### State of Oregon Department of Environmental Quality 

# Summary of Changes to 1200

- A Permit Requirements

Category Old 1200

- A New 1200

- A

Best Management

Practices Implement best management practices (BMPs) that are appropriate for the site and describe the BMPs in a Stormwater Pollution Control Plan (SWPCP). Added mandatory BMP requirements (for example, “erosion and sediment control, spill prevention response”). Additional erosion and sediment control requirements (for example, preventing sediment track out).

Water Quality

Based Effluent

Limits Do not cause a violation of in

- stream water quality

standards. Do not cause or contribute to a violation of instream water quality standards.

Uncommingled mine dewatering water from certain categories of facilities are subject to

numeric effluent limits.

Benchmarks Meet statewide stormwater discharge concentration benchmarks total suspended solids, settleable solids, pH and oil and grease. Meet lower TSS benchmarks.

Facilities subject to numeric effluen t limits for TSS or pH are not also subject to benchmarks.

Other

Pollutants Facilities that discharge to impaired waters for sediment or turbidity have the option to sample their discharge based on a turbidity value of 160 NTU or implement

additional BMPs

. Added permit eligibility requirements for new discharges to impaired waters without water quality restoration plans.

Removed the turbidity monitoring option.

Impairment

Pollutants No requirement Facilities discharging to waters impaired for the following pollutants, but for which there is not a total maximum daily load (TMDL), must monitor twice per year for these pollutants:

New facilities discharging into waters impaired with any of the above pollutants must prevent any exposure to the pollutant in their discharge, document in the facility’s SWPCP that the pollutant is not present at the site, or provide information to DEQ or Agent that their discharge would not cause or contribute to a water quality standards violation.

New facilities discharging to a water that has a TMDL must co mply with the requirements of the TMDL, if any exists Aldrin Heptachlor

Arsenic Iron

Arsenic (tri) Lead

Chlordane Mercury

Copper PCBs (Concrete Batch Plants only)

DDT Temperature (mine dewatering only)

DDT Metabolite (DDE) Zinc

Dieldrin

### Category Old 1200

- A New 1200

- A

Benchmark

Exceedances Within 30 days of receiving water quality sample results that exceed a benchmark concentration, submit Action Plan that contains (1) results of review, (2) a corrective action, (3) and an implementation schedule. Complete Tier I corrective actions are required when stormwater sample results exceed benchmark or impairment reference concentrations. Tier I requirements are similar to responses in the old permit, except only submit t o DEQ or Agent changes made to SWPCP based on investigation. Retain Tier I corrective action report on site and submit to DEQ or Agent upon request.

Tier II corrective actions are required if a second

- year geometric mean concentration exceeds

a benchmark. Must implement treatment BMPs within two years. Professional engineer or certified engineering geologist must design and stamp the portion of the SWPCP addressing

the treatment measures.

Sampling Sample 4 times per year. Samples must be collected at least 14 days apart. Added requirement to monitor during first 12 hours of a stormwater discharge event (This does not apply to discharges of mine dewatering water).

Monitoring

Waiver Monitoring waiver can be obtained for individual parameters after four consecutive samples collected are

at or below the benchmark or exceedance due to background or natural conditions. Monitoring waiver can be obtained for individual parameters after four consecutive samples

are at or below the benchmarks or reference concen trations based on geometric mean evaluation or due to background natural conditions.

Waivers are not available for numeric effluent limits.

Inspections Regular inspections of diversion ditches, seepage ponds and receiving waters during operation.

Mont hly inspections of areas where potential spills of significant materials or industrial activities occur, and where stormwater control measures, structures, catch basins, and treatment facilities are located. Added daily inspections of active clearing, grading and excavation areas when stormwater discharge is occurring.

Reduced inspection requirements for unstaffed or inactive sites to every three months during the rainy season.

Added that permit holders mu st document inspection results in a report and retain it on site