NC0004944_Final Permit_20180705

Permit NC0004944
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF WATER RESOURCES
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provisions of North Carolina General Statute 143-215.1, other lawful
standards and regulations promulgated and adopted by the North Carolina Environmental
Management Commission, and the Federal Water Pollution Control Act, as amended,
Salisbury Investments I, LLC
is hereby authorized to discharge wastewater and stormwater from a facility located at
Edge Water Treating, LLC
7401 Statesville Blvd.
Salisbury
Rowan County
to receiving waters designated as North Second Creek in the Yadkin -Pee Dee River Basin in
accordance with effluent limitations, monitoring requirements, and other conditions set forth
in Parts I, II, III, and IV hereof.
The permit shall become effective July 1, 2018.
This permit and the authorization to discharge shall expire at midnight on November 30, 2022.
Signed this day June 15, 2018
Linda Culpepper, Interim Director
Division of Water Resources
By Authority of the Environmental Management Commission
Page 1 of 20

Permit NC0004944
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES Permits issued to this facility, whether for operation or discharge are hereby
revoked, and as of this issuance, any previously issued permit bearing this number is no longer
effective. Therefore, the exclusive authority to operate and discharge from this facility arises under the
permit conditions, requirements, terms, and provisions included herein.
Salisbury Investments I, LLC is hereby authorized to:
1. Continue to operate an existing Class WW -4 (2.305 MGD) activated -sludge
wastewater treatment facility located at Edge Water Treating, LLC (7401
Statesville Blvd., Salisbury) in Rowan County. The treatment system referenced
herein includes the following components:
• Bar screen and grit removal;
• Chlorine contact (sanitary wastes)
• Two covered equalization tanks;
• Three aeration basins (one out -of -service);
• Anaerobic groundwater treatment unit (out -of -service);
• Three secondary clarifiers (one out -of -service);
• Three aerated polishing ponds;
• Chemical additional facilities;
• Aerobic digestion;
• Sludge dewatering; and
• Instrumented flow measurement.
2. Discharge from said treatment works through outfall 001 at the location specified
on the attached map into North Second Creek, currently a class C water in the
Yadkin -Pee Dee River Basin.
3. Continue to discharge stormwater associated with industrial activity through five
outfalls (outfalls A, B, C, D, and 5) as shown on the attached map. Modifications
to the stormwater conveyance system are authorized by this permit in accordance
with documentation to be included in the facility's Stormwater Pollution
Prevention Plan (construction activities must be authorized under NPDES
General Permit NCGO10000).
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Permit NC0004944
Part I
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
[15A NCAC 02B.0400 et seq., 02B.0500 et seq.]
Beginning on the effective date of this permit and lasting through the expiration date, the
Permittee is authorized to discharge from Outfall 001. Such discharges shall be limited and
monitored3 by the Permittee as specified below:
PARAMETER
[eDMR Code]
EFFLUENT LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Average
Daily
Maximum
Measurement
Frequency
Sample
pe
Sample
Location2
Flow [50050]
2.305 MGD
Continuous
Recording
Effluent
BODS [C0310]
60.0 pounds/day
149.0 pounds/day
3/Week
Composite
Effluent
NH3 as N [C0610]
23.0 pounds/day
46.0 pounds/day
Weekly
Composite
Effluent
Total Suspended Solids
[C0530]
96.0 pounds/day
294.0 pounds/day
3/Week
Composite
Effluent
Fecal Coliform [31616]
(geometric mean)
200/100 mL
400/100 mL
Weekly
Grab
Effluent
Dissolved Oxygen [00300]
Daily Average > 5.0 mg/L
3/Week
Grab
Effluent
Dissolved Oxygen [00300]
Monitor and report (mg/L)
See Note 1
Grab
U,D
Conductivity [00094]
Monitor and report (pmho/cm)
See Note 1
Grab
U,D
Temperature [00010]
Monitor and report (°C)
See Note 1
Grab
U,D
Total Copper [01042]
23.1 pg/L
1 27.3 pg/L
Monthly
Composite
Effluent
Total Mercury3 [COMER]
Monitor and report (ng/L)
Annually
Grab
Effluent
pH [00400]
> 6.0 and < 9.0 Standard Units
3/Week
Grab
Effluent
Chronic Toxicity' [TGP3B]
Quarterly
Composite
Effluent
40 CFR 414 Subpart I
See A. (2)
Notes•
1. The permittee shall submit all discharge monitoring data electronically using the Division's eDMR
system [see A. (4)].
2. U: upstream at least 100 feet from the outfall. D: downstream approximately eight miles from the
outfall or at Highway 601. Instream samples shall be collected three times per week during the
months of June, July, August, and September and once per week during the remaining months of
the year.
3. The facility shall use EPA method 1631E for all effluent Mercury analyses.
4. Chronic Toxicity (Ceriodaphnia) P/F @ 34% with sampling in February, May, August, November
[see A. (3)]. Toxicity monitoring shall coincide with metals monitoring.
THERE SHALL BE NO DISCHARGE OF FLOATING SOLIDS OR VISIBLE FOAM IN OTHER THAN TRACE AMOUNTS.
ANALYTICAL DATA WHICH IS LESS THAN THE PRACTICAL QUANTITATION LEVEL SHALL BE REPORTED AS
SUCH AND CONSIDERED ZERO FOR THE PURPOSES OF CALCULATING AVERAGES.
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Permit NC0004944
A. (2.) Effluent Limitations and Monitoring Requirements- OCPSF parameters
[15A NCAC 02B.0400 et seq., 02B.0500 et seq.]
Beginning on the effective date of this permit and lasting through the expiration date, the
Permittee shall comply with the effluent limitations and monitoring frequencies established
below for Outfall 001.
➢ All OCPSF parameters shall be Grab samples collected Annually at the Effluent
PARAMETER
eDMR Code
EFFLUENT LIMITATIONS
Monthly Average'
Daily Maximum'
Acenaphthene - [34205]
0.048 pounds/day
0.129 pounds/day
Acenaphthylene - [34200]
0.048 pounds/day
0.129 pounds/day
Acrylonitrile - [34215]
8.4 pg/L
8.4 pg/L
Anthracene - [CO220]
0.147 pg/L
0.147 pg/L
Benzene - [34030]
0.081 pounds/day
0.297 pounds/day
Benzo(a)anthracene - [C0526]
1.04 pg/L
1.04 pg/L
3,4-Benzofluoranthene - [C0531]
1.04 pg/L
1.04 pg/L
Benzo(k)fluoranthene - [CO242]
1.04 pg/L
1.04 pg/L
Benzo(a)pyrene - [CO247]
1.04 pg/L
1.04 pg/L
Bis(2-ethylhexyl) phthalate - [QD100]
0.225 pounds/day
0.610 pounds/day
Carbon Tetrachloride - [32102]
0.039 pounds/day
0.083 pounds/day
Chlorobenzene - [34301 ]
0.033 pounds/day
0.061 pounds/day
Chloroethane - [85811]
0.227 pounds/day
0.586 pounds/day
Chloroform - [32106]
0.046 pounds/day
0.101 pounds/day
2 -Chlorophenol - [34586]
0.068 pounds/day
0.214 pounds/day
Chrysene - [C0320]
1.038 pg/L
1.038 pg/L
Di -n -butyl phthalate - [39110]
0.059 pounds/day
0.125 pounds/day
1,2 -Dichlorobenzene - [34536]
0.168 pounds/day
0.356 pounds/day
1,3 -Dichlorobenzene - [34566]
0.068 pounds/day
0.096 pounds/day
1,4 -Dichlorobenzene - [34571]
0.033 pounds/day
0.061 pounds/day
1, 1 -Dichloroethane - [34496]
0.048 pounds/day
0.129 pounds/day
1,2-Dichloroethane - [32103]
0.149 pounds/day
0.461 pounds/day
1,1-Dichloroethylene - [34501]
0.035 pounds/day
0.055 pounds/day
1,2-trans-Dichloroethylene - [34546]
0.046 pounds/day
0.118 pounds/day
2,4-Dichlorophenol - [34601]
0.085 pounds/day
0.245 pounds/day
1,2-Dichloropropane - [QD541]
0.334 pounds/day
0.503 pounds/day
1,3-Dichloropropylene - [77163]
0.063 pounds/day
0.096 pounds/day
Diethyl phthalate - [34336]
0.177 pounds/day
0.444 pounds/day
2,4 -Dimethylphenol - [34606]
0.039 pounds/day
0.079 pounds/day
Dimethyl phthalate - [34341]
0.042 pounds/day
0.103 pounds/day
4,6-Dinitro-o-cresol - [34657]
0.170 pounds/day
0.605 pounds/day
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Permit NC0004944
2,4-Dinitrophenol - [34616]
0.155 pounds/day
0.269 pounds/day
2,4-Dinitrotoluene - [34611]
0.247 pounds/day
0.623 pounds/day
2,6-Dinitrotoluene - [C0826]
23.8 pg/L
23.8 pg/L
Ethyl benzene - [34371 ]
0.070 pounds/day
0.236 pounds/day
Fluoranthene - [C0376]
0.322 pg/L
0.322 pg/L
Fluorene - [34381]
0.048 pounds/day
0.129 pounds/day
Hexachlorobenzene - [C0700]
0.01 pg/L
0.01 pg/L
Hexachlorobutadiene - [39702]
0.044 pounds/day
0.107 pounds/day
Hexachloroethane - [QD396]
0.046 pounds/day
0.118 pounds/day
Methyl Chloride - [34418]
0.188 pounds/day
0.415 pounds/day
Methylene Chloride - [34423]
0.087 pounds/day
0.194 pounds/day
Naphthalene - [34696]
0.048 pounds/day
0.129 pounds/day
Nitrobenzene - [34447]
0.059 pounds/day
0.149 pounds/day
2-Nitrophenol - [34591]
0.090 pounds/day
0.151 pounds/day
4-Nitrophenol - [34646]
0.157 pounds/day
0.271 pounds/day
Phenanthrene - [34461]
0.048 pounds/day
0.129 pounds/day
Phenol - [34694]
0.033 pounds/day
0.057 pounds/day
Pyrene - [34469]
0.055 pounds/day
0.146 pounds/day
Tetrachloroethylene - [34475]
0.048 pounds/day
0.122 pounds/day
Toluene - [34010]
0.057 pounds/day
0.175 pounds/day
1,2,4-Trichlorobenzene - [QD551]
0.149 pounds/day
0.306 pounds/day
1,1,1 -Trichloroethane- [34506]
0.046 pounds/day
0.118 pounds/day
1,1,2 -Trichloroethane- [34511]
0.046 pounds/day
0.118 pounds/day
Trichloroethylene - [39180]
0.046 pounds/day
0.118 pounds/day
Vinyl Chloride - [39175]
0.227 pounds/day
0.586 pounds/day
Total Chromium - [QD034]
2.425 pounds/day
Total Chromium - [C0034]
146.5 pg/L
Total Cyanide - [00720]
14.65 pg/L
57.3 pg/L
Total Lead - [01051]
8.62 pg/L
196.7 pg/L
Total Nickel - [01067]
109.1 pg/L
873.8 pg/L
Total Zinc - [0 1092]
2.294 pounds/day
5.703 pounds/day
A. (3.) Chronic Toxicity Pass/Fail Limit (Quarterly)
[15A NCAC 02B.0200 et seq.]
The effluent discharge shall at no time exhibit observable inhibition of reproduction or
significant mortality to Ceriodaphnia dubia at an effluent concentration of 34.0%.
The permit holder shall perform at a minimum,guarterli monitoring using test procedures
outlined in the "North Carolina Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised
December 2010, or subsequent versions or "North Carolina Phase II Chronic Whole Effluent
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Permit NC0004944
Toxicity Test Procedure" (Revised- December 20 10) or subsequent versions. The tests will be
performed during the months of February, May, August, and November. These months
signify the first month of each three-month toxicity testing quarter assigned to the facility.
Effluent sampling for this testing must be obtained during representative effluent discharge
and shall be performed at the NPDES permitted final effluent discharge below all treatment
processes.
If the test procedure performed as the first test of any single quarter results in a
failure or ChV below the permit limit, then multiple -concentration testing shall be
performed at a minimum, in each of the two following months as described in "North
Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised -December
2010) or subsequent versions.
All toxicity testing results required as part of this permit condition will be entered on the
Effluent Discharge Monitoring Form (MR -1) for the months in which tests were performed,
using the parameter code TGP313 for the pass/fail results and THP313 for the Chronic Value.
Additionally, DWR Form AT -3 (original) is to be sent to the following address:
Attention: North Carolina Division of Water Resources
Water Sciences Section/Aquatic Toxicology Branch
1621 Mail Service Center
Raleigh, NC 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Water Sciences Section no later
than 30 days after the end of the reporting period for which the report is made.
Test data shall be complete, accurate, include all supporting chemical/ physical
measurements and all concentration/ response data, and be certified by laboratory
supervisor and ORC or approved designate signature. Total residual chlorine of the effluent
toxicity sample must be measured and reported if chlorine is employed for disinfection of the
waste stream.
Should there be no discharge of flow from the facility during a month in which toxicity
monitoring is required, the permittee will complete the information located at the top of the
aquatic toxicity (AT) test form indicating the facility name, permit number, pipe number,
county, and the month/year of the report with the notation of "No Flow" in the comment area
of the form. The report shall be submitted to the Water Sciences Section at the address cited
above.
Should the permittee fail to monitor during a month in which toxicity monitoring is required,
monitoring will be required during the following month. Assessment of toxicity compliance is
based on the toxicity testing quarter, which is the three month time interval that begins on
the first day of the month in which toxicity testing is required by this permit and continues
until the final day of the third month.
Should any test data from this monitoring requirement or tests performed by the North
Carolina Division of Water Resources indicate potential impacts to the receiving stream, this
permit may be re -opened and modified to include alternate monitoring requirements or
limits.
NOTE: Failure to achieve test conditions as specified in the cited document, such as
minimum control organism survival, minimum control organism reproduction, and
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Permit NC0004944
appropriate environmental controls, shall constitute an invalid test and will require
immediate follow-up testing to be completed no later than the last day of the month following
the month of the initial monitoring.
A. (4.) ELECTRONIC REPORTING OF MONITORING REPORTS
[G.S. 143-215.1(b)]
Federal regulations require electronic submittal of all discharge monitoring reports (DMRs)
and program reports. The final NPDES Electronic Reporting Rule was adopted and became
effective on December 21, 2015.
NOTE: This special condition supplements or supersedes the following sections within Part II
of this permit (Standard Conditions for NPDES Permits):
• Section B. Signatory Requirements
(11.)
• Section D. (2.) Reporting
• Section D. (6.) Records Retention
• Section E. (5.) Monitoring Reports
1. Reporting Requirements [Supersedes Section D. (2.) and Section E. (5.) (a)]
The permittee shall report discharge monitoring data electronically using the NC DWR's
Electronic Discharge Monitoring Report (eDMR) internet application.
Monitoring results obtained during the previous month(s) shall be summarized for each
month and submitted electronically using eDMR. The eDMR system allows permitted
facilities to enter monitoring data and submit DMRs electronically using the internet.
Until such time that the state's eDMR application is compliant with EPA's Cross -Media
Electronic Reporting Regulation (CROMERR), permittees will be required to submit all
discharge monitoring data to the state electronically using eDMR and will be required to
complete the eDMR submission by printing, signing, and submitting one signed original
and a copy of the computer printed eDMR to the following address:
NC DEQ / Division of Water Resources / Water Quality Permitting Section
ATTENTION: Central Files
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
If a permittee is unable to use the eDMR system due to a demonstrated hardship or due
to the facility being physically located in an area where less than 10 percent of the
households have broadband access, then a temporary waiver from the NPDES electronic
reporting requirements may be granted and discharge monitoring data may be submitted
on paper DMR forms (MR 1, 1. 1, 2, 3) or alternative forms approved by the Director.
Duplicate signed copies shall be submitted to the mailing address above. See "How to
Request a Waiver from Electronic Reporting" section below.
Regardless of the submission method, the first DMR is due on the last day of the month
following the issuance of the permit or in the case of a new facility, on the last day of the
month following the commencement of discharge.
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Permit NC0004944
Starting on December 21, 2020, the permittee must electronically report the following
compliance monitoring data and reports, when applicable:
• Sewer Overflow/Bypass Event Reports;
• Pretreatment Program Annual Reports; and
• Clean Water Act (CWA) Section 316(b) Annual Reports.
The permittee may seek an electronic reporting waiver from the Division (see "How to
Request a Waiver from Electronic Reporting" section below).
2. Electronic Submissions
In accordance with 40 CFR 122.41(l)(9), the permittee must identify the initial recipient at
the time of each electronic submission. The permittee should use the EPA's website
resources to identify the initial recipient for the electronic submission.
Initial recipient of electronic NPDES information from NPDES-regulated facilities means
the entity (EPA or the state authorized by EPA to implement the NPDES program) that is
the designated entity for receiving electronic NPDES data [see 40 CFR 127.2(b)].
EPA plans to establish a website that will also link to the appropriate electronic reporting
tool for each type of electronic submission and for each state. Instructions on how to
access and use the appropriate electronic reporting tool will be available as well.
Information on EPA's NPDES Electronic Reporting Rule is found at:
https: / /www.federalregister.gov/documents/2015 / 10 /22 /2015-24954 /national-
pollutant-discharge-elimination-system-npdes-electronic-reporting-rule
Electronic submissions must start by the dates listed in the "Reporting Requirements"
section above.
3. How to Request a Waiver from Electronic Reporting
The permittee may seek a temporary electronic reporting waiver from the Division. To
obtain an electronic reporting waiver, a permittee must first submit an electronic
reporting waiver request to the Division. Requests for temporary electronic reporting
waivers must be submitted in writing to the Division for written approval at least sixty
(60) days prior to the date the facility would be required under this permit to begin
submitting monitoring data and reports. The duration of a temporary waiver shall not
exceed 5 years and shall thereupon expire. At such time, monitoring data and reports
shall be submitted electronically to the Division unless the permittee re -applies for and is
granted a new temporary electronic reporting waiver by the Division. Approved electronic
reporting waivers are not transferrable. Only permittees with an approved reporting
waiver request may submit monitoring data and reports on paper to the Division for the
period that the approved reporting waiver request is effective.
Information on eDMR and the application for a temporary electronic reporting waiver are
found on the following web page:
http://deg.nc.gov/about/divisions/water-resources/edmr
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Permit NC0004944
4. Signatory Requirements [Supplements Section B. (11.) (b) and Supersedes Section B.
11. d
All eDMRs submitted to the permit issuing authority shall be signed by a person
described in Part II, Section B. (11.)(a) or by a duly authorized representative of that
person as described in Part II, Section B. (11.)(b). A person, and not a position, must be
delegated signatory authority for eDMR reporting purposes.
For eDMR submissions, the person signing and submitting the DMR must obtain an
eDMR user account and login credentials to access the eDMR system. For more
information on North Carolina's eDMR system, registering for eDMR and obtaining an
eDMR user account, please visit the following web page:
http: / /deg.nc.gov/about/divisions/water-resources/edmr
Certification. Any person submitting an electronic DMR using the state's eDMR system
shall make the following certification [40 CFR 122.22]. NO OTHER STATEMENTS OF
CERTIFICATION WILL BE ACCEPTED:
7 certify, under penalty of law, that this document and all attachments were prepared
under my direction or supervision in accordance with a system designed to assure that
qualified personnel properly gather and evaluate the information submitted. Based on my
inquiry of the person or persons who manage the system, or those persons directly
responsible for gathering the information, the information submitted is, to the best of my
knowledge and belief, true, accurate, and complete. I am aware that there are significant
penalties for submitting false information, including the possibility of fines and
imprisonment for knowing violations. "
5. Records Retention [Supplements Section D. (6.)]
The permittee shall retain records of all Discharge Monitoring Reports, including eDMR
submissions. These records or copies shall be maintained for a period of at least 3 years
from the date of the report. This period may be extended by request of the Director at any
time [40 CFR 122.41].
A. (5.) NUTRIENT REOPENER for HIGH ROCK LAKE
[G.S. 143-215.1(b)]
This permit may be reopened and modified to implement nutrient requirements in
accordance with any future TMDL and/or nutrient management strategy for High Rock Lake.
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Permit NC0004944
Part I, Section B.
1. FINAL LIMITATIONS AND CONTROLS FOR STORMWATER DISCHARGES
During the period beginning on the effective date of the permit and lasting until the facility begins coverage under
an industrial stormwater permit, the permittee is authorized to discharge stormwater from outfalls A, B, C, D, and
5. Such discharges shall be controlled, limited and monitored as specified below.
a) STORMWATER POLLUTION PREVENTION PLAN
The permittee shall develop and continue to update a Stormwater Pollution Prevention Plan (SPPP), herein after
referred to as the Plan. The Plan shall be considered public information and shall include, at a minimum, the
following items:
(1) Site Overview. The site overview shall provide a description of the physical facility and the potential
pollutant sources which may be expected to contribute to contamination of stormwater discharges. The
site plan shall contain the following:
(a) A general location map (USGS quadrangle map or appropriately drafted equivalent map), showing
the facility's location in relation to transportation routes and surface waters, the name of the
receiving water(s) to which the stormwater outfall(s) discharges, or if the discharge is to a municipal
separate storm sewer system, the name of the municipality and the ultimate receiving waters, and
accurate latitude and longitude of the point(s) of discharge. The general location map (or
alternatively the site map) shall identify whether each receiving water is impaired (on the state's
303(d) list of impaired waters) or is located in a watershed for which a TMDL has been
established, and what the parameter(s) of concern are.
(b) A narrative description of storage practices, loading and unloading activities, outdoor process areas,
dust or particulate generating or control processes, and waste disposal practices. A narrative
description of the potential pollutants which could be expected to be present in the stormwater
discharge from each outfall.
(c) A site map drawn to scale (including a distance legend and north arrow) showing: the site property
boundary, the stormwater discharge outfalls, all on-site and adjacent surface waters and wetlands,
industrial activity areas (including storage of materials, disposal areas, process areas, loading and
unloading areas, and haul roads), site topography, all drainage features and structures, drainage areas
for each outfall, direction of flow in each drainage area, industrial activities occurring in each drainage
area, buildings, existing BMPs, and impervious surfaces. The site map must indicate the percentage
of each drainage area that is impervious.
(d) A list of significant spills or leaks of pollutants that have occurred at the facility during the three (3)
previous years and any corrective actions taken to mitigate spill impacts.
(e) Certification that the stormwater outfalls have been evaluated for the presence of non-stormwater
discharges. The permittee shall re -certify annually that the stormwater outfalls have been
evaluated for the presence of non-stormwater discharges. The certification statement will be
signed in accordance with the requirements found in Part II, Standard Conditions, Section B,
Paragraph 11. The permittee shall re -certify annually that the stormwater outfalls have been
evaluated for the presence of non-stormwater discharges.
(2) Stormwater Management Strategy. The stormwater management strategy shall contain a narrative
description of the materials management practices employed which control or minimize the exposure of
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Permit NC0004944
significant materials to stormwater, including structural and nonstructural measures. The stormwater
management plan, at a minimum, shall incorporate the following:
(a) Feasibility Study. A review of the technical and economic feasibility of changing the methods of
operations and/or storage practices to eliminate or reduce exposure of materials and processes to
stormwater. Wherever practical, the permittee shall prevent exposure of all storage areas, material
handling operations, and manufacturing or fueling operations. In areas where elimination of
exposure is not practical, the stormwater management plan shall document the feasibility of diverting
the stormwater runoff away from areas of potential contamination.
(b) Secondary Containment Requirements and Records. Secondary containment is required for:
bulk storage of liquid materials; storage in any amount of Section 313 of Title III of the Superfund
Amendments and Reauthorization Act (SARA) water priority chemicals; and storage in any amount
of hazardous substances, in order to prevent leaks and spills from contaminating stormwater runoff.
A table or summary of all such tanks and stored materials and their associated secondary
containment areas shall be maintained. If the secondary containment devices are connected to
stormwater conveyance systems, the connection shall be controlled by manually activated valves or
other similar devices (which shall be secured closed with a locking mechanism), and any stormwater
that accumulates in the containment area shall be at a minimum visually observed for color, foam,
outfall staining, visible sheens and dry weather flow, prior to release of the accumulated stormwater.
Accumulated stormwater shall be released if found to be uncontaminated by any material. Records
documenting the individual making the observation, the description of the accumulated stormwater,
and the date and time of the release shall be kept for a period of five (5) years. For facilities subject
to a federal oil Spill Prevention, Control, and Countermeasure Plan (SPCC), any portion of the SPCC
Plan fully compliant with the requirements of this permit may be used to demonstrate compliance
with this permit. The Division may allow exceptions to secondary containment requirements for
mobile refuelers, as with the exemption provided by amendments to federal SPCC regulations, as
long as appropriate spill containment and/or diversionary structures or equipment is used to prevent
discharge to surface waters. Exceptions do not apply to refuelers or other mobile tankage used
primarily as bulk liquid material storage in a fixed location in place of stationary containers.
(c) BMP Summary. A listing of site structural and non-structural Best Management Practices (BMP)
shall be provided. The installation and implementation of BMPs shall be based on the assessment of
the potential for sources to contribute significant quantities of pollutants to stormwater discharges
and data collected through monitoring of stormwater discharges. The BMP Summary shall include a
written record of the specific rationale for installation and implementation of the selected site BMPs.
The BMP Summary shall be reviewed and updated annually.
(3) Spill Prevention and Response Plan. The Spill Prevention and Response Plan (SPRP) shall
incorporate an assessment of potential pollutant sources based on a materials inventory of the facility.
Facility personnel (or the team) responsible for implementing the SPRP shall be identified in a written
Est incorporated into the SPRP and signed and dated by each individual acknowledging their
responsibilities for the plan. A responsible person shall be on-site at all times during facility operations
that have the potential to contaminate stormwater runoff through spills or exposure of materials
associated with the facility operations. The SPRP must be site stormwater specific. Therefore, an oil
Spill Prevention Control and Countermeasure plan (SPCC) may be a component of the SPRP, but may
not be sufficient to completely address the stormwater aspects of the SPRP. The common elements of
the SPCC with the SPRP may be incorporated by reference into the SPRP.
(4) Preventative Maintenance and Good Housekeeping Program. A preventative maintenance and
good housekeeping program shall be developed. The program shall list all stormwater control systems,
stormwater discharge outfalls, all on-site and adjacent surface waters and wetlands, industrial activity
areas (including material storage areas, material handling areas, disposal areas, process areas, loading and
unloading areas, and haul roads), all drainage features and structures, and existing structural BMPs. The
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Permit NC0004944
program shall establish schedules of inspections, maintenance, and housekeeping activities of
stormwater control systems, as well as facility equipment, facility areas, and facility systems that present a
potential for stormwater exposure or stormwater pollution. Inspection of material handling areas and
regular cleaning schedules of these areas shall be incorporated into the program. Timely compliance
with the established schedules for inspections, maintenance, and housekeeping shall be recorded in
writing and maintained in the SPPP.
(5) Employee Training. Training programs shall be developed and training provided at a minimum on an
annual basis for facility personnel with responsibilities for: spill response and cleanup, preventative
maintenance activities, and for any of the facility's operations that have the potential to contaminate
stormwater runoff. Facility personnel (or team) responsible for implementing the training shall be
identified, and their annual training shall be documented by the signature of each employee trained.
(6) Responsible Party. The Stormwater Pollution Prevention Plan shall identify a specific position(s)
responsible for the overall coordination, development, implementation, and revision to the Plan.
Responsibilities for all components of the Plan shall be documented and position assignments provided.
(7) SPPP Amendment and Annual Update. The permittee shall amend the SPPP whenever there is a
change in design, construction, operation, or maintenance which has a significant effect on the potential
for the discharge of pollutants to surface waters. All aspects of the Stormwater Pollution Prevention
Plan shall be reviewed and updated on an annual basis. The annual update shall include an updated
Est of significant spills or leaks of pollutants for the previous three (3) years, or the notation that no
spills have occurred. The annual update shall include written re -certification that the stormwater outfalls
have been evaluated for the presence of non-stormwater discharges. The annual update shall include a
documented re-evaluation of the effectiveness of the BMPs listed in the BMP Summary of the
Stormwater Management Strategy. The annual update shall also include a review and comparison of
sample analytical data to benchmark values over the past year, including a discussion about Tiered
Response status.
The Director may notify the permittee when the Plan does not meet one or more of the minimum
requirements of the permit. Within 30 days of such notice, the permittee shall submit a time schedule to
the Director for modifying the Plan to meet minimum requirements. The permittee shall provide
certification in writing (in accordance with Part II, Standard Conditions, Section B, Paragraph 11 to the
Director that the changes have been made.
(8) Facility Inspections. Inspections of the facility and all stormwater gstems shall occur as part of the
Preventative Maintenance and Good Housekeeping Program at a minimum on a semi-annual schedule,
once during the first half of the year Qanuary to June), and once during the second half Quly to
December), with at least 60 days separating inspection dates (unless performed more frequently than
semi-annually). These facility inspections are different from, and in addition to, the stormwater
discharge characteristic monitoring required in Section B. 1. b) (8) — Qualitative Monitoring below.
(9) SPPP Implementation. The permittee shall implement the Plan. Implementation of the Plan shall
include documentation of all monitoring, measurements, inspections, maintenance activities, and
training provided to employees, including the log of the sampling data and of actions taken to
implement BMPs associated with the industrial activities, including vehicle maintenance activities. Such
documentation shall be kept on-site for a period of five years and made available to the Director or the
Director's authorized representative immediately upon request.
b) MINIMUM MONITORING AND REPORTING REQUIREMENTS
(1) Analytical monitoring of stormwater discharges shall be performed as specified in Table 1. All
samples shall be collected from a discharge resulting from a measureable storm event. The required
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Permit NC0004944
monitoring will result in a minimum of six (6) analytical samplings being conducted over the term of the
permit at each stormwater discharge outfall (SDO).
A measurable storm event is a storm event that results in an actual discharge from the permitted site
outfall. The previous measurable storm event must have been at least 72 hours prior. The 72 -hour storm
interval does not apply if the permittee is able to document that a shorter interval is representative for local
storm events during the sampling period, and the permittee obtains approval from the local Regional Office
Supervisor.
(2) If the stormwater is controlled by a detention pond, and that pond discharges only in response to a
storm event exceeding a 25 -year, 24-hour storm, the pond shall be considered a non -discharging
stormwater control system and not subject to NPDES requirements, unless the discharge causes a
violation of water quality standards.
(3) Stormwater samples analyzed in accordance with the terms of this permit shall be submitted on forms
provided by the Director. The permittee must report the results from all samples taken within the
monitoring period as specified in the Standard Conditions of this permit, and as supplemented or
superseded by electronic DMR reporting requirements in Part I, Section A(4.). 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.
(4) Specific monitoring requirements:
(a) Monitoring in Table 1 applies to all of the stormwater discharges associated with industrial activity
that discharge to the surface waters of the state.
Table 1. Analytical Stormwater Monitoring Requirements
Discharge
Characteristics
Units
Measurement
Fre uencyl
Sample
Type2
Sample
Location3
Total Suspended Solids
m /L
semi-annual
Grab
SDO
Biological Oxygen Demand (BOD), 5-
day, 20 -C
mg/L
semi-annual
Grab
SDO
Non -polar Oil and Grease, by EPA
Method 1664 (SGT -HEM)
mg/L
semi-annual
Grab
SDO
Total Nitrogen 4
m /L
semi-annual
Grab
SDO
Total Phosphorus (TP)4
m /L
semi-annual
Grab
SDO
pH
standard
semi-annual
Grab
SDO
Total Rainfalls
inches
I semi-annual
I Rain Gauge
-
Footnotes:
1 Measurement Frequency: Twice per year during a measureable storm event.
2 Grab samples shall be collected within the first 30 minutes of discharge.
3 Sample Location: Samples shall be collected at each stormwater discharge outfall (SDO) unless
representative outfall status has been granted.
4 The permittee may discontinue monitoring for TN and TP after four (4) consecutive samples if all values
are below the benchmarks in Table 4.
5 For each sampled measureable storm event the total precipitation must be recorded. An on-site rain
gauge or local rain gauge reading must be recorded.
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Permit NC0004944
The permittee shall complete the analytical samplings in accordance with the schedule specified below in
Table 2, unless adverse weather conditions prevent sample collection (see Adverse feather in Stormwater
Definitions). Sampling is not required outside of the facility's normal operating hours. 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.
Table 2. Monitoring Schedule
Monitoring period'
Sample Number
Start
End
Year 1 — Period 1
1
July 11 2018
December 31, 2018
Year 1 — Period 2
2
January 1, 2019
June 30, 2019
Year 2 — Period 1
3
July 1, 2019
December 31, 2019
Year 2 — Period 2
4
January 1, 2020
June 30, 2020
Year 3 — Period 1
5
July 1, 2020
December 31, 2020
Year 3 — Period 2 and
During Renewal Process2
6+
January 1, 2021
March 31, 2021
Footnotes:
1 If no discharge occurs during the sampling period, the permittee must record "No Flow" on a monitoring
report within 30 days of the end of the sampling period and maintain this record in the SPPP.
2 Maintain semi-annual monitoring during permit renewal process. The applicant must continue semi-annual
monitoring until the renewed permit is issued or a separate NPDES Stormwater Permit is issued.
(b) Facilities which have any vehicle maintenance activity occurring on-site which uses more than 55
gallons of new motor oil per month when averaged over the calendar year shall perform analytical
monitoring as specified below in Table 3. This monitoring shall be performed at all stormwater
discharge outfalls which discharge stormwater runoff from vehicle maintenance areas, in accordance
with the schedule presented in Table 2. All analytical monitoring shall be performed during a
measureable storm event.
Table 3. Analytical Monitoring Requirements for On -Site Vehicle Maintenance
Discharge Characteristics
Units
Measurement
Frequencyl
Sample
Type2
Sample
Location3
H
standard
semi-annual
Grab
SDO
Non -polar Oil and Grease, by EPA
Method 1664 (SGT -HEM)
mg/l
semi-annual
Grab
SDO
Total Suspended Solids SS
mg/1
semi-annual
Grab
SDO
Total Rainfall4
inches
semi-annual
Rain gauge
New Motor Oil Usagegallons/month
semi-annual
Estimate
-
Footnotes:
1 Measurement Frequency: Twice per year during a measureable storm event, for each year until either
another permit is issued for this facility or until this permit is revoked or rescinded. See Table 2 for
schedule of monitoring periods through the end of this permitting cycle.
2 If the stormwater runoff is controlled by a stormwater detention pond a grab sample of the discharge from
the pond shall be collected within the first 30 minutes of discharge from the pond.
3 Sample Location: Samples shall be collected at each stormwater discharge outfall (SDO) that discharges
stormwater runoff from area(s) where vehicle maintenance activities occur.
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Permit NC0004944
4 For each sampled measureable storm event the total precipitation must be recorded. An on-site or local
rain gauge reading must be recorded.
Monitoring results shall be compared to the benchmark values in Table 4. The benchmark values in Table 4
are not permit limits but should be used as guidelines for the permittee's SPPP. Exceedances of benchmark
values require the permittee to increase monitoring, increase management actions, increase record keeping,
and/or install stormwater Best Management Practices (BMPs), as provided in 3. below.
(5) The permittee shall report the analytical results from each sample within the monitoring period. The
permittee shall compare monitoring results to the benchmark values in Table 4. The benchmark values
in Table 4 are not permit limits but should be used as guidelines for the permittee's Stormwater
Pollution Prevention Plan (SPPP). Exceedances of benchmark values require the permittee to increase
monitoring, increase management actions, increase record keeping, and/or install stormwater Best
Management Practices (BMPs) in a tiered program. See the descriptions of Tier One and Tier Two.
Table 4. Benchmark Values for Analytical Monitorin
Discharge Characteristics
Units
Benchmark
Total Suspended Solids (TSS)
mg/L
100
Biological Oxygen Demand (BOD)
m /L
30
Non -polar Oil and Grease, by EPA
Method 1664 (SGT -HEM)
mg/L
15
Total Nitrogen
m /L
30
Total Phosphorus
m /L
2
PH
standard
6 - 9
Tier One
If. The first valid sampling results are above a benchmark value, or outside of the benchmark range, for any
parameter at any outfall;
Then: The permittee shall:
1. Conduct a stormwater management inspection of the facility within two weeks of receiving sampling
results.
2. Identify and evaluate possible causes of the benchmark value exceedance.
3. Identify potential and select the specific: source controls, operational controls, or physical improvements
to reduce concentrations of the parameters of concern, or to bring concentrations within the benchmark
range.
4. Implement the selected actions within two months of the inspection.
5. Record each instance of a Tier One response in the Stormwater Pollution Prevention Plan. Include the
date and value of the benchmark exceedance, the inspection date, the personnel conducting the
inspection, the selected actions, and the date the selected actions were implemented.
Tier Two
If. During the term of this permit, the first valid sampling results from two consecutive monitoring periods are
above the benchmark values, or outside of the benchmark range, for any specific parameter at a specific
discharge outfall;
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Permit NC0004944
Then: The permittee shall:
1. Repeat all the required actions outlined above in Tier One.
2. Immediately institute monthly monitoring for all parameters at every outfall where a sampling result
exceeded the benchmark value for two consecutive samples. Monthly (analytical and qualitative)
monitoring shall continue until three consecutive sample results are below the benchmark values or
within the benchmark range.
3. If no discharge occurs during the sampling period, the permittee is required to record "No Flow" on a
monthly monitoring report to comply with reporting requirements.
4. Maintain a record of the Tier Two response in the Stormwater Pollution Prevention Plan.
During the term of this permit, if the valid sampling results required for the permit monitoring periods exceed
the benchmark value, or are outside the benchmark range, for any specific parameter at any specific outfall on
four occasions, the permittee shall notify the DWR Regional Office Supervisor in writing within 30 days of
receipt of the fourth analytical results. DWR may but is not limited to:
• require that the permittee revise, increase, or decrease the monitoring frequency for the remainder of the
permit;
• require the permittee to install structural stormwater controls;
• require the permittee to implement other stormwater control measures; or
• require that the permittee implement site modifications to qualify for the No Exposure Exclusion.
(6) If a facility is required to sample multiple stormwater discharge locations, the permittee may petition the
Director to sample at a reduced number of outfalls. These outfalls would be granted "Representative
Outfall Status" (ROS). DWR may grant Representative Outfall Status if discharges from a single outfall
are representative of discharges from multiple outfalls. Approved ROS will reduce the number of
outfalls where analytical sampling requirements apply. Qualitative observations shall be recorded for all
outfall locations.
(7) This site discharges to impaired waters experiencing problems with nutrient loading (High Rock Lake
watershed). If a Total Maximum Daily Load (TMDL) is approved for this segment of North Second
Creek or High Rock Lake, the permittee may be required to monitor for the pollutant(s) of concern in
the future and submit results to the Division of Water Resources. The Division will consider the
monitoring results in determining whether additional BMPs are needed to control the pollutant(s) of
concern to the maximum extent practicable.
If additional BMPs are needed to achieve the required level of control, the permittee will be required to
(1) develop a strategy for implementing appropriate BMPs, and (2) submit a timetable for incorporation
of those BMPs into the permitted Stormwater Pollution Prevention Plan.
(8) Qualitative monitoring requires a visual inspection of each stormwater outfall regardless of
representative outfall status and shall be performed as specified in Table 5, during the analytical
monitoring event. [If analytical monitoring is not required, the permittee still must conduct semi-annual
qualitative monitoring.] Qualitative monitoring is for the purpose of evaluating the effectiveness of the
Stormwater Pollution Prevention Plan (SPPP) and assessing new sources of stormwater pollution.
Table 5. Qualitative Stormwater Monitoring Requirements
Discharge Characteristics
Frequency1
Monitoring Location2
Color
semi-annual
SDO
Odor
semi-annual
SDO
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Permit NC0004944
Clarity
semi-annual
SDO
Floating Solids
semi-annual
SDO
Suspended Solids
semi-annual
SDO
Foam
semi-annual
SDO
Oil Sheen
semi-annual
SDO
Erosion or deposition at the outfall
semi-annual
SDO
Other obvious indicators of stormwater
pollution
semi-annual
SDO
Footnotes:
1 Measurement Frequency: Twice per year during a measureable storm event, for each year until either
another permit is issued for this facility or until this permit is revoked or rescinded. The applicant must
continue semi-annual monitoring until the renewed permit is issued or a separate NPDES Stormwater
Permit is issued. See Table 2 for schedule of monitoring periods through the end of this permitting
cycle.
2 Monitoring Location: Qualitative monitoring shall be performed at each stormwater discharge outfall
(SDO) regardless of representative outfall status.
In the event an atypical condition is noted at a stormwater discharge outfall, the permittee shall document the
suspected cause of the condition and any actions taken in response to the discovery. This documentation will
be maintained with the SPPP.
(9) The permittee shall record the required qualitative monitoring observations on the SDO Qualitative
Monitoring Report form provided by the Division, and shall retain the completed forms on site. Visual
monitoring results should not be submitted to the Division, except upon DWR's specific requirement to
do so.
C) REQUIREMENT TO APPLY FOR SEPARATE STORMWATER PERMIT
The permittee is not authorized to discharge stormwater after the expiration date. In order to receive
automatic authorization to discharge beyond the expiration date, the permittee shall submit forms and fees as
are required by the agency authorized to issue permits no later than 180 days prior to the expiration date,
unless permission for a later date has been granted by the Director. (The Director shall not grant permission
for applications to be submitted later than the expiration date of the existing permit) [40 CFR 122.21(d)].
The permittee must apply separately to the North Carolina Division of Energy, Mineral, and Land
Resources (DEMLR) Stormwater Program for a separate NPDES Stormwater Discharge Permit no
later than June 3, 2022.
d) RECORDS RETENTION
Along with the Stormwater Pollution Prevention Plan (SPPP), qualitative monitoring shall be documented
and records maintained at the facility. Copies of analytical monitoring results shall also be maintained on-site.
The permittee shall retain records of all monitoring information, including all calibration and maintenance
records and all original strip chart recordings for continuous monitoring instrumentation, and copies of all
reports required by this individual permit for a period of at least 5 years from the date of the sample,
measurement, report or application. This period may be extended by request of the Director at any time.
d) BYPASSING OF STORMWATER CONTROL FACILITIES
Bypass is prohibited, and the Director may take enforcement action against a permittee for bypass unless:
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Permit NC0004944
(1) The bypass was unavoidable to prevent loss of life, personal injury or severe property damage; and
(2) There were no feasible alternatives to the bypass, such as the use of auxiliary control facilities, retention
of stormwater or maintenance during normal periods of equipment downtime or dry weather. This
condition is not satisfied if adequate backup controls should have been installed in the exercise of
reasonable engineering judgment to prevent a bypass which occurred during normal periods of
equipment downtime or preventive maintenance; and
(3) The permittee submitted notices as required under, Part III, Section C of this permit.
If the Director determines that it will meet the three conditions listed above, the Director may approve an
anticipated bypass after considering its adverse effects.
e) Stormwater Definitions
(1) Adverse Weather
Adverse conditions are those that are dangerous or create inaccessibility for personnel, such as local
flooding, high winds, or electrical storms, or situations that otherwise make sampling impractical. When
adverse weather conditions prevent the collection of samples during the sample period, the permittee must
take a substitute sample or perform a visual assessment during the next qualifying storm event.
Documentation of an adverse event (with date, time and written narrative) and the rationale must be
included with SPPP records. Adverse weather does not exempt the permittee from having to file a
monitoring report in accordance with the sampling schedule. Adverse events and failures to monitor must
also be explained and reported on the relevant DMR.
(2) Best Management Practices (BMPs)
Measures or practices used to reduce the amount of pollution entering surface waters. BMPs may take
the form of a process, activity, or physical structure. More information on BMPs can be found at:
http: / /www.epa.gov/npdes /national-menu-best-management-practices-bmps-stormwater#edu.
(3) Bulk Storage of Liquid Products
Liquid raw materials, manufactured products, waste materials or by-products with a single above ground
storage container having a capacity of greater than 660 gallons or with multiple above ground storage
containers having a total storage capacity of greater than 1,320 gallons.
(4) Municipal Separate Storm Sewer System (MS4)
A stormwater collection system within an incorporated area of local self-government such as a city or
town.
(5) No Exposure
A condition of no exposure means that all industrial materials and activities are protected by a storm
resistant shelter or acceptable storage containers to prevent exposure to rain, snow, snowmelt, or runoff.
Industrial materials or activities include, but are not limited to, material handling equipment or activities,
industrial machinery, raw materials, intermediate products, by-products, final products, or waste
products. DWR may grant a No Exposure Exclusion from NPDES Stormwater Permitting requirements
only if a facility complies with the terms and conditions described in 40 CFR §122.26(8)
(6) Measureable Storm Event
A storm event that results in an actual discharge from the permitted site outfall. The previous
measurable storm event must have been at least 72 hours prior. The 72 -hour storm interval may not
apply if the permittee is able to document that a shorter interval is representative for local storm events
during the sampling period, and obtains approval from the local Regional Office Supervisor in writing.
(7) Point Source Discharge of Stormwater
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Permit NC0004944
Any discernible, confined and discrete conveyance, including but specifically not limited to, any pipe,
ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, or concentrated animal
feeding operation from which pollutants are or may be discharged via stormwater to waters of the state.
(8) Representative Outfall Status
When it is established that the discharge of stormwater runoff from a single outfall is representative of
the discharges at multiple outfalls, the DWR may grant representative outfall status. Representative
outfall status allows the permittee to perform analytical monitoring at a reduced number of outfalls.
(9) Secondary Containment
Spill containment for the contents of the single largest tank within the containment structure plus
sufficient freeboard to allow for the 25 -year, 24-hour storm event.
(10) Section 313 Water Priority Chemical
A chemical or chemical category which:
(a) Is listed in 40 CFR 372.65 pursuant to Section 313 of Title III of the Superfund Amendments and
Reauthorization Act (SARA) of 1986, also titled the Emergency Planning and Community Right -to -
Know Act of 1986;
(b) Is present at or above threshold levels at a facility subject to SARA title III, Section 313 reporting
requirements; and
(c) That meets at least one of the following criteria:
(i) Is listed in appendix D of 40 CFR part 122 on either Table II (organic priority pollutants),
Table III (certain metals, cyanides, and phenols) or Table IV (certain toxic pollutants and
hazardous substances);
(ii) Is listed as a hazardous substance pursuant to section 311(b) (2) (A) of the CWA at 40 CFR
116.4; or
(iii) Is a pollutant for which EPA has published acute or chronic water quality criteria.
(11) Significant Materials
Includes, but is not limited to: raw materials; fuels; materials such as solvents, detergents, and plastic
pellets; finished materials such as metallic products; raw materials used in food processing or production;
hazardous substances designated under section 101 (14) of CERCLA; any chemical the facility is required
to report pursuant to section 313 of Title III of SARA; fertilizers; pesticides; and waste products such as
ashes, slag and sludge that have the potential to be released with stormwater discharges.
(12) Significant Spills
Includes, but is not limited to: releases of oil or hazardous substances in excess of reportable quantities
under section 311 of the Clean Water Act (Ref: 40 CFR 110.10 and CFR 117.21) or section 102 of
CERCLA (Ref. 40 CFR 302.4).
(13) Stormwater Associated with Industrial Activity
The discharge from any point source which is used for collecting and conveying stormwater and which
is directly related to manufacturing, processing or raw material storage areas at an industrial site.
Facilities considered to be engaged in "industrial activities" include those activities defined in 40 CFR
122.26(b)(14). The term does not include discharges from facilities or activities excluded from the
NPDES program.
(14) Stormwater Discharge Outfall (SDO)
The point of departure of stormwater from a discernible, confined, or discrete conveyance, including
but not limited to, storm sewer pipes, drainage ditches, channels, spillways, or channelized collection
areas, from which stormwater flows directly or indirectly into waters of the State of North Carolina.
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Permit NCOOO4944
(15) Stormwater Runoff
The flow of water which results from precipitation and which occurs immediately following rainfall or
as a result of snowmelt.
(16) Total Flow
The flow corresponding to the time period over which the sample collection occurs. The total flow
calculated based on the size of the area draining to the outfall, the amount of the built -upon
(impervious) surfaces within the drainage area, and the total amount of rainfall occurring during the
sampling period.
(17) Total Maximum Daily Load MDL)
TMDLs are written plans for attaining and maintaining water quality standards, in all seasons, for a
specific water body and pollutant. (A list of approved TMDLs for the state of North Carolina can be
found at htW://deq.nc.gov/about/divisions/water-resources/planning/modeling-assessment/tmdls.
(18) Vehicle Maintenance Activity
Vehicle rehabilitation, mechanical repairs, painting, fueling, lubrication, vehicle cleaning operations, or
airport deicing operations.
(19) Visible Sedimentation
Solid particulate matter, both mineral and organic, that has been or is being transported by water, air,
gravity, or ice from its site of origin which can be seen with the unaided eye.
(20) 25 -year. 24 hour storm event
The maximum 24-hour precipitation event expected to be equaled or exceeded, on the average, once in
25 years.
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