HomeMy WebLinkAboutNCS000549_Permit Modification MOD-SW018 PartII-Pg13_20160620Permit No. NCS000549 - Minor Modification effective June 20, 2016
Stormwater outfalls SW015, SW016, and SWO17 have been removed or permanently
abandoned, and monitoring requirements no longer apply. The following parameters shall
be monitored during a measurable storm event from the areas draining the substation
pad and surrounding area, rail line improvements, and powerhouse stormwater
drainage previously routed to wastewater outfall 002A, through the outfall
designated SW018 (18" RCP), discharging to the Catawba River (Mountain Island Lake).
Table 10. Analytical Monitoring Requirements for SW018
Discharge
Measurement
Sample
Sample
Characteristics
Units
Fre uenc 1
Type2
Location3
Total Suspended Solids TSS
m L
semi-annual
Grab
SDO
Non -Polar Oil & Grease by
mg/L
semi-annual
Grab
SDO
EPA Method 1664 SGT -HEM
40 CFR Part 423 Appendix A:
Grab
SDO
Priority Pollutant Metals - Ag, As, Be,
mg/L
semi-annual
Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se, Tl, Zn4
Boron4
mg/L
semi-annual
Grab
SDO
pH4
standard
semi-annual
Grab
SDO
Total Rainfa115
Rain
-
inches
semi-annual
Gauge
Footnotes:
1-3 Refer to Table 1, Footnotes 1-3
4 These parameters shall be monitored only if coal or coal ash is transported through the drainage
areas of these outfalls during the semi-annual monitoring period in Table 11. Mercury shall be
measured by EPA Method 1631E.
Refer to Table 1, Footnote 4
Should the permittee identify or create any new stormwater outfalls; remove any
stormwater outfalls identified in this permit; or alter any drainage areas that change
the potential pollutants in runoff discharged through corresponding outfalls, the permittee
will submit a request to NC DEMLR to modify this permit. For any newly discovered pipes
or outfalls, the permittee must evaluate the structure and provide a report of the status and
planned actions to NC DENR within 14 days. The permittee must either (1) request
modification of this permit and modify the SPPP accordingly, or (2) eliminate potential
discharges by removal, plugging, or combination of both.
The permittee shall complete the analytical samplings in accordance with the schedule
specified in Table 11, unless adverse weather conditions prevent sample collection (see
Adverse Weather in Definitions). A minimum of 60 days must separate Period 1 and
Period 2 sample dates, unless monthly monitoring has been instituted under a "Tier Two"
response. Inability to sample because of adverse weather conditions must be documented
in the SPPP and recorded on the DMR. The permittee must report the results from each
sample taken within the monitoring period (see Part III, Section E). However, for purposes
of benchmark comparison and Tiered response actions, the permittee shall use the
analytical results from the first sample with valid results within the monitoring period.
Part II Page 13 of 19