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McSorley Creek

Biomonitoring Program

Friends of Saltwater State Park regularly assess the water quality of the McSorely Creek using protocols from the Global Water Watch Program using the training they received from the Sno-King Watershed Council. Water quality assessments include chemical tests, bacteriological tests, and stream biomonitoring.


Monitoring the biotic life in a stream gives us an overall picture of the water quality over time, as it is a direct view of the community of plants and animals living in the stream. Monitoring a stream through chemical and bacterial tests give us an indication of water quality only at the moment of sampling. The presence of a diverse population of macroinvertebrates is a good indication of a healthy stream.



Macroinvertebrates include insects that are in their larval stage as well as their adult stage, various types of worms, small mollusks, and small crustaceans. Macroinvertebrates vary in their ability to tolerate adverse conditions, and a biotic index can be used to calculate the abundance of pollution sensitive organisms. A higher score of sensitive invertebrates indicates a better stream quality than a lower score, showing an increase in pollution tolerant species.

This stonefly is a "Sensitive" pollution intolerant macroinvertebrate

Friends of Saltwater State Park include macroinvertebrate hands on studies for visiting school groups

Crawfish are classified as "Somewhat sensitive" invertebrates

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