Volunteers Measure Stream Health

by Ashley Rawhouser

Skagit Rivers Stewards started as a cooperative project, in 1997, between the U.S. Forest Service and North Cascades Institute. The original purpose was to use biologic monitoring to measure the health of aquatic communities throughout the Skagit river system and to see if those communities were changing through time as a result of either human activities or natural phenomenon.

In 1999 the Skagit Fisheries Enhancement Group joined the effort and helped to expand the program to include monitoring effects of stream restoration projects.

Assessing the success of stream restoration projects often depends on the goals of the restoration project. These goals can include reducing fine sediment and non-point pollution inputs; decreasing water temperature; improving fish passage, or increasing habitat diversity. There are a number of physical measurements, which can be conducted to assess change in these attributes which include: pebble counts, conductivity, pH, nitrate and phosphate concentrations, hourly temperatures using computerized data loggers and the list goes on and on.

Ultimately, we are interested in the organisms that use cold clean water, deep pools, clean gravels and large woody debris. Since the SFEG is doing all of this restoration work to enhance the Skagit fisheries, it tentatively appears that monitoring salmon, trout, and char should be the way to go. But what would happen if the fish don’t use the newly restored habitat as a result of a disturbance or catastrophic event down stream of the restoration project? We might falsely judge the restoration work to be flawed. This is one of the reasons why monitoring macroinvertebrates - aquatic insects and other bottom dwelling organisms – is important in assessing the biological integrity of stream.

At the completion of the 2001 field season Skagit River Stewards have collected macroinvertebrates from 40 different sites.

Amy Hill and Ashley Rawhouser, biologists with the UF Forest Service, conduct training on how to
sample aquatic insects to determine stream health.

Macroinvertebrates are good indicators of

water quality and habitat condition because:

· They live in the streams not only year round but some species for several years. As a result they are good barometer of stream health because some of them will die when water conditions become harmful for even a short while.

· Macroinvertebrates live in streams and sections of streams from which fish may be excluded.

· Because they are relatively sedentary, they are confined to specific areas and can’t flee pollution and other degradation as fish (hopefully) can. This low mobility helps to give better site specific information.

· Different species of insects have differing tolerances to environmental degradation. This means that examining the different types of macroinvertebrates present can indicate overall stream health or what types of degradation it may be experiencing.