NCS000597_SCM Response_20221003

111111111IN
hdrinc.com
September 28, 2022
RECEIVED
DEMIR-Stormwater Program
Ms. Brianna Young, MS via email at: Brianna.YoungCancdenr.aov
Industrial Individual Permits Coordinator
Stormwater Program
Division of Energy, Mineral and Land Resources
North Carolina Department of Environmental Quality
1612 Mail Service Center
Raleigh, North Carolina 27699-1612
Subject: Zinc Management & Metal Removing SCMs
Permit No. NCS000597
Galvan Industries
7315 Galvan Way, Cabarrus County, Harrisburg, NC
Dear Ms. Young,
On behalf of Galvan Industries, Inc. (Galvan), HDR Engineering, Inc. of the Carolinas
(HDR) has prepared the flowing summary of site work to fulfill requirements B-10 and B-11
of Individual Permit NCS000597 issued to Galvan on May 12, 2022. Specifically, Galvan
has begun implementation of zinc and metal control procedures to reduce concentrations
in monitored outfalls at the site.
B-10. Conditions for Zinc Management
The permittee shall develop, maintain, and implement a Zinc Management Plan to
specifically address preventative maintenance and good housekeeping in response to
historic benchmark exceedances. The permittee shall submit the Zinc Management Plan
to the Division's Mooresville Regional Office for approval within 6 months of permit
issuance. The approved Zinc Management Plan shall be fully maintained and
implemented at the site within one year.
B-11. Metal Removing SCMs
The permittee shall design, install, and monitor SCMs at all Stormwater Discharge
Outfalls, that have been shown to remove or reduce metals in stormwater discharges. The
schedule shall be as follows from permit issuance: conduct the first period of scheduled
analytical monitoring [see D-1, paragraph (d)], submit the SCM designs to the Division's
Mooresville Regional Office for approval within 6 months of first analytical sample; install
the approved SCMs within 6 months of approval; monitor for metals in the stormwater
discharge from the SCMs on a quarterly basis for a period of 2 years. Samples shall be
taken during a measurable storm event. Quarterly discharge monitoring reports shall be
440 S. Church Street. Suite 1200. Charlotte. NC 28202
T 704 338 6700 F 704 338.6760

Ms. Brianna Young
September 28, 2022
Page 2
submitted to the Division's Mooresville Regional Office. At the end of the 2-year monitoring
period, the permittee shall evaluate the effectiveness of the SCMs in conjunction with
DEMLR. At that time, the permit may be modified based on this evaluation.
In response to these two requirements, Galvan has executed a contract with Terra Nova
Solutions (TN) to improve stormwater quality at the site. TN plans to rework approximately
455' of drainage ditch at the facility. The drainage ditches will be regraded and lined with
non -woven geofabric and limestone surge stone. Two (2) check dams will be installed to
slow flow during heavy rainfall events and capture sediment transported to outfalls via the
ditches. The limestone surge stone will serve to slow flow, capture sediment, and buffer
potentially low pH prior to entering the stormwater discharge outfalls
TN will also install one (1) 16-foot-long limestone check dam around Outfall #2 on the
southern portion of the site. Check dams will have blankets with MetalCompliant filter bags
from Gullywasher designed to filter zinc -laden stormwater prior to discharge. In addition to
limestone surge stone around Outfall #2, Gullywasher inserts will also be installed in two
stormwater drop inlets at the site (OF #1 and upstream of Outfall #1). The drainage ditch
feeding into Outfall #1 will be lined with limestone, filter bags, and check dams. The filter
bags and drop inlet inserts can be periodically washed and are expected to last
approximately 2 to 3 years, depending on site specific sediment loading and frequency of
maintenance. Areas proposed for improvement are shown on Figure 1.
Effectiveness of these proposed zinc management and SCM improvements will be
monitored through monthly qualitative and quantitative monitoring, in accordance with
condition D-1(e) of the Permit.
Should you have any questions or need additional information, please contact Mark Filardi
at [phone] or Mark. FilardiiQhdrinc.com.
Sincerely,
HDR Engineering, Inc. of the Carolinas
Mark P. Filardi, P.G.
Senior Geologist / Project Manager
enclosure
Cc: James Moore, NCDEQ
Laurens Willard, Galvan
Laurens Y. Willard, Galvan
Harshad Londhe. Galvan

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' sas , Check Dam around OF #2
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and Gullywasher Insert
_ 656
-
. -. —
`', Legend
6` Y `l.
" Limestone, Check Dams, and Site Boundary
Gullywasher Filter Bags
662 Limestone, Check Dams, and Norfolk Southern Rail Line
scc� s� :. T'.' Gullywasher Filter Bags 656 10
....,•_�s4 4
658 6so 4 `, 4 ad�kfs \ Generalized Stormwater Flow
656 Direction
4 ,
n52 666 ssa '
166,
s6 s266° j Limestone Ditch
�5 \
s F " 4 NPDES Outfall
bag 01
670
a6 •672 \ t L 66-
+ i w
NOTES:
2. PROPERTY BOUNDARY FROM MECK ENBURG AND CABARRUS COUNTIES' GIS WEB REPOSITORIES 0 50 100 200 300
3. RAIL FROM MECKLENBURG OPEN MAPPING REPOSITORY Feet
4. RAIL ROW ESTIMATED FROM 100' BUFFER AROUND RAIL LINE
F)l
NPDES OUTFALL MAP
GALVAN INDUSTRIES, INC.
NCDWQ GENERAL PERMIT #NCG030000
CABARRUS COUNTY, NORTH CAROLINA
DATE
SEPTEMBER 2022
FIGURE
1