NC0000272_Responses to EPA Region 4 Questions_20220401

Responses to EPA Region 4 questions regarding Evergreen Packaging 2014 Canton Mill 316(a)
Demonstration
C. C. Coutant
February 17, 2020
Several questions have arisen during EPA's review of the January 2014 Canton Mill §316(a)
Demonstration in support of an Alternative Effluent Limitation (variance). These informal
questions were expressed in several January 2020 emails between Karrie-Jo Robinson -Shell of
EPA Region 4 and Mike McGee, consultant for Evergreen Packaging. This note provides
answers for, and comments on, the questions, including citations to relevant locations in the
document. It is hoped that these responses are helpful to EPA in establishing that the
Demonstration meets the standards of proof required by the Clean Water Act, its implementing
regulations (40 CFR 125.70 — 125.73; known as Subpart H), and subsequent EPA administrative
decisions.
The Table of Contents of the 2014 Demonstration provides a good guide to the document.
Background information on the purpose, §316(a) requirements, facility operation, and the
receiving -water ecosystem is provided in the Introduction. Since this Demonstration is the latest
in a series, the 1977 EPA guidelines ask for explanations of anything that has changed since the
last Demonstration (also provided in the Introduction and in the biothermal assessments).
Summaries of the 2012-2013 study plans, both thermal and biological, are presented in Section
2. The biothermal assessments are summarized Section 3, with topical headings that match the
assessment elements, Indicators of Appreciable Harm, and RIS found in the EPA regulations.
The main text concludes with the Master Rationale related to the proposed Alternative Effluent
Limitation, as required in the 1977 EPA guidelines. Appendices give the details of the
temperature (Appendix A) and biological studies (Appendix B), a description of the fish
reintroduction program for historically extirpated fish (Appendix C), a description of an
anomalous fish kill (Appendix D), relevant statutes and regulations (Appendix E), and the
NCDENR-approved 2012 study plan (Appendix F).
The first set of questions relates to compliance with eight instructions included as an attachment
to a February 22, 2010 letter from James D. Giattina, Director, Water Protection Division, EPA
Region 4 to Colleen H. Sullins, Director, Division of Water Quality, North Carolina Department
of Environmental and Natural Resources. The letter was in response to EPA's review of the 2006
§316(a) Demonstration for the thermal discharge from the Canton Mill. The instructions were
intended as guidance for the subsequent 2014 permit application.
The instructions are quoted below (italics), followed by our response:
a) include available information on wildlife in the lake (sic) areas based on communications
with North Carolina's Wildlife Management Agency. See item 1 above [A population
typically characterized by diversity at all trophic levels].
Wildlife was covered in the Demonstration (note that the water body is a river, not a
lake). The Executive Summary summarizes the evidence. The field studies included
reports of several bird and mammal species typical of aquatic habitat, and studies of
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salamanders and crayfish. There was further elaboration in the main text for crayfish
(pages 88-89) and salamanders (pages 90-91). Table 4-1 of the main text indicates that
"protection and propagation of a BIC " is "partially" supported for Wildlife due to low
abundances of crayfish and salamanders, which would normally occur in the river or
riparian areas. Wildlife information is also presented in Appendix B, page 80.
There is some discrepancy between the regulations and the criteria in the Giattina letter.
The regulations at 125.71(c) state that a Balanced Indigenous Community "means a
biotic community characterized by diversity" and other factors. The Giattina letter,
however, inserts "at all trophic levels" after diversity. The letter further elaborates:
A population typically characterized by diversity at all trophic levels" [underlined in
the original] means that all of the major trophic levels present in the unaffected
portion of the water body should be present in the heat affected portions. EPA
recognizes that community structure differences will occur, however, the number of
species represented in each trophic level in the unaffected portions should be
reasonably similar in the heat -affected portions of the water body.
There are two interpretations of Region IV's definition. The first sentence in the above
explanation seems to refer to the community as a whole ("...all of the major trophic
levels present in the unaffected portion..."). That is, there are taxa present that represent
all of the major trophic levels —primary producers, decomposers, consumers. The second
sentence of the explanation appears to state that that there needs to be a demonstration of
diversity within each trophic level ("...the number of species represented in each trophic
level in the unaffected portions..."). That is, it would require identification to species of
each producer, decomposer, and consumer. Such a task would go beyond the EPA
guidelines for any biotic category. The 1977 guidelines for wildlife state (page 61):
Other Vertebrate Wildlife [underlined in the original]. Data will be required in
relatively few cases for this biotic category. In those cases where data is required, the
type of data needed is decided by the applicant. The data selected should be the least
amount of data necessary to complete this section of the demonstration.
This demonstration followed that guidance, and interpreted the regulations to mean that a
detailed species count was not needed for each trophic level.
b) include a diagram depicting the thermal plume under the worst case scenario and
address the presence or absence of a zone of passage for which fish can travel around the
plume.
The thermal plume pattern at different river flow rates (2.18, 2.63, 3.48, 11.86, and 16.54
m3/s), was summarized on page 3 of the main text, "The thermal plume from the outfall
mixes rapidly across the majority of the river during low Pigeon river flow rates, with a
small remaining temperature difference (-0.5°C) from side to side at the Fibreville
Bridge." Details are provided in Appendix A beginning on appendix page 31. Detailed
figures (Figure 84 on Appendix A page 89) through Figure 88 on Appendix A page 93)
depict aerial views of the plume and several graphs of temperature at distances and travel
times from the discharge. Figure 85 shows the plume most clearly on the aerial photo
(dark zone). Temperature decline is rapid and there is a clear zone of passage along the
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right side (facing downstream) at all flows until temperatures have declined to non -
harmful levels.
c) Provide information of (sic) which fish collected are either heat -sensitive or nuisance
species. See item 4 above. [Non -domination of pollution -tolerant species]
The referenced assessment criterion, "Non -domination of pollution -tolerant species", is
discussed on pages 5 and 6 of the main text's Executive Summary and pages 57-58
(§3.2.5) of the main text, where general pollution tolerance and thermal tolerance are
both discussed. In this section, reference is made to detailed descriptions including
thermal tolerance of individual species (§3.3). This demonstration has the benefit of
repeated studies in 1995, 2000, and 2012, which demonstrate important trends in species'
abundance as recommended by EPA's Environmental Review Board in the Brayton Point
case (ERB 2006. Environmental Administrative Decisions 12:490-707). The extensive
data (Appendix B) for the 2012 study were compared to data from the earlier studies to
demonstrate a general trend of decreases in thermally tolerant species and increase in
intolerant species over time downstream of the thermal discharge under the conditions of
successive permits (see the history of degradation and recovery in § 1.4.3 and §3.2.19 and
RIS descriptions in §3.3 of the main text).
Further, the main text at page 57 notes that two reference areas in an adjoining watershed
show a fish community similar to that of the Pigeon River downstream of the thermal
discharge (Appendix B, Table 3.2.1-4, on page 53). These two reference areas have
habitats more similar to the Pigeon River below the discharge than the upstream Pigeon
River reference area. Within the Pigeon River, Appendix Table 3.2.1-7 shows fish
species restricted to or much more abundant in the thermally affected zone from the mill
to Waterville Lake with comparisons to other zones. With the exception of common carp,
which is declining over time, no nuisance fish species are abundant. Some indigenous
species are now uniquely present there under recent permit conditions due to re -
introductions of once -extirpated species (sponsored, in part by Evergreen). As noted on
page 58 and §3.2.15 (page 60) of the main text, there was a local zone of nuisance blue-
green algae with associated heat -tolerant midge larvae in the thermal plume in summer
that is low in magnitude and duration and does not affect the overall riverine aquatic
ecosystem (consistent with the EPA Administrator's 1979 decisions in the case of
Wabash and Cayuga plants).
d) provide a list of any lake (sic) species that are endangered or threatened in accordance
with federal and state regulations.
Threatened or endangered aquatic species status in the Pigeon River is discussed in
§3.2.7 (page 58) of the main text. There are two listed mussel species that had been
extirpated below the mill historically (§ 1.5.2.5). Details are provided on each in §3.4.1.1
and §3.4.1.2 on pages 83-86. One has been re -introduced successfully in the river
downstream of the mill by the reintroduction project (§3.3.1 on pages 77-79 of Appendix
B, and Appendix C).
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e) analyze and present data to clearly demonstrate that affected communities have not
shifted to primarily heat tolerant assemblages.
See item c, above.
J) include recent data or information on benthic invertebrates. See item 1 above.
g)
Benthic invertebrates have been a major part of the field studies since inception of the
§316(a) demonstrations in the 1980s. See pages 64, 67-68, 77-79 and 83-90 of the main
text for a summary of results and §3.1 (pages 22-47) of Appendix B for the data and
analyses. Species richness, a measure of diversity, is discussed on page 23 of Appendix
B, with data on pages 24-37. EPT taxa richness (thermally intolerant insect larvae
Ephemeroptera, Plecoptera, and Trichoptera) are discussed on page 38. The North
Carolina benthic biotic indexes (NCBI) for reference and thermally affected sites on the
river were calculated and are discussed on page 38 of Appendix B. Historical
comparisons of the benthos were discussed and data presented in §3.1.2 of Appendix B
(pages 39-47).
analyze and present all data to demonstrate that community assemblages in the heat -
affected portions of the receiving water body are not significantly different from the non -
affected communities with regard to the number of non -indigenous species in the
assemblages.
The study included Principal Component Analysis of fish communities in six reference
areas for comparison with nine sites in the heat -affected portion of the Pigeon River
between the mill and Waterville reservoir and three sites in Tennessee downstream from
the hydropower facility (Executive Summary of main text on page 6, map on page 24 of
the main text, and pages 72-76 of Appendix B). Four were in the river and tributaries
upstream of the mill's discharge and two were in reaches of similar habitat in the nearby
Swannanoa River in the same French Broad River watershed. Comparisons were made
for all species, indigenous and non -indigenous. Statistical analysis of the PCA results
indicated no statistical difference between reference and heat -affected sites.
The use of six reference areas incorporates the variation among reference sites for
comparison with the heat -affected zones (most §316(a) demonstrations use only one
reference site). That is, the difference between heated and reference zones is compared to
the variation among several reference zones to see if the heat -affected zone falls in the
range of variation among otherwise similar reference sites. All raw data are included in
tables in Appendix B.
The fish community analyses also incorporated two indices of biotic integrity: (1) the
TVA IBI Protocol that focused on native (indigenous) species and heat tolerances, per the
emphasis on indigenous species in the regulations (tables 2.3-1 and 2.3-2 of Appendix B,
on text pages 21 and 22, respectively), and (2) the NCDENR (now "DEQ") protocol that
emphasizes tolerant versus intolerant species (Appendix B Table 2.3-2 on page 22). Both
protocols' scores showed localized fish community depression at the site immediately
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below the discharge in 2012 but some historically high scores farther downstream (For
TVA, Table 3.2.3-1 on page 65 and Figure 3.2.3-1 on page 66). A similar pattern was
shown by TVA and NCDENR protocols (Table 3.2.3-2 on page 67).
For the benthic community, macroinvertebrate samples were collected from 14 mainstem
sites, six tributaries, and two reference stations (page 22 of Appendix B followed by data
tables on pages 24-37). Data from these collections were used to calculate the North
Carolina Biotic Index (NC BI, per request of NC DENR) and EPT taxa richness (EPT
Index). These indices provided a bioclassification for each station (Excellent, Good,
Good -Fair, Fair, Poor). These classifications (in Appendix B Table 3.1.1-2) were used as
a gauge for comparisons among stations and to detect negative influences (narrative on
page 38). These scores showed a local depression of the benthic community immediately
downstream of the discharge ("Fair") whereas other mainstem sites were either "Good"
or "Good -Fair." The general improvement shown by historical comparisons (trends from
1995 to 2012) were presented on pages 39 and 47 (text) and Table 3.1.2-1 on pages 40-
47.
h) include a thermal modeling study based on historical effluent temperatures and operating
conditions to determine appropriate permit limits for temperature.
As noted in the Table of Contents (page ii), a thermal modeling study was a major
component of the §316(a) Demonstration, with a summary in the main text (pages 41-44)
and a detailed Appendix A. The study consisted of several parts: (1) temperature
monitoring at 14 mainstem Pigeon River stations, six tributary stations, and two reference
stream stations in an adjacent watershed during summer and winter conditions, (2)
preparation of a one-dimensional thermal model of the Pigeon River from upstream of
the Mill to Waterville Lake using hydrological, meteorological, and temperature data, and
(3) characterization of the size and shape of the thermal plume (zone of initial mixing)
between the outfall and the established thermal -compliance monitoring location 0.4 miles
downstream of the discharge (pages 42-43 of the main text). This latter effort included
both in situ temperature measurements and use of the plume dispersion model, CORMIX.
Detailed source data, methods for measurement and modeling, and results in the form of
text, tables and figures are presented in Appendix A. The models allowed calculation of
expected river temperatures under a variety of ambient conditions (river flow,
temperature, meteorology) and thermal discharge (volume, temperature), including cases
not actually observed in field studies. The models were used to estimate the magnitude
and duration of heat -affected river temperatures, as required by the regulations and
subsequent EPA administrative decisions for other discharges. These temperatures were
correlated with results of biological sampling (Appendix B). The thermal modeling
results, combined with the biological data, provided evidence in support of the proposed
Alternative Effluent Limitation (page 15 and the Master Rationale on pages 94-95 of the
main text).
Additional questions:
January 27, 2020 email from Karrie-Jo Shell to Carla Dollar and Bridget Staples (all of EPA
Region 4):
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1. I could not find in any of the appendices where the thermal influence from the mill
ended in the river, so I assumed it was at RM 61.0, which is 2 miles downstream of
the mill. Either NC or the mill will need to send a diagram of the thermal plume
showing the edge of the plume.
There are three ways to inform that matter: (1) the detailed measurements of the thermal plume
between the Mill's thermal discharge (RM 63.1) and the compliance -monitoring location at the
Fibreville Bridge (RM 63.0) taken at different river flows during the 2012 field study; (2) the
CORMIX modeling of the thermal plume in that zone (CORMIX is an EPA -approved model of
thermal plumes); and (3) the one-dimensional thermal modeling of the river from above the Mill
(RM 64.9) to the upper reaches of Waterville Lake (RM 45.3). Each of these approaches is
summarized in Section 2.2 of the main text and described in detail in Appendix A.
It is helpful to look at Figures 84-93 at the end of Appendix A. The temperature -monitoring
station for compliance has been at the Fibreville Bridge, downstream from the Mill and its
discharge. Figures 84-93 focus on that one -tenth -mile reach of river. It has long been assumed
that this location represents the point at which the plume is well mixed with the river (and
provides convenient access for measurements). The figures show the plume in aerial photos,
delta-T plots of the average plume temperature, and color -coded vertical and horizontal profiles
of delta T.
Each figure is described in Appendix A on page 34-36. The dark plume can be seen in the
Google Earth images on Figures 84-86 as it spreads from the discharge. The middle image is a
graphical representation of the plume as predicted by CORMIX, showing the plume reaching
nearly across the river when temperatures have dropped markedly. Just below the middle image
are the transit times (minutes) for the plume to reach a given location. Mixing times to near fully
mixed are a matter of a few minutes at most flows. The lower image is a graph of the average
increase in temperature of the plume at a given distance and travel time downstream of the
outfall. Figures 87 and 88 show a comparison of the CORMIX modeling to the measured thermal
cross sections. The top two images of each figure show the interpolated, measured thermal cross
sections at the railroad bridge (top) and Fibreville Bridge. The plume is not completely mixed
even at Fibreville Bridge (especially at moderate -to -high flows), leaving a zone of passage.
Those studies clarify the location of the plume. There is, however, a signature of residual
warming of the river downstream of the point of complete mixing. This aspect is covered by the
one-dimensional model described beginning on page 27 of Appendix A.
2. There are some species that are not present both up- and down -stream.
Yes, species occurrence in the sampling is irregular among stations and there isn't a
straightforward comparison of upstream versus downstream zones. For that reason, the study
included more than one reference location so that the species composition of the heat -affected
zones could be compared to the aggregate of six reference areas, four of which were in the
Pigeon River and two in similar habitats in a nearby river in the same watershed.
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3. Also, we need to know from NC which species are heat tolerant or not, in order to
see if there has been a shift to more heat -tolerant species down -stream of the mill.
Lastly, we need the same sort of summary for the benthic macro -invertebrates, also in
Appendix B.
Heat tolerance of the RIS is included in the main text, Section 3.3. Also, on page 5 of Appendix
B the pollution tolerances of fish species collected in the 2012 study were summarized: eight
intolerant, four tolerant, 29 intermediate, and four not rated by the NCDENR. The pollution
intolerant rock bass and smallmouth bass were collected at all mainstem stations both upstream
and downstream of the thermal discharge. The intolerant rainbow trout was collected only in the
Tennessee portion of the river. The thermally tolerant common carp were found scattered
downstream of the Mill (RM 63) to RM 10.3 and white suckers from three sites in North
Carolina. Only five thermally tolerant green sunfish were collected, one at RM 69.5 upstream of
the Mill and five at RM 10.3 in Tennessee. Redbreast sunfish (non-native) was the most common
tolerant species, occurring at all sites except one in Tennessee (RM 24.7). The ratio of rock bass
to redbreast sunfish from 2005 to 2012 was used as a measure of the thermal -tolerance trend in
the community. The ratio improved from 1:10.2 in 2005 to 1:5.6 in 2012, a 45% improvement in
numbers of the intolerant species relative to its non -indigenous, tolerant competitor. This
improvement came during the time of the permitted thermal discharge.
For the benthic invertebrates, the thermally intolerant EPT taxa (see above) in 2012 were present
and higher in the station immediately downstream of the Mill (RM 63.0) than in 2005 (Appendix
B, page 6). EPT ratios (EPT taxa vs. total taxa) were lower in the 7.5 miles downstream of the
Mill (five stations, 0.25 to 0.32) than in the reference areas (six stations, 0.23 to 0.52) (Table
3.1.1-2 on page 37 of Appendix B) but not so much as to be overtaken by the tolerant taxa.
January 28, 2020 email from Karrie-Jo Shell to Mike McGee (NC) [my numbering]
1. During the majority of the time, can the mill document there is a "zone of passage"
around the thermal plume for the fish? There are some graphs in appendix A which
we are taking a closer look at.
See response to question 1 from the January 27 email.
2. Also, the data may show there is an abundance of fish downstream of the plume, but
we need to know if they are more nuisance or heat -tolerant ....same for the benthos.
See response to question 2 from January 27.
3. At what point in the main stem of the river does surface water meet the NC WQS for
temp? In other words, how far does the thermal plume extend. I know this will be flow
and seasonally dependent. The North Carolina Water Quality Standard for
temperature is: not to exceed 2.8 degrees C above the natural water temperature, and
in no case to exceed 29 degrees C. 15A North Carolina Administrative Code 2B.0211
(18).
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See response to question 1 from January 27 for the plume information. The one-dimensional,
longitudinal model of river temperatures indicates a median modeled increase in weekly average
temperature due to the Mill's thermal loading to be 3.1 ° at Fibreville (the compliance station, 0.4
miles downstream of the discharge), 2.5° at the Above Clyde station (4.1 miles downstream),
and 1.5° at the Hepco USGS station (7.8 miles downstream) (Appendix A, page 2 and Table 12
on page 29). None of the temperatures at Above Clyde or Hepco exceed 29°. Although it isn't
very clear, Figure 83 of Appendix A shows the downstream extent of various delta T values as
calculated from data from 2006 to 2013. The numerical data that are behind that figure are not in
the report but may be available. The purpose of the Alternative Effluent Limitation is, however,
to set permit limits for the protection and propagation of a BIP/BIC even when the NC WQS for
temperature are likely to be exceeded.
4. In general, what do we know about the D.O levels near the thermal plume?
Dissolved oxygen was discussed as one factor in the topic of interaction of thermal discharge
with other pollutants, one of the topics in the EPA regulations (Section 3.2.17 on page 61 of the
main text). The state standard for DO is met downstream of the Mill. As reported in the text,
from January 1, 2004 to December 31, 2008, the daily average DO did not drop below NC's
standard of 5.0 mg/L for Class C streams. Further, data from 2010 through 2019 also show no
levels below 5.0 mg/L at Fibreville or downstream stations..
5. What is the overall cooling efficiency /capability of the cooling towers? There was
mention of the use of axillary cooling capacity. How often does this occur? Maybe the
mill needs to address O&M of the towers?
The Mill uses cooling towers to cool process water for reuse in the manufacturing process.
Portable, rented cooling towers were used once, in December 2016, to address the delta T issue
during extreme low flow.
6. Lastly, there needs to be a conclusionary statement regarding the endangered
species. It appears that there is/was at least one specie; I just want to make sure there
will not be a "take" related to the mill's thermal plume.
Threatened and Endangered Species were addressed in Section 3.2.7 (page 58) of the main text.
There were only two mussel species listed federally or by the state. They are discussed
individually in detail in sections 3.4.1.1 and 3.4.1.2, and in the main text's Executive Summary
on page 8 (but not highlighted there as a T&E issue). These sedentary benthic organisms had not
been found in the Pigeon River in modern times, either in the heat -affected portion or upstream.
Subsequent to the 2005 demonstration, one of them was found to occur far upstream of the Mill.
Because natural recolonization of the sedentary species is problematic, it has been reintroduced
following studies demonstrating that it can survive and grow in the heat -affected zone. The
second species has been proposed for reintroduction, also. The listed mussels constitute a
reestablishment of once -extirpated species' populations rather than a take, and thus were not
treated as being at risk of harm.
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In overall summary, we realize there are two objectives for EPA's (Ms. Shell's) comments: (1)
to see if the topics she mentions were included in the last 316(a) demonstration and biological
report, and (2) to ensure that they are covered in the study plan for a next round of studies in
support of a demonstration for permit renewal, should that be needed. These are fair questions. .
Although the comments aren't quite clear about whether a new biological study is needed for
permit renewal, the draft permit [A. (12)] seems clear that a new study will be needed unless
nothing about the discharge or the biota in the river has changed.
I understand that it is sometimes difficult to pinpoint the exact relevant text in a long document.
In spite of the EPA Environmental Appeals Board not liking checklists, here is where a checklist
of decision criteria with an index to location in the document might have been helpful for
reviewers. [EAB (EPA Environmental Appeals Board). 2006, page 556. Environmental
Administrative Decisions 12:490-707.]
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