Analyzing the Reservoir Beneath Our Feet: Denver Water's Aquifer Storage and Recovery Pilot Project

Denver Water’s long-term planning indicates the need to develop additional water supplies.  Uncertainties such as climate change and population growth could present scenarios with serious challenges to meeting future water needs for our customers.  To address these scenarios Denver Water is investigating new types of potential supplies, including aquifer storage and recovery, or ASR.  Denver Water is conducting a pilot project to evaluate whether ASR using the Denver Basin aquifers is a technically and economically feasible method to increase water supplies.  Denver Water could benefit from ASR if it were able to store water in the aquifers during wet years and recover the water to help meet demands in dry years.  To access the aquifers, wells would be drilled into the Denver Basin throughout Denver and connected to the potable water distribution system.  Along the Front Range region of Colorado, several utilities have employed, with varying degrees of success, ASR within the Denver Basin.  Within the City and County of Denver, there are relatively few Denver Basin wells; so data on the formations and their productivity is limited. In 2015, Denver Water drilled four exploratory boreholes within Denver to help fill hydrogeologic data gaps. Standard geophysical logging was conducted in the boreholes as well as nuclear magnetic resonance (NMR) logging.  Used for many years in the oil exploration industry, NMR logging technology has only recently been adapted for use in groundwater resources investigations.  An analysis of potential aquifer productivity was performed using the logging data gathered from the four boreholes along with data from operating Denver Basin wells.  Findings of the analysis will be used to help identify a site for an ASR pilot well facility, which will be operated to further evaluate the viability of ASR for Denver Water.