Tuesday, November 25, 2008

MPCA Stormwater Monitoring Requirements - Proposed Requirements

The Minnesota Pollution Control Agency has released its revised general permit for stormwater discharges from industrial sites. The current general permit was written in 1997, and the upcoming revision will reflect major changes in stormwater permitting requirements.

Review a summary of the MPCA industrial permit

The most important proposed change in the draft permit compared to the current MPCA general permit is the requirement to sample stormwater discharges.

Flowchart of Draft MPCA Stormwater Monitoring Requirements

All permittees will collect and analyze at least four quarterly samples during Year 2 of permit coverage. These samples will be compared to “benchmark” concentrations. Depending on the results, further quarterly samples may need to be collected in Year 4 and 5, and corrective actions may be required. Additional reporting, including a “Benchmark Exceedence Report” and evaluations will be required for dischargers who continue to exceed benchmark concentrations. All sample results will be reported to MPCA.

Related Links:

Further information on stormwater benchmarks

Further information on selecting stormwater monitoring techniques

Comparison of stormwater benchmarks to typical discharge data

For further information contact Caltha LLP at
Caltha LLP Website

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