The Denver Basin has four aquifers that supply water to Colorado well owners. Once the water in an aquifer is used up, there is no way to replace it. We are pumping water from the aquifer, faster than it can be replenished. The Aquifers from the uppermost to the lowest are:
Dawson (upper and lower)
Arapahoe (upper and lower)
Laramie Fox Hills.
Most of Black Forest wells are in the lower Dawson aquifer which is confined. A confined aquifer has layers of impermeable rock. Consequently, almost no water recharges the aquifer or evaporates from it. Snow and rain water take decades to recharge the aquifer and it is estimated that less than 1 percent of precipitation actually are absorbed back into the aquifer. Below is a short slide show about Denver Basin Aquifers
No Natural Resource Has Greater Significance For The Future Than Water