20151001155949136

SOUTHERN ENVIRONMENTAL LAW CENTER
Telephone [phone]
Via electronic mail
601 WEST ROSEMARY STREET, SUITE 220
CHAPEL HILL, NC 27516-2356
October 1, 2015
Donald R. van der Vaart, Secretary
North Carolina Department of Environmental Quality
1601 Mail Service Center
Raleigh, North Carolina 27699-1601
donald.vatidet•vaart c ..nedenr.gov
Facsimile 919-929-9421
Re: First Set of Comments on Errors in Duke Energy's Comprehensive Site
Assessments at Buck, Allen, and Cliffside Coal Ash Ponds
Dear Mr. van der Vaart:
At a recent hearing before the North Carolina Superior Court regarding alleged
contamination at Duke Energy's ("Duke") coal ash ponds, counsel for the Department of
Environmental Quality ("DEQ") invited the public to comment on Duke's
Comprehensive Site Assessments ("CSAs") for its coal ash ponds. As part of the
comment process, and on behalf of the Yadkin Riverkeeper, Waterkeeper Alliance,
MountainTrue, Catawba Riverkeeper Foundation and itself (collectively, the
"Conservation Groups"), the Southern Environmental Law Center provides these
comments to alert DEQ to critical flaws in Duke's CSA for the Buck Steam Station
("Buck"), Allen Steam Station ("Allen"), and Cliffside Steam Station (Cliffside). In
particular, Duke:
(1) offered conclusions to DEQ and the public unsupported by its
currently incomplete assessments,
(2) failed to evaluate the groundwater in the deep bedrock aquifer
closest to the neighboring drinking water wells,
(3) failed to drill monitoring wells that would tap into groundwater at
the same depths as neighboring drinking water supply wells,
(4) made assumptions that dramatically underestimate the speed at
which contaminated groundwater travels, and
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Donald van der Vaart, Secretary
October 1, 2015
Page 2
(5) ignored or failed to collect critical data from neighboring drinking
water wells needed to accurately evaluate whether coal ash
pollutants are contaminating those wells.
In particular, by turning a blind eye to residential drinking water wells and
bedrock contamination generally, Duke's CSAs mischaracterize the current and future
risks to the drinking water supply for hundreds of people living and working near these
facilities, whose primary source of clean water is the bedrock aquifer portion of the
groundwater system. DEQ cannot recommend clean-up priorities or determine corrective
action, as required by the Coal Ash Management Act without this missing information.
DEQ must require Duke to correct these errors without delay.
The Conservation Groups note that there may be many other errors in addition to
these glaring and significant omissions in these CSAs. In addition, similar problems may
pervade Duke's CSAs for its other coal ash facilities. Although these CSAs are available
on the DEQ website,' numerous CSA figures are unreadable, distorted, or lacking most or
all of the information that they are intended to present. As a result, the Conservation
Groups have not been able to fully evaluate the results or adequacy of Duke's
assessments, assumptions, and interpretations. We expect to identify additional areas of
concern upon further evaluation of Duke's CSAs, and upon gaining access to complete
and accurate figures and data.
1) Duke's Incomplete CSAs Do Not Support Its Public Assertions.
Duke admits that its CSAs are not complete, and that supplemental CSAs are
needed. See, e.g., Cliffside CSA at 37,70,121; Buck CSA at ES -9; Allen CSA at ES -15.
The CSAs are plagued with problems, including the errors highlighted in the following
sections. And DEQ has in no way approved the CSAs. Yet in its CSAs and in press
statements describing them, Duke offers assurances it cannot support with these
incomplete and flawed CSAs.
For example, with respect to Buck, Duke asserts with unearned confidence that
"Groundwater flow is predominately in the north direction toward the Yadkin River and
is downgradient from and not towards off-site receptors." Buck CSA at ES -2. Similarly
with respect to Allen, Duke assures DEQ and the public that that there is no risk of coal
ash contamination to neighboring drinking water wells in the Belmont community
because the direction of groundwater flow at the site is away from those homes. Allen
CSA at ES -2. At Cliffside, too, Duke claims that offsite migration to the Broad River
and into bedrock poses no imminent hazard to human health or the environment, before
completing the work necessary to justify—or disprove—that assertion. Cliffside CSA
ES -2. And across all three sites, Duke suggests that areas of groundwater contamination
remain confined to discrete areas on its property notwithstanding its failure, at this point,
to complete work required to delineate the extent of contaminated groundwater plumes.
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Donald van der Vaart, Secretary
October 1, 2015
Page 3
DEQ has apparently accepted many of these unsubstantiated preliminary
statements as definitive fact. Earlier this week, DEQ entered into an agreement with
Duke that purports to settle groundwater violations at all 14 of Duke's North Carolina
coal ash facilities while requiring interim action to address groundwater contamination at
only four of those sites because it accepted Duke's assertion that only those facilities
have "demonstrated offsite groundwater impacts in isolated areas that are [sic] impacting
private wells in the Comprehensive Site Assessments conducted pursuant to LAMA."
See Settlement Agreement, Duke Energy Progress, Inc. v. NC Dept. of Envt. and Natural
Res., Div. of Water Resources, Office of Administrative Hearings, No. 15 EHR 02581
(Sept. 29, 2015).-
Because
015).
Because of deficiencies and errors in its analysis of groundwater contamination in
the fractured bedrock at these sites, Duke has dismissed with a wave of its hand one of
the most concerning threats at its coal ash disposal sites—the contamination of drinking
water wells. As discussed further below, the data gaps and incomplete analysis that
remain, as well as outright errors, undermine the basic conclusion offered by Duke to
DEQ and the public that Duke's coal ash contamination is not impacting neighboring
families or the environment at these sites.
2) Duke Failed to Study the Bedrock Aquifer in the Area Nearest to the
Residential Drinking Water Wells.
The most obvious and egregious deficiency of Duke's bedrock aquifer assessment
at Buck is its failure to assess any bedrock aquifer areas to the south, southeast, and
southwest of its coal ash basins—the precise areas where the majority of the residential
wells are located. See Buck CSA Figure 6-7; Figure 1 below. And Duke reports no
evaluation of the bedrock aquifer system beyond its property boundary. Duke's single,
purported `background' bedrock monitoring well (BG1BR) was `dry,' and thus it
provides no information about contaminant concentrations, hydraulic head, or local
groundwater flow. By characterizing the bedrock aquifer for only half of the Buck site—
the portion furthest from the bedrock residential wells—Duke has omitted information
that is critical to determining the full extent of the groundwater contamination and risk at
Buck.

Donald van der Vaart, Secretary
October 1; 2015
Page 4
Figure 1: Excerpt of Buck CSA Figure 6-7, Modified to Include Nearby Drinking
Water Wells
3) None of Duke's Bedrock Monitoring Wells Serve as an Apples -to -Apples
Comparison with Off -Site Drinking Water Wells at Buck.
Not only did Duke neglect to install any bedrock monitoring wells near
neighbors' wells at its Buck or Allen sites, the handful of distant bedrock wells it
attempts to rely on are improperly constructed. To serve as the basis for determining
groundwater levels and directional flow as compared to residential wells, it is well-
established that monitoring wells must draw water from the same range of depths as
residential wells. The depth of the well and the length of the opening in the well are two
related but distinct concepts: a well could be 200 feet deep, but only open from a depth
of 100-105 feet, with the rest enclosed in casing. In this example, contaminated
groundwater flowing through a crevice in the bedrock at a depth of 50, 110, or 210 feet
would not be detected in the well. To serve as a useful comparison to residential wells,

Donald van der Vaart, Secretary
October 1, 2015
Page 5
the openings through which Duke's monitoring wells withdraw groundwater must be at a
depth and length similar to the openings in nearby residential drinking water wells.
Contrary to this well-established principle, Duke's bedrock monitoring wells at
Buck, for example, extend no deeper than 200 feet below the ground surface, while some
residential wells extend 600 or more feet below the ground surface. In an unpredictable,
fractured -bedrock aquifer system such as the one underlying the Buck site, it is not
possible to evaluate the likelihood of contamination to drinking water wells by studying
groundwater exclusively at much shallower depths. Duke's bedrock monitoring wells at
Buck also draw water from vertical openings that are only five feet long (CSA Table 6-
9), while the vertical openings on residential wells near Buck range around 20 to 500 feet
in length (CSA Table 4-1). As a result, Duke's test methods did not replicate the real-
world conditions in which the residential wells operate. It is futile and misleading to
compare the static water levels in these dissimilar wells, or to translate those levels into
directional flow of the aquifer at the depths from which residents are drawing their
drinking water.
4) Errors in Analysis and Faulty Assumptions Undermine the Assurances
Offered in Duke's Allen and Cliffside CSAs.
Duke's Allen and Cliffside CSAs each suffer from serious fundamental errors or
data gaps that cloud the conclusions offered by Duke Energy.
For example, Duke's contractor has dramatically underestimated the hydraulic
conductivity in bedrock at the Allen site, leading Duke to suggest in its CSA that site
conditions are preventing groundwater from migrating off its property. In truth, however,
the data collected for the CSA, when analyzed with the proper method, suggests that
bedrock at the site is just as permeable as the overlying unconsolidated soils.
Duke used an incorrect method to compute hydraulic conductivity values for all
of the bedrock aquifer slug tests at Allen. As a result of these errors, the Allen CSA
underestimates the actual, measured bedrock permeability by a factor of 50 to 100. These
errors led Duke to offer unsupported hydrogeologic interpretations and conclusions in the
Allen CSA with regard to groundwater flow and chemical transport rates and directions
(horizontal and vertical). Because the permeability of the weathered bedrock is similar to
the overlying soils, the CSA interpretation that the bedrock acts as a lower confining
layer for groundwater flow and chemical transport is incorrect.
Therefore, the CSA conclusions that (1) all site groundwater discharges into the
Catawba River (Lake Wylie) and (2) groundwater and dissolved coal -ash constituents are
restricted from migrating to the west toward the residential and water supply wells are not
supported by the data. The significant hydraulic conductivity of the bedrock formation is
further demonstrated by the large measured downward hydraulic gradient (i.e., downward
flow component) from overburden to bedrock at many well clusters across the site.

Donald van der Vaart, Secretary
October 1, 2015
Page 6
Although these data clearly contradict the CSA conclusion that all site -related
groundwater and dissolved coal -ash contaminants discharge into the river, the CSA
neither addresses the high permeability of the bedrock nor the significant downward
groundwater flow component at the Allen site.
Of particular importance is the strong downward groundwater flow component
along most of the eastern site boundary next to the Catawba River. Based on the
hydraulic data presented in the CSA, at most only a portion of the site groundwater is
discharging into the river. Much more hydrogeologic data (e.g., vertical hydraulic
gradients beneath the river and in the riverbed, riverbed permeability, soil permeability
beneath the river bed, etc.) are needed to address this major data gap.
In a related error, Duke Energy's mistaken interpretations of bedrock permeability
led Duke to prematurely dismiss the potential for westward and downward groundwater
flow and contaminant transport to impact the many private and public water supply wells
located very close to the compliance boundary. No off-site bedrock monitoring wells
were installed and hydraulic analyses were not performed to evaluate the effects of
groundwater extraction from these wells on three-dimensional site groundwater flow.
These CSA data gaps are even more important in light of Duke's errors in measuring
bedrock permeability.
Moreover, at Cliffside Duke offers assurances that contaminated groundwater is
not affecting offsite receptors without having completed the analysis necessary to support
that conclusion. Duke's Cliffside CSA admits that "[h]eterogeneities, with regard to
groundwater flow, were not identified" and presumably not studied. Cliffside CSA 111.
Stated differently, Duke interpreted some evidence to mean that some groundwater
flowed in a given direction at some parts of the site, and then expanded that narrow
evidence intro a general assumption pervading the CSA, without completing the work
needed to test that assumption. These oversimplifications are inconsistent with the
complexity of the fractured bedrock geology at the site and do not support Duke's
proffered conclusion that contamination from Duke's coal ash impoundments ponds is
not affecting neighboring drinking water wells.
5) Duke Disregarded Groundwater Analytical Data for Sampled Off -Site
Drinking Water Wells near Buck, Allen, and Cliffside.
Across the Buck, Allen, and Cliffside CSAs, Duke chose not to evaluate bedrock
groundwater in critical areas of inquiry outside its property. Duke identified nearly 200
known or suspected water -supply wells within 0.5 miles of the Buck facility compliance
boundary. Yet Duke did not measure the water levels in these wells, nor did it determine
which direction contaminated groundwater flows on the southern side of the Buck site.
Although CSA Appendix B includes other categories of data and measurements for 90 of
these water -supply wells tested under the "NCDENR Well Water Testing Program"
(CSA Section 4.3), Duke did not evaluate or incorporate those data in the context of their
Groundwater Characterization (Section 10.0) or their Risk Assessment (Section 12.1.5).

Donald van der Vaart, Secretary
October 1, 2015
Page 7
Duke's CSA states, without any supporting analysis, that there is no real or
potential impact by any constituent of interest ("COI") from the Buck coal ash ponds to
any of the water -supply wells located within at least 0.5 miles: "All of the off-site private
water supply wells are upgradient of the ash basin" (page 86), "...the source does not
appear to be impacting COI concentrations toward off-site receptors immediately south
and east of the Buck site..." (page 105), and "No information gathered as part of this
CSA suggests that water supply wells or springs within the 0. 5 -mile radius of the
compliance boundary are impacted by the source. " (page 110). Without a full,
transparent analysis of all information available from these neighboring water -supply
wells, DEQ cannot fully or accurately characterize the risks of contamination from the
Buck and Allen coal ash ponds.
Similar data gaps and unsubstantiated conclusions are pervasive throughout
Duke's Allen CSA. At Allen, Duke did not collect fundamental data about water levels
or well construction information from the field of residential drinking wells immediately
adjacent to Duke's property boundary. Neither has Duke at this point analyzed the
hydraulic impact of pumping from residential and public drinking water wells on the
prevailing groundwater flow direction at the site. Without that data and analysis in hand,
neither Duke nor DEQ have a fair basis for their representations to the public that
residential wells in the Belmont community are not impacted by coal ash contamination.
And Duke's proposal to address this deficiency with future modeling at some point will
not close this information gap. A verified model is only as good as the data that inform
its development. Without adequate testing of bedrock wells in the Belmont community,
Duke cannot substantiate its assurances that the families in that community are not
affected by coal ash pollution.
Conclusion
DEQ must require Duke to correct all of these errors promptly. To do so, DEQ
must require Duke to:
(1) drill new bedrock monitoring wells on the southern side of the Buck
coal ash lagoons, equivalent to the number of bedrock monitoring
wells on the northern side of the lagoons,
(2) drill new bedrock monitoring wells at the Allen and Cliffside sites at
locations designed to gain a full understanding of the migration of
contaminants through fractured bedrock at those sites,
(3) ensure that the openings in each of these wells is at a representative
depth and of a comparable length as those in the residential drinking
water wells,

Donald van der Vaart, Secretary
October 1, 2015
Page 8
(4) evaluate the static water level in these bedrock monitoring wells and
in the existing residential wells,
(5) reassess downward groundwater flow at the Allen facility and better
assess the extent to which site groundwater flows into the Catawba
River,
(6) evaluate the effects of pumping from residential and public water
supply wells at Allen and Buck,
(7) properly assess hydraulic conductivity in bedrock at its Allen site, .
and
(8) complete the work required by DENR to be conducted as part of its
CSAs and reevaluate its premature conclusions when that work is
done.
Without this information, DEQ cannot accurately assess the full extent of the risk
to human health and the environment at these sites or appropriately prioritize the site
based on that risk. And until Duke takes corrective action to cure its flawed CSAs, the
public cannot be assured that Duke will take appropriate corrective action to remedy its
coal ash contamination.
Sincerely,
Myra Blake
Staff Attorney
MDB/lap
cc: Stanley (Jay) Zimmerman, Director, Division of Water Resources, Central Office
Bruce Parris, DEQ Mooresville Regional Office
Harry Sideris, Senior Vice President of Environmental, Health & Safety, Duke
Energy
Anita LeVeaux, North Carolina Department of Justice
Jim Cooney, Womble Carlyle