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Recent non-perennial streamflow research using the USGS gaging network and US EPA Streamflow Duration Assessment Methods (SDAMs)
Citation:
Hammond, J. AND K. Fritz. Recent non-perennial streamflow research using the USGS gaging network and US EPA Streamflow Duration Assessment Methods (SDAMs). US Geological Survey Water Mission Area Seminar Series, Virtual, August 25, 2021.
Impact/Purpose:
The purpose of the seminar is to present on USGS and USEPA projects that can inform the monitoring, mapping, and modeling of streams that do not have year-round flow or non-perennial streams.
Description:
Non-perennial streams are those that don’t flow continuously throughout the year. They constitute >50% of the global stream network length with >70% of the network in dry regions. Flow dynamics in these streams and rivers partly control ecological, biogeochemical function for these and downstream areas. Despite their importance, monitoring of non-perennial streams and rivers is sparse nationally and globally, especially for small drainages. Two alternate approaches (1) analysis of long-term USGS gaging records and (2) USEPA Streamflow Duration Assessment Methods (SDAMs) provide contrasting but complimentary information allowing in depth analysis of non-perennial stream dynamics. Recent studies using the USGS gaging work explored (1)"Spatial patterns and drivers of nonperennial flow regimes in the contiguous U.S", (2)"Pervasive changes in stream intermittence across the United States" and (3) "The drying regimes of nonperennial rivers", with recommendations to preserve and extend gaging of non-perennial streams and rivers. SDAMs are rapid, reach-scale indices or models that use physical and biological indicators to predict flow duration class (specifically, perennial, intermittent, or ephemeral). The U.S. Environmental Protection Agency is working cooperatively with the U.S. Army Corps of Engineers and other partners across the nation to develop regional SDAMs to help implement many federal, state and local programs (https://www.epa.gov/streamflow-duration-assessment). The presentation will describe the process used to develop SDAMs, examples of regional SDAMs, and future steps to complete nationwide coverage. While non-perennial USGS gaging provides information on long-term temporal dynamics, USEPA SDAMs provide more spatially extensive short-term information needed for implementing management decisions. Together, the two approaches provide opportunities to advance categorization and contextualization of non-perennial streamflow dynamics across the U.S.