Study examining extrapolation limits of bioassessment scores in engineered channels

SCCWRP and its partners have launched a study exploring the spatial extent to which ecological condition scores calculated for sites in engineered and modified channels may be extrapolated to upstream and downstream reaches.

The study, launched in December, is a follow-up to a 2017 pilot study examining this extrapolation issue in six watersheds. The 2017 study found that the extent to which bioassessment scores can be extrapolated varies by watershed, limiting scientists’ ability to offer general rules of thumb for extrapolating bioassessment scores.

Stream managers don’t have the resources to conduct bioassessment work along every stream reach in California, underscoring watershed managers’ interest in understanding the limits of extrapolating condition scores.

The follow-up study will focus on sites with channel engineering in both Northern and Southern California; results are expected to be available in summer 2019.