A RAPID FIELD ASSESSMENT METHOD TO IDENTIFY PERENNIAL, INTERMITTENT AND EPHEMERAL STREAMS OF THE ARID SOUTHWEST
Streamflow duration (FD) must be characterized to inform watershed management decisions and implement water policy. Models that predict stream discharge have informed databases that designate FD across the United States. However, validation of FD predictions remains difficult without standardized field protocols to determine FD. Our goal was to inform development of a rapid field assessment method that could identify streams as perennial, intermittent or ephemeral in the arid southwest. We visited 36 streams with FD characterized by local experts and USGS gages in New Mexico, Arizona and California. Assessments were conducted with two protocols developed in the pacific northwest (PNW) and New Mexico (NM) which produced the same designation at 58% of sites. The PNW method correctly determined FD at 81% of sites versus 67% by the NM method and was less likely to designate a site as perennial (17%), than the NM method (42%). FD was underestimated at eutrophic, perennial sites that lacked ephemeroptera and was overestimated at ephemeral sites with hydrophytes and where slope was low compared to the PNW. This study highlights challenges of FD assessment across regions with variable geomorphology and degree of human impact.
Julie Kelso (Primary Presenter/Author), ORISE Environmental Protection Agency, email@example.com;
Raphael Mazor (Co-Presenter/Co-Author), Southern California Coastal Water Research Project, firstname.lastname@example.org;