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Groundwater in Michigan

Groundwater quality and quantity in the Great Lakes Basin is poorly understood despite abundance of surface water. Natural groundwater discharge plays an important role in supplying the tributaries that feed the Great Lakes (~67% of their volume), trout streams, wetlands, and inland lakes.

“The extent to which groundwater quantity and quality affect the overall function of the Great Lakes system is currently unknown” - USGS

Public supply and irrigation are the largest uses of groundwater in Michigan accounting for 77% of groundwater withdrawals, at an average of 208.9 and 208.5 MGD (million gallons per day) respectively, with industry and livestock making up the remaining balance.

45% of Michiganders rely on ground water for drinking water
Agriculture is perhaps the fastest growing sector drawing on groundwater in Michigan with approximately 1/3 of Michigan's 10,000 irrigation wells being drilled in the last 10 years
SW Michigan is a hub of agriculture with a number of economically significant and specialty crops, the vast majority of which are irrigated (all seed corn, chipping potato, snap beans, tomato, pepper, summer squash, and pickling peppers are irrigated and nearly 80% of blueberries)

Concerns

Fallacy of Universal Ubiquity

Water conservation and water use BMP are not common concerns among Michiganders due to abundant surface water.

“How do you convince the Michigan public to conserve water, whether it be from the surface or ground, when they are surrounded by four of the largest lakes on the planet and live in a state with over 10,000 inland lakes?”

Over Withdrawal

Increasing reliance on irrigation in response to climate change. Growing season precipitation is expected to decrease by 5-15% by the end of the century. There has been a >150% increase in the number of high-capacity irrigation wells in Michigan since 1997.

Reduced flow in streams
Water table drawdown causing residential and shallow agricultural wells to run dry
Over pumping groundwater increases the concentrations of naturally occurring contaminants like chloride and arsenic

Recharge

Subsurface drainage techniques used to manage excessive soil moisture in wet months prevents groundwater recharge by diverting soil moisture into surface water (i.e. rivers and great lakes system) rather than into aquifers.

~40% of cropland in Michigan uses subsurface drainage systems
Subsurface drainage diverted into streams can exacerbate flood risks
Declining water tables due to groundwater withdrawals exceeding recharge rates

Contamination

Nutrients like nitrogen and chemical pesticides and herbicides contaminating groundwater. Primarily due to fertilizer and herbicide/pesticide usage in agriculture. While fertilizer use has been on a slight decline in Michigan since its peak in 2000 (down about 8% over 10 years), pesticide/herbicide use still widespread.

Nitrogen contamination in drinking water can cause blood disorders in children and complications with pregnancy
Pesticide exposure linked with multiple cancers

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