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Check out our Year End Report and see all of the cool work River Watch has been doing in the Minnesota River Basin.

Minnesota River Watch Final REport
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In the first ever Cross-Grade Collaborative Project, Prior Lake High Schoolers led students from Redtail Elementary through an exploration of macroinvertebrates* and how they can help scientists assess the health of a waterway. The lesson was preceded by two days of macroinvertebrate collection (one day of practice, one day of actual collection). Prior Lake River Watch Teams identified 15 different species among the wide variety of macroinvertebrates netted from the Credit River right across the street from both schools.


The day of the lesson, groups of elementary students were paired with 2-4 High School students, who led them through a game and lesson on the importance of macroinvertebrates. The students were then able to view the collection of local macroinvertebrates under microscopes. It was incredible to see the High Schooler’s get to stretch their teaching muscles and engage younger students in a hands-on activity.


I need to extend a huge thanks to all of the teachers involved in planning the activity day, and collaborating with River Watch to bring this amazing experience to fruition!


Macroinvertebrate Lesson Background

Macroinvertebrates are water bugs that are big enough to view without a microscope. The biodiversity of macroinvertebrate species is a good indicator of the health of a stream. On this metric, the Credit River sampling site excels with 15 unique species identified, and more that were not conclusively identified.

More importantly however, is the identification of pollution sensitive macroinvertebrates, like the Mayfly Larvae. Mayfly larvae are particularly sensitive to pollution due to their external gills. Most species of Mayfly have 7 or more sets of external gills, which they use to draw water into their bodies and filter the oxygen from the water. The act of drawing water into their bodies exposes their internal processes to any pollutants to the water. The Prior Lake River Watch collected a staggering amount of mature mayflies, indicating that during the spring season, the Credit River contained low levels of pollution.





Over the past 2 weeks, 5 schools have sampled across the watershed:


School of Environmental Studies

Sampling the Vermillion River where it crosses Farmington, the SES students were greeted by clear waters nearly flowing out of the banks. The experienced crew got right to work and discovered a mostly healthy waterway, All of the metrics fell within a healthy range expect nitrates. Both samples taken on 4/13 were above the 3 mg/L range. This is not great for the river health, but also not particularly surprising due to all of the water flushing into the system from the snow melt. It will be important to collect nitrate readings in May to see if the high level of nitrates sustains itself into late Spring.


Eden Prairie High School

Eden Prairie High School's River Watch team sampled for their first time on 4/17 at Purgatory Creek in Purgatory Park. The morning was brisk, but the crew stuck it out and got a few rounds of sample data collected. It was a little too cold to find any bugs, but that didn't stop the crew from searching through the icy water (2.5 C/36 F). With no previous River Watch samplings to compare it to, the crew collected their baseline data. The Specific Conductivity (salt content), and the nitrates were both outside of healthy levels, so it will be interesting to compare it to the levels in May after the winter runoff has moved through the system.


Tri-City United

Two Tri-City United science classes sampled a creek connecting 2 rural lakes. When we sampled this site in the fall, the creek was completely dry. This time the creek was out of the banks, feeding nearby wetlands a constant supply of highly oxygenated water. It was great to see a wide variety of birds flying and swimming about under the mostly sunny skies. The crew found the levels of nitrates to be 3 timed higher than is healthy. There were some nearby farm fields, that according to the students, have started applying fertilizer already this spring. It will be interesting to see if the wetlands are effected by the high nitrate levels, or if all the existing vegetation can absorb the excess nutrients.


Bloomington Jefferson

The AP Biology students from Bloomington Jefferson enthusiastically embraced the impending Earth Day energy and started their sampling session with an awesome trash collecting session, transforming the aesthetic of the 9-Mile Creek Access. With 2 hours at our disposal, teams of students took turns collecting data, scooping for bugs, and picking up more trash. The bug collecting team really outdid themselves, finding 7 unique macroinvertebrates, some of which are highly sensitive to pollution (stonefly larvae). The macro survey combined with the water data indicated a basically healthy waterway, with slightly elevated salt levels.


Prior Lake High School

Six classes sampled the Credit River over two days. The first day was cold and rainy. It was great to see students brave the elements to collect a days worth of data. The data investigation was made less treacherous thanks to the shelter of the bus. It is worth noting that the river had elevated nitrate levels all day, likely due to the large quantity water dumped into it the previous day.

The second day of sampling, was cold, but without rain. Groups of students searched for bugs with minor success, while others picked up trash, and collected water data. The data from the second day indicated there was still elevated nitrate washing through the system. Luckily the portion of the river drains into a large wetland, which can likely absorb the excess nitrates.


Thanks to all the teams who have sampled so far this spring. I look forward to sampling with you in May!

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