Stream ‘bugs’ will help guide funding for future stream restoration

One of the goals established by the Puget Sound Partnership is to improve freshwater quality in 30 streams throughout the region, as measured by the Benthic Index of Biotic Integrity, or B-IBI.

Benthic invertebrates range in size from those easily seen with the naked eye to those that cannot be spotted without the use of a microscope. Photo: C. Dunagan
Benthic invertebrates range in size from those easily seen with the naked eye to those that cannot be spotted without the use of a microscope. // Photo: C. Dunagan

Simply described, B-IBI is a numerical measure of stream health as determined by the number and type of bottom-dwelling creatures that live in a stream. My latest article published in the Encyclopedia of Puget Sound describes in some detail how this index works. Here’s the basic idea:

“High-scoring streams tend to have a large variety of ‘bugs,’ as researchers often call them, lumping together the benthic species. Extra points are given for species that cannot survive without clean, cool water. On the other hand, low-scoring streams are generally dominated by a few species able to survive under the worst conditions.”

Because benthic invertebrates have evolved over time with salmon and other fish, many of these important “bugs” are primary prey for the fish that we value highly. Said another way, “healthy” streams — as measured by B-IBI — tend to be those that are not only cool and clean but also very good habitats for salmon.

The goal, or “target,” for freshwater quality was approved by the Puget Sound Partnership in 2011, after consultation with many experts. Many stormwater projects have been undertaken throughout Puget Sound with the goal of cleaning up the runoff going into streams. Those efforts are expected to result in improved water quality. Still, not much attention has been given to zeroing in on the B-IBI target itself or even finding 30 streams with a B-IBI rating of “fair” that could converted to “good” with some extra effort.

The entire restoration process is beginning to change under the so-called Implementation Strategies, which are designed to focus efforts on improving the indicators of ecosystem health. For background, check out the story “Implementation Strategies will target Puget Sound Vital Signs” in EoPS.

Experts are beginning to develop an Implementation Strategy for B-IBI, which is expected to prioritize funding to improve water quality in measurable ways. Details are still to come, but studies by King County have begun to pave the way by identifying ideas for restoring candidate streams. Check out “Strategies for Protecting and Restoring Puget Sound B-IBI Basins.”

It will be interesting to see what techniques rise to the top for improving 30 streams throughout the region and how future funding will be redirected to this new effort.

Leave a Reply

Your email address will not be published. Required fields are marked *

Before you post, please complete the prompt below.

Please enter the word MILK here: