Skip to main content
U.S. flag

An official website of the United States government

Relative performance of three stream bed stability indices as indicators of stream health

October 30, 2017

Bed stability is an important stream habitat attribute because it affects geomorphology and biotic communities. Natural resource managers desire indices of bed stability that can be used under a wide range of geomorphic conditions, are biologically meaningful, and are easily incorporated into sampling protocols. To eliminate potential bias due to presence of instream wood and increase precision of stability values, we modified a stream bed instability index (ISI) to include measurements of bankfull depth (dbf) and median particle diameter (D50) only in riffles and increased the pebble count to decrease variability (i.e., increase precision) in D50.The new riffle-based instability index (RISI) was compared to two established indices: ISI and the riffle stability index (RSI). RISI and ISI were strongly associated with each other but neither was closely associated with RSI. RISI and ISI were closely associated with both a diatom- and two macrovertebrate-based stream health indices, but RSI was only weakly associated with the macroinvertebrate indices. Unexpectedly, precision of D50 did not differ between RISI and ISI. Results suggest that RISI is a viable alternative to both ISI and RSI for evaluating bed stability in multiple stream types. With few data requirements and a simple protocol, RISI may also better conform to riffle-based sampling methods used by some water quality practitioners.

Publication Year 2017
Title Relative performance of three stream bed stability indices as indicators of stream health
DOI 10.1007/s10661-017-6291-x
Authors Paul C Kusnierz, Christopher Holbrook
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Monitoring and Assessment
Index ID 70192947
Record Source USGS Publications Warehouse
USGS Organization Great Lakes Science Center