WI0300466_Rescission Request_20240103

No WithersRavenel
Our People. Your Success.
January 2, 2024
State of North Carolina
Department of Environmental Quality
Division of Water Resources
1636 Mail Service Center
Raleigh, North Carolina 27699
Attn: Mr. Michael Rogers, P.G.
Reference: Infiltration Gallery Closure Plan
Former Community Cash and Carry
11330 NC Highway 801
Mount Ulla, Rowan County, North Carolina
Non -Discharge Permit Number: W10300466
Groundwater Incident Number: 27036
UST Number: MO-6501
WR Project Number: 23-0307-Z
Mr. Rogers:
WithersRavenel, Inc. (WR) is contracted to provide environmental consulting services with the
North Carolina Department of Environmental Quality (NCDEQ) Federal & State Lead Program at
the Former Community Cash and Carry site (NCDEQ Incident #27036). The results of the May
2023 groundwater sampling event indicated that the concentrations in the monitoring wells are
below the 15A NCAC 2L Groundwater Quality Standards (2L Standards). Two recovery wells
(RW-1 and RW-4) indicated concentrations above the 2L Standards. These recovery wells are
not located within the infiltration gallery. In addition, inactive water supply well WSW-1 was
abandoned in September 2023. Based on the sampling results and the water supply well
abandonment, the NCDEQ is granting the site a notice of No Further Action. Therefore, NCDEQ
requested the shut -down of the remediation system and the abandonment of the wells and
infiltration gallery associated with the site.
Infiltration Gallery
The infiltration gallery was constructed in June 2011 by excavating an approximately 32 feet by
52 feet area. The depth of the infiltration gallery is approximately 8 feet with the exception of an
area 20 feet long and 16 feet wide in the southeast corner of the infiltration gallery where the
depth is approximately 20 feet. The infiltration gallery is filled with gravel (M67 stone) to within
approximately 3 feet of grade. A layer of geotextile fabric was placed over the M67 stone, and
the distribution piping and soil backfill is located above the geotextile fabric. Treated ground
water flows into the gallery through a horizontal 50-foot long, 8-inch diameter PVC header pipe
and twenty-five (25) horizontal 28-foot long, 2-inch diameter screens. Two (2) 2-inch diameter
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Our People. Your Success.
observation wells are set within the infiltration gallery. The pump and treat remediation system
associated with the infiltration gallery was installed in October 2011 and the system became
operational in March 2012.
The system is in compliance with the Division of Water Quality (DWQ) Underground Injection
Control (UIC) permit #W10300466 granted to Polytec, Inc.
Planned Closure Activities
As part of the closure activities, the piping associated with the infiltration gallery will be
abandoned in place by grouting the 50-foot long, 8-inch diameter PVC header pipe and the
twenty-five horizontal 28-foot long, 2-inch diameter screens, and the two (2) 2-inch diameter
observation wells. Four air sparge wells (AS-1 through AS-4) and two recovery wells (RW-2 and
RW-6) located within the infiltration gallery will be abandoned. The remaining monitoring wells
(MW-1R, MW-1DR, MW-2D, MW-3, MW-5 through MW-8, and MW-10 through MW-12) and
recovery wells (RW-1, RW-3, RW-4, RW-5, and RW-7) associated with the site incident will also
be abandoned. The piping connecting the remediation system effluent to the infiltration gallery
will be cut at the surface prior to abandonment and power to the remediation system will be
disconnected. An estimated 450 gallons of neat cement/bentonite grout is expected to be
required to abandon the pipes associated with the infiltration gallery and the monitoring wells,
air sparge wells, and recovery wells. The infiltration gallery is covered with a geotextile fabric and
a three-foot soil cap. Once the piping to the infiltration gallery is abandoned, it will be rendered
unusable for disposal of fluids and will not serve as a source of contamination.
WR understands that the NCDEQ Federal & State Lead Program would like to have the
abandonment completed as soon as possible to rescind the permit prior to incurring the 2024
Annual Fees. Should you have any questions regarding the attached, please do not hesitate to
contact us at [phone].
Cordially,
WithersRavenel
Flora D Souza, CHMM
Environmental Project Scientist II
Eliza A. Allyn, P. r.
Environmental Project Geologist II
cc: Mr. Scott Ryals, P.E., NCDEQ -DWM (via email)
Former Community Cash & Carry - NCDEQ Incident #27036
Infiltration Gallery Closure Plan
WR Project # 23-0307-Z
January 2024
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