Manistee River Water Quality Data
Stream Teams currently monitor water quality at five locations within the watershed, Flowing Wells, Big Cannon Creek, Big Devil Creek, Maple Creek and Pierson Creek. Stream Teams perform a habitat assessment (fall only) and collect macroinvertebrates from each site, this data is used to compute a Stream Quality Index score (SQI) which will be used to benchmark changes in water quality over time. A full summary of our methods and procedures can be found in our Quality Assurance Project Plan (QAPP). Full individual stream reports are available online in the MiCorps data exchange network, records can also be attained by contacting Au Sable directly. Biennial reports will be produced following our fall and spring collection events. A final year-end report will be distributed in August.
Understanding the SQI:
The Stream Quality Index is a measure of stream health and water quality based on the presence or absence of specific orders (and some families) of macroinvertebrates typical of healthy cold-water streams. Macroinvertebrate orders (and some families) are categorized into three groups according to how well they tolerate pollution: Group 1) Sensitive, Group 2) Somewhat-sensitive, and Group 3) Tolerant. Groupings are weighted to account for discrepancies in pollution tolerances with Group 1 organisms weighted higher than Group 2, and Group 2 higher than Group 3. Species abundance is also accounted for in the weighting scale with higher sample counts for each order receiving a higher weight than lower sample counts (with the exception Group 3). Macroinvertebrates within a stream sample are identified to the necessary taxonomic level, recorded and scored. An example macroinvertebrate data sheet can be viewed or downloaded here.
Understanding Macroinvertebrate Family Data:
Identifying our macroinvertebrate samples to the family taxonomic level can give us more precise data and a more complete understanding of stream health. For example, the order Ephemeroptera (mayflies) is typically associated with high water quality, which is true in general. However, some mayflies do not need high water quality to survive and may be present in water typically associated with very poor water quality. Identifying our sample to the family level can, in some instances, help account for pollution tolerance discrepancies within orders. Family data can be viewed or downloaded on the MiCorps Data Exchange, or by contacting Au Sable.
*Total number of families represented in the sample
**Total number of families of Ephemeroptera, Plecoptera, and Trichoptera (mayflies, stoneflies, and caddisflies respectively) represented in the sample
*** Total number of sensitive familes represented in the sample (adapted from the Hilsenhoff biotic index). Organisms rated 0-2 (scale 0-10) by Hilsenhoff were considered sensitive.
Some notes and reminders about interpreting the data: All data should be considered preliminary until after our third year of collecting (Fall 2017). This will give time to increase our sample size and create a more reliable baseline of data. Note also that while SQI scores correspond with a qualitative rating (excellent, good, fair, poor), these ratings do not necessarily represent overall health of a particular stream. Taken alone, each score reflects a single sampling in time within a single stretch of stream and should be measured against historical sampling trends within that same sampling site, not necessarily against other streams or tributaries. Questions regarding data and sampling can be directed to the Project Manager, Paul Wiemerslage.