On October 21, 2009, the Washington Department of Ecology (WDOE) reissued its Industrial Stormwater General Permit (ISWGP). The general permit was issued under the authority of the Clean Water Act (CWA), 33 U.S.C. §§ 1251 et seq., and Washington state's Water Pollution Control Act, Chapter 90.48 RCW. The reissued ISWGP is effective January 1, 2010 and will replace the prior ISWGP that expired in April of 2009.
The ISWGP is a statewide permit that applies to facilities conducting industrial activities that discharge stormwater to a surface water body or to a storm sewer system that drains to a surface water body. Approximately 1,200 facilities that discharge stormwater associated with industrial activities are presently covered by the ISWGP. The reissued ISWGP contains a number of changes that are directed toward reducing the amount of pollutants in industrial stormwater including mandatory best management practices (BMPs) as well as sampling and reporting requirements. Existing dischargers covered by the ISWGP may need to adjust their stormwater programs to meet the conditions contained in the reissued ISWGP.
Mandatory BMPs
The reissued ISWGP imposes mandatory operational and structural source control BMPs. For instance, covered operations must implement the following nonexclusive list of mandatory BMPs:
- Vacuum paved surfaces at least once per quarter;
- Use drip pans or equivalent containment measures during all petroleum transfer operations; and
- Inspect all equipment for leaking fluids and take leaky machinery out of service until it is repaired.
The mandatory BMPs must be implemented no later than July 1, 2010. Permittees must also update their Stormwater Pollution Prevention Plan to reflect the mandatory BMPs no later than July 1, 2010.
New Sampling Requirements and Benchmarks
The reissued ISWGP alters the sampling requirements for covered facilities. Significantly, the reissued ISWGP requires all facilities to conduct quarterly sampling for copper. The reissued ISWGP sets the benchmark for copper at 14 ug/L and 32 ug/L for facilities in Western and Eastern Washington, respectively.
Certain categories of industrial groups face additional sampling requirements as well. For instance, WDOE imposed new sampling requirements and benchmarks for facilities involved with the timber product industry (24xx) and paper and allied products (26xx). Those facilities are now required to conduct quarterly sampling for COD and TSS. The reissued ISWGP sets the benchmark levels for COD and TSS at 120.0 mg/L and 100 mg/L, respectively.
The reissued ISWGP requires that facilities sample the discharge from the first fall storm event of each year.
Conclusion
Industrial operations should review their stormwater program to ensure that it complies with the reissued ISWGP.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.