When it comes to enhanced aquifer recharge, ADWR will need to reconsider its one-size-fits-all approach.
“Enhanced aquifer recharge” refers to an ADWR proposal to modify its formula for allocating recharge credits through the state’s Underground Water Storage program. The program currently dedicates — or “cuts” — 5 percent of recharge credits to the aquifer for certain non-effluent projects; consequently, for every 100 AF of water stored, only 95 AF can be later recovered. Recharge and recovery sites need not be co-located, as long as they lie within the same AMA. As part of its Fourth Management Plan update, ADWR is considering linking the size of the “cut” (from 0 to 20 percent) to the distance between the recovery and recharge locations; the greater this distance, the greater the cut. All existing storage credits would be grandfathered and not subject to changes.
Under current law, water can be recharged outside the zone of influence of recovery pumping. Consequently, ADWR’s proposed change addresses a longstanding, significant problem with Arizona groundwater code: the “hydrologic disconnect.” AMAs can achieve safe yield and show overall withdrawals balanced with recharge — on paper, at least — but groundwater levels can still be declining in certain areas.
Local water providers will need to support this proposal before they can advocate for any associated statutory changes that will be required. To gain this support, ADWR will probably need to distinguish between AMAs, which warrant separate consideration because of the differences in the hydrogeologic settings, available water supplies, and existing infrastructure within each. For example, in the Phoenix AMA, providers in the East Valley are concerned about “hot spots” — areas of focused groundwater decline — that will worsen in the coming decades. Some providers recommend incentivizing recharge operations in these “special enhancement areas.” Within the Tucson AMA, where the municipal sector has already reached safe yield, similar hot spots are also a concern.
However, in these situations, the hydrogeologic disconnect may be unavoidable in the short term, since the locations of existing recharge basins and recovery wellfields cannot be readily modified. Increasing cuts to the aquifer with no benefit to providers will translate to higher costs and customer rates. Furthermore, providers worry that increasing the cuts will not only fail to produce direct benefits but could actually discourage the use of CAP water and effluent supplies, which require expensive infrastructure investments.
On October 9, ADWR is kicking off a multi-month stakeholder process to consider these issues and develop a policy / regulatory framework for managing storage and recovery. To be accepted by the regulated community, any proposal may need to offer a little less stick and more carrot. At a minimum, it should not negatively impact current recharge activities.