11/10/22 AEG Event about Deep Aquifer Discharge

Map – Summary of Aquifer Depletion in the U.S. 1900-2008 (USGS 2013, https://pubs.usgs.gov/sir/2013/5079)

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ABSTRACT
   The Green infrastructure concept that is already widely applied for managing stormwater could be expanded to include the recharge of deep aquifers, as part of the design of future sustainable, long-term groundwater remediations systems. “Green infrastructure” is defined by the United States Environmental Protection Agency (USEPA) as “a cost-effective, resilient approach to managing wet weather impacts that provides many community benefits.” Nationwide, it seems that the vast majority of green infrastructure projects completed to date involve diverting stormwater or treated wastewater to recharge shallow water table aquifers. The Green infrastructure approach could help balance the over pumping of deep aquifers, as well as provide an important new component in the design of long-term groundwater remediations systems.   
   Groundwater testing and treatment inevitably involves the discharge of large volumes of water; a process that is difficult to manage and needs to be “greened up.”  Building in an option for approved deep groundwater discharge into a big project early, could reduce costs and improve performance. For example, early in a project, the discharge of pump test water direct to groundwater could help avoid the difficult process of discharging to the local sewers.  For long term projects, deep aquifer discharge could replace burdensome permitted discharges of very large volumes of treated water to the local POTWs.

   Groundwater extracted from deep and confined aquifers is often “mined” and is depleted faster than it recharges. Groundwater is a renewable resource, although not immediately, and the mining of deep groundwater temporarily disrupts a portion of the natural water cycle. Extracted groundwater from deep or confined aquifers is used at the ground surface and also ultimately makes its way into the ocean, thereby contributing to sea level rise. The United States Geological Survey (USGS) estimates that the depletion of combined aquifers in the U.S. alone accounted for 3.1 millimeters per year, or 2.3 percent of the observed rate of sea level rise between 2001 and 2008.