Mahomet Aquifer
What is an Aquifer?
Contrary to popular belief, an aquifer is not a free flowing underground river or lake. Actually, an aquifer is a body of rock or sediment that is completely saturated – water is in it and all around it. It can be made of sand, gravel, sandstone, or other rocks that store and transmit water. What goes in an aquifer stays in an aquifer.
The water within an aquifer most often begins as rain or snow melt that seeps into the ground. The amount of water that makes its way to the aquifer varies widely from place to place depending on the type of surface and underlying soils. Once underground water will continue to be pulled downward until it reaches an impermeable layer of rock. The movement of water through small pores and the spaces between rocks acts as a natural filtering process, purifying the water and removing sediment.
The Mahomet Aquifer
Thick sand deposits deep underground are responsible for producing the aquifers pristine waters are typically found 300 feet below the surface. These deposits average close to 100 feet thick, and may be as much as 200 feet in some places. However, because the land surface elevation drops near the Illinois River, the aquifer reaches the surface at its western boundary. While many of the recharge areas have been inferred, actual mapping and knowledge of these recharge areas are not complete.
Why is the Aquifer Important?
The Mahomet Aquifer is the primary source of drinking water for more than 500,000 people in 14 Illinois counties. The Aquifer provides an estimated 220 million gallons of water per day to communities, industry, agriculture, and rural wells in Illinois. Should the quality of aquifer's water be compromised and become unusable, the remaining surface water resources would not be able to meet the daily demands of our growing region.
Groundwater resources are interconnected and cross jurisdictional boundaries, such as counties and municipalities. So, it is essential we work together to promote informed policy decisions that address the aquifer's vulnerabilities. Should the Mahomet Aquifer be compromised, it would be catastrophic for every community across the region.