NC0089699_Meeting Agenda_20170714

NTE Reidsville Energy Center, Rockingham County
PCN/NPDES Permit Review - Agency Coordination Meeting
Friday, July 14, 2017 @ 1Oam
USFWS Raleigh Ecological Services — 551B Pylon Drive, Raleigh, NC
Agenda
- Introductions
- Project Location Overview
- Intake Overview
-- issues for consideration: screen sizing, percentage of stream flow during instantaneous
low flows; maximum withdrawal capacity
-- Specific questions/comments for discussion:
• What is the maximum the intake structure can withdraw (MGD)?
• "A quantitative estimate of the area in which a "particle is likely to be drawn into the
intake " is more difficult. Given the intake capacity is a small fraction of the mean annual
discharge of the Dan River (i.e. 0 63%), most of the river's flow in the mainstem call be
reasonably assumed to be "unlikely " to be drawn into the intake."
- NPDES Permit Overview
-- 3rd facility within very close proximity to other two facilities on Dan R. (Duke Energy
Dan River Steam Station & Belews Creek Steam Station)
-- issues for consideration. temperature; effluent constituents; inadequate T/E species
analysis in EAA
-- Specific questions/comments for discussion:
Is it typical to use half of the detection limit to project average constituent
concentrations? It seems that using half does not equate to average (pg 5 of Application)
The 8 sampling events conducted between September 2016 and February 2017 does not
consider summer and spring (page 6) and 8 samples seems inadequate.
We are concerned about the temperature of the water discharged into the Dan River,
particularly in winter. Furthermore, different maximum temperatures are reported in the
documents. On pg. 8 it indicates that the discharge temperature will not exceed 80
degrees F but Appendix A indicates the maximum would be 85 2 degrees F. On pg. 110,
it indicates the worst -case conditions would be 81 6 degrees. In winter, the average low
in January was recorded as 40 6 degrees F so that could be a difference of 20 degrees if
water at the max temp is discharged.
Some constituents exceed water quality crtena at the end of pipe.
15A NCAC 2B 0204 indicates the regulatory mixing zones discharges in freshwater
should not result in acute toxicity to aquatic life or prevent free passage of aquatic
organisms, etc. The discharge entering the mixing zone is 7x concentration, which is a
concern Aquatic life is still expected to occur within the mixing zone, especially more
sedentary species like mussels. Need to consider instantaneous low flow conditions for
the mixing zone.

• In comparison with the NC 15A NCAC 02B Surface Water Quality Standards table
(6/30/16), several of the effluent characteristics from NTE discharge exceed and/or occur
within the acute or chronic levels for the Freshwater Aquatic Life standards.
• The document does not detail -he impacts of the discharge, or withdrawal, on aquatic
species, with particular attention to federally and state protected species.
• The bathymetry data collected to determine if compliance with NC's mixing zone
regulations was conducted in February 2017. This was not conducted during times of low
flow (pg. 10).
• As a dynamic river system, we have concerns regarding the impact of discharge
constituents and temperature on aquatic life during instantaneous low flows. Although the
7Q 10 was used for calculations, we would like for the instantaneous low flow conditions
to be used to determine the impacts of discharge (temperature, amount, and constituents)
and withdrawal.
• Pg. 10, it is stated that due to the small size of the mixing zone and rapid mixing of
effluent, the change of temp is not expected to result in adverse impacts to the criteria
listed in 15A NCAC 2B.204; however, there is no data supporting this claim, particularly
during winter months when the water discharge may be significantly higher than the
receiving waters.
• Is it possible to filter the constituents out of the water prior to discharge?
- Action Items
- Next Steps