New Industrial Stormwater General Permit Regulations In Effect

Implementation of mandatory BMPs is required under the New Permit unless site conditions render a BMP unnecessary.  It is the permittee’s responsibility to demonstrate exemption from BMP requirements.  The mandatory BMPs are categorized as:  1) Operational Source Control; 2) Structural Source Control; and 3) Treatment.  Operational Source Control BMPs include quarterly vacuum sweeping of paved surfaces, catch basin maintenance, vehicle and equipment inspections, and fuel storage and handling protocols, along with employee training, monthly inspections, and record-keeping procedures.  Structural Source Control BMPs require that all cleaning operations be performed indoors, under cover, or in bermed areas, and that drain wash water be collected for treatment or storage.  Treatment BMPs such as construction and use of detention ponds, oil-water separators, biofiltrations, or constructed wetlands must be implemented by facilities unable to achieve discharge compliance through Source Control BMPs.

New Sampling Requirements

The New Permit requires quarterly sampling of stormwater discharge, including sampling of discharge during the first “fall storm event” after October 1 of each year.  The New Permit eliminates the previous permit’s “qualifying storm event” sampling requirements, instead allowing sampling within the first 12 hours of stormwater discharge or as soon as practicable thereafter, with an explanation for a delay.  Although permittees are not required to sample beyond regular business hours, under unsafe conditions, or during quarters in which no discharge occurred, submittal of a Discharge Monitoring Report is required for every monitoring period, whether or not the facility discharged stormwater that period.

Benchmarks

The previous permit contained both Action Levels and Benchmarks for parameters monitored in stormwater discharge.  The New Permit retains only Benchmark values, resulting in corrective actions’ now being triggered by Benchmarks, rather than by Action Levels as in the past.  The New Permit retains the four core Benchmark parameters of turbidity, pH, oil and grease, and zinc, and adds copper as a mandatory sampling parameter for all permitted facilities.  Commenters have noted that the Benchmarks for copper at eastern and western Washington facilities are at or possibly below background levels for surface water or even rainwater.  The addition of copper as a mandatory sampling parameter will require many metals scrap and recycling facilities to install stormwater treatment systems.  Under the New Permit, turbidity and zinc levels will trigger corrective actions at the same levels as the old Benchmark values, rather than at the higher Action Levels that triggered corrective actions under the previous permit.  The oil and grease numeric Action Level and Benchmark have been replaced with the criterion “no visible sheen.”

Old Versus New Corrective Action Standards

Similar to the previous permit, the New Permit requires certain industrial sectors to perform additional monitoring against Benchmark values.  The New Permit adds new mandatory sampling parameters for the metals, air transportation, and timber products industries.

Attaining Benchmark Criteria

A permittee may suspend sampling for one or more parameters (with the exception of visible oil sheen) when four consecutive quarterly samples collected after January 1, 2010 meet the Benchmark monitoring criteria.  However, if a permittee fails to collect a sample during a quarter in which discharge occurred, the consecutive quarter tally reverts to zero.  If a permittee does not collect a quarterly sample because no discharge occurred, that quarter is not counted in the tally, but the tally does not revert to zero.

Corrective Action

Exceeding Benchmark values results in escalating levels of adaptive management.  Permittees who exceed a Benchmark value for a single parameter for any two quarters during a calendar year must complete Level 2 corrective action, which involves revision of the SWPPP to include Structural Source Control BMPs intended to effect achievement of Benchmark values in subsequent discharge monitoring.  Permittees who exceed a Benchmark value for a single parameter for any three quarters during a calendar year must complete Level 3 corrective action, which involves revision of the SWPPP to include Treatment BMPs.  The portion of the SWPPP that addresses Level 3 corrective action must be designed and stamped by a licensed Professional Engineer, Geologist, Hydrogeologist, or certified professional in stormwater quality.

Reporting

Recommendations

Because the New Permit requires significant modifications to most industrial facilities’ stormwater management programs, industrial permittees should review the New Permit and initiate steps to ensure compliance with the new stipulations.  Modifying SWPPPs and preparing to implement required BMPs should become an immediate priority to ensure that compliance deadlines are met.  Farallon recommends that permittees seek professional technical and legal assistance to minimize the risk to business operations that may result from noncompliance.

Additional information about the New Permit is available on the Ecology Web site.  A complete listing of the activities requiring permit coverage and the associated Standard Industrial Classification Code groups are provided in Table 1 of the New Permit.

For questions regarding stormwater management,
or for additional information,
please contact Paul Grabau at (360) 527-0241
or Jerry Portele at (425) 295-0800.