The Huron River Watershed Council conducts aquatic benthic macroinvertebrate sampling in the winter, spring, and fall every year.
Aquatic Benthic Macroinvertebrates are particular types of insects, crustaceans, gastropods, and mollusks. The word “benthic” refers to the bottom of a lake or stream, the word “macro” means they are large enough to see with the naked eye, and “invertebrates” are creatures without backbones.
Staff and volunteers visit rivers and creeks across the Huron River Watershed and collect samples of these critters that live in the stream and on the streambed. Benthic macroinvertebrates are good indicators of water and habitat quality because they live in the water year-round and are exposed to all of the stressors and threats that the stream faces, such as chemical pollution, high and low flows, fast and stagnant water, and erosion, to name a few.
For full results see the 2024 BioMonitoring Report For past data, check out our BioMonitoring dashboardSummary of 2024
Of the 61 sites regularly monitored by HRWC, 40 of them are unchanging over time, 8 are getting better, and 8 are getting worse. Five sites are too new to yet judge.
Of the 56 sites with enough data to assess their long-term health, 7 are “Excellent” and 14 are “Good” with macroinvertebrate populations much higher to slightly higher than average. 20 are “Fair” and 15 are “Poor” with macroinvertebrate populations slightly to much lower than average.
2024 Highlight: A near-record breaking sample
The highlight of 2024 was obtaining a near-record breaking sample at the Huron River: Zeeb Road. With 30 insect families found, this is the third best sample collected by HRWC since monitoring began in 1992. The Huron at Zeeb Road is a gorgeous location! There is so much varied habitat here—riffles, pools, vegetation, submerged logs, rocks, sand, cobbles, wetland margins, and more. The location supports so much life because the habitat is so healthy!
Many sites see improvements in water quality
Of the sites that are getting better, Mann Creek: Van Amberg Road, Fleming Creek: Warren Road, and Huron Creek in Hudson Mills Metropark are the most exciting, since they already have excellent macro populations and are becoming real gems of the Watershed. These are creeks that we want to protect. Mill Creek: Mill Creek Park, Fleming Creek: Parker Mill Park, Boyden Creek: Delhi Road, Malletts Creek at Chalmers, and Port Creek at Armstrong Road are also getting better through time.
Mill Creek
The improvements in Mill Creek have occurred since the Mill Creek dam was removed in 2008.
Mallets Creek
Malletts Creek has been improving for about 15 years now, ever since Washtenaw County put serious investment in improving the stream’s flashy water flow and eroding banks. In Fall 2012, we found a finger net caddisfly for the first time. In Fall 2024, we found a flathead mayfly for the first time. Neither of these macros is an unusual find in a healthy stream, but in Mallett’s Creek, these are indicators that conditions continue to improve!
Port Creek
For the first time, we are happy to report improvements in Port Creek’s (small creek near Flat Rock) macroinvertebrate population. While normally a poor creek, we have had a couple of years of good samples here, and the population is statistically increasing.
Some creeks are declining in health
Of the sites declining, the largest concern is Davis Creek near South Lyon, as multiple sites in this growing community are getting worse and this is a trend that has continued for several years now. The creek at Silver Lake Road used to be a gem of a location, but consistent declines have pulled this creek down to just slightly above average. Other declining locations include Chilson Creek, South Ore Creek, and Norton Creek.
2024 Stonefly Search challenges
We really struggled to sample stoneflies in January 2024. Due to a very heavy rain one day before the sampling event, most streams were flooded with a combination of rainwater and snowmelt. Most teams could not successfully get in the water. Because the Stonefly Search uses Presence and Absence data, we decided to keep those samples where stoneflies were successfully found, and disregard samples where they were not found as if the team never even went there. In this way, 2024 Stonefly Search was more of a “Presence” study only as we are not recording the absences.
Volunteer for our 2025 macroinvertebrate collection events!
Macroinvertebrate collection will continue in 2025 for our 33 year in a row. If you enjoy spending time outside, and wish to see a new creeks and rivers around Washtenaw, Wayne, Oakland, and Livingston Counties, then this is the activity for you! Sign up here!
Stonefly Search 2025 is Saturday, January 18th 2025. Learn more and register at hrwc.org/stonefly.