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Oregon Revises Its Clean Water Act, National Pollutant Discharge Elimination System Industrial Stormwater Permit

Oregon has proposed changes to its industrial stormwater permit, which covers approximately 800 facilities throughout the state. The changes include lowered pollutant benchmarks, new corrective action requirements, and several industry-specific changes. While the revision is not necessarily groundbreaking, industrial facilities that discharge stormwater in Oregon must closely examine these permit changes to ensure compliance, and facilities in other states should take note of the changes to gauge what may be changing in their state in future permit revisions.

Most states are authorized to implement EPA’s NPDES program, as is Oregon through its Department of Environmental Quality (DEQ). DEQ is now proposing changes to its NPDES Industrial Stormwater Discharge Permit, which regulates industrial stormwater from a variety of industrial activities including manufacturing, transportation, mining, steam electric power industries, scrap yards, landfills, certain sewage treatment plants, and hazardous waste management facilities. Currently, DEQ estimates that approximately 800 facilities are registered under this permit in Oregon.

DEQ states that its goal in this permit revision is to “write clear and concise conditions aimed at uniform implementation throughout the state.” DEQ NPDES Industrial Stormwater Permit Evaluation Report, at 6, available at:

In doing so, DEQ has consolidated two formerly separate permits (1200-Z and 1200-COLS) and changed several important requirements.

The new permit lowers the stormwater discharge concentration benchmarks for copper, lead, and zinc. The new copper benchmark is based on the newly adopted aquatic life criterion for copper that requires use of the biotic ligand model, which is based on evaluation of eleven different water quality parameters, rather than the hardness based calculations used in the previous benchmark calculation. Changes to the zinc and lead benchmarks are based on a reassessment of the risk based water quality model. In addition, the total suspended solids benchmark is reduced in the new permit for facilities that discharge to the Portland Harbor Superfund site to prevent recontamination of the site.

Under the current permit, a single exceedance of a statewide benchmark, sector-specific benchmark, or impairment reference concentration triggers a Tier I investigation and a Tier I report. However, if there has been a Tier II implementation, an exceedance must be addressed with a Tier II investigation and a Tier II Benchmark Exceedance Report. Both corrective actions follow the same process, but the primary difference between the two corrective actions is that the Tier I investigation is focused on source control best management practices and implementing new narrative technology based effluent limits (TBELs), such as housekeeping and minimization of exposure, and the Tier II corrective action is focused on source removal and stormwater treatment.

The new permit combines the Tier I corrective action and the post-Tier II Exceedance Report processes into Tier I corrective action. Now, a single exceedance of a regional benchmark, sector-specific benchmark, or impairment reference concentration requires a corrective action process in which source control, TBELs, and treatment best management practices (if applicable) are evaluated.

While the changes described above are not drastic, hundreds of Oregon facilities will be impacted by the revised permit terms. Industrial facilities that discharge stormwater in Oregon must closely examine these permit changes to ensure compliance, and facilities in other states should take note of the changes to gauge the future of their own states’ permit provisions.

DEQ accepted public comment on the revised permit through June 19, 2017. The new permit is slated to take effect July 1, 2017, and all existing permit registrants must submit a renewal application to maintain coverage. More information, including the draft permit and associated documents, can be found at the DEQ’s website regarding the permit revisions at

(Sarah J. Wightman)