New Washington State Sand and Gravel General Permit Sets Lower Turbidity Standard

On August 17, 2011, the Washington Department of Ecology (“Ecology”) proposed modifications to its current Sand and Gravel General Permit (“S&G Permit”) which will tighten limits for turbidity in surface water discharges from mining, concrete and asphalt operations.[1] In the most recent S&G Permit, which took effect in October 2010, Ecology raised the turbidity limit after concluding that the turbidity standard in the past two S&G Permits was a “mistake.”[2] The change led to an administrative challenge by an environmental group, and Ecology agreed to modify the current S&G Permit as part of a settlement.[3] Ecology’s recent modification restores the turbidity limit to the pre-2010 standard, a limit that had been in place for the past ten years. The S&G General Permit covers approximately 950 facilities within Washington State. Ecology’s modified S&G Permit will take effect on October 1, 2011.

Background

The Clean Water Act[4] (“CWA”) prohibits discharges of pollutants from a point source into waters of the United States without a National Pollutant Discharge Elimination System (“NPDES”) permit.[5] NPDES permits “place limits on the type and quantity of pollutants that can be released into the Nation’s waters, and must set forth effluent limitations,”[6] which are specific restrictions on the quantities, rates, and concentrations of chemical, physical, biological or other constituents, such as sediment or turbidity, discharged into navigable waters from point sources.[7] EPA has delegated much of the responsibility for administering the NPDES permit program to the states.[8] Under EPA-delegated authority, Ecology administers the NPDES program in Washington pursuant to the Water Pollution Control Act (“WPCA”), Chapter 90.48 RCW.[9]

Ecology’s NDPES program utilizes two types of permits – individual and general.[10] Individual permits are written on a site-specific basis; while general permits can be written to cover point sources having common elements, such as similar operations or waste discharges. General permits reduce the administrative burden on both industry and regulators, allowing a variety of related facilities within a specific industry type to apply for coverage under a common permit. Like individual permits, general permits include technology-based effluent limits, applicable water-quality based effluent limits, additional discharge requirements, monitoring, reporting, and recordkeeping requirements, and general permit conditions. Ecology’s S&G Permit covers process water, stormwater, and mine dewatering water discharges associated with certain mining, concrete, and asphalt operations.[11]

The 2010 S&G Permit – Ecology Raises the Turbidity Limit

Ecology must reissue a general permit every five years.[12] Ecology’s previous S&G Permit expired on February 5, 2010. The Agency proposed a new version of the permit on August 4, 2010 (“2010 S&G Permit”). Similar to permits in the past, the 2010 S&G Permit imposed effluent limits for various pollutants such as pH, total suspended solids, and turbidity; other discharge limits; general permit conditions; and requirements for monitoring, reporting, and development and implementation of a site management plan, which addresses spill procedures and the prevention of stormwater pollution, erosion, and sedimentation. Unlike the previous two S&G Permits, however, the 2010 S&G Permit raised the maximum daily effluent limitation for turbidity from 50 to 71 Nephelometric Turbidity Units (“NTU”), while maintaining the monthly average turbidity limit at 50 NTU. Turbidity is a measure of the cloudiness or lack of clarity of water, caused by the scattering or absorption of light by sediment, algae, or other particulates suspended in water. Chronic and high levels of turbidity can impair photosynthesis and stunt aquatic growth, thereby negatively affecting aquatic life and other “beneficial uses” of water bodies. High turbidity is also considered an “indicator” of other potential pollutants within a discharge, because metals and/or bacteria may attach to suspended particles.

The previous maximum daily effluent limit for turbidity had been in effect for a decade, remaining unchanged through 2 S&G Permits. However, Ecology explained that a change was necessary. Relying on Ecology’s Permit Writer’s Manual, the Agency calculated that the maximum daily limit for turbidity should be higher than the monthly average: “The fact sheet for the [prior S&G Permit] defined the basis of the turbidity limit of 50 as ‘economically achievable.’ There is no explanation in the previous permit as to why the daily maximum was set at the same number as the monthly average. Ecology assumes this was a mistake and therefore the daily maximum for turbidity is reinstated in the permit at 71 NTU.”[13]

In August 2010, the Puget Soundkeeper Alliance (“PSA”) appealed the 2010 S&G Permit to the Pollution Control Hearings Board, and industry advocates intervened on Ecology’s behalf.[14] The 2010 S&G Permit, including the modified turbidity limits, took effect on October 5, 2010.

Modifying the 2010 S&G General Permit – Ecology Lowers the Turbidity Limit

Following settlement discussions between the interested parties, Ecology released a modified version of the 2010 S&G Permit (“Modified Permit”) on August 17, 2011. The Modified Permit proposed lowering the maximum daily turbidity limit from 71 to 50 NTU. The revised limit took industry advocates by surprise. The Washington Aggregate and Concrete Association commented that it was “profoundly disappointed” that Ecology had “capitulated” to the PSA’s demands and urged Ecology to reconsider the change.[15] Ecology justified the modification by explaining that although it originally considered the 50 NTU maximum daily limit to be a “mistake,” it now considered the level to be “appropriate”: “The discharge monitoring data for [the previous S&G Permit] showed a compliance rate of 96% with the daily maximum of 50 NTU. This compliance rate is a good target rate for determining a performance-based or [best professional judgment] limit, and it also represents [all known, available, and reasonable methods of prevention, control, and treatment, or] AKART. Given that the 50 NTU [limit] was in the prior two permits, and in light of the compliance rate with the 50 NTU limit, Ecology believes the reduction to the previous limit of 50 NTU is appropriate.”[16] The Modified Permit takes effect on October 1, 2011.

For more information on this article, please contact Russell Prugh or any other member of Marten Law’s Permitting and Environmental Review, Water Quality, or Water Resources practice groups.