A REVIEW OF WATER LEVEL CHANGES IN THE DENVER BASIN BEDROCK AQUIFERS

Wells completed in the Denver Basin Aquifers provide a potable water supply to many Colorado Front Range communities and individuals from Colorado Springs to Kersey. The Denver Basin Aquifers are characterized by interbedded sandstone, siltstone, mudstone, shale and minor coal deposits generally under artesian conditions, with transmissivities ranging from less than one to 15,000 gallons per day per foot. Pumping from the Denver Basin Aquifers exceeds natural recharge. As a result, water is being “mined” from the Denver Basin Aquifers and water levels are declining at various rates across the Basin.

Pumping is not evenly distributed across the areal extent of the Denver Basin; rather, the majority of pumping occurs in relatively small areas to serve development, primarily in Douglas County, Northern El Paso County and Arapahoe County. Historic water level data were reviewed across the Basin, and these data indicate that due to the location of pumping and relatively low transmissivities of the Denver Basin Aquifers, water level decline effects are concentrated near the centers of pumping, with decline rates in some cases exceeding 40 feet per year. Outside of centers of well pumping, decline rates are less, on the order of zero to ten feet per year.

Proper record keeping and analysis of water level data are important tools for water users to evaluate water level changes, future well yields, pumping costs and additional drilling needs.