Ottawa County pursues plan for groundwater management

Alexander Sinn • Sep 13, 2018 at 12:00 PM

Groundwater wells are drying up in Ottawa County, while salt levels are on the rise. 

Armed with new research, the county has developed a management plan to help reverse these trends.

A Michigan State University study in 2012 found that water levels in the deep bedrock aquifer system have been dwindling over the past 20 years. This confirmed reports from residents in Allendale Township, who had trouble drawing from wells and needed municipal water lines extended to their homes.

Farmers irrigating soybean crops have also complained that their crops were damaged by water with high levels of sodium chloride.

In parts of the county, chloride levels in the bedrock are rising above the recommended standard for drinking water, which is less than 250 milligrams per liter (mg/L), and agricultural irrigation, which is less than 70 mg/L.

Chloride levels indicate the level of salt in the water, according to Paul Sachs, the county’s director of planning and performance improvement. Some levels have been as high as 500 mg/L.

A second study, begun in 2014 and finalized this past spring, found that declining groundwater exists where thick layers of clay deposits are preventing water from re-entering the bedrock aquifer. As groundwater is continually pumped out of the aquifer, the system is not recharging fast enough to keep up with demand.

The bedrock aquifer, known as the Marshall Formation, is naturally rich in sodium chloride. As water levels decline, salt in the bedrock is mixing with groundwater at an increasing rate.

Higher salt levels can corrode pipes, damage crops and affect people with high blood pressure.

Historical data has shown some areas in Ottawa County have had a drop in water level as much as 40 feet in the past 50 years, according to county officials. Estimates show those levels could drop another 10-15 feet in the next 20 years.

Most sites with high chloride levels are in the center of the county south of the Grand River and at sites along the Grand River.

The first component of the management plan will entail producing pamphlets and online information to spread awareness of the importance of water conservation, Sachs said. 

“That’s going to be instrumental in moving forward to help mitigate this challenge countywide,” he said. “There’s this perception that water is ubiquitous. It’s a limited resource. Oftentimes, there’s a perception that it doesn’t apply to me or it doesn’t apply to us.”

Well inspection programs will also be explored and septic regulations will be reviewed. Extensions of municipal infrastructure may be necessary to get water to residents whose wells have dried up.

To avoid issues in the future, the plan will provide guidelines for local municipalities to ensure building projects do not take a further toll on the environment.

Sachs said the county’s plan should be finalized by spring 2019.

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