Aquifer Storage & Recovery (ASR) Overview

ASR is a water management tool whereby aquifers are used as a reservoir to store excess water that is later withdrawn for use. Commonly in this process, aquifer zones containing brackish water are flushed by displacement with fresh water. Fresh water can then be stored in either treated or untreated form. ASR well systems can store more than a billion gallons of treated potable water and later withdraw this water for direct distribution to water customers.

Water Resource Storage
In areas where water availability is limited on a seasonal basis, excess water can be stored in the subsurface in very large volumes during wet periods and later withdrawn during dry periods to meet demands. ASR can function in the manner of a traditional surface reservoir. Aquifer storage eliminates evaporative losses and minimizes environmental impacts. Many types of water can be stored with minimal or no pretreatment.

Wastewater Reuse Systems - Wet Season Storage
For wastewater systems that reuse reclaimed water for irrigation, ASR can be used to store treated wastewater during periods of low irrigation demand such as wet weather periods. This can eliminate the need for above ground storage tanks or ponds and avoid surface discharges

Reduce the Size of Water Treatment Plants
The ability to store very large volumes of treated potable water in the subsurface means water treatment plants can be designed for average daily demands. With ASR, peak daily and maximum monthly demands are satisfied by withdrawing the stored water and directly distributing it to customers without retreatment. Numerous municipal utilities are applying ASR in this manner to reduce costs and increase the efficiency of operations

Aquifer Recharge
In areas where over-pumpage of groundwater has reduced groundwater levels and aquifer yield, or where the resource is threatened by salt water intrusion, ASR principles can be applied to recharge the aquifer. The water recharged can be recovered through the same wells used to inject the water or through other wells located nearby. In the case of recovery using remote wells, the location and design of the recharge wells must be carefully selected.

ENTRIX offers comprehensive services for designing, permitting, and installing ASR systems.