Evaluation of the Stream Function Assessment Methodology (SFAM) in watersheds of the Puget Sound lowlands
Year: 2018
Type: article
Abstract: Effective stream management requires identification of anthropogenic degradation effects on stream functioning. However, few stream assessment protocols aim to evaluate stream functions (i.e., ecosystem processes), integrate multiple disciplines, and combine stream reach assessment with landscape-level context. To address these shortcomings, several agencies in Oregon collaborated to develop the Stream Function Assessment Methodology (SFAM). However, SFAM has yet to be tested against established protocols and some SFAM metrics have no equivalent data sources outside of Oregon. I conducted SFAM (2015 draft version) on 36 stream reaches in Water Resource Inventory Area 8 in Washington State. I compared SFAM scores to commensurate data from King County and the State of Washington Department of Ecology, and I evaluated the potential effects of unavailable data inputs through simplified sensitivity analyses. Overall, SFAM rarely correlated with measures of anthropogenic degradation or stream condition. The high proportion of SFAM function metrics measuring physical structures in the riparian area appeared to reduce the correlation with established measures of degradation. SFAM value scores generally reflected physical degradation of the watershed but not necessarily functioning of stream processes. The sensitivity analyses revealed small, predictable changes in SFAM outputs; however, the changes were not consistent across metrics. Many of the potential concerns identified through these analyses appear to also be relevant to the 2018 released version of SFAM. While a rapid stream function assessment like SFAM could help quantify mitigation efforts, SFAM needs more validation through empirical, quantitative evidence before being used for stream management.
Author: Michelle Bahnick
Language: English
Subfield: Earth-Surface Processes
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2941971625