Aquifer Storage Recovery: Econonics and Recent Technical Advances

R. David G. Pyne
ASR Systems LLC, Gainesville, Florida USA (email: dpyne@asrsystems.ws)

ISMAR6 in Scottsdale, Arizona, yielded several IAH commissions for subsequent work needed to reinforce the fabric of MAR.  My commission was to pull together information on ASR Economics.  Since 2007 information has been gathered from a variety of sources, steadily improving the understanding of what are the typical costs for storing water underground through wells.  This has included evaluation of typical unit capital and operating costs, the associated range of unit capital and operating costs, and significant contributing factors. 

Marginal costs for water storage in ASR wells have also received attention.  The ability to store water underground during times when it is most available for recharge, for recovery when most needed, becomes economically more favorable if the water is priced according to its marginal cost for storage and marginal value for recovery.  Marginal cost to produce another unit quantity of water during recharge months usually includes power, chemicals and residuals disposal, which are often quite low.  During recovery months the marginal value for many locations is relatively high, as determined by the cost for implementing the next most cost-effective water supply alternative.  Marginal cost pricing of water is driving an increasing number of regional ASR programs. Leasing water storage rights is also emerging as a potentially valuable new tool to help resolve political disputes regarding water ownership and control. 

Several important ASR technical and regulatory advances have occurred recently in the United States, each of which is contributing to reducing the cost of ASR and increasing its general applicability for storing water underground through wells.  Among these, the “Target Storage Volume” concept is increasingly accepted as an economical and viable tool for ensuring acceptable recovered water quality, particularly for water storage in brackish aquifers and in aquifers containing metals such as arsenic.  Stacking of water storage vertically in multiple aquifers at the same location is increasingly being applied, such as at Orangeburg, South Carolina.  Large scale applications of ASR to meet regional water storage needs are being developed, such as for Etowah Water Bank, Georgia.  Agricultural ASR applications are underway in Washington, using the Surficial Aquifer as part of the treatment process.  Some significant advances have occurred in federal and state ASR regulatory programs.

Subject Area Preference:        Oral
                                                Regulations, Governance, Economics