EPA Pacific Northwest stream tool being tested in Southwest

Posted May 4, 2018
SCCWRP and its partners will evaluate whether a tool that rapidly distinguishes intermittent streams from ephemeral streams in the Pacific Northwest can be used in the arid Southwest, such as this Riverside County creek, above. The creek is classified as a perennial stream, so researchers want to know if the Pacific Northwest tool correctly rules out the stream as neither intermittent nor ephemeral.

SCCWRP and its partners have launched a study to investigate whether a stream management tool that can rapidly distinguish intermittent streams from ephemeral streams in the Pacific Northwest is feasible for application in the U.S. Southwest.

The tool, developed by the U.S. Environmental Protection Agency, Region 10, determines a stream’s flow duration based on easily observed field indicators, such as presence of wetland vegetation and certain families of aquatic insects.

Streams that are intermittent vs. ephemeral have different regulatory requirements in some cases, making it important that streams are classified correctly. Intermittent streams are defined as streams that have sustained seasonal flows from snow melt and groundwater, whereas ephemeral streams only experience brief surface flows from runoff.

Site selection and field training began in March. SCCWRP and its partners will test the Pacific Northwest tool in coastal and desert streams in California, as well as streams in Arizona and New Mexico.

More news related to: Bioassessment, Ecohydrology