P.B., Fang, Z., Hovinga, R, M., SSPEED Meeting, Houston, Texas, November 16, 2007

37. Fang, Z. and Bedient, P.B. “Real-time Hydraulic Prediction Tool – Floodplain Map Library
(FPML)”. American Water Resources Association 2007 Annual Conference, Albuquerque, New
Mexico, November 12-15, 2007
38. Fang, Z. and Bedient, P.B. “Enhanced NEXRAD Radar-based Flood Warning System with
Hydraulic Prediction Feature: Floodplain Map Library (FPML)”. American Geophysical Union
2007 Fall Meeting, San Francisco, CA. December 10-14, 2007
39. Fang, Z. and Bedient, P.B. “The Future of Flood Prediction in Coastal Areas” Severe Storm
Prediction, Evacuation, and Education from Disasters Conference, Rice University, Houston
Texas, May 8-10, 2007
40. Bedient, P.B. and Fang, Z. “Radar-based Flood Warning System Using Dynamic Floodplain Map
Library.” Proceedings of World Environmental & Water Resources Congress 2007,
Environmental and Water Resources Institute (EWRI), ASCE, Tampa, Florida, May 15-19, 2007
41. Bedient, P.B., and C. Penland “A Radar Based FAS for Houston’s Texas Medical Center” IDRC
Conference, Davos, Switzerland, Aug 2006.
42. Safiolea, E. and P.B. Bedient "Comparative Analysis of the Hydrologic Impact of Land Use
Change and Subsidence in an Urban Environment" Proceedings of AWRA GIS Conference,
Houston, TX, May 8-10, 2006.

 17

43. Bedient, P.B., Fang, Z., and R. Hovinga "Prediction for Severe Storm Flood Levels for Houston
Using Hurricane Induced Storm Surge Models in GIS Frame" Proceedings of AWRA GIS
Conference, Houston, TX, May 8-10, 2006.
44. Fang, Z., Safiolea, E., and P.B. Bedient "Enhanced Flood Alert and Control Systems for
Houston" Proceedings of 25th American Institute of Hydrology Conference, Baton Rouge, LA,
May 21-24, 2006.
45. Gordon, R. and P.B. Bedient "Rice University Engineers Without Borders: An Exercise in
International Service Learning" Proceedings of the ASE Education Conference, Chicago, June
18-21, 2006.
46. Gordon, R., Benavides, J.A., Hovinga, R., Whitko, A.N., and P.B. Bedient "Urban Floodplain
Mapping and Flood Damage Reduction Using LIDAR, NEXRAD, and GIS" Proceedings of the
2006 AWRA Spring Specialty Conference: GIS and Water Resources IV, Houston, TX, May 810, 2006.
47. Fang, Z. and P.B. Bedient "IP2 Houston Flood Alert and Response-2006" CASA Meeting, Estes
Park, Co, October 16-17, 2006.
48. Safiolea, E., Bedient, P.B., and B.E. Vieux "Assessment of the Relative Hydrologic Effects of
Land Use Change and Subsidence Using Distributed Modeling" (July 2005).
49. Holder, A.W., Hoblit, B., Bedient, P.B., and B.E. Vieux “Urban Hydrologic Forecasting
Application Using the NEXRAD Radar in Houston” Proceedings of the Texas Section American
Society of Civil Engineers, Austin, TX, pp. 279-288, April 5-8, 2000.
50. Benavides, J.A., Pietruszewski, B., Stewart, E., and P.B. Bedient “A Sustainable Development
Approach for the Clear Creek Watershed” Proceedings of the Texas Section American Society of
Civil Engineers, Austin, TX, pp. 269-278, April 5-8, 2000.
51. Bedient, P.B., Rifai, H.S., and C.W. Newell "Decision Support System for Evaluating Pump-andTreat Remediation Alternatives" Pollution Modeling: Vol. 1, Proceedings for Envirosoft 94,
November 16-18, 1994, San Francisco, CA, Edited by P. Zannetti, Computational Mechanics
Publications, Wessex Inst of Technology, Southampton, UK.
52. Hamed M.M. and P.B. Bedient “Uncertainty Analysis of Natural Attenuation in Groundwater
Systems,” Proceedings of the In Situ and On-Site Bioremediation Symposium, New Orleans, LA,
1997, 1:43-48.
53. Hamed, M.M., Holder, A.W., and P.B. Bedient “Evaluation of Reaeration Using a 3-D
Groundwater Transport Model” Proceedings of the In Situ and On-Site Bioremediation
Symposium, New Orleans, LA, 1997, 1:75-80.
54. Holder, A.W., Bedient, P.B., and J.B. Hughes “TCE and 1,2-DCE Biotransformation Inside a
Biologically Active Zone” Proceedings of the First International Conference on Remediation of
Chlorinated and Recalcitrant Compounds, Monterey, CA, May 18-21, 1:219-224, 1998.
55. Hamed M.M. and P.B. Bedient “Uncertainty Analysis of Natural Attenuation in Groundwater
Systems” Proceedings of the In Situ and On-Site Bioremediation Symposium, New Orleans, LA,
1997, 1:43-48.
56. Hamed, M.M., Holder, A.W., and P.B. Bedient “Evaluation of Reaeration Using a 3-D
Groundwater Transport Model” Proceedings of the In Situ and On-Site Bioremediation
Symposium, New Orleans, LA, 1997, 1:75-80.

 18

57. Hamed, M.M., Bedient, P.B., and J.P. Conte “Probabilistic Modeling of Contaminant Transport
in the Subsurface” Proceedings of the International Association of Hydro geologists Conference
Solutions ‘95”, Edmonton, Canada, June 4-10, 1995.
58. Bedient, P.B., Rifai, H.S., and C.W. Newell "Decision Support System for Evaluating Pump-andTreat Remediation Alternatives" Pollution Modeling: Vol. 1, Proceedings for Envirosoft 94,
November 16-18, 1994, San Francisco, CA, Edited by P. Zannetti, Computational Mechanics
Publications, Wessex Institute of Technology, Southampton, UK.
59. Burgess, K. S., Rifai, H. S., and P. B. Bedient "Flow and Transport Modeling of a Heterogeneous
Field Site Contaminated with Dense Chlorinated Solvent Waste" Proceedings of the Petroleum
Hydrocarbons and Organic Chemicals in Ground Water: Prevention, Detection, and Restoration,
Houston, TX (Nov. 10-12, 1993).
60. Hamed, M., Conte, J., and P. B. Bedient "Reliability Approach to the Probabilistic Modeling of
Ground Water Flow and Transport" Proceedings of the Petroleum Hydrocarbons and Organic
Chemicals in Ground Water: Prevention, Detection, and Restoration, Houston, TX (Nov. 10-12,
1993).
61. Rifai, H.S. and P.B. Bedient "Ground Water Contaminant Modeling for Bioremediation: A
Review" Proceedings of the 4th Annual Symposium on Ground Water: The Problem and Some
Solutions, The Gulf Coast Hazardous Substance Research Center, Lamar University, Beaumont,
Texas, 101-121 (April 2-3, 1992).
62. Thomas, J.M., Duston, K.L., Bedient, P.B., and C.H. Ward "In Situ Bio-restoration of
Contaminated Aquifers and Hazardous Waste Sites in Texas" Proceedings for the Petro-Safe 92,
3rd Annual Environmental and Safety Conference for the Oil, Gas & Petrochemical Industries,
Houston, TX, Vol. 3, pp. 889-898 (1992).
63. Bedient, P.B., Long, G.P., and H.S. Rifai "Modeling Natural Biodegradation with BIOPLUME
II" Proceedings of the 5th International Conference, Solving Ground Water Problems with
Models, Dallas, Texas, pp 699-714. (February 11-13, 1992).
64. Robinson, G.C. and P.B. Bedient "Modeling a Time-Variant Source of Contamination"
Proceedings of the Petroleum Hydrocarbons and Organic Chemicals in Ground Water:
Prevention, Detection, and Restoration, Houston, Texas, pp. 531-540. (November 20-22, 1991).
65. Chang, C. and P. B. Bedient "Multiphase Unsaturated Zone Flow and Transport Model for
Ground Water Contamination by Hydrocarbon" Proceedings of the Petroleum Hydrocarbons and
Organic Chemicals in Ground Water: Prevention, Detection, and Restoration, Houston, Texas,
pp. 515-529 (November 20-22, 1991).
66. Bedient, P.B., Vance, L.A., and H.S. Rifai "Implementation of Wellhead Protection Programs
Utilizing Geographical Information Systems" Proceedings of the Eighth National Conference on
Microcomputers in Civil Engineering, University of Central Florida and The American Society of
Civil Engineers, Orlando, Florida, pp. 87-90 (October 1990).
67. Rifai, H.S., Bedient, P.B., and C.J. Newell "Review and Analysis of the Toxicity Characteristics
Composite Landfill Model" Proceedings of the Petroleum Hydrocarbons and Organic Chemicals
in Ground Water: Prevention, Detection and Restoration, The Association of Ground Water
Scientists and Engineers (NWWA), Houston, Texas, pp.143-157 (October 1990).
68. Rifai, H.S. and P.B. Bedient "A TC Model Alternative for Production Waste Scenarios"
Proceedings of the First International Symposium on Oil and Gas Exploration and Production
Waste Management Practices, U.S. Environmental Protection Agency, New Orleans, LA, pp.

 19

955-965 (September 1990).
69. Chang, C.C., Wise, W.R., Klopp, R.A., and P.B. Bedient "In Situ Source Release Mechanism
Study at an Aviation Gasoline Spill Site: Traverse City, Michigan" Proceedings of the Fourth
National Outdoor Action Conference on Aquifer Restoration, Ground Water Monitoring and
Geophysical Methods, Las Vegas, NV, pp. 459-473 (May 1990).
70. Hopkins, L.P., Newell, C.J., and P.B. Bedient "A Hydrogeologic Database for the Hazardous
Waste Regulatory Modeling" Proceedings of the Petroleum Hydrocarbons and Organic
Chemicals in Ground Water Conference, National Water Well Association, Houston, TX, pp.
265-279 (November 1989).
71. Alder-Schaller, S.E. and P.B. Bedient "Evaluation of the Hydraulic Effect of Injection and
Pumping Wells on In Situ Bioremediation" Proceedings of the Petroleum Hydrocarbons and
Organic Chemicals in Ground Water Conference, National Water Well Association, Houston,
TX, pp. 191-201 (November 1989).
72. Smythe, J.M., Bedient, P.B., and R.A. Klopp “Cone Penetrometer Technology for Hazardous
Waste Site Investigations” Proceeding of the Second National Outdoor Action Conference on
Aquifer Restoration, Ground Water Monitoring and Geophysical methods, Association of Ground
Water Scientists and Engineers, Las Vegas, NV, pp. 71-94 (1989).
73. Rifai, H.S. and P.B. Bedient "Bio-restoration Modeling of a Pilot Scale Field Experiment"
Proceedings of the National Water Well Association on Solving Ground Water Problems with
Models, Indianapolis, IN, pp. 1187-1203 (1989).
74. Wheeler, M.F., Dawson, C., and P.B. Bedient "Numerical Modeling of Subsurface Contaminant
Transport with Biodegradation Kinetics" Proceedings of the NWWA Conference on Petroleum
Hydrocarbons and Organic Chemicals in Ground Water, Houston, TX, pp. 47l-489 (1987).
75. Newell, C.J. and P.B. Bedient "Development and Application of a Ground Water Modeling
Database and Expert System" Proceedings of the NWWA Conference on Petroleum
Hydrocarbons and Organic Chemicals in Ground Water, Houston, TX, pp. 559-578 (1987).
76. Rifai, H.S. and P. B. Bedient "BIOPLUME II - Two Dimensional Modeling for Hydrocarbon
Biodegradation and In Situ Restoration" Proceedings of the NWWA Conference on Petroleum
Hydrocarbons and Organic Chemicals in Ground Water, Houston, TX, pp. 431-450 (1987).
77. Wheeler, M.F., Dawson, C.N., and P.B. Bedient "Numerical Simulation of Microbial
Biodegradation of Hydrocarbons in Ground Water" Proceedings of the NWWA/IGWMC
Conference on Solving Ground Water Problems with Models, Denver, CO, February 10-12, Vol.
1, pp. 92-109 (1987).
78. Chiang, C.Y. and P.B. Bedient "Simplified Model for a Surcharged Stormwater System"
Proceedings of the Third Int'l Conf. on Urban Storm Drainage, Goteborg, Sweden, pp. 387-396
(1985).
79. Wang, T.H., Curran, C.M., Bedient, P.B., and M.B. Tomson "Ground Water Contamination at
Conroe Creosote Waste Disposal Site" Proceedings of the Second Int'l Conf. on Ground Water
Quality Research, OSU University Printing Services, Stillwater, OK, pp. 50-52 (1985).
80. Borden, R.C., Bedient, P.B., and T. Bouvette "Modeling Ground Water Transport at Conroe
Creosote Waste Site" Proceedings of the Second Int'l Conf. on Ground Water Quality Research,
OSU University Printing Services, Stillwater, OK, p. 88-90 (1985).

 20

81. Todd, D.A. and P.B. Bedient "Use of Qual-II to Model Stream Protection Alternatives"
Proceedings of the ASCE 1984 National Conference on Environmental Engineering, Los
Angeles, CA, June 1984, pp. 60-65 (1984).

Invited Lectures (Recent)
1. The Resilience and Adaptation to Climate Risks Workshop: NASA Johnson Space Center and the
Houston/Galveston Area, March 8, 2012, Houston, Texas
2. Bedient, P.B., SSPEED Conference. Chair and Organizer, “Hurricane Ike, Revisited,” September
14, 2009, Houston, Texas.
3. Bedient, P.B., SSPEED Conference. Chair and Organizer, “Severe Storm Prediction and Global
Climate Impact in the Gulf Coast,” Sponsored by American Institute of Hydrology. October 2931, 2008, Houston, Texas. (Attended by over 150 guests and speakers).
4. Bedient, P.B., SSPEED Conference. Chair and Organizer, “Severe Storm Prediction and Global
Climate Impact in the Gulf Coast,” Sponsored by American Institute of Hydrology. October 2931, 2008, Houston, Texas. (Attended by over 150 guests and speakers).
5. Bedient, P.B., Robinson, and H., Fang, Z. (2008). “Distributed Hydrologic Model Development
in the Topographically Challenging Yuna River Watershed, Dominican Republic”. Meeting in
Dominican Republic before the President October 20, 2008.
6. Bedient, P.B. (June, 2008) Plan for the Dominican Republic Flood Study, before the Ministers of
Education, Environment, and Economic Development.
7. Bedient, P.B. "Advanced Flood Alert Systems in Texas" International Disaster Response
Conference, Daves, Switzerland, August 28, 2006.
8. Bedient, P.B. "IP2 Flood Alert System for Houston" CASA Meeting NSF Review, UMASS.
April, 2006.
9. Bedient, P.B. "Severe Storm Impacts in the Gulf Coast" Severe Storm Impacts and Disaster
Response in Gulf Coast, Houston, Rice University, March 15-16, 2006.
10.

Bedient, P.B. "Living with Severe Storms in the Gulf Coast- Scientia Lecture" Rice
University, Houston, TX. (September 2005).

11. Bedient, P.B., Fang, Z., Safiolea, E., and B.E. Vieux "Enhanced Flood Alert System for Houston"
2005 National Hydrologic Council Conference: Flood Warning Systems, Technologies and
Preparedness, Sacramento, California. (May 16-20)
12. Fang, Z. and Bedient, P.B. “Enhanced Flood Alert and Control Systems for Houston”
Proceedings of the 25th American Institute of Hydrology Conference: Challenges of Coastal
Hydrology and Water Quality. Baton Rouge, Louisiana, May 21-24, 2006.
13. Fang, Z., Bedient, P.B., and R. Hovinga “Prediction of Severe Storm Flood Levels for Houston
Using Hurricane Induced Storm Surge Models in a GIS Frame” Proceedings of AWRA 2006
Spring Specialty Conference: GIS and Water Resources IV. Houston, Texas, May 8-10, 2006.
14. Bedient, P.B. "Impacts of Climate Change on Transportation Systems and Infrastructure” Gulf
Coast Study, Lafayette, LA. (May 2005)

 21

15. Capiro, N.L., Da Silva, M.L.B., Stafford, B.P., Alvarez, P.J.J., and P.B. Bedient "Changes in
Microbial Diversity Resulting from a Fuel-Grade Ethanol Spill" Eighth International Symposium
on In Situ and On-Site Bioremediation, Baltimore, MD. (June 2005).
16.

Safiolea, E. and P. B. Bedient "Assessment of the Relative Hydrologic Effect of Land Use
Change and Subsidence Using Distributed Modeling” EWRI Watershed Management
Conference, Williamsburg, VA. (July 9-22, 2005)

17. Capiro, N.L., Stafford, B., He, X., Rixey, W.G., and P.B. Bedient “A Large-Scale Experimental
Investigation of Ethanol Impacts on Groundwater Contamination” Presentation at the Fourth
International Conference on Remediation of Chlorinated and Recalcitrant Compounds; Monterey,
CA; May 2004.
18. Capiro, N.L., Da Silva, M.L.B., Stafford, B.P., Alvarez, P.J.J., and P.B. Bedient “Changes in
Microbial Diversity Resulting from a Fuel-Grade Ethanol Spill” Accepted for Presentation at The
Eighth International Symposium on In Situ and On-Site Bioremediation; Baltimore, MD. June
2005.
19. Safiolea, E. and P.B. Bedient “Analysis of Altered Drainage Patterns and Subsidence Impact
Using a Distributed Hydrologic Model” AWRA Annual Water Resources Conference in Orlando
FL, November 2004.
20. Safiolea, E. and Philip B. Bedient ” Assessment of the Relative Hydrologic Effect of Land Use
Change and Subsidence using Distributed Modeling” EWRI Watershed Management Conference
in Williamsburg VA, Jul19-22, 2005.
21. Bedient, P.B. and J.A. Benavides “Use of QPE and QPF for Flood Alert (FAS2) in the Houston,
TX Test Bed“ CASA NSF ERC Conference, “ Estes Park, CO, October, 2004.
22. Capiro, N.L., Adamson, D.T., McDade, J.M., Hughes, J.B., and P.B. Bedient “Spatial Variability
of Dechlorination Activity Within a PCE DNAPL Source Zone” Presentation The 7th
International Symposium In Situ and On-Site Bioremediation; Orlando, FL; June 2003
23. Benavides, J.A. and P.B. Bedient "Improving the Lead-Time and Accuracy of a Flood Alert
System in an Urban Watershed" 2003 AWRA Annual Conference, San Diego, California,
November 2003.
24. Whitko, A.N. Bedient, P.B., and S. Johnson "Sustainable Flood Control Strategies in the
Woodlands – Thirty Years Later" 2003 AWRA Annual Conference, San Diego, California,
November 2003.
25. Safiolea E., Hovinga, R., and P.B. Bedient " Impact of Development Patterns on Flooding in
Northwest Houston using LIDAR Data” 2003 AWRA Annual Conference, San Diego, California,
November 2003
26. Benavides, J.A. and P.B. Bedient "Improving the Performance of a Flood Alert System Designed
for a Rapidly Responding Urban Watershed" 2003 Conference on Flood Warning Systems
Technologies and Preparedness, Dallas, Texas. October 2003.
27. Bedient, P.B., Holder, A., and Baxter Vieux “A Radar-Based Flood Alert System (FAS)
Designed for Houston, TX” International Conference on Urban Storm Drainage, Portland, OR,
September 2002.
28. Holder, A., Stewart, E., and P.B. Bedient “Modeling an Urban Drainage System with Large
Tailwater Effects under Extreme Rainfall Conditions” International Conference on Urban Storm

 22

Drainage, Portland, OR, September 2002.
29. Glenn, S., Bedient, P.B., and B. Vieux “Analysis of Recharge in Ground Water Using NEXRAD
in a GIS Format” AWRA Summer Specialty Conference, Keystone, CO, July, 2002.
30. Bedient, P.B. “Flood ALERT System (FAS) for Brays Bayou and the TMC” T.S. Allison: A
Brays Bayou Event, Rice University Conference Presentation, and November 13, 2001.
31. Bedient, P.B. “Flood ALERT System for the Texas Medical Center” Hurricanes and Industry,
Houston Conference Presentation, November 7, 2001.
32. Bedient, P.B. and J.A. Benavides "Analyzing Flood Control Alternatives for the Clear Creek
Watershed in a Geographic Information Systems Framework" presented at ASCE's EWRI Spring
2001 World Water & Environmental Resources Congress Conference.
33. Hoblit, B.C., Bedient, P.B., B.E. Vieux, and A. Holder “Urban Hydrologic Forecasting:
Application Issues Using WSR-88D Radar” Proceedings American Society of Civil Engineers
Water Research, Planning and Management 2000 Conference, Minneapolis, MN, August 2000.
34. Spexet, A., Bedient, P.B., and M. Marcon “Biodegradation and DNAPL Issues Associated with
Dry Cleaning Sites” Proc. Natural Attenuation of Chlorinated Solvents, Petroleum and
Hydrocarbons Conference, Bruce Alleman and Andrea Leeson Eds., 5(1), pp. 7-11, Battelle
Press, Columbus, Ohio, 1999.

 Duke Energy Memorandum Regarding CAMA
Requirements

Memorandum Regarding CAMA Requirements

I. Introduction

The purpose ofthis document is (1) to estabiish Duke Energy?s compliance with the groundwater
assessment and corrective action requirements of the North Carolina Coai Ash Management Act
and (2) to identify information relevant to the Department?s assessment and prioritization of
coal ash surface impoundments for closure under CAMA. As explained further below, Duke Energy has
submitted all groundwater information required by CAMA to date and will continue to submit information
required by the Department pursuant to CAMA authority. As a result, there is no basis for any finding by
the Department that Duke Energy has faiied to compiy with CAMA. Further, the information submitted by
Duke Energy, supplemented by other avaiiable, relevant information, is sufficient for the Department to
make an evidence-based assessment of the factors that CAMA requires for impoundment prioritization;
as a result, it would be legal error forthe Department to prioritize the surface impoundments without full

consideration of, and findings of fact on, each of the factors.

it. Compliance with Groundwater Assessment and Corrective Action
groundwater assessment and corrective action provisions are located at North Carolina

General Statutes 1. Duke Energy has complied with subsections and as follows:

A. Subsection - Groundwater Assessment

Subsection requires Duke Energy to, at each of its surface impoundments, do three things:
(1) submit a proposed Groundwater Assessment Plan for approval by the Department, (2) begin
implementing a Groundwater Assessment Plan approved by the Department, and (3) submit a
Groundwater Assessment Report describing all exceedances of groundwater quality standards

associated with the impoundment. Duke Energy has met each of these requirements.

As you are aware, Duke Energy submitted draft Groundwater Assessment Plans for ail of its
surface impoundments in North Carolina on September 25, 2014. The Department provided comments
on November 5, 2014, and Duke Energy submitted revised Groundwater Assessment Plans on

December 30, 2014. The Department conditionally approved the Plans on various dates earlier this year,

NCDENRO194488

and Duke Energy began implementing each plan within 10 days of approval. Groundwater Assessment
Reports describing all exceedances of groundwater quality standards associated with the various surface
impoundments were submitted to the Department in August and September. The Department?s approvai
of the plans reflected a determination that the plans met CAMA requirements. Duke Energy?s
implementation of the plans, including the conditions of approval, under the Department?s close oversight,

further supports a conclusion that the requirements of Subsection were met.

According to the plain ianguage ot Subsection Duke Energy?s compliance with the
requirements does not depend on the substantive content of the Groundwater Assessment Reports.
Duke Energy was required to make pians to assess various groundwater factors, which it did. The
Department approved the plans, thereby determining that the Pians wouid assess those groundwater
factors. Duke Energy diligently implemented the Plans. There is no further requirement in Subsection
or anywhere else in CAMA, that the results ofthe groundwater assessments definitively establish or
disprove the existence of any condition at a site. In fact, CAMA anticipates that groundwater
assessments performed under Subsection may not supply all the information desired by the
Department?Subsection requires Duke Energy to include in a proposed Groundwater Corrective
Action Plan "[a]ny other information related to groundwater assessment required by the Department.?
Had the General Assembly anticipated that Groundwater Assessment Reports wouid be definitive
documents, there would have been no need to authorize the Department to request additionai information

in the proposed Corrective Action Pians.

B. Subsection - Corrective Action

Similarly, Subsection requires Duke Energy to do two things: (1) submit a proposed
Groundwater Corrective Action Plan, and (2) begin implementing the Groundwater Corrective Action Plan
once it has been approved bythe Department. The deadiine for completion of the first requirement has
not yet passed. The Department and Duke Energy agreed that the corrective action plans would be
submitted in two parts, and Duke Energy has submitted the first part for fourteen sites with surface

impoundments. The deadiine for submission of the second part has not yet arrived.

NCDENRO194489

The Corrective Action Pians contain each of the elements from Subsection that were to be
included in the first part submittals. The Corrective Action Plans were prepared by qualified professionals
and contain work performed to the industry standard. Additional information wiil be submitted in the part
two submittals. it is premature to evaluate Duke Energy?s compliance with this requirement until the

submittals are compiete.

Ill. Prioritization of Surface lmpoundments

Under CAMA, the Department is charged with developing proposed classifications of
surface impoundments according to the procedures in North Carolina General Statutes 
The prioritization must be based on ?a site?s risks to public health, safety, and welfare; the environment;
and natural resources.? N.C. Gen. Stat. In assessing the risks, the Department must
evaluate groundwater data submitted under 1, discharge information submitted under 
BOA-309.212, and any other information deemed relevant. Further, the Department must consider all of

the foilowing:

00 Any hazards to pubiic health, safety, or welfare resulting from the impoundment.
00 The structural condition and hazard potential ofthe impoundment.

00 The proximity of surface waters to the impoundment and whether any surface waters are
contaminated orthreatened by contamination as a result of the impoundment.

00 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 quaiity standards and all significant factors affecting contaminant
transport.

00 The location and nature of all receptors and significant exposure pathways.

(X) The geologicai and hydrogeologicai features influencing the movement and chemical and
physical character of the contaminants.

00 The amount and characteristics of coal combustion residuals in the impoundment.
co Whetherttie impoundment is located within an area subject to a 100-year flood.
00 Any other factor the Department deems relevant to estabiishment of risk.

The Department must issue written deciarations, including findings of fact, documenting a

proposed risk classification.

NCDENRO194490

This section requires the Department to make decisions based on the available evidence
regarding each of the listed factors.1 It would not be consistent with this requirement forthe Department
to make a classification decision based soiely on one factor and disregard valid information about the
others. Further, the section anticipates that the Department will make decisions before complete
information about a site is available. For example, it does not require the Department to compietely know
the vertical and horizontai extent of soil and groundwater contamination for each site; rather it requires
that the Department consider information concerningthe vertical and horizontal extent. Similariy, it does
not require the Department to know all factors that might conceivably affect contaminant transport or all
conceivabie exposure pathways; it requires the consideration only of signi?cant factors affecting

contaminant transport and significant exposure pathways.

Additional support for this conclusion is found in the fact that this section defines an iterative
process by which evoiving data, review, and commentary are used to classify surface impoundments as
low, intermediate, or high risk. This iterative process begins with a provisionally proposed classification by
the Department by December 31, 2015 and extends for a minimum (no maximum) of six months while
feedback and additional data are received and evaluated bythe Department and the Coat Ash

Management Commission.

Taken as a whole, this section requires the Department to make evidence-based decisions using
the best available information in the record. Duke Energy has submitted substantial evidence into the
administrative record. Any classification should be based on this evidence, with the understanding that
additional information requests may be relevant to the degree of certainty in the classification but do not

undermine the validity of the classification.

iV. Conclusion
The Groundwater Assessment Plans, Groundwater Assessment Reports, and Groundwater
Corrective Action Plans submitted by Duke Energy to the Department meet the requirements of 

and provide vast data, analysis, and findings. Chief among the findings is a determination by iicensed

 

1 Aside from CAfi/lA, the North Carolina Administrative Procedure Act requires that agency decisions be
supported "by substantial evidence . . . in View of the entire record as submitted.? GS. 1508-51 

4

NCDENRO194491

environmental geologists that none of the sites pose an imminent hazard to human health orthe

environment.

Duke Energy is committed to meeting the Department?s expectations by providing additional data,
tully ieveraging the time provided by iterative process to ensure tinal ciassitications refiect the
best science and engineering. Nonetheless, Duke Energy has compiied with all of requirements
to date, and available information is sufficient forthe Department to develop classifications as required by

CAMA.

NCDENRO194492

2-19-15 NCDENR Conditional Approval of Revised
Groundwater Assessment Work Plan

 

 
    


NCDEN

North Cato-tints: Department at am Naturat ?gsgumes

Pat Mammy Damatd? van ate; Vaart
Gwamar Seycmtaty
Fabruary 1.9, 20-} 5

Mr. Harry Sideris
S??i?f VicaeP?resident
Environment, Health, and SafEty

Duke Energy
526 Swath Church Straw:
Mail Dude ECBXP

Chariottaj NC 28202

Re; Cliffsids Swath Station
NPDEYS Permit Na. and Cleveland Counties, North Catalina
Camtditimal Approval (tf Revised Grgundwater Assessment Wark Plant

Dear Mr. Sideris:

On December 31,, 2.014, the Divi'simt Of Water Riasources raceivad the mvised
Gmundwater Assassmem Plan, (GAP) far the aboVe listed fatality;   a rcvised GAP was submitted
in to the Division?g Review oj'sz/mdwater Assessment Work Plan. letter date? Novembar
4, 2014 ragardittg requiremmts of the (30211 Ash Management An 2014 (3.8. A
review of the plan has been commath and set/amt deficiencies items requiring clari?catiun were
noted., In arder to keepthe sita assessment activities: cm a timely schedule, the Division has apprcavad
the; revised under the candition that the follawing deficient it.ng are addressed in the
Gtoun?watar Assessment Repnrt:

Cnmm?m Sa?tion 5.3 Site Charagtaristics:

The initial site mneeptuat sitemmd?l (ISCM) section Qf'the reviscd GAP (1035 not pmvi?s a.
clear, cahesive description 9f haw constituents of'petential may migats
the saum?s} t0 the recep?t?rs through variants pathways.. It is that. there
is; infe?nation availath to devetop an ICSM, but data are not prasented in a manner such as
grmmutwatar alevatimn maps: ge-olagic maps, crmas~sactia-ons that depict detailed site
canditians} ?ow diagrams, car in: a tabulatad fannat t0 illuStrate what's data gaps. may exist.
Duke Energy should all existing {tam at the site and be prepared to: collect
additional data if the Divisimn detcmitta? that additianal data gaps exist. Cmtinued site
wmeptual made] developmmt Shauld, faltaw guidelines similar to thosa presented in the
Ame?can Standar?s 1?63?:ng Measures E1689 - QSQOM) Standard Guid?: far Dev-6E0ng
Concepmal Site Models for Cantaminated 311525 to direct. data mileatieny data interpretath
and matte} devel?pment 

dctailed hydrage?lngic and grcauttdwater mhemistry r?parts fat: the *Ctiffside facility
were: net cited or referancad in the rsvised GAP. Th3 I??p??sj titlad ?Gasmanagement 3f
$36 Matt Same-e ?amers Raleigh Carmina 35994535 
Phane: Qt tntemet: 

An Equa? me?unity a ?tt?tma?ve Aattott Emptayerw Maria {it gm by racyciatt pater

NCDENR0063401

 

 Combustion By~l3roducts and Lowa?v'olmns Wastes: A Southeastern Site? {Electric
institutsg 1993i)  ?Fists of Htllity LGW'?Vslums
Wastes with Highu?xfslums C0211 Edy-Precincts: CL Sits? (Electric Fewer
Research 1997), assists sud {tats to the
sits assessment and should bs used in sits sits
assessment and sits development.

is tilts report titled at White Material Obsewsd in Ssspags,
Inactive Ash Basin #5 Main Stsam Statisn? (HDR
Esginssring, Ins. Qt'ths Csmlinss. April ll} slassld he used in the site assessment.
and in GSA report. If to 
and (pr) assessment exist, they salsa hs used and
in this GSA report.

Ssctiss 7.0 Sits Assessment

Duke Energy ts F?s sud Mn anti 
is sampliams well data. print ts installing additional wells nesdsd to delineate
the extent sf elevated Fe and Mn. To meet the CSA and CAP mandated by the
C931 Ash Management Act, Duke shsuid the nsstisd far Es and. Mn
delineation upon revised GAP approval. Any to evaluate histamine data may be
in ass} sits-tins with the installation and sampling 

Ssctisn Ash and. Sail Ratings-z

For tastings sutsids ash bastss and ash stm'sgs areas, the rsvised GAP statss that
ls?horst-sry an. will depend 011 the nstut?s and quantity st?
msts?s} it is ?st the sstid phase will
be and fer st sash sampled just
shave the water tattle, just the water tab-ls, transition zone, 
bsdrec'li ??ssturss).

Section 7. i .2 Msnitszfing Wells:

Shallsw msnitsr WsstIs is the revised GAP text :10 .sst match the quantity of
shallsw wells is 8. vsrify the qusntittss sf s21 wells
(shallow, and contained in the test, Table 8, and Figure 3
and the Of?ss vis small the smsunts fat sash.

Maxis well cluster ts a Iscsti'sn immediately to the tltsis at the
active pond dam, an area where 0f COPCs liksiy.
Analytical results ??Gm is. this vicinity have: displayed elevated st"
lass-on and COPCs.

(30111131th Section 7.1.4 Wells

Arid the tsltowisg well s} ABABR, b} s) sud d)
ts address data gaps st bath within the basins and at the
tos of the active: sand.

NCDENR0063402

 Cemment Seetlen 7.2 Groundwater Sampling anti Analysis-1

Diteetien provided in the EPA Region 1 Lew Stress Purging and. Sampling fer
the Celleetien ef Samples free} Meelterlng Wells (2840) sheeld be
fellewed ettictly and any deviatlene item the must he approval by the
Divislee amt dec-umented Fet- example, sample's she?eld feet he celleeted
until pH ie stabilized within :e 0.1 fer three eenseeutive readings rather than i 0.2 written
in the GAP. 'l?empetetute' and Sgeei?e eemluetivity reedlege sheuld stabilize within 3%
the three lvefere samples are. collected instead et? 18% meted in the
GAP. Ales mete that if the pumping rate is SQ lew that tlite ?ewuthreughveell?ehember
volume lee replaced within a :3 minute interval. the time between measurements
should be increased accordingly.

The prepesed menitet well leeatiens in and amend Unit 5 app-eat to be fer
purposes of greendwater assessme?et in this: area of the site. However. thie tile-es net
er imply epprevel of locations for pmpeseg ef NPDEE eempllettee monitoring
at? the Unit 5 Inactive Ash Basin. Fer more infametiee please eenteet the Regional
Of?ce.

Fer at" tadlumfuranium groundwater sampling: a} mid. lee-etions 
SKSIJD, and and la) remove Mle ll") and 8&3 SID.

Cemetth Section 7.2.1 Cempliance antl Vt?'tl?tm?y Menite??ng Wells:

lt l3 expected that all welle and sueset 0f voluntary meltltet wells will be
sampled and analyzed as part efthe Site assessment.

:9 Comment Section 7.7.5 Daniele of Conceptual law Medal:

Seek Creel; should be included as feature in gmumlwater ?ew anal transport
modeling ?te fer petential eentamineet trenepett te the creek and. for mass ?uxes
in antl eut ef the medel domain. if it eppeers that containing eenetltueete
abeve the standards is discharging te Seek Creek. it is expected that treesth date
eelleettlen aed leadellng, be carried em: 2153 discussed in the; general comment e-f
this letter.

 

Gentle:th Seetiee 9.6 (ISA Repett:

Previtle the fellewlng additional maps in the GSA report: a} a. Shaded relief reap create-{l
frem LEDAR digital elevation models and b) e- slte- wide orthepltete map showing sell fill
areas. {exclude site be'underies, impeundments, and all theility and water Supply wells on
bath maps. lnfetmetlen teem the N-Ol?lh' Carellne Division at? Energy. Mineral ant-l. Latte
Resources regarding basin and dam censtmetiefn should be as applicable,
into the site assessment repert.

See ce'mmeet 39 in the Diw?sien?s Review Of .Asgemmeet Work Plan. letter
dated November 4, 2014 tilt a list ef the gee-legit: ewes sections. that. the .Divieien weultli
like te see presented in the GSA repett, each 
the 01' ether metlellng Slteuld else be represented by a geelegte
cross section.

NCDENR0063403

In additiany technicai diractinn that wi? Servaas; the basis 0f expactations for cample?an oftha site
assessment is provided at Attachment E. Failure, to, addrem the de?cient items- stated abuve will
result in Duke Enargy mat being in campliance with the S'tagtad statutes. Fat (3.3 
(3) and, (4), ym}. must begin implementation of the revised GAP an March 13 2015 and the
Agsessmenf Report is due-an AuguSt 18:, 2813 It is our understanding that 13er
Energy may have t0 ab?tain additianal permits ta facilitate installation 53f (231132111 manimxing wells; En
?the event pmnits are Headed far this purpasa, Duke, Energy should take an steps necassafy cansistent
with the law avoid deiaying campletimn (31f the: assessment rep?rt

If?y?cru have- any questiuns?, pleasa mutaati Ted Campba? at (828); 296-4683.,

Sincerely?

 4/

-   if;

 Acting Dita;th
Bivigion 0f Water Resourcas-
cc: m? 
Cantral Files

DENR Secretary - Den van der Vaxart
(mm; Wiliiam Miller) 440 Sauth Church Street? Suita 19003 Cha?mta, NC 28202

NCDENR0063404

 

attachment 1
Page 1 of 5

?uke Eoergv GAP Review lesoes

The items identified in this Groundwateressessment Plan (GAP) review summary are provided for
discussion for the various parties to agree technicel direction and content in the revised
comereilenslve site assessments (CSAS), and corrective action plans 

?reeodweier Meni?iorieg

1. A schedule for continued groundwater monitoring is mandated by the C.an Ash Management
Act 281d. Ara interim plan slieuid irsclode at ieasi: two rounds-5' of gromdiwater samples coliected
and analyzed in 215315, The analyticai results of the first round of data collected in: 2015- wooaid be
included in the (ISA report, whiie the results of the seceod round? wooid be submitted as a CSA
addendum, efter data can be eveloated, a pie n: for? cominded groundwater monitoring ca 
be developed for implementation in 2015.

2. Sit-es impacted by inorganics are typiceiiy mariaged using a tiered site analysis which inciudes
four elements as referee-emcee in gee/eoo/ewor/ 13%:

a Demonstration of active contaminant remove-i from groundwater 8: die-solved oiome


a Determination of the mechanism and rate of attenuation;

49 Determination ofthe longetenn capacity for attenuation and stability of immobilized
contaminants, before, during, and after any proposed remedial activities; and?

a Design of performance monitoring program, inciodiog defining triggers for assessing
the remedial action strategy failure, and establishing a contingency oiasnc

reference and the framework described above" meme be used as aooliceoie to meet
the corrective .ectien irl 15A NQAC-GZL $1036..

3. Because" of uncertainty concerning theeite?s to attenuate contaminants over the long
term given potentially changing geochemical conditions, ?there is as need to address the eiements
oi?ihe tiered site analysis described eioove and collect appropriate samples as part of the CSA 
Cid-i development, and continued groundwater monitoriog

ii. The Division of Water Resources (Division) Birector is responsible for establishing background
ievels for COPCS in groundwater. This determination is: based on information and data provided
by the responsible early; aeci "may include formai Statistical testing using background weiis with
at ieast four rounds of data. Wells ideoci?ed as ?background? areeuoject to periodic review
based on a refined understanding of site and hydrogeoiogic conditions. in generai,
each facility must have a background well or welie screened or open to each of the dominth
?ow systems that occur at the site and are associated with groundwater contamination. My
questions cor?lcemirig adequacy of background monitoring locations or conditions at the
facilities should be directed to the. Regienei officee,

NCDENR0063405

Attachment 1
Page 2 of 6

5.

Deiineation oi the groundwater contaminant plume associates with ceai combustion residuais is
a requisement of the investigation anti if efi3--site monitoring weiis are ultimately required to
eerform this task, then it is expected that 1tits-5e activities wili be complieteci as part of. the
groundwater assessment activities anti included in the finai report. Documentation ofthe effort
to gain eff?site access, or right of way permits, be of?siie aCCess is denied or
alternate means of assessing the area were not availabie within the aiiocated timeframe {such
as within righbofuways}.

site Assessment

taste Requirements and Samniing Strategy

1.,

Robustclata collection is warranted to support timely completion: of site assessments and
subsequent corrective action plans because of the impending deadlines for sompietion of CSAs
anti CAPS, scale and geoiogic complexity of tits sites, the chalilenges of modeling heterogeneous.
systems, and site osrox?irnity tn potentiai. human ansi sensitive? ecosystem resents-rs.

Robust data collection wili be focused aiong strategicaiiy positioned fiowoath transectle from
asii ponci source tn potentlai receptor was an efficient 'appteach for model development
(anaiytical, geochesmicai, groundwater flow, and transport) in support of risit assessment and
CAP deveiopment, Data collected to support evaiuation of site conditions aiong the fiowpath
transects should be located aiong or ostensibly proximate. to the modeied transects.

The dataset seveinned eiong proposes! iiowgp-ath: transects will insiucie any information nee-tied
to determine constituent concentrations, conduct Kc! tests, anti perform batch geochemicali
mo'deiing in rnultioie iiow horizons as appropriate, This data inciudie a) soiid phase starnnle
cniiectien fer iici measurement and batch geechemicai motieling, inorganic analysis and
speciation, and other parameters identified in Genera! {Tornment #4 ofthe Ninvember xi, 2014
comments issued in; DWR, b} soiuti?on phase samoie coilection for totai and dissoived
inorganic ana-iysis of total concentrations, small note filtration for disseiveci satin-pies, etc, and Cl-
slug, constant/failing head, and packer testing. The soiiti phase samoie mineralogy, totai
concentration resuits, measurements, and other geochemicai parameters will he used as
input for speciation caicuiations of ratios sensitive constituents calsoeiateoi lay
PHREEQC or simiiar program modeling wilii he performeo
to identify note ntiai mineral nhases, estimated species speciation and sons-entrations, and will
be performed varying key soiubility controlling parameters to predict minerai phases,
speciation, anal concentrations under varying conditions. Soiid samples for Kti tests from
locations where moderateiy to strengi?y conditions are anticipated snali be frozen upon
ceiiectien and tested in glove box conditions 112}. Refer to 
Section for the data collection and characterization needed to support the four-?tiered anaiysis
discusses above.

Speciasiens for groundwater and surface water sampiessitooid include: Fe, Mn, and any 
whose speciation state may affect toxicity er leg. As, Cr, Se, or others if apoiicabie).
This speciation at)in for groundwater sampies coiiecteci at wells located aiong proposed

NCDENR0063406

Attachmeei 1
Page 3 of 5

Ill


12,

13.

iievvpath transects and in wells where these constituents exceed 2L groundwater standards as
weii es ier surface water samples eelieeteci within: ash irnpeenriments.

Seiid phase samples sineil be analyzed fer: minerals present, chemical eemeesitien ei oxides,
hydrous Mn, and AL oxides centerit; meisture content; particle size analysis; plasticity,
speeifii: gravity,- peresitir; er eiher physical preserries er analyses needed te
premise input to a chosen medel. The Divisien reservesthe right so request, enelvsis fer organic,
carbon era recent, organic careenate content (as apprepriete if site eeneitiens warrant), er ieri
exchange capacities, if needed te eerne-i-ete the site assessment process,

In addition is Conducting the SPLP leechahle inorganic communes analysis for seiecteri ash
samples to evaluate the potential for leaching of censiituems to grouridwater, the ieesheb-ie
analysis shoeie else be Conducted for seme seil samples from lecetion?s iaerieeth the pends,
within the plume, anti eutsirie the plume to eveiuete peteritiai from native seiis.
in edditien te celiectieg solid phase samples ensite for lid seii samples shseulri be
else eeliected from unaffected se'i'is within greuerliwater flew pathway t0 evaluate hell's) or
hydrees ierreus oxide.

Reel: sampies fer analyses sheuld he collected as eemmented? in General Cemmeni ii
of the November 4, 29314 GAP cemrneets is-isueel i331 BWR. This GAP review comment indicated
the}: the semeiebi coliected from bedrer well soil and: reek sore-s sheii be analyzed, at: a
minimum, for the feliewirig?: type of material, lermatie-n irerri which it ?came, minerals present,
Chemical cempesitien es hydrous Fe, Mn, and oxides cement, surface area, mois?i?ure
cement, ete; however, these__analvses were net mentiened the. see The {Divisien reserves
the right to request eeaiysis for organic carhe-n cement, ergenie eazrbeeate cement, end irm
exchange capacity if needed is: cempiete the site essessmerii: ere?eess,

The ceai ash and seii anelyte lists shouie match the greeneweter enalyte iisrs.

Total uranium analysis sheultl be analyzed where taste? radium is snaivzed fer greimdweter.

if eealvtieal resuits from a seep sample exceed 2i. standards-thee- t?he area in the vicinity ml? the
sample leeatien sheeld lee investigated for greuntiiwater cents mieatieri. ii enaiyiieal results.
from a surface water sample exceed 23 standards, then the area in the vicieity el?the sameie
lee-etien should be investigated fer gree-ridweter eeutamineiien.

Surface water/seep samples shouici be during beseilew emulsions. and that the
groundwater monitoring (Wis anti sampling} Sherrie meter at about: the same time.
Measurement ef st-reamilew iri selecteci per'e nnis'i' streams is exee-eiee as needed in supper-t of
simeulatiee/ceiibreiien 0i flow and transport mecieis; major rivers that serve as greuririwater
divides are nice included in this expectatiee.

{lenceptuel Merrie! Elements

in ihe CSA report, data gaps remaining sheuid be. specifically identified anri summarized.
Site heteregeneities sheuie ire identified and described with respect te; e} their nature, is)
their sceie and density, c) the extent ite which the date Che reeterizes
them, ti) hevv the medeling accounts for them, e) and how they affect modeling uncertainty.

NCDENR0063407

Attachment 1
"Page ii {if 6'

3. The impact of data gaps and site heterogeneities shieuid he described in relatien to the

eiements develehecl in the. Site Cenceetuai Model anti Fate and Transport
Masai subsectines.

For sites in the Piedment er Meenteins, the CSA Repert sheuid indecis- a subsection within the
Site Geniegy and Sectitin titi-ed ?Structural Geeiegs". This sectien sheeld
eescnhe: a} foliations, in) shear zones, c) fracture trace anaiysis and ti) other structural
cempenents anticipated to be reievant to iiew and cantaminant transplant at: the site.

Duke Energy wili incieirie a poster?sized sheetisi E) temhihing tabulated analyticai
assessment resuits {greendwateh surface water, and ieachate samples); muitieie sheets may
he needed in present the data. This shouid he provisieci in szddiitien to the individuai armistice!i
resuiis tables that wiil he prepared fer the tepetts Arty questiens (something farms-t or
content of the anaiytical result summaries shouitl he directed t0 the Regieniall Office-st

Geochemical Madeing

3..



The Division agrees that a geecheinicai model ?iceuspieti? to a 3?5} fate anti transmit metiei is
inappropriate given the size anti sompiexity at the sites anti the extremeiy iarge amount of data
resuiteci to eaiihrate such a medei. Rather, a ?hatch? geochemical nae-deli approach should be
sufficient for sacsessfuiiy sempleting the site assessment settler cei'tettive attien pian.
Samples coliesteci fer ?hatch? geechemicai anaiysis sheuld he focused siting er dieiensihiy
pieximate to ilow?path transects. -

Te swipe-rt successful hatch geochemical metieiineg, disseiveti greendwater-sa matiies ee-iiecteii
aieeg a contaminant fiewpath transect sheuid he Obtained using a 0?1. um fiiter. This help
ensure a? true dissniveci phase sample. Note that the dissei?ved? samples are far assessment
purposes Unis: anti may not he used fer hureeses ?of campiiance meniteringi if there is
uncertainty about which areas/weils he used in the hatch geechemical modeling, the initial
mend ei assessment sarmniirig at the can utilize the {3.45 am fitter until the contaminant
flew path transeets are selected {Since determined, Elle-ice Enseth can git} hack and re??sampie the
weiis needed for geochemicai medeiing using the 0.1 are fitter. it is recegnizeci that the use. of a
{11 um he diffieuit fer weils?wiih eievated turbidity; in this case, it is 
that Duke Energy use two fiiters in series (the water initialiv passes through a 04:5 um 
remove larger particies prier to passing through the 0.1 um filter}. infermatien fer a disposable
Giant fieici fiite?r designed specificaliy fer sampling gteundwater fer metai anaiysis is ptevicietl at
the felts-wing iink: if field comparisons mi
{3.1 versus 0515 micron fiitratinn at several transect welis at a: given site Show no significant
differences between the two methods; then GAS micree fiiters may he used? for evaluating the
disseieed phase eencentratiens ai thai site.

in snppert of the abjectives sf Generai Comment #2 of the Nievemher 23:, 2014 GAP comments
issued by DWR, {Jake Energy shnuid acid a column titled "relative resin-x" to the analytical results
te retard the far that insatieni?sam-eie date. The series.
determination should be based on observes DO, (RP, and any other teievant measures and
presented for histeric and new sampies {weiis ash here water, setfaee waters, eta). Reiatiee

NCDENR0063408

Attainment 1
Page 5 of 



rtedox designations may include ?iron red wing sui?fate ramming?, mildly axidiring, moderately
Gridizing; etc. and be with a statrsmerit about the of ca?ef?idence ii"; the
designation based amaurit and quality of data,

{hike Energy shaii also evaluate: a) spatial geochemical trends acmss the facility am} along
seirected flaw paths, in} t-emparal geoclwmical trends where absewabie {such as for c'arrmliance
b?-Lindary waits), airing with the iikeiy reamri it)? the change lag, increase in mammal recharge,
prim dewatering anti subsequent reversal ?at groundwater flow directium inundation: {if well
tram river at'fiorici stage? etc.) in Stigma-rt of the CAP. This evfaluatimn step will require! a
comparison at geachemical conditions overtime with rainfall data, notabie ash capping,
dewatering, disposal/remwai, mother piani- Dperatims, etc. The quality of existing
geechemical tiara will be evaluateti using fie-id mete-s, cae'libra-timn records, amt cmsistemy in
3?9de measuremerits (egi EH vs, raw 

Groundwatar Mudeis

1.

The technicai direction tar develmping the iatta anti transth modeli?g will fallow guideiims
f?und in Groundwater Madeing Peiicy, NCDEMR DWQ, May 31, 200?, and discussinns
canducted between Duke Energy and their consuitants with: the Bivisicn. Ultimate directien for
completim (3f fate and transmit madelg be gravided by the Bivisim.

The CAP Report should inciuda a subsection within Gmundwater Modeling Resuits titted ?Site
Conceptual Winder that summarizes, fer purposes. of model the
umieratanding: of the phy?sicai arici themit?al Setting t3"? the: site anti shaii includt, at a:

minimum: a} the site setting (hydrageaiagy, dominant flow zones; heterogeneities, areas of
pruncunced vertical head gradients, areas of recharge and discharge, spatiaei of
gemhemicai caritiitioris acrasg the site, and rather lactate; 225 l3} source areas and
estimath mass loading. histary, receptors, {le chemical behavinr and? t) likely
retentim mechanisms irir {2039(35 and haw the mechanisms are expected to respom tr; Changes
in geochemical wriditiciris.

Madeling be included in the Corrective Action: Plan The four-tiered analysis.
previousiy referenced and appragriate medaiing should? he r-oimucted, and the mass flux
rairiilatiims ?ascribeci in the ahrmiri be performed,

The CAP Repnrt shall provide se?arate subsectionsg fur reporting gr??un-dwater flow madeis and
fate anti tranSport mudeis.

The CAP Repart shmuld include subsectians within Groundwater Mmie?iing Results titiecl
?Grauntiwater Mariel Deveiopment? that clesrrilmc?rsg for each chase-n madel: a} purpose of model,
buiit?in assumptisns, medal extent, grid, layers-s) haundary canditions, initial? mmiitians, and
otherg as listed in {iivisimn guidance. inalude in: this sectl?ri as at ?etemgeneities and
how the madells) account for this lag. duai porosity mediating, equivaiam porous maciia
aggroaci}, etc?}. Separate subseations shouid be claveloped for the gramdwater flaw mnd?ei,
fate and transmit mode?, and batch gegchemical medals, respectively.

Reports should include a subsection within Gratin?water Modeling- Resuaits titled
rGr0umdwater Model Caiibratian? that describes, for each medal used, the process used t0

NCDENR0063409

 

Attachment 1
?age of 6

the modci, the 20985 {if input and calibration variables (far exa?mpl?e, hydrauiic
canductivitiac) thai: were used, the actuai (measm?ed) versus modeiec? resui?ia for ali kw
variabieg, and others. Separate subsectians Shouid be deveioped for the gmundwater fiow
medei, fate and transmit mcdeij and batch geachemicai mocieiis}, re-Sgectiveiy.

?22 Reparts gimuiij inciudc a subsectiG-n within: Gmundiwater Ma-dei?ng Results 'titied
?Gmum?water Mode! Sensitivity Analyais? that deccribes, fer each mode; uS-cui, the pmcess used
it) evaluate madei uncertainty, uariabie racges tested; and the key sensitivities. Separate
su?bseciiona should be develm-ped for the gmund?water fate and? {rampart mm?ei,
anci batch geachemic?ai madam), i?esgjectiveiy.

?eveicpment {if Kd T?rms

1, Kc? "testicg and mc?eimg in support of CAP devempmem i-i?iciude ail? abme
the MGM 15A 02L .Dl??ig) standards in ash ieachate, ash pure water, er compiiance boundary
weii groundwater sampies.

2.- The seiacted Kid used in transport mod-ef?ng cften wiif mam-un?t? affe??i the ?uke
Energy shouici acknowiedge ihis ccncept anci dacumen-t within the transmit madciing section?g)
0f the CAP w?idaiy recagnized limitations inhemnt in the estimation (if the K6 {arm

Risk Assessmam

1, vaide references for guidance and paientia! sampi?ng methodaimgy miatad to candiucting a:
baseiine ecologicai risk assessme?t or habitat assessment, if warranted.

NCDENR0063410

9-18-15 NCDENR Draft Comprehensive Site Assessment
Comments

 
      

 
 

 

 

A

ENE

North Carolina Department of Environment and Natural Resources

Pat McCrory Donald R. Van der Vaart
Governor Secretary

September 18, 2015

.Mr. Harry Sideris

Senior Vice-President
Environment, Health, and Safety
Duke Energy

526 South Church Street

Mail Code EC3XP

Charlotte, NC 28202

 
   
  

ountres, North 

nsive Site
CSA has
its review
on of data
addressed
16, 2015

General Comments

While the CSA Report provides data to develop a general understanding of site conditions, the
report fails to fully explain the factors affecting the occurrence, movement, and transport of
constituents that exceed groundwater quality standards as required by CAMA 09.21 1. The
relationship between the coal ash basins and the side and downgradient distribution of constituents
of interest (COIs) is not well developed in the report. Using site data to understand and
communicate why a contaminantis elevated in one area (or location) and low in another is essential
to asisessing fate, transport, and risk to receptors prior to the development of a CAP.

The CSA Report fails to adequately characterize the horizontal and vertical extent of contamination
in some areas of the facility as described in the speci?c comments below.

The CSAReport fails to quantitatively estimate background concentrations in groundwater and use
these estimates as a basis of comparison to side or downgradient well data. The Report should
provide provisional estimates of constituent concentrations using site data. The estimates are needed

1636 Mail Service Center, Raleigh, North Carolina 27699-1 $36
Phone: 919e807-6484tlnternet: 

An Equal Opportunity \At?rmative Action Employer Mode in part by recycled paper

NCDENRO194077

Cliffside Steam Station
September 18, 2015
Page 2 of 8

to compare ash leachate?impacted groundwater to background levels for purposes of assessment and
GAP development.

Specific Comments
The data gaps and de?ciencies noted during review of the CSA Report include the following:

0 The Division expects a ?provisional estimate for purposes of assessment of the
background concentration level for each constituents of interest (C015) in groundwater to be
established in order to evaluate the results of the CSA Report consistent with the CSA
Guidelines and CAMA requirements to describe all exceedances of North Carolina
Administrative Code (NCAC) Title 15A Chapter 02L.0202 groundwater quality standards
(ZLStandards). PEPA determinations should be made using data from all available historic
background sampling events from compliance wells MW -21D, MW -24D, MW-24DR, and
1V1W -25DR (see section 2.10, p.13), and from CCP land?ll monitoring wells 
and (permit #8106). The CCP Lined Land?ll wells are about 1500 ft. SW and
upgradient of Unit 5 basin and represent comparable geologic conditions. Data from
compliance wells are available from. 14 events; data from CCP land?ll monitoring wells are
available from 7 events. Data outliers in?uenced by turbidity should be removed prior to the
PEPA determination.

PEPA determinations for the V, CO, and that were not historically analyzed in
either the compliance or landfill monitor wells should be made using data from
background assessment wells and
current data from and 

All background data used in the PEPA determinations should be presented in the
CSA addendum. The addendum should also include the methodology used to
determine the PEPA and a list of the removed outliers. See section 3.2.5, p. 19.

0 C01 determinations should include constituents in native soil or sediment that are mobilized
to groundwater due to changes in geochemical conditions brought about by coal ash storage
or CAP implementation. Section 7.7 should consider and include C015 from the
groundwater component.

0 C01 determinations should consider hexavalent chromium.

Radionuclide sampling should be conducted in wells (background), 
MW-24DR, anus, as?4s, owner 1s, and 13-48?81. and
results provided.

0 Although the geochemical site conceptual model (GSCM) presented in section 13.3 provides
a ?bullet list? of factors that may affect leaching, sorption and desorption, and precipitation
and dissolution, the list is so generic that it is of limited value and says nothing about what is
being observed geochemically at Cliffside Steam Station (CSS). While the CSA includes

NCDENRO194078

Cliffside Steam Station
September 18, 2015
Page 3 of 8

raw contaminant concentrations, selected valence state data, pH, dissolved oxygen, eH, TDS,
alkalinity, and other data in various tables and ?gures throughout the report, these were not
used or interpreted to develop a conceptual understanding of contaminant mobility and
transport at CSS. The GSCM section 13.3 should provide a summary narrative of the current
understanding of geochemical conditions across the site (different areas will be characterized
by different conditions and should be described accordingly) and how they are expected to
affect individual contaminant mobility and transport. Specifically, the GSCM narrative
should describe, based on site data: a) the source of iron and manganese in groundwater (coal
ash versus native soil) and how these constituents are solubilized/mobilized and (or)
precipitated at CSS, b) the source of each of the other COIs (coal ash versus native soil), c)
the mechanism(s) and conditions under which each COI would be expected to be mobilized
or attenuated at CSS, d) prevailing geochemical conditions (ie. pH and eH) in C01 source
areas and along identified ?ow path transects A, C, H, J, and (see Fig 11?1), and e) any
other factors relevant to the occurrence and mobility of contaminants at CSS. Information in
the GSCM narrative should explain what is known about why a C01 is found at elevated
concentrations in one area of CSS and at very low concentrations in another. it is understood
that geochemical modeling wiil be performed as part of the CAP and that the GSCM will
undergo revisions as part. of that process.

0 Boron, sulfate, TDS, and other concentrations are irregularly distributed, even within a given
source area of CSS. An understanding of the hydrogeologic and geochemical causes behind
these irregular distributions in soil and in groundwater along a
presumed ?owpath is needed to improve the hydrogeologic site conceptual model (HSCM),
GSCM, and numerical models to be used in the CAP development. These are considered to
be significant factors affecting contaminant occurrence and transport. The HSCM and the
GSCM should address these concentration irregularities and their causes.

0 Additional monitoring wells are needed to improve the understanding of the extent and
source of TDS in areas of MW-23D, GWAH 14D, and GWAH4D.

0 Although data needed to develop a HSCM are provided in various tables, ?gures, and
appendices throughout the CSA, there is not the GAP?required section that interprets this
information in a summary narrative needed to evaluate CSA results of contaminant extent
and movement, ensure compliance with CSA. guidelines and CAMA, and assess modeling
results and CAP. Section 6.2.4, Hydrogeologic Site Conceptual Model, is the section that is
supposed to provide this narrative; instead it lists the types of data that comprise the HSCM
and the sections in which these data may be found. Narrative about the site is limited to the
sentence that states that ?the direction of the movement of the contaminants is towards Suck
Creek and Broad River, as anticipated.? Section 6.2.4 should include a stand?alone narrative
for each area and its corresponding downgradient footprint for which a coal ash source has
been identified. The source areas include, but may not be limited to, the active ash pond,
units 1-4 basin, unit 5 basin, and ash storage areas. The narrative should summarize the
current conceptual hydrogeologic understanding of that area of CSS. Each narrative should
describe: a) the character of the connected three?part groundwater system in
which ?ow occurs and where units are particularly thick or thin, b) how, where, and how

NCDENRO194079

Cliffside Steam Station
September 18, 2015
Page 4 of 8

much recharge occurs in that area, c) horizontal and vertical flow directions in that area, d)
the areas of discharge, e) locations in that area that do not follow the HSCM for the area and
why, and f) data gaps that affect the ability to understand a) through c) above. Areas of CSS
that do not ?t the generalized HSCM should be discussed in the narrative. These four
narratives should be presented in a revised HSCM.

0 Base maps (Figs 4-5, 6-2, 6-6, 6-7, 6-8, 7-1, 8-1, 9-1, 10-46, of CSS should show all
surface water features. Currently the CSA ?gures are missing a number of streams,
tributaries, seeps, and wetlands. An accurate HSCM is dependent in part upon a complete
picture of where groundwater is discharging to the surface. Section 12.2.2.9 states that the
June 2015 AMEC Natural Resources Technical Report identified 26 wetland areas, 28
drainage features, 16 intermittent streams, and 12 perennial streams at the site. These surface
water bodies should be incorporated into all figures (plan view and cross sections) and, as
appropriate, into the HSCM narratives.

0 To better understand groundwater recharge, ?ow, and discharge at CSS, the CSA needs to
include a map depicting vertical gradients between shallow and deeper flow systems across
the facility using water level data from all paired/clustered wells. The hydrologic
implications of these gradients on ?ow and transport should be discussed in the HSCM
narratives in section 6.2.4.

0 Because the mobility of iron. and manganese is controlled by geochemically-mediated (pH,
eH) precipitation rather than sorption onto iron hydroxides (and Kd measurements are not
particularly relevant to Fe and Mn concentrations along a flow path), a separate sub-section
should be provided in section 13 that describes how the fate and transport of these
constituents will be modeled.

a shallow system well in the SW corner of the active ash pond contains Co and
Mn above 2L. GWA-26D, a deep system well in this location contains Sb, TDS, and 
above 2L. This well pair is about 700 ft east of Suck Creek, a potential receptor. Because
there are no wells between and Suck Creek and the flow directions are
uncertain here, an additional well pair should be installed NW of adjacent to
Suck Creek and sampled to better understand local ?ow directions, complete the mapping of
horizontal extent in this area, and ensure that an otherwise unknown source of contamination
is not discharging to Suck Creek in this area.

0 Additional wells are needed in the area near monitor wells ABZS, MW SS, and to
refine the understanding of groundwater ?ow and contaminant transport in this COI impacted
vicinity of Suck Creek. Existing data seem to contradict, locally, the HSCM in this area.
The HSCM should be revised, using new and existing data, to describe the direction of local
contaminant ?ow in this vicinity of Suck Creek where groundwater COIs have been
observed. This is particularly important because Section 5-2, p.28 states that the ?Slope-
aquifer system (LeGrand) prevents groundwater from typically moving beneath a perennial
stream.? However, the shallow WT map in ?g 6?6 seems to refute this in the area near
monitor wells ABZS, MWSS, and where shallow groundwater flow seems to be

NCDENRO19408O

Cliffside Steam Station
September 18, 2015
Page 5 of 8

toward Suck Creek from the east and away from Suck Creek and toward the Broad River
from the western side of Suck. Creek. In this case it appears that the Broad River (a higher
order stream) controls local ?ow directions in the vicinity of this segment of Suck Creek (a
lower order stream). Note that the 710 ft contour on Fig 6?6 appears to be incorrectly drawn
in the area of monitor wells ABZS, MW SS, and GWA-33 S, and the deep well MW23D may
not. be comparable to nearby shallow wells for purposes of mapping the potentiometric
surface of shallow groundwater.

a shallow system well in the western arm of the active ash pond about 300 ft
upgradient of Suck Creek, contains As, Co, Fe, Mn, and T1 above 2L. Nearby
shallow system wells and contain Corespectively, above 2L, Water levels in these wells suggest that groundwater
?ow is toward Suck Creek to and toward Broad River 
to In order to better understand contaminant transport and discharge in
this area, additional wells should be installed and sampled. The additional wells and
(or) drive points will help better understand local flow directions in the vicinity of
Suck Creek and complete the mapping of horizontal extent in this area.

0 GWA-33 S, a shallow system well west of the active ash pond and about. 400 ft west
of Suck Creek contains Co, Fe, Mn, and above 2L. Local ?ow directions are
poorly understood in this area, particularly near/at Suck Creek. For example, shallow
sulfate exceedances shown in Fig show groundwater depicted as moving from
west to east toward Suck Creek. However, this interpretation runs counter to the
water level measurements on Fig 6-6 and assumes, without supporting ?eld
measurements, that the elevation of Suck Creek in this area is less than the water level
elevation in S. In contrast, shallow water levels in ABZS (74312), MWSS
(729.96), and GWA3SS (7l6.52) indicate that groundwater flow moves from east
(ABZS, 743.12) to west (Suck Creek), and from Suck Creek westward toward GWA-
338 (716.52).

0 deep/bedrock flow system wells located about 4-00 ft SW of 
and about 200 ft from Suck Creek, contain Fe, Mn, 804, TDS and Fe, respectively,
above 2L. Deep/bedrock wells are lacking in this area, and, as a result, horizontal and
vertical flow gradients are uncertain, particularly near/at Suck Creek.

0 The additional wells and (or) streamside drive points should be installed, measured,
and sampled to better understand the local hydrology in this area of CSS.
Determining the contaminant source (plant to the west or ash pond to the east),
horizontal and vertical flow directions and contaminant extent, and the extent to
which contaminants are discharging to Suck Creek is important in modeling,
assessing site risk, and developing a CAP. The purpose of the new wells is to better
understand local flow directions, the role of Suck Creek on local ?ow, and, based on
these ?ndings, ensure that the horizontal and vertical extent for each C01 in this area
has been determined and mapped. New wells should include a shallow well at
(MW23D is screened from 36-46 ft and MW23DR is screened from 45-
95 ft; soil/sap extends to a depth of 43 ft here), a well pair to the west of MW23D,
and wells/well pairs/drive points at other locations near/at Suck Creek. If near?stream
piezometers and (or) well pairs are needed to understand vertical gradients and

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Cliffside Steam Station
September 18, 2015
Page 6 of 8

contaminant movement in this area, they should be installed and sampled. Given the
scales involved here, understanding ?ow in this area of CSS should be based on water
level measurements and contaminant concentration data rather than relying on ?ow
and transport model results that are based only on data from the currently installed
wells.

0 A revised HSCM narrative and potentiometric and isoconcentration map(s) should be
provided and results used in modeling.

6 The area of shallow boron exceedances in the vicinity of just west of the active
ash pond in Fig currently depicts groundwater as moving to the northwest
approximately parallel to Suck Creek. This assumption should be checked by installing
additional monitor wells and measuring water levels and selected contaminant concentrations
in this vicinity. If near?stream drive points and (or) well pairs are needed to understand
vertical gradients and contaminant movement in this area, they should be installed and
sampled. Determining ?ow directions and the extent to which contaminants are discharging
to Suck Creek is important in assessing site risk and developing a CAP. Given the scales
involved here, understanding ?ow in this area of CSS should be based on water level
measurements and contaminant concentration data rather than relying on flow and transport
model results that are based on data from currently installed wells. After new wells are
installed water levels in this area should be re-measured and a revised potentiometric map(s)
should be provided.

0 The CSA fails to determine extent of ash in both of the side-by? side ash storage areas (see
sections 3.2 p. 15 and 7.2 p. 40). There was no ash sample collected from ?eastern? ash
storage area and the extent. of ash is uncertain in both. Borings should be added and results
provided. Refer to GAP for boring depth protocols.

0 Although samples between the waste boundary and compliance boundary in the
ash storage area (see section 8.5.2.2 p. 55) were not speci?ed in the GAP, it is now apparent
that they should be collected in this area to help delineate the extent of ash and groundwater
contaminants. Results should be provided.

0 a shallow system well west of the unit 5 basin contains Co and Mn above 2L. In
an effort to determine the source of elevated Co in this location and evaluate whether this
well does, in fact, represent background conditions, an additional we11(s) are needed in this
vicinity. The purpose of the well(s) is to better de?ne groundwater flow directions here and
evaluate whether the Co level is isolated or not and the extent to which geochemistry may
affect the Co concentrations observed.

0 GWA-4D, a deep system well north of the unit 5 basin contains Co, Fe, Mn, and TDS above
2L. The Broad River, a receptor, is about 1000 ft. downgradient and source determination is
limited in this area. An additional deep well should be installed in this area to assist in
source determination and to help map the potentiometric surface and horizontal extent of
contamination in this area.

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Cliffside Steam Station
September 18, 2015
Page 7 of 8

0 To model the particularly high contaminant concentrations in groundwater beneath the unit 5
basin, we need a ?ow path transect (Fig 11-1) from US-ZD, U5-3D, and a newly
installed well close to the discharge area along the Broad River. The revised transect and
associated data, cross sections, and interpretations should be included in the CSA addendum,
groundwater models, and the CAP.

The CSA fails to de?ne the vertical extent of contamination in the area of the Unit 5 basin.
Need additional bedrock wells in the Unit 5 basin to replace dry wells, ideally in proximity to
or clustered with U5-7D, and US-SD.

0 Because of the large size of Unit 5 basin, additional pore water sample(s) should be collected
and results provided.

9 The CSA fails to define the extent of ash in Unit 5 basin (see section 7.4.1 p. 42). Only 2 (of
17) borings were located in ash. Borings should be added and results provided in an
addendum. Refer to GAP for boring depth protocols.

0 Regarding section 7 .42 p. 42, well was not sampled during the GSA. The well
should be sampled and results provided.

0 The CSA failed to sample CLFOSS, and
(see section 7.6). These should be sampled and the results interpreted and
presented.

0 Need to sample 1D, GWA-3 1BR, U5-3 S, U5-4BR, and GWA-6S. These were dry and
were not sampled during CSA. If these are still dry during the upcoming sample event,
replacement wells are needed.

0 Need to sample porewater in US-ZS-SL. This was not sampled during CSA.

Other de?cient items or clari?cations shall also be addressed in the CSA Supplemental Report.
These items are attached to this letter.

The comments provided in this letter were based on a preliminary review of the CSA Report. The
Division. is continuing to review the report and may provide additional comments in subsequent
letters, if appropriate. Failure to address the de?cient items may result in the assessment of civil

penalties and/or the use of other enforcement mechanisms available to the State. If you have any
questions, please contact Ted Campbell at (828) 296-4500.

Sincerely,

S. Jay Zimmerman, P.G., Director

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September 18, 2015
Page 8 of 8

Division of Water Resources

Attachm ent

cc: WQROS ARO
WQROS Central Files
DENR Secretary Don van der Vaart
HDR (Attn: William Miller) 440 South Church Street, Suite 1000, Charlotte, NC 28202

NCDENRO194084