07_NCS000467_IDDE Monitoring Plan_20211208

TOWN of 301 5 Brooks Street
Wake I orest. NC 27587
WAKE FOREST r 919.435.9400
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Illicit Discharge Detection and Elimination ODDS)
Monitoring Plan
Introduction
An illicit discharge is defined as: "Any discharge to a MS4 that is not composed entirely of stormwater
except discharges pursuant to an NPDES permit (other than the NPDES MS4 permit), allowable non-
stormwater discharges, and discharges resulting from fire -fighting activities". These allowable non-
stormwater discharges are listed below from Section 12.5.8 of the UDO:
a) Water line flushing;
b) Landscape irrigation;
c) Diverted stream flows;
d) Rising ground waters;
e) Uncontaminated ground water
infi`tration (as defined at 40 CFR
35.2005(20));
f) Uncontaminated pumped ground
water;
g) Discharges from potable water sources;
h) Foundation drains;
i) Air conditioning condensation;
j) Irrigation water;
k) Springs;
1) Water from crawl space pumps;
m) Footing drains;
n) Lawn watering;
o) Individual residential car washing;
p) Flows from riparian habitats and
wetlands;
q) Dechlorinated swimming pool
discharges;
r) Street wash water; and
s) Other non-stormwater discharges for
which a valid NPDES discharge permit
has been approved and issued by the
State of North Carolina.
All other discharges not included in this list are considered illicit because stormwater systems are not
designed to handle non-stormwater discharges.
Dry Weather Flow Inspections
Dry weather inspections will be made at major outfalls and other priority areas. Several factors influence
the frequency of inspections (including site history and outfall condition). In general, major outfalls will
be inspected at least once within the 5-year permit term. Dry weather screening of outfalls/manholes
will occur after a dry period of at least 72 hours. Discharges from the MS4 during dry periods could be
from an allowable non-stormwater discharge. If pollutants are suspected, based on visual monitoring or
sampling, source identification should be pursued. If sampling is required, it will be done on an as

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WAKE FOREST
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needed basis to help determine the characteristics of the flow. Tracing and source identification will
confirm if pollutants are truly present and help highlight the source.
All town staff and crews who work in the field will receive basic training to facilitate identification of
illicit discharges. Broader education for all town staff will promote more efficient identification of
potential illicit discharges. Informal assessments within the Town's jurisdiction are to be incorporated
during routine maintenance, inspections, or survey activities. These are expected to be reported to the
Town's Stormwater Division if there are signs of an illicit discharge. Prior to any inspector completing a
outfall inspection, training will be issued by the Stormwater Engineer. On -site training for the inspectors
performing dry weather flow inspections will occur as needed.
Field Inspections and Data
SeeClickFix is used to track external reports of non-Stormwater discharges. Inspection forms and
previously documented inspection reports can be found in NewWorld. When performing inspections of
the high priority major outfalls and Stormwater Control Measures (SCM), the NewWorld inspection
forms will be utilized. Information from both SeeClickFix and NewWorld can be filtered to allow the
Town to view historical events and classifications.
Priority Area Process
Priority areas are locations that present higher potential for spills, leaks, or illicit discharges. Priority
areas that fit that description, and are currently monitored, include but are not limited to:
Transportation facilities, Commercial facilities, Industrial facilities, Institutional facilities, Municipal
operations, areas with older sewer infrastructure, and locations where illicit discharges have been
observed in the past. The Town has identified these areas using Wake County's land usage maps, and
has created a business inventory layer to identify major outfalls within industrial zones.
The Town of Wake Forest has over 860 outfalls within its jurisdiction. Through a prioritization process,
over 154 major outfall and manhole locations have been identified and will have screening performed
on them at least once per permit term. These outfalls are identified using the prioritization process
discussed below:
Drainage Area: Outfalls greater than or equal to 35 inches in diameter are identified;
Land use type(s): Outfalls greater than or equal to 12 inches diameter that drain a portion of industrial
land use are given higher priority;

TOWN Of ioI S Brooks 5ireei
Wakc Forest, NC 2718
WAKE FOREST i 919 435.9400
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Accessibility: Areas where accessibility is an issue are temporarily managed by identifying the first
upstream manhole for the current inspection. Outfall accessibility should be coordinated with the
property owner to ensure access for future inspections.
Storm Sewer Age: Storm sewer age is determined using storm sewer as-builts and the relative age of
buildings in the catchment area with older storm sewers being prioritized over more recent storm
sewers;
Condition of Sanitary Sewer: Areas where frequent Sanitary Sewer Overflows are reported can be
prioritized for inspections;
Historical Notifications of Suspected Illicit Discharges: outfalls with a history of complaints are prioritized
regardless of any of the above considerations.
Citizens are encouraged to report illicit discharges through SeeClickFix as it helps determine the outfalls
that are inspected. Illicit discharges reported through SeeClickFix will be responded to by a member of
the Town's staff as soon as they have been notified of the incident report.
How to Identify Sources of Pollution
Types of Illicit Discharges and their Sources
When an illicit discharge is identified at an outfall it will be followed upstream to track down the source
or the general origin area. More information on the types of illicit discharges and their potential origin is
explained below.
In order to properly identify an illicit discharge, it is important to understand the different types. This
requires an understanding of surrounding land use characteristics and frequency of potentially
discharges. There are three (3) different illicit discharges based on their discharge frequency:
Transitory Illicit Discharge: These are typically a one-time event, and can result from spills, dumping, and
line breaks. These types of discharges are often the most difficult to investigate and trace back to its
source due to their sporadic occurrence.
Intermittent Illicit Discharge: These are discharges that occur periodically. They can occur several hours
per day, week, or over the course of months or even years.
Continuous Illicit Discharge: These are direct connections into the MS4 can be from sanitary sewers,
cross connections, infrastructure problems with a sanitary sewer system, or malfunctioning household

TOWN o, f )01 S. Brooks Srrcei
%Vakc Forctit. NC. 2758
WAKE FOREST r 919 435.94oO
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septic systems. Due to the constant flow, this type of discharge is the easiest to find, investigate, trace
and eliminate from the MS4.
The highest priority in the elimination of illicit discharge is to find and remove sources of continuous or
intermittent discharges in the MS4,
if it is difficult to determine if the water source is an illicit discharge, a water quality testing kit can be
provided by the Assistant Stormwater Engineer to test the alkalinity, pH, hardness, and chlorine levels
from a sample of the water source.
Activities that Produce Transitory or Intermittent Illicit Discharges
Land Use
Likely Source Locations
Condition/Activity that Produces Discharge
Residential
•
Multi -family
•
Car Washing
•
Duplex
•
Driveway C'ean ing
•
Single Family
•
Dump ng/Spills
•
Equipment Wash -downs
Commercial
•
Car Dealers/Rental Car
•
Building Maintenance (power washing)
Companies
•
Dumping/Spills
•
Car Washes
•
Landscaping/Grounds Care (irrigation)
•
Commercial Laundry
•
Outdoor Fluid Storage
•
Gas Stations
•
Parking Lot Maintenance (power
+
Auto Repair Shops
washing)
•
Carpet Cleaners
•
Vehicle Maintenance/Repair
•
Mobile Food Vendors
•
Wash -down of Greasy Equipment &
+
Nurser'es and Garden
Grease traps
Center
Industrial
•
Auto Recyclers
+
A' Commercial Activities
•
Construction Vehicles
•
Industrial Process Water or Rinse Water
Washouts
.
Loading and Un-loading Area Wash-
•
Distribution Centers
downs
•
Food Processing
•
Outdoor Material Storage (fluids)
•
Garbage Truck Washouts
•
Paper and Wood Products
•
Petroleum Storage
•
Printing
Municipal
•
Landfills
•
Building Maintenance (power washing)
•
Maintenance Depots
•
Dumping/Spills
•
Municipal Fleet Storage
•
Landscaping/Grounds Care (irrigation)
Areas
•
Outdoor Fluid Storage
•
Public Works Yards
.
Parking Lot Maintenance (power
•
Streets and Highways
washing)
0
Other County Facilities
0
Road Maintenance

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TOWN of
WAKE FOREST
101 5 Brooks Strcci
\ ake Forest- NC 2758
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• Emergency Response
• Vehicle Maintenance/Repair
SOURCE: Modified from Illicit Discharge Detection and Elimination: A Guidance Manual far Program
Development and Technical Assessments, Center for Watershed Protection, 2004, p. 12, Table 2
Activities that Produce Continuous Illicit Discharges
Land Use Condition/Activity that Produces Discharge
Residential • Failed sanitary sewer infiltrating into storm drain
• Sanitary sewer connection into storm drain
• failed septic systems discharging to storm drain system
Commercial/Industrial • Failed sanitary sewer infiltrating into storm drain
• Process water connections into storm drain
• Sanitary sewer connection into storm drain
Municipal • Failed sanitary sewer infiltrating into storm drain
• Sanitary sewer connection into storm drain
Source: Table 2-2 from Guidelines and Standard Operating Procedures for Stormwoter Phase 11
Communities in Maine, Casco Bay Estuary Partnership.
Procedures for Eliminating Sources of Pollution
The process of eliminating an illicit discharge will depend on the source and its characteristics. Town
staff have the right to access, monitor, and sample all parts of the MS4 per Section 32-441 of the Town
Code of Ordinances.
When an illicit discharge or connection is identified or suspected the appropriate stormwater staff
should respond to the incident by identifying and working with the party responsible. Following the
regulatory mechanisms and enforcement policies starting in Section 32-444 of the Town Code of
Ordinances, the stormwater staff should notify and work with the responsible party to find a solution to
the violation so that the illicit discharge or connection can be eliminated. Each notice of violation (NOV)
needs to be recorded so that the Town can keep track of first-time violators or repeat offenders.
Procedures for Maintaining Outfall Access
If an outfall is submerged, either partially or completely, or inaccessible, field staff will proceed to the
first accessible upstream manhole or structure for the inspection and report the location on the
inspection form. Field staff should continue to the next upstream structure until the is no longer an
influence from the receiving water on the visual inspection or sampling.
Section 32-441 of the Town Code of Ordinances states that the Town shall be permitted to access to
properties and that any obstructions must be removed to allow for safe and easy access. Any temporary

i
TOWN of
WAKE FOREST
3l) I S. Brooks Srreci
Wake I'ore�a, NC 27587
1 Qi9.`I35.9` 00
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or permanent obstruction to safe and easy access to the property to be inspected and/or sampled shall
be promptly removed by the operator at the written or oral request of the town and shall not be
replaced. The cost of clearing such access shall be born by the person. Enforcement action as stated in
the Town Code of Ordinances may be taken if the property owner refute access.
How the IDDE Monitoring Plan is Assessed
Tracking the data collected for the WE Monitoring Plan is important for the assessment and
refinement of the Monitoring Plan. The SWMP identifies measurable goals for IDDE in it's respective
BMP table and performing an annual assessment of the program is essential in achieving those goals.
A few suggested steps to assess the effectiveness of the Town's IDDE Monitoring strategies include:
• Evaluate how effective different enforcement and compliance measures are at eliminating illicit
discharges. This evaluation is accomplished by reviewing the number of discharges eliminated.
• Evaluate the number of illicit discharges or suspected illicit discharges that were reported by
different detection methods. This can help determine which detection methods are the most
effective. Further evaluation can be performed by looking into which detection methods worked
for Maintenance/Street crews, the citizens of the Town, etc.
• Evaluate areas of strengths and weaknesses in staff training materials. This can be based off
staff feedback and illicit discharge reporting results.
• Review difficulties that were encountered when following the IDDE Monitoring Plan, performing
dry weather screening, etc. and how they can be improved.
By tracking data, the program can be evaluated and determine whether goals are being met. The
assessment strategies listed above should not be considered the definitive list used to assess the
program. Instead, they should be used as a foundation to build off and make adjustments in order to
gradually move the IDDE monitoring plan forward.