IS THE DENVER BASIN OVEREXPLOITED OR UNDERMANAGED?

There has been much talk recently about the over-exploitation and the depletion of Denver Basin aquifer resources. However, given that less than 5 percent of the total water resources of the Denver Basin are currently being used, the question is whether, in fact, the Denver Basin aquifers are being over-exploited or whether they are being under-managed.

Historically, water supply entities have been able to develop the Denver Basin aquifers as their principal, or sole, source of water, and have these Denver Basin wells provide both the annual and peak summertime demands. Recently, however, with hydraulic conditions in the Denver Basin aquifers changing, and wells beginning to have problems with meeting peak demands, the management of these resources has not changed commensurately.

Denver Basin wells which historically have been able to produce several hundred gallons per minute are now being reduced significantly as water levels decline to below the top of the formations. Historically-high heads that have provided a large driving force to wells are now diminished and, because of generally low aquifer transmissivities, drawdown related to pumping is relatively localized around the well. Therefore, the Denver Basin aquifers are not being drained regionally, it is simply that the aquifers cannot now produce at the same rates that they have historically produced under confined aquifer conditions. At the same time, there is continuing growth along the Front Range which is putting more demands on Denver Basin aquifer wells. These factors exacerbate the perception of an over-exploitation of the Denver Basin as a whole.

There are a number of potential means to mitigate this ongoing dilemma related to water management of Denver Basin aquifer resources. These measures include (a) maximizing reuse to allow more equilibrated pumping of Denver Basin aquifer wells, (b) managing pumping rates by using surface storage, (c) developing additional supplies, (d) satellite well fields, and/or (e) regional water management districts. It will be necessary to implement water management plans in the future if the Denver Basin aquifers will be an ongoing source of supply for the Front Range water supply entities.