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Special Use Areas and the Short Term Storm Water Characterization Study

Most storm water permit holders have permits that are for “Storm Water Discharges Not Associated with Special-Use Areas.” However, others have a stormwater permit for “Storm Water Discharges Associated with Special-Use Areas.” The difference is that the latter has provisions for completing a Short Term Storm Water Characterization Study (STSWCS). The STSWCS is additional monitoring requirements for a facility that requests authorization to discharge storm water from designated “special-use” areas. Special-use areas include the following:

  • Secondary containment structures required by state or federal law. A STSWCS is required if storm water is discharged from secondary containment structures to surface water of the state. This would be the case for a facility subject to the secondary containment requirements of federal SPCC Plans or state PIPPs.

Secondary containment facilities are able to forgo a STSWCS by rerouting storm water either to the sanitary sewer or to the ground such as a grassy area which infiltrates and does not run off into surface waters.

  • Lands on Michigan’s List of Sites of Environmental Contamination

A STSWCS is required if on-site contamination could potentially be co-mingled with storm water runoff. Typically, a STSWCS would be required if the contamination is present in the top 6 inches of the soil.

  • Other areas with activities that may contribute pollutants to storm water

A STSWCS may be required for a facility that has compliance issues and EGLE believes storm water may be violating Water Quality Standards.

The purpose of the STSWCS is to evaluate the quality of the storm water being discharged from a special use area. Within six months of coverage, the permittee must submit a STSWCS plan. Upon approval of the STSWCS plan, the permittee shall begin monitoring the authorized discharge. The STSWCS results are required to be submitted to EGLE.

Similar to Visual Assessment requirements, at least one grab sample shall be collected during the first 30 minutes of the discharge for each qualifying storm event. Additionally, composite samples may be required during the first three hours of a discharge.

CFR is a certified storm water operator and is experienced in providing environmental compliance and monitoring support for companies required to have a storm water permit. CFR can also assist you in determining if your facility is required to have a storm water permit based upon rules in 40 CFR Part 122.26 an EGLE permit guidance. CFR has been helping industry navigate surface water compliance for over 30 years. Contact CFR to learn more about how we can assist your environmental compliance needs.

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