06_NCS000427_IDDE Plan_20230502

Town of Cary
ILLEGAL DISCHARGE DETECTION ELIMINATION PLAN (IDDE)
Introduction
Cary has been working with neighboring communities to address impairments to the Neuse and Cape
Fear Rivers. This Illicit Discharge Elimination Plan (IDDE) is based on a watershed approach to improve
the water quality in the Neuse and Cape Fear Rivers. It is dependent on the cooperation between the
community, Wake County agencies, the NC Division of Water Quality (NC DWQ), the NC Department of
Transportation (NC DOT), and all other municipal owner/operators of separate storm sewer systems
within the community. The IDDE outlines elements the Town will implement and areas where cooperation
with other owners of separate storm sewer systems is important.
The Town of Cary is located primarily in the Neuse River Basin. The remainder of the community is
located in the Jordan Lake watershed within the Cape Fear River Basin. The Jordan Lake watershed is
currently being developed and provides a unique opportunity to plan for proactive, as well as reactive
measures, in an effort to improve the water quality of the water supply lake. Within this watershed, our
community's IDDE will reflect current and future local priorities, and will primarily focus on measures of
prevention.
Legal Basis
In March 2000, the Town of Cary adopted an Illegal Discharge Ordinance. This ordinance provides the
Town with the basic legal tools to conduct investigations, determine sources of illicit discharges and
enforce the termination of illicit discharges up to, and including, fines and/or incarceration.
Detection, Part One: Locating Problem Areas
Illicit discharges and connections to the Town's separate storm sewer system will be identified using the
following techniques:
• Town employees will be trained to conduct proper inspections, screen, and test outfalls. Training of
Stormwater Staff, Public Works, Building & Inspection Services and Grounds employees to also be
observant for illicit connections during their daily job functions will be conducted annually.
• Town employees will perform window screening by visiting commercial properties to see if any illegal
discharges are being done and looking at dumpster areas,
• Cary's GIS will be used to highlight Town owned properties. A file review and field survey will be
conducted during the first year to identify all storm sewer on these properties and properly locate the
storm sewer on the computer maps.
• Visual screening of outfalls in the storm sewer system that are under the control of the Town will be
done as part of the stormwater infrastructure inventory. A minimum of 10% of the outfalls will be
reviewed annually.
• Public Works Pretreatment Group that performs inspections of grease traps maintenance will look at
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trash containment, grease rendering areas and other discharges noted and provide monthly
spreadsheet to the Stormwater division to follow up.
• Dry weather field screening of outfalls will be conducted as needed. Dry weather is defined as periods
where there has not been precipitation or snow melt for 2 days. The location screened will be located
on the community map of the storm sewers.
• Locations identified by visual screening and complaints as requiring follow up will be prioritized and
revisited during dry weather periods. Outfalls potentially discharging polluting material during dry
weather periods will be tested based on water quality problems found in the river, screening tests,
and odor, color, and visual observations. Assistance in sample collection and testing will be
requested when a significant pollutant or complex problem is found.
Detection Part Two: Finding the Source
• Complaints related to the discharge of polluting materials will be investigated as they are reported.
Currently, calls relating to discharging of improper materials into the separate storm sewer system are
directed to the Public Works & Utilities and then forwarded to Water Resources. The complaints are
investigated as staff are informed of the complaints.
• Water sampling and testing will be conducted as necessary to locate the source of the illicit
discharge.
• Suspicious discharges will be prioritized based on the estimate of the impact on the watershed.
• Investigation of suspicious discharges will be made by visual inspection and/or testing of discharges
within the storm drainage system upstream of the suspicious discharge. Other options that will be
considered in locating illicit connections or discharges include televising the storm sewer or dye
testing premises in the area where there is a discharge. Letters may be sent to residents and
businesses alerting them to the problem that is under investigation to solicit their assistance in finding
the source. A building by building evaluation may also be used in areas where a problem has been
isolated to a small area.
Removing/Correcting Illicit Connections
• The Town of Cary has developed a map identifying outfalls to waters of the state under Cary
jurisdiction. Investigations will be made to find the sources of pollutants. Those responsible for
discharges will be notified for correction and followed to assure correction is satisfactorily completed.
• Existing ordinances will be used to address illicit discharges and connections. Assistance may be
requested from the Wake County Department of Environmental Health or the NC Division of
Environmental Quality to obtain correction. If current ordinances are not adequate to result in
correction of illicit discharges, a new ordinance will be prepared. If an ordinance change is needed to
correct illicit discharges, the changes will be presented to the Town Council.
• The Town of Cary performs smoke testing annually through the Public Works department to locate
and eliminate sources of illicit connections and sources of stormwater infiltration.
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• The Town of Cary Stormwater Division will manage the Illicit Discharge Elimination Program. Cary's
Stormwater Services Manager or his designee will be responsible for implementing the plan. Town
staff and/or private contractors may be used to conduct the illicit detection surveys.
Minimizing Seepage from Septic Systems and Sanitary Sewers
• The Town of Cary is not a municipal agency that evaluates permit applications or inspects installation
of on-site wastewater disposal systems (OSWW), also referred to as septic systems. These functions
are conducted by the Wake County Environmental Health Department or, in the case of large
discharges NC Department of Environmental Heath. The Town will coordinate its IDDE with the
Wake County EHD to assist in mitigating problems with seeping OSDS. In the past, the Town has
had a history of extending sanitary sewers to service areas of failing OSDS when funds are available;
several projects have been completed and one is currently being implemented. The Town does not
encourage the use of OSDS for new development and requires the project proponent to be
responsible for such infrastructure improvements. The Town of Cary will also implement a program
that will require connection to a sanitary sewer if the conventional system is failing or they are
obtaining a permit to increase the amount of water use by adding additions to the house.
• Sanitary sewer systems operated by The Town of Cary are designed to service the lowest floor levels
(basements) of buildings in the community. Consequently, most sanitary sewers are a minimum of
12 - 15 feet deep, which is well below the level of most storm drainage facilities, thus minimizing the
potential for an illicit connection emanating from a separate sanitary sewer. Cross connections of this
type usually result in clear water accessing the sanitary sewers, which is also a cause for action by
the Town to eliminate unwanted sources.
• OSWW found to be experiencing problems or failing will be referred to the Wake County
Environmental Health Department. If sanitary sewers are not available, short and long term solutions
for sewage disposal must then be devised.
• If overflows of sanitary sewer manholes or cross connections to a storm sewer are detected, they are
addressed as part of the Town's maintenance program
General Prevention
• For additions to existing facilities which have existing OSWW, Cary will require an evaluation of the
septic system by the Wake County EHD. This will be required prior to the Town signing off for the
building permit.
• Cary inspects installation of all new storm and sanitary sewers.
General Awareness
• Cary is implementing a Stormwater Public Education Program which is a water quality public
education program for residents, businesses, and schools that includes specific information about
illicit discharges and connections. See Cary's Stormwater Public Education Program for more
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detailed information.
• The existing complaint system will be enhanced through coordination with the Public Works & Utilities
• Cary now has 311 system to report IDDE.
Implementation Schedule
• A system to log, investigate, track, and resolve complaints will be in place. 311 salesforce.
• The storm sewer map will be updated to reflect Cary owned storm sewer on Town properties.
• Areas in the community will be prioritized for visual screening.
• Town employees will be trained to be observant for illicit discharges, about proper inspection
procedures for surveying for illicit discharges, and about the system available to report their findings.
• A visual screening of the outfalls will begin. The Town storm sewer map will be updated to reflect
areas screened on an annual basis.
• A list of illicit discharges and connections and correction status will be prepared.
• The legal basis for correcting illicit discharges will be reviewed and revisions developed to administer
the program when it is found that revisions are needed.
• All activities related to this IDDE will be tracked and documented.
• A summary report of complaints received, investigated and the results of the investigation will be
prepared.
• Suspicious outfalls that had a dry weather flow during visual screening will be tested for suspected
pollutants.
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