Rapid growth in the Atlanta urban area has outstripped locally available water supplies. Since 2001 water levels in existing surface reservoirs have twice dropped to very low levels, creating great concern regarding regional water supply reliability and sustainability. More water storage is needed. Virtually all focus regarding new water sources has been on the need for more surface reservoirs, however environmental and other considerations suggest considerable uncertainty about whether these are viable. Based upon preliminary analysis of long-term climatological records, and with the current population, such droughts are expected about once every ten years. With increasing population a greater drought frequency will become more common. Measures need to be implemented to address these concerns.
The potential exists for development of supplemental water supplies through underground storage in alluvial aquifers in west-central Georgia and in carbonate aquifers of northwest Georgia. Recharge will be accomplished through aquifer storage recovery (ASR) wells, storing treated drinking water during times when excess water is available, and recovery of water from the same wells when it is needed. The ASR technology is now being applied at more than 95 wellfields nationwide in about 20 states, plus several other countries. The largest is for Las Vegas Valley Water District, with a peak recovery capacity of 157 MGD (480,000 AFY). ASR wellfields are, in essence, water banks. ASR wells will supplement the yield, sustainability and reliability of existing and new surface reservoirs.
Proposed storage capacity of EWB is 1,500,000 acre feet (AF), with facilities capable of recharge at daily rates up to about 125 million gallons per day (MGD) (140,000 acre feet per year, AFY) during wet weather and other times when water supply and treatment capacity exceeds water demand, and recovery at rates up to 250 MGD (280,000 AFY) for durations of up to six months during droughts. By comparison, the average water demand of the Atlanta urban area in 2000 was about 500 MGD while peak day demands were approximately 970 MGD. EWB would significantly improve regional water supply reliability at relatively low capital cost and negligible environmental impact. Participation in EWB for water storage and recovery would be open to approximately 35 public utilities and industries on a first-come, first-served basis, comprising a public private partnership.
 ASR technology for storing water underground is proven and cost-effective. This technology is now being applied worldwide to create underground water banks, thereby storing water where it is safe and not subject to substantial losses due to evaporation and transpiration. ASR technology was pioneered by EWB member David Pyne about 30 years ago, and he has written the only book published on ASR.
 The Etowah Water Bank (EWB) provides a viable, cost-effective subsurface water storage option, supplementing other regional water sources. Most of the water supply alternatives available to the Atlanta area will need to be implemented to some extent, so an ASR portion of the solution will supplement, not compete with other options. Principal alternatives include additional surface storage reservoirs, water conservation and reuse. As water wholesale and retail rates increase in future years, some water conservation will automatically occur, reflecting water demand elasticity, however there will likely continue to be a great need for supplemental water supplies to support expected growth of the Atlanta urban area.
Development of Etowah Water Bank wellfields offers the opporunity to augment streamflows during droughts on the Coosa River and the Chattahoochee River at the Alabama and Florida State lines, respectively. This goal can probably be achieved at far lower cost compared to other water supply and water storage options. Confirmation of the viability of this approach would help to defuse the 'Tri-State Water Wars' litigation which has continued for 20 years between Georgia, Florida and Alabama and threatens to expand to include Tennessee. Ultimate resolution of the multiple lawsuits by the courts would create winners and losers, thereby entailing considerable risk to all parties involved in the litigation. The Etowah Water Bank offers the opportunity for all parties to be winners.
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