Streamflow Duration Assessment Method (SDAM) Status by Region
Currently, the EPA and partners are developing or modifying existing SDAMs for use across the U.S.
Map of Study Regions
Map of SDAM study regions, based on regions identified in the U.S. Army Corps of Engineers Ordinary High Water Mark Scientific Support Document (figure modified from Wohl et al. 2016).
Regional Updates
Pacific Northwest
The SDAM for the Pacific Northwest was developed through a partnership between the U.S. EPA, the U.S. Army Corps of Engineers, and Oregon’s Department of State Lands. The method resulted from a study conducted on 264 stream reaches across the range of hydrologic landscapes of Oregon, Idaho, and Washington.
Arid West
The beta SDAM for the Arid West was released in March 2021. The beta method is available for a one-year preliminary implementation period while EPA and partners continue an expanded data collection effort in 2021 to inform the refinement of the final SDAM for the Arid West. The beta method results from a multi-year study conducted at 89 reaches across 7 states in the Arid West.
Western Mountains
A beta method for the Western Mountains was released in December 2021. The beta method results from a multi-year study conducted at 140 stream reaches across 9 states. The beta method is available for a one-year preliminary implementation period while EPA and partners continue an expanded data collection effort in 2022 to inform the refinement of the final SDAM for the Western Mountains.
Great Plains
A beta method is currently being developed for the Great Plains. A total of 290 sites were sampled as part of baseline and validation data collection. One hundred and eighty baseline reaches were instrumented with conductivity loggers and visited a total of three times in 2019-2020. One hundred and ten validation reaches were visited in spring and summer of 2020. During each site visit, a rapid field assessment was conducted using hydrological, geomorphological, and biological candidate indicators of streamflow duration. Candidate indicators were identified through a literature review of existing streamflow duration methods and indicators used throughout the U.S. and considered for applicability to the Great Plains.
Northeast and Southeast (including Puerto Rico and U.S. Virgin Islands)
Baseline data collection and validation site sampling is underway. Candidate indicators were identified through a literature review of existing streamflow duration methods and indicators used throughout the U.S. and considered for applicability in the Northeast and Southeast. Two hundred and forty baseline reaches were instrumented with conductivity loggers in 2020 and will be visited two more times by fall of 2021. An additional one hundred and sixty validation reaches are also being visited in 2021.
Alaska, Hawaii, and the Pacific Island U.S. Territories
Candidate indicators are being identified through a literature review of existing streamflow duration methods and indicators used throughout the U.S. and considered for applicability in Alaska, Hawaii, and the U.S. Territories in the Pacific Ocean.
Initial study site selection is underway. If you have information on sites with known hydrology in Alaska or Hawaii (particularly non-perennial stream reaches), our team would like to hear from you. Please Contact Us directly via email.