Cape Fear Steam Station (6)

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NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Charles Wakild, P E
Governor Director
March 21, 2012
Mr. Randy Cox
Carolina Power and Light
d/b/a Progress Energy Carolinas, Inc.
Cape Fear Steam Plant
500 CP&L Road
Moncure, North Carolina 27559
Ileo Freeman
Secretary
Subject: Draft NPDES Stormwater Permit
Permit No. NCS000550
Progress Energy Carolinas, Inc. -
Cape Fear Steam Electric Plant
Chatham County
Dear Mr. Cox:
Enclosed with this letter is a copy of revised draft NPDES stormwater permit for the Cape Fear
Steam Electric Plant. Please review the draft permit very carefully to ensure a thorough
understanding of the conditions and requirements each contains.
Thank you for joining our meeting with Duke Energy last November to discuss your questions and
concerns with the proposed stormwater permits for coal fired power plants. As we explained,
efforts to permit those power plants consistently across the state led to a comprehensive
stormwater monitoring scheme for all similar plants. The original draft permit for the Cape Fear
plant contained the same requirements as other NDPES stormwater permits issued for coal-fired
power plants since 2009.
Changes to Draft Permit and Permitting of Coal -Fired Power Plants
The revised draft permit reflects a more recent NPDES stormwater permit template, which the
Stormwater Perrnitting Unit (SPU) Implemented for all industrial stormwater permits this year (not
just power plants). Standard template changes include the requirement to monitor during a
"measureable storm event," rather than "representative storm event." Based on discussion at the
November meeting and your comments, we have also proposed new monitoring requirements.
These changes reduce metals monitoring significantly. The Division will continue to structure
stormwater permits for all coal-fired power plants as consistently as possible across the state, as
described below.
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location 512 N Salisbury St Raleigh, North Carolina 27604
Phone [phone] FAX [phone]
Internet www ncwaterouali+y om
An Equal Oppununnv 1 Affirmative Ac.tiun Emoluver
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NorthCarohna
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Progress Energy Carolinas, Inc
March 21, 2012
Page 2 of 4
This draft permit contains monitoring for conventional pollutants COD, TSS, 0&G, and pH because
they are general indicators of potential stormwater contaminants at these types of sites. Data from
permitted power plants and new permit applications indicate these parameters sometimes exceed
or fall outside of benchmark ranges. The pH is also critical to characterizing toxicity of metals.
This draft permit also includes monitoring for mercury (Hg) and selenium (Se). Both metals are
in coal combustion waste ash, a potential stormwater contaminant at these sites. All waterbodies in
the state are impaired for mercury, and a statewide mercury TMDL is under development. Studies
by N.C. State University researchers suggest that selenium may be taken up in fish in preference to
mercury at locations inclose proximity to coal-fired power plants (Sackett et al, 2010). Regional
deposition may influence mercury discharge concentrations, and therefore field blank data must be
reported. DWQ has not identified a conflict with sampling during a stormwater event and
employing Method 1631 for analysis when the intent is to characterize stormwater discharges (and
not uncontaminated wastewater discharges).
Permits for these plants will include aluminum (Al) monitoring if sample results submitted with
the application exceed the stormwater benchmark concentration of 0.75 mg/1, or if no data are
available (as in this case). North Carolina does not currently have a water quality standard for
aluminum, but there are federal recommended water quality criteria. An aluminum benchmark
does not apply unless the waterbody is ever impaired for aluminum or for biological integrity.
Power plants discharging stormwater to waterbodies impaired for copper (Cu), zinc (Zn), or
other priority pollutant metals will monitor for those metals. Biological impairment also
prompts copper and zinc monitoring, and possibly other metals associated with coal ash.
Exceptions may be made (and monitoring required) for metals or other toxicants for plant sites
discharging to waterbodies that are not impaired if data or other information evidences a possible
problem with stormwater discharges. However, in general, these permits will not require
monitoring for all priority pollutant metals as originally proposed. Where applicable, permits will
offer alternatives to copper and zinc benchmarks. Copper or zinc monitoring does not apply at the
Cape Fear plant site.
There is no benchmark that triggers monthly monitoring for mercury. Also, sampling for metals
may be discontinued after four consecutive samples are below the benchmark or below 12 ng/1 of
mercury In some cases, nutrient monitoring (total nitrogen and/or total phosphorus) will apply
because of nutrient problems in the river basin. The draft permit for this site includes annual
nitrogen and phosphorus monitoring because of nutrient concerns in the Cape Fear River.
This drat perrnit allows qualitative monitoring to be limited to representative outfalls if the
remaining outfalls can be observed once per the permit term. Exceptions may be made if the
regional office agrees outfalls are truly inaccessible or cannot be made safe without excessive
burden on the permittee; or the regional office determines some outfalls warrant more periodic
observation.
Plants Shutting Down
Draft permits for plants scheduled to shut down within the five-year permit term include
monitoring for the same parameters based on the criteria explained above Annual sampling
without benchmarks that trigger monthly monitoring is proposed for the Cape Fear Electric Steam
Station, contingent on the company submitting a plan within six months of the permit effective date

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Progress Energy Carolinas, inc
March 21, 2012
Page 3 of 4
to outline the shutdown schedule and clean-up details. This plan should include a demonstration
that past or present industrial activities will longer have the potential to pollute stormwater.
Please note that the Division is still obligated to review any request for permit rescission and to
consider site conditions after the shutdown before approving the request. The Division may also
require more frequent monitoring at a plant scheduled to shut down if discharge data or in -stream
data justify concern about in -stream standard violations.
Site Specific Conditions
During a site visit with the Raleigh Regional Office on September 8, 2011, we discussed the four
stormwater discharge outfalls (SDOs) that are applicable under this permit. The SDOs were SW -
001, SW -008, SW -002, and SW -003. The revised draft permit again does not require sampling from
SDOs SW -001 and SW -008 (inactive,ash ponds) as long as there are no discharges from events less
than the 25 -year, 24-hour storm. Please review footnote 3 under Part II, Section B. Table 2 for the
proposed conditions.
During that site visit, we also discussed the most appropriate sampling location and discharge
frequency for SDOs SW -002 and SW -003. The plant correctly relocated SW -002 closer to the
receiving water. We understand that standing water may sometimes introduce groundwater
influences to the sample; however, sampling upstream of this point would omit additional
treatment gained by flow through the field upland in that drainage area. DWQ recommends that
plant personnel use best professional judgment in sampling upstream of this point if flooding
conditions prevent sampling at the outfall (but as close to the outfall as possible) and in
documenting possible interference by groundwater here.
Plant personnel explained that SW -003 only discharges in response to larger rain events—around 3
inches or more—and asked how to target times when flows occur. To assist personnel responsible
for stormwater sampling, we advise the company to determine the minimum rainfall amount that
results in a discharge based on the drainage area and past experience. The company should
consider using a calculation method like the Simple Method [described in Chapter 3 of the DWQ
Best Management Practices (BMP) Manual, found here
http-//portal ncdenr org/web/wq/wslsu/bmp-manual] to estimate runoff from the drainage area
that corresponds to a certain size storm and observations of flow. Documenting that information in
the Stormwater Pollution Prevention Plan (SPPP) would provide guidance about when to
reasonably expect rainfall to produce a discharge and would support a record of "No Flow" from
SW -003 for the sample period as long as no events above that amount are recorded. The outfall
should still be periodically observed to fulfill qualitative monitoring.
Finally, during the visit we also confirmed that SW -006 discharges to the wastewater discharge
canal and ultimately to wastewater outfall 007, Covered by the NPDES wastewater permit.
Comment Period
Because of the significant changes, the Division will re -notice this revised draft permit NCS000550
for another public comment period. Please submit any comments to the appropriate Stormwater
Permitting Unit (SPU) no later than thirty (30) days following your receipt of the draft. We also
welcome the opportunity to meet with Progress Energy again to discuss the proposed permits
U the piibilC notice period

Progress Energy Carohnas, Inc
March 21, 2012
Page 4 of 4
Comments should be sent to the address listed at the bottom of this page. If no adverse comments
are received from the public or from you, this permit will be issued in about two montiis. If you
have any questions or comments concerning these draft permits, please contact Bethany
Georgoulias at [phone] or Bethany georgoulias@ncdenr gov
Sincerely,
Bradley Bennett
Supervisor,
Stormwater Permitting Unit
References
Sackett, D.K., D. D. Aday, J.A. Rice, W G. Cope, and D. David Buchwalter, 2010, Does proximity to coal-
fired power plants influence fish tissue mercury? Ecotoxicology 19:1601-1611. DOI:
10.1007/s10646-010-0545-5.
cc Raleigh Regional Office, Water Quality Section (w/attachment)/ A. Romanski
Robin Bryson, Progress Energy (via e-mail)
Fred Holt, Progress Energy (via e-mail)
Stormwater Permitting Unit
Attachments