Oregon Offers Streamflow Duration Assessment Method

The U.S. Army Corps of Engineers, U.S. Environmental Protection Agency, and Oregon Department of State Lands on March 6 made available a new tool to help identify waters that may be subject to those agencies’ regulatory jurisdiction.

The Oregon Streamflow Duration Assessment Method is a scientific tool for quickly analyzing more than 20 environmental factors to distinguish between ephemeral, intermittent ,and perennial streams.

That data will be used to determine whether a stream may be subject to jurisdiction under Section 404 of the Clean Water Act and the state of Oregon’s Removal-Fill statute.

Conducting work that impacts such streams, such as placing fill in them to prepare a site for future construction, often requires a permit from the Corps’ Regulatory Branch and DSL’s Removal-Fill Permit Division.

“Teams of scientists have field-tested the method to assess its clarity and ease of use,” said Richard Parkin, director of EPA’s Office of Ecosystems, Tribal and Public Affairs in Seattle. “We believe this method is a major step in evaluating streams and ensuring environmental protection of our water resources.”

Use of the method is recommended but not required, said Mike Turaski of the Corps’ Regulatory Branch. “We encourage regulators, consultants, and natural resource specialists to use the method, because it will make it easier to provide the information the Corps and DSL need to make more timely and predictable jurisdictional determinations,” he said.

The agencies have released the method for use as an interim version. It will be tested for one year before it is finalized, and the agencies encourage practitioners and the public to provide comments on their experience using it.

The agencies will hold training sessions in Portland, Medford, and LaGrande, Ore., this spring to help interested parties become more familiar with the method. For information, go to http://yosemite.epa.gov/R10/ecocomm.nsf/wetlands/oregonstreamflow.