2015 10 30 Comments from SELC on Roxboro Steam Plant Assessment

SOUTHERN ENVIRONMENTAL LAW CENTER
Telephone [phone] WEST ROSEMARY STREET, SUITE 220 Facsimile 919-929-9421
CHAPEL HILL, NC 27516-2356
October 27, 2015
VIA EMAIL AND U.S. MAIL
RECEIVED
Citce of the 5ecreiary
OCT 302015
Mr. Donald R. van der Vaart, Secretary
North Carolina Department of Environmental Quality r)eper#rrtc nt of EnVrcnmeni
1601 Mail Service Center and k1 *,Q Ur'
Raleigh, North Carolina 27699-1601
Re: Comments on Roxboro Steam Plant Comprehensive Site Assessment
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 sites, counsel for the Department of
Environmental Quality ("DEQ") invited the public to comment on Duke's Comprehensive Site
Assessments ("CSAs" ). On behalf of the Roanoke, River 'Basin Association, the Southern
Environmental Law Center submits the following first set of comments on Duke's CSA for its
Roxboro Steam Plant in Semora, N.C.
The Roxboro CSA misrepresents the data collected at the site to claim that the ash basins
are separated from the groundwater, when in fact they appear to be deeply submerged up to 70
feet deep into the groundwater. This misrepresentation pervades many sections of the report and
will prevent any accurate assessment of the required corrective action and closure method going
forward, unless DEQ instructs Duke Energy to correct this fundamental flaw.
Fundamental Flaw — The Roxboro Coal Ash Is Submerged Over 50-70 Feet Deep In the
Groundwater
Groundwater levels measured at the site show that the coal ash at Roxboro is submerged
over 70 feet deep into the groundwater in the 1973 basin and over 50 feet deep into the
groundwater in the 1966 ash basin. The water levels measured at the site are presented in Table
6-6 and in the well schematics on Figures 6-1 and 6-2 (which are also reproduced in Figures 6-3
and 6-4). They show the bedrock water levels being at or near the top of the ash basins. This
indicates that there is no separation between the basins and the groundwater — instead, the
groundwater is saturating the ash basins. The basins extend down over 50 to 70 feet below the
measured water levels.
Despite the fact that the data measured at the site show the basins. are deeply submerged
in the groundwater"the CSA erroneously depicts the basins as being seprated from'the
groundwater. 'Figures 6-1 through 6-4 show solid dark blue lines for groundwater that are drawn
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to avoid the basins, erroneously depicting a separation between the basins and the groundwater.
There is absolutely no basis for these depictions. According to Table 6-5, the groundwater
elevation measured in transition zone wells is higher than that measured in bedrock monitoring
wells in six of the eight locations where both transition zone and bedrock monitoring wells are
co -located. The water elevation at the remaining two locations is only slightly below that
measured in the bedrock. Thus, the water level data do not back up Duke Energy's claims of
unsaturated regolith or transition zones beneath the ash pore water. Indeed, the CSA's
illustrations and statements — claiming that unsaturated zones separate the coal ash from the
groundwater — directly contradict the measured data. In short, the CSA seriously misrepresents
the issue of coal ash in unlined pits being located 50 to 70 feet below the water table, allowing
contaminants to leach out indefinitely.
This error is pervasive. The CSA erroneously relies on these misrepresentations of the
groundwater level when, for example, it claims in Sections 6,2.2 and 18.5 that the
regolith/saprolite or transition zones between the ash basins and the bedrock are almost entirely
unsaturated. In fact, the opposite appears to be true, based on the measured groundwater levels
at the site.
This issue is vitally important for the Coal Ash Management Act process. Duke Energy,
DEQ, and the Coal Ash Commission (if in operation at the time) will need accurate information
on whether a closure method can separate the coal ash from the groundwater and what types of
remediation will be required. This fundamental flaw must be corrected now, because this report
will inform the groundwater modeling Duke Energy will submit in its Corrective Action Plan,
which in turn will inform recommendations on groundwater remediation, site prioritization,
including whether or not the basins will be excavated and whether Duke Energy will be allowed
to rely on natural attenuation of groundwater pollution.
In this case, any closure method and remediation plan must take into account the fact that
the coal ash at Roxboro is submerged 50-70 feet deep in the groundwater. In particular, capping
the basins in place will do nothing to resolve this problem because the coal ash will continue to
be a source of pollution that remains in contact with the groundwater. Because the Roxboro
CSA erroneously depicts the groundwater levels at the site relative to the ash basins, it must be
corrected.
Page 24, Section 6.0, Site Geology and Hydrogeology - This section describes the
cross-sections in Figures 6-3 and 6-4 (which are also contained in Figures 6-1 and 6-2) as
illustrating flow path conditions in the vicinity of the ash basins. Unfortunately, these figures,
and all subsequent figures based upon these cross-sections, fail to accurately display the water
levels. The groundwater and pore water levels depicted on the figures do not match the water
levels actually measured at the site. The measured levels are indicated on the well schematics
included in the figure. For instance, Section A -A' (Figure 6-1 and 6-3) shows the "water level"
beneath the 1973 Active Ash Basin, indicated by a solid dark blue line, confined to the top of
bedrock at location ABMW-02BR, even though the measured bedrock water level on the well
schematic (indicated by a green triangle) is near the top of the ash basin. That measured
elevation is also consistent with Table 6-6. Yet the depictions of the water level in these figures
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directly contradict the measured water levels by purporting to show significant separation
between the ash basins and the groundwater. The depictions must be corrected to accurately
represent the conditions measured at the site.
The misrepresentation of the water level in these figures leads to other contradictions as
well. Section A -A' shows infiltration from the discharge canal migrating though the regolith and
transition zones to recharge groundwater — yet the ash pore water is shown, with no basis, as
being contained within the 1973 Active Ash Basin and not migrating through the regolith and
transition zones. Permeability test results from the regolith and transition zone show no low -
permeability materials capable of containing the pore water. Table 6-5 shows that the
groundwater elevation measured in transition zone wells is higher than that measured in bedrock
monitoring wells in six of eight locations. In the absence of any head data from wells or
piezometers screened in the transition zone showing unsaturated conditions beneath and adjacent
to the ash basins, it is inaccurate and misleading to indicate that ash pore water and ground'Arater
are separate systems.
Page 27, Section 6.2.1, Groundwater Flow Direction — The description of groundwater
flow directions presented in the report and depicted in Figure 6-5 is inadequate and ignores much
of the available water level data from the Site. In particular, it contains no information about
groundwater flow in, under, or around the ash basins.
The first paragraph of Section 6.2, Site Hydrogeology, correctly specifies that
"[g]roundwater at the Site exists under unconfined, or water table, conditions within the
regolith/saprolite zone, the transition zone and/or in fractures and joints of the underlying
bedrock. The water table and bedrock aquifers are interconnected." This description correctly
represents the groundwater data measured at the site and discussed above.
Yet Section 6.2.1 describes the groundwater flow directions based only on bedrock water
levels (Figure 6-5), as if bedrock were the only geologic unit in which the water table is
encountered. As was previously discussed, the separation between groundwater and ash pore
water presented in this report is indefensible. Ash pore water at this site is simply groundwater
that is currently within the basin. All relevant water elevation data, including pore water and
surface water elevation: data, must be used to prepare a water table map of the Site. The report
must be corrected to provide a more complete discussion of groundwater flow directions.
Page 28, Section 6.2.2, Hydraulic Gradients - This section erroneously claims the
saprolite or transition zone is unsaturated, and thus erroneously indicates that ash pore water
tends to be perched, or separated from the groundwater. These statements directly contradict the
description of Site Hydrogeology provided in Section 6.2 and the data collected at the site, all of
which indicate that the groundwater is unconfined and the ash basins are saturated by
groundwater. No data included in this CSA back up the claim of perched ash pore water that is
separated from the groundwater table. Measured heads within the bedrock and ash indicate that
groundwater occurs under unconfined conditions. Piezometers or wells screened within the
transition zone beneath the impoundments were not installed. No other evidence supporting the

existence of an unsaturated zone beneath the impoundments is cited. In the absence of evidence
of an unsaturated zone, the description of hydraulic gradients should be revised to be consistent
with the description of Site Hydrogeology and the measured water levels.
Page 116, Section 18.4, Horizontal and Vertical Extent of Soil and Groundwater
Contamination - Another way the CSA erroneously and artificially tries to represent the ash
basins as confining pollutants to the basins is in its description of the vertical movement of
groundwater. Here, the CSA does acknowledge the elevated groundwater head measured in the
bedrock, but draws a completely unsupported conclusion from it. Section 18.4 states that "[t]he
vertical impact of the COIs ["constituents of interest"] is also limited by the upward
potentiometric levels of bedrock wells in the ash basin area, which is well above the bottom of
the ash basins ...." In other words, the CSA claims that because the hydraulic head in the
bedrock groundwater is higher than the bottom of the ash- basins, groundwater must be flowing
up into the basin rather than carrying coal ash pollutants down and out of the basin and into the
groundwater flowing beneath the site. However, this statement totally ignores the pore water
head measured in the basin itself, which is generally greater than that measured in the bedrock
groundwater and thus would tend to cause water and pollutants to flow downward into the
bedrock from the ash basin. And indeed, the vertical groundwater gradients shown in Table 6-8
show predominantly downward gradients, directly contradicting the claim in this section.
Downward vertical gradients between the pore water and bedrock groundwater will drive flow
from the ash basins into underlying units — regardless of the relative elevations of the bottom of
the basins and bedrock groundwater head. Accordingly, Section 18.4 and its erroneous
assumption about the movement of groundwater and pollutants must be corrected.
Other Concerns
Page 12, Section 2.10.2, Upgradient Wells GMW-8 and GMW-9 — This section
incorrectly identifies GMW-8 as being located upgradient/side-gradient of the landfill.
However, examination of the Bedrock Water Level Map (Figure 6-5) shows that well GMW-8 is
located downgradient — not upgradient or side -gradient — of both the unlined and lined landfills.
Analytical results from GMW-8 show concentrations of boron, chloride, iron, manganese,
sulfate, and total dissolved solids (TDS) that are greater than 2L standards and apparently are
increasing. The location of GMW-8 downgradient of the landfills is consistent with the observed
elevated and increasing concentrations of ash -related constituents. This error highlights the need
for a better evaluation of groundwater flow directions and pathways than has been provided in
this document. In order to ensure an accurate measurement of groundwater conditions, DEQ
must instruct Duke Energy that GMW-8 is not a valid background well.
Page 28, Section 6.2.3, Hydraulic Conductivity - The re�orted hydraulic conductivity
of a single sample, AB -04 (Table 6-10), was reported as 8.0 x 10" cm/sec. This result appears to
be erroneous because it is 3 to 4 orders of magnitude lower than hydraulic conductivity tests
performed on other ash samples from this site as well as ash samples from numerous other sites.
The result also appears erroneous because it is uncommon for a sample of coal ash to be
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described as "fine -medium sandy clay." Accordingly, this result should not be incorporated into
site characterization or groundwater model development efforts.
Page 60, Section 11.2, Hydrostratigraphic Layer Properties — Cross-sections
presented in this section (Figures 11-1 through 11 -20) show concentration contours for various
constituents based on concentrations detected in monitoring wells. Many of these figures are
misleading because they do not consider the probability that contaminants have migrated outside
of the ash basins. Infiltration of this water through the underlying ash and into the regolith,
transition zone and bedrock have undoubtedly resulted in elevated contaminant levels below and
adjacent to the basins. This is supported by the recorded water levels at the site, showing that the
bottom of the coal ash in the basins is located 50-70 feet below the water table, and the vertical
hydraulic gradient in the ash basins is predominantly downward. Accordingly, the figures
should be revised.
Conclusion
The Roxboro CSA goes out of its way to misrepresent the relationship between the
groundwater at the site and the ash basins. The data collected at the site show the ash basins are
saturated deep in the groundwater. Yet the CSA claims the basins are separated from the
groundwater by an unsaturated zone that appears, based on all the measurements in the report,
not to exist. No accurate groundwater model, remediation plan, site prioritization, or closure
plan can be developed based on these misrepresentations. These fundamental flaws in the
Roxboro CSA must be corrected in order to ensure an accurate analysis of the extent of the coal
ash and groundwater continuation at the site. We ask you to require Duke Energy to correct
these flaws in the CSA and its subsequent reports and models.
Thank you for your consideration of these comments.
Sincerely,
Frank S. Holleman
Nicholas S. Torrey
cc: Stanley (Jay) Zimmerman, Director, Division of Water Resources, Central Office
Jane Bernard, DEQ Raleigh Regional Office
Harry Sideris, Senior Vice President of Environmental, Health & Safety, Duke Energy