Ecology tightens water-quality standards for local rivers
By Marcy Stamper
Methow Valley News
Stricter water-quality standards for the Methow and Okanogan rivers went into effect last Thursday (Dec. 21), establishing new thresholds for temperature and oxygen levels to aid fish.
The new standards have been set by the state Department of Ecology in response to federal disapproval of Washington’s previous limits for surface water.
Ecology completed revisions to overall water quality standards in 2003. The agency planned to fine tune the standards by looking at individual watersheds and uses for each body of water, according to Mark Hicks, senior analyst for water quality standards at Ecology.
At the time, the federal Environmental Protection Agency was in favor of this plan, said Hicks, but a court case in Oregon invalidated this two-phased approach. Instead, since not all water uses listed in the state’s database were accurate and appropriate, EPA issued a disapproval of Washington’s standards in March 2006, according to Hicks.
Basically, said Hicks, EPA did the work Ecology intended to do, identifying the waterways with uses that required more stringent protection.
Ecology is required to identify and protect all existing and potential water uses, said Hicks, such as drinking water supply, recreation and spawning.
The biggest focus of EPA’s disapproval, said Hicks, was for rivers and streams where salmon and steelhead spawn during the summer. Spawning requires colder temperatures and the old standard permitted warmer water for growth of older fish. Once EPA identified more-sensitive sites for spawning, the water temperature threshold had to be set lower, he said.
The colder temperature will also be a favorable environment for growing fish, said Hicks.
The standards encompass both protection of existing healthy conditions and restoration to bring a stream or waterway into compliance, said Hicks. The overall aim is to create a healthy riparian corridor that will allow the river to stay cool for more of its journey to the ocean. This includes narrower, deeper channels and more vegetation to provide shade.
The new, stricter standards are based entirely on sensitive fisheries uses of the waterways identified by EPA, said Hicks, and do not take actual water temperatures into account.
Other possible sources of warmer water are discharges from wastewater treatment plants, but these discharges are typically small enough that when mixed with river water they do not significantly raise the temperature, said Hicks.
The other component of the new standards is an increase in dissolved oxygen, necessary so that adequate oxygen can penetrate through the gravel to reach developing eggs and embryos. Cooler waters support higher oxygen levels, according to Hicks.
Ecology and other agencies continually monitor waterways for compliance, and any practical effects on the Methow and Okanogan rivers will not be known until the agencies assess individual watersheds, said Hicks. The potential impact on people and their activities will be very site-specific, and in most cases will not require any changes, he said.
Existing permits will be reviewed over time to ensure the new standards are met, according to Ecology.
Hicks believes EPA is likely to approve the new standards, although formal approval is not expected until the summer.