Turbidity and Brennan Woods
June 6, 2018
We are pleased to introduce a new communications feature for the Clear Lake Township Land Conservancy. We sometimes hear questions or concerns from several sources at the same time about current conservancy or environmental topics in the Clear Lake Township.
This periodic short column allows Conservancy Executive Director Bridget Harrison to give all of us the same answer at the same time. If you have or hear such questions or concerns, let Bridget know by email email@example.com or phone call, (260) 316-1397. Also, help us by spreading the word about this new source of reliable and timely information about community and environmental questions in the Clear Lake Watershed.
Q.: George from the West Shore asks: The Lake has seemed murkier than usual this spring. Have the timber cutting and prescribed burns at Brennan Woods caused this?
A.: Bridget: Good observation, George, but we do not believe the harvest and prescribed fires are the source. Instead, we are seeing the result of extremely heavy rainfall this spring. Clear, clean water is one of the Conservancy’s ultimate goals, but it’s a complex effort. Let’s explore a bit more.
Where’s the cloudy water coming from this spring? NOAA confirms that spring 2018 has been the wettest spring here in four years, with total rainfall more than 6 inches above normal. All Clear Lake water sources have contained more sediment this spring due to the heavy rainfall. Sediments from the four ditches (Teeters, Brouse, Smith and Patterson) around the Lake are contributors to the cloudy water as heavy rainfalls wash materials into the ditches that ultimately feed into Clear Lake. As the rainfall decreases, the turbidity should reduce.
We call water clarity “turbidity”. Turbidity is one of 8 criteria the Conservancy has tested four times a year consistently since 2008 under the Hoosier River Watch program. Turbid water is cloudier and results from suspended matter such as clay, silt, organic and inorganic matter. Overall turbidity at Clear Lake has been acceptable but it varies by season. The big weekends such as Memorial Day and the Fourth of July produce significant turbidity due to the churn of boat traffic.
The Brennan Woods & Clear Lake Nature Preserve restoration project anticipated the risk of erosion as timber was cleared and brush removed. We and our project partner, Blue Heron Ministries, inspect Brennan Woods often and monitor conditions closely. We have not found significant or increased erosion this spring. Most runoff studies involve “clear cuts” or total clearings of land. Our timber harvest was a selective removal, meaning that only a select number of trees were taken versus a clear cut. As part of our restoration effort, we intentionally left a significant number of trees that should provide good protection of the forest soil. Our spring inspections support this result.
Clear, clean water is one of the Conservancy’s ultimate goals, but it’s a complex effort. Thanks for your interest in improving water quality because it is a community effort. Reach out if you are interested in being part of the water quality testing team: firstname.lastname@example.org.