River Roundup volunteers at their monitoring site. Photo by John Lloyd

The 2021 River Roundup was a great success– we had many volunteers serve on teams that visited streams across the Huron River Watershed in order to collect aquatic macroinvertebrates.  These samples help HRWC staff better understand the water and habitat conditions across all of our streams.  When high numbers of macros are found, and when a variety of different types of macros are found, this means that we have a healthy ecosystem at the location.  And the opposite is true as well– few macros, and/or few different types, tell us there is something happening in that stream to reduce water quality and habitat value.  In the Huron River Watershed, we have excellent streams and poor streams, and many in between.

The full 2021 results are available here (https://www.hrwc.org/wp-content/uploads/River-Roundup-Summary-oct-2021.pdf), but this short blog serves to provide my take on changes going on in the last six years or so.  Each time I analyze the results, I rank HRWC’s 60 macroinvertebrate sites from best to worst, 1 to 60.  These numbers always shift a little each season depending on natural variability, like changes in weather or stream flow that can alter macro populations. However, one way to see if sites are changing for good or ill is if their ranking shifts considerably.  I compared the 2015 to the 2021 rankings to look for these significant changes to better understand how things have changed in that time frame.

Of course, each of the 60 sites has its own story in the data, but we only have limited room on a blog, so I am going to highlight 3 problems and 3 successes.

3 problems

  1. Mill Creek on M-52.  Ranked 9th in 2015, it is now ranked 31. This change is not statistically significant because it is mostly the result of two bad samples in a row.  We found 18 families in 2015 (which is quite good) , 8 families in 2017 (bad but not terrible), and 11 families in 2021 (still less than average).  This is quite a decline, but at this point, just merits a call-out and a note that it needs to be watched for continued bad samples.
  2. Letts Creek on M-52.  Ranked 24 in 2015, it is now ranked 41. This is getting interesting.  Why are two sites on the same road doing so much worse? (They are several miles from each other, but still….) Letts Creek IS significantly declining in macroinvertebrates. This isn’t just a couple bad sample but consistent pattern over the last decade. HRWC and EGLE both plan on doing follow up sampling on Letts Creek in 2022.
  3. Mill Creek on Ivey Road. Ranked 31 in 2015, it is now ranked 46.  Okay, now I am concerned.  All 3 of these sites are considered the headwaters of Mill Creek.  Like Letts Creek, this piece of Mill is also in a decline for the last 10 years.

Sometimes I learn things just by typing up this blog. I knew already that Lett’s Creek macroinvertebrate population was in a decline, for reasons unknown though there are plans on investigating closer.  But seeing all three of these sites come out as declining is upping the ante for the need to learn more about the Mill Creek headwaters. It is possible these areas, close to Chelsea, are rapidly expanding areas of development. Urban sprawl is one of the worst things for streams as it introduces constant and almost untraceable non-point source pollution.

3 successes

Thanks goodness there is good news, too.

  1. Horseshoe Creek at Merrill Road.   Ranked 39 in 2015, it is now 21.  Horseshoe Creek is quite degraded as it runs through Whitmore Lake, but this downstream section in Hamburg is quite healthy and picturesque.
  2. Fleming Creek at Galpin Road.  Ranked 26 in 2015, it is now 10.  Fleming Creek is healthy across the entire watershed (we sample at 4 locations in Fleming Creek), but this is the most improved location on Fleming.
  3. Davis Creek at Doane Road.  Ranked 45 in 2015, it is now 30.  Davis Creek is has substantial urban sprawl pressures on it, and for many years Davis Creek was in a decline.  The problem is still there, but the last couple of sample at Doane Road have been much better.

There we have it! Six highlights from our volunteer’s work, but obviously, the work isn’t done.  One of the best parts of the River Roundup is how long it has been going on.  The first few sites have been monitored since September 1992.  That means we are about to hit 30 years!  Thirty years of tracking river health and educating residents of the Huron River Watershed!