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Ottawa County deep aquifer may be threatened
MSU research points to potential future problem of too many wells there.
The Ottawa County Planning Commission has learned from Michigan State University researchers that the deep aquifer under the center of the county may not be able to recharge sufficiently, under current levels of pumping.
“We are at a critical crossroads right now with the main aquifer in the county,” said Mark Knudsen, director of the Ottawa County Planning and Performance Improvement Department. “I don’t think there is much awareness of the consequences of some of the things that are happening. This study really provides us a clear window of what could occur in the future, and we’re hoping to get the word out.”
The study he referred to was presented at the county Planning Commission meeting earlier this week by four MSU researchers. It indicates that there may be “some gradual mining” of the deep aquifer, according to Jon Bartholic, director of the Institute of Water Research at MSU. That means deep wells could be removing the lowest groundwater — particularly in the bedrock — and that water may not be replenished sufficiently because a higher, thick layer of impermeable clay prevents much water from seeping down there.
Bartholic also said there appears to be an increasing concentration of salt water in some wells in Ottawa County, which is indicative of a significant drawdown of the fresh water that normally is on top of the salt water.
Bartholic was careful to emphasize several times that this is “a preliminary study” based on existing data compiled by the state of Michigan on water wells drilled over the past several decades throughout the state.
When asked how significant the data is, Bartholic said it is “really substantial. But again, it is preliminary.”
“Clearly it is an indication that further studies need to be done and I think it is great that the planning agency (in Ottawa County) is looking at this, so that strategies can start to be developed to make sure we have a sustainable water supply,” said Bartholic.
Knudsen said a positive aspect of the MSU study is that it is being done “at a point in time where we can be proactive, rather than reactive, and preserve to a great extent the aquifer that we do have, and the quality we hope to maintain.”
“But we are seeing that the study definitely shows a correlation between the amount of pumping that is currently going on, and a drop in the aquifer itself,” added Knudsen.
He said that as the water level drops far below ground, chloride — salt — becomes more concentrated in the lowest layer of water.
“As a result, we’re seeing more chloride in more wells, and we’re seeing higher concentrations of chloride in wells,” said Knudsen. In some cases, he said, it appears the chloride level is above acceptable drinking water standards and at levels that negatively affect plants that are watered with it.
There is a shallower aquifer throughout much of the country that moves through glacial till, and many homeowners’ wells tap into that, as opposed to the deep aquifer reached by large wells put down for industrial use or heavy agricultural irrigating.