NCG120038_Representative Outfall Status Request_20091109

MiCHARDSON SMITH GARDNER
FNGrMERING & CrEOLOGIC:AI.
NC LIC. NO. C-0828 (ENGINEERING)
November 9, 2009
Mr. Steve W. Tedder
Water Quality Regional Supervisor
NCDENR — Division of Water Quality
Winston-Salem Region
585 Waughtown Street
Winston-Salem, North Carolina 27107
RE: Representative Outfall Status Petition (NCG #120038)
Davidson County Solid Waste Facility
Thomasville, North Carolina
Dear Mr. Tedder,
As you are aware, Davidson County has been performing stormwater inspections and
monitoring in compliance with their NPDES permit (#120038). Currently, county
personnel are monitoring a total of nine (9) sedimentation basin outfalls. Per our site
meeting on October 29t" 2009, Richardson Smith Gardner & Associates, Inc. on behalf
of Davidson County is submitting this petition for representative outfall status as
described in Part III, Section D of the permit guidelines for Stormwater General Permit
NCG120000.
Industrial Activities
The Davidson County Landfill facility is located off of Roy Lopp Road in Lexington,
North Carolina and operates under NC Solid Waste Permit 29-06. The landfill facility
includes a + 32 acre Subtitle D municipal solid waste (MSW) landfill (Phase 1), an active
MSW landfill (Phase 2 — Area 1), a separate C&D landfill unit, a white goods area, a
recycling building, a landfill office, scales and scalehouse, and one closed unlined MSW
landfill unit (Holly Grove Landfill Areas I and II).
Davidson County's landfill receives municipal solid waste originating from residential,
commercial, and industrial sources as permitted under its Solid Waste Permit.
Stormwater runoff associated with the development of the site has been delineated by
drainage area as shown on Figure 1 (attached). Currently, there are nine (9) outfall
points for the Phase 1 and 2 MSW operations, the closed MSW units. Of these areas,
only three are currently active and receive waste (Phase 1 landfill which will be closed
before the end of 2009, Phase 2- Area 1 landfill unit, and the C&D landfill unit).
As was noted during our meeting, several areas of the site have been closed, or have
not yet been developed past the point of construction road installation. Closed areas
include the Holly Grove Landfill, and the majority of the Phase 1 landfill (which will stop
receiving waste prior to the end of 2009 and will begin final closure of the remaining
14 N. BOYLAN AVE RALEIGH, NC 27603 • TEL. [phone] • FAX [phone] WWW.RSGENGINEERS.COM

Mr. Tedder
November 9, 2009
Page 2 of 3
areas). Three of the sedimentation basins located in the Phase 2 area were installed
primarily for construction. In these instances, the areas draining to the sedimentation
basins have been stabilized with an established stand of grass. All sedimentation
basins at the site are maintained and kept in proper working order.
Potential Pollutant Exposure
The Davidson County Landfill potential pollutants are (1) the active landfill, (2) vehicular
traffic, and (3) the leachate storage areas. The active landfill is the primary potential
pollutant area as defined by the general permit. The leachate storage tank area
functions to collect stormwater that comes into contact with waste prior to transportation
to the local Publicly Owned Treatment Works (POTW). This storage area includes
glass -fused -to -steel bolted tanks inside a secondary containment. Lastly, vehicle traffic
associated with waste disposal, operations, and maintenance are transient across the
site.
Proposed Representative Outfalls
RSG has performed an our evaluation of potential pollutant exposures at the site, and
the condition of closure/stabilized areas seen during our site visit to determine which
sedimentation basins would be more representative of any effect site activities may
have on stormwater and receiving streams. Based upon this evaluation, we request the
following outfalls be utilized for future monitoring:
3.
1. Phase 2 SBX— This sedimentation basin is directly adjacent to the active Phase
2 Area 1 landfill unit.
2. Phase 2 SB 4 — Although this sedimentation basin is not located near any site
activities, it is located adjacent to a large wetland area and therefore monitoring
will continue in this area.
3. Phase 1 SB 2 — This sedimentation basin is directly adjacent to the active Phase
1 landfill which will cease operations prior to the end of 2009.
4. Phase 1 SB 4 — This sedimentation basin is adjacent to the White Goods/Scrap
Metal area of the site.
5. C&D SB 9 — This sedimentation basin is directly adjacent to the active C&D
landfill unit.
These locations are shown on the attached Figure 1. These sedimentation basins will
yield data that is the most representative of any impact the operation of the site may
have on stormwater. Based upon this evaluation, we request that other sedimentation
basins on -site be removed from future monitoring requirements.