Stream flow duration tool being adapted for use in U.S. Great Plains region

SCCWRP and its partners have begun adapting a tool that can rapidly distinguish among intermittent, ephemeral and perennial streams for use in the U.S. Great Plains region, building on SCCWRP’s prior successes adapting this tool for the U.S. Arid Southwest and Western Mountains regions.

The stream flow duration tool, which determines a stream’s flow duration based on easily observed field indicators, is based on a tool developed by the U.S. Environmental Protection Agency for use in the Pacific Northwest.

Field data collection for the Great Plains region began with a training exercise in October.

Watershed managers need to be able to distinguish streams with different flow durations because in certain cases, they are subject to different regulatory requirements. Many non-regulatory management decisions also require stream flow information.

Perennial streams have uninterrupted flow year-round. Intermittent streams have sustained seasonal flows from snow melt and groundwater. And ephemeral streams only experience brief surface flows from runoff.

The EPA is interested in having SCCWRP and its partners adapt the stream flow duration tool to eventually encompass the entire U.S., including Alaska and Hawaii, as early as 2023.