Huge glacial aquifer under Ottawa County shrinking from overuse, water study finds.

ZEELAND, MI — Sitting on the edge of the vast waters of Lake Michigan, you’d think Ottawa County would never have a problem with fresh water.

Not so says a recent study titled “Ottawa County Water Resources,” conducted by the Institute of Water Research at Michigan State University.

The study reports that the glacial aquifer under the region is shrinking.

“We’re having the same problem as the (western United States). Wells going dry. Salt water getting into the water supply,” said Mark Knudsen, director of Ottawa County Planning and Performance Improvements.

Knudsen told members of the Zeeland AMBUCS on Monday that water table studies from 2000 to 2010 show the glacial aquifer under the county has declined by 3 meters, or about 11 feet, since the previous decade.

Knudsen’s talk was the first time the study had been publicly discussed outside of county staff.

“We had wells run dry three years ago in an Allendale subdivision and high levels of sodium chloride – or saltwater – corroding plumbing in Robinson Township,” he said.

The problem is a geological one. During the last ice age, glaciers left a bowl structure of water holding material under the state. The problem is that about 10 miles east of Lake Michigan, the good water layers like the Marshall Formation start getting covered up by thick clay deposits.

“Farming, industrial and home use are taking the water out from under the clay deposit faster than it can return,” said Knudsen, noting clay allows water to move through it but at a much slower rate than sand or gravel.

“The MSU study calls it ‘mining the water’ and the impact is going to get worse over time.”

The bright spot is the area that runs along the Lake Michigan coastline, which is made up mostly of sand and aggregate and allows water to move into subsoil faster. But less snowfall and this summer’s drought is also affecting that area.

Knudsen said $100,000 has been committed by Ottawa County for a second study by MSU to evaluate how quick and serious the aquifer depletion will be, and offer alternatives to solve the problem.

Right now, we don’t know if this could be a serious problem in 10 years or 70 years. That’s one of the things the study will determine.”

The second problem being created by the diminishing glacial aquifer is an increase in sodium chloride in well water in Ottawa County.

“The study found that sodium chloride at 250 parts per million or more was found in 10 percent of county wells tested in the past decade, compared to only 4 percent in previous reports,” Knutsen said. The report said sodium chloride is in the substructure beneath Michigan and is being drawn up into the water supply as the glacial aquifer is dropping.

The MSU report said these problem are being experienced across the state and the studies being conducted for Ottawa County could become a model for the rest of the state.11945099-large

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