Recovery Efficiency Assessment of an ASR Well Using Groundwater Models

W. Guo, R. Maliva and T. Missimer
Schlumberger Water Services USA, Inc.
1567 Hayley Lane, #202, Fort Myers, FL 33907

Aquifer Storage and Recovery (ASR) has become an effective means of water resources management in many places. ASR is particularly effective where water availability varies seasonally.  A measure of the success of an ASR system can be evaluated by the recovery efficiency.  The success of an ASR system depends on a number of factors such as aquifer transimissivity, vertical permeability of confining units, native water quality, regional groundwater flow gradient, etc.  

Although the success of an ASR system depends on the location of the system, and site-specific hydrogeological conditions, a modeling assessment of the limiting factors can still provide useful insight for ASR site selection and system design.  A model with variable density groundwater flow and solute transport was developed using the USGS computer code SEAWAT to evaluate how the physical characteristics of the aquifer system impact ASR recovery efficiency.  Typical aquifer parameters from some existing and potential ASR sites were used in the model.

A number of major parameters that have the potential to impact the recovery efficiency of an ASR system were evaluated using the model, including aquifer transimissivity, vertical anisotropy, heterogeneity, dispersivity, native water quality and regional groundwater flow gradients. The cycle recovery efficiency from each simulation was calculated and compared. The results of this numerical study indicate that aquifer vertical anisotropy, heterogeneity, native water quality and regional gradients are the most significant factors for the recovery efficiency of an ASR system.