require examination of related issues that were not addressed in any detail during the workshop, but are important to the overall assessment of ASR feasibility and effectiveness. Some of the topics that should be addressed in the design and evaluation of ASR systems are listed below.
Once information from this work is available, it may be important to refine the analysis of overall performance of surface and subsurface storage, particularly if anticipated recovery efficiency for ASR differs significantly from the value of 70% assumed in model runs used to develop the CERP.
Estimated evaporation losses from surface reservoirs should be compared with anticipated subsurface losses to the aquifer during ASR in order to quantify relative performance of surface and subsurface storage options.
A significant increase or decrease in recovery efficiency would dictate re-examination of the number of wells required for a regional ASR system.
Similarly, if recharge capacities for efficient operation of ASR wells differ significantly from 5 million gpd (19,000 m3/day) assumed in the CERP, it may also be necessary to re-evaluate the number of wells required to provide the necessary storage capacity.
Estimates of energy costs for long-term operation should include contingencies for possible changes in fuel costs over the anticipated project life.
As a final comment, the CROGEE notes that the CERP calls for ASR to be implemented in phases. The Committee agrees that phased implementation is an appropriate strategy and strongly recommends a) thorough evaluation of the environmental effects of each incremental increase in scale of ASR, and b) ongoing adaptive assessment of the program.