County commission approves Coldwater River and Blackhawk dams review by drain commissioner
Branch County commissioners gave Drain Commissioner Mike Hard authority Tuesday to address issues with two dams under his supervision on the Coldwater River and the Blackhawk Mill Pond.
Marble-Coldwater Chains of Lakes
Hard said the county never established a legal lake level in establishing the board for the 2,700-acre chain of nine lakes.
Hard explained that to establish the lake level, it is necessary to determine which properties benefit from the lake to determine the assessment district.
An engineering study is required before the legal action can be filed.
The petition will request authority to adjust the lake level for higher summer recreation levels and lower winter levels.
Hard also warned at an April meeting of the Marble-Coldwater Lake Board that the state Department of Environment, Great Lakes, and Energy believes the dams on Marble Lake at the Sauk River and on Coldwater Lake for the Coldwater River should be reclassified and rebuilt to withstand a 1% or 100-year storm.
"It was fine before, but all of a sudden, it's not going to withstand a 100-year flood. They want a design for this great big overflow channel" at the Coldwater River dam, Hard said. "A 100 foot wide spillway is serious money."
Construction is costly, with the only land available to the west because of I-69 on the east side.
Hard said EGLE does not have a water flow model for a lake chain with rivers at each end like the Marble/Coldwater chain.
The lake board approved the commissioner's suggestion of installing wireless monitors on the five primary lakes at a cost of $15,000 a year to determine actual lake levels after rains in real time.
Board member Bill Benjamin from Ovid Township suggested the study should cover at least four to five years.
Kinderhook Township Supervisor Wayne Barnes said the monitor cost is minor compared to the cost of new dams.
Hard said, "Once we get some significant rain events, we can do the calculations to prove what we actually need, not what (EGLE) thinks we need."
The cost of all work on the chain is split equally between the 3,000 to 4,000 parcels around the lake.
Blackhawk Dam
In August 2018, water almost washed out the earthen sides of Blackhawk Dam just east of Behnke Road on the Coldwater River.
Hard called in crews from Modert Excavating. The excavators filled the holes with rock and dirt and lowered the pond level by about three feet.
If the dam had given way, a surge of water 7 to 10 feet high washing down the river and into South Lake could have gone through the channel at U.S. 12, flooding Pine Knob.
Hard met with most owners around the pond, who expressed interest in restoring the dam to raise the pond level. "Everyone who was in attendance would like to look at rebuilding this dam," Hard told county commissioners.
The drain commissioner will hire an engineer first to determine which landowners would benefit from the work to establish an assessment district, then explore potential designs for dam restoration.
Hard said of the project, cost, and assessments, "Let's investigate further and let them know exactly what the cost is going to be."
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Hard is working on a timetable for both the lake-level petition and the Blackhawk project.
— Contact Don Reid: dReid@Gannett.com
This article originally appeared on Coldwater Daily Reporter: Blackhawk, Coldwater River dams under study by drain commissioner
