The Central Arizona Groundwater Replenishment District (CAGRD) has been for 20 years the legal mechanism by which subdivisions based on mined groundwater can have that groundwater replenished by someone else somewhere else. The promise of CAGRD replenishment fueled the boom in real estate development in the three-county service area by eliminating the pesky Assured Water Supply problem. The Arizona Department of Water Resources must approve a Plan of Operation for CAGRD every 10 years, and the new plan must be delivered to ADWR on January 1, 2015. If ADWR doesn’t approve the new plan, CAGRD can’t guarantee replenishment, real estate development dependent on groundwater halts, and several cities lose their Designations of Assured Water Supply. Given the power of real estate developers, the continued economic viability of CAGRD is a big deal.
Under the old 2005 plan, a huge chasm grew between the replenishment obligation represented by all those subdivisions platted during the boom years and the water supply available to meet that obligation. Under the proposed Plan of Operation, that gap is whittled down by more realistic estimates of demand, including downsized growth projections and reducing or eliminating the obligation tied up in zombie subdivisions that will not be built for years, if ever. The annual replenishment figure is now around 35,000 acre-feet and could reach 86,900 acre-feet by 2034.
But on the supply side the estimates are far more ephemeral. CAGRD must identify water supplies that are planned to be used (maybe) plus those that are potentially available. CAGRD beefed up its financial resources over the last few years with new annual membership dues, higher rates, and bonding authority. Using this money, CAGRD has aggressively sought out new water supplies. CAGRD walked away with most of the Non-Indian Agricultural (NIA) re-allocation some months ago. They are buying excess CAP water, leasing reclaimed water, and looking for Long-Term Storage Credits to buy from any willing sellers. CAGRD now holds 36,533 acre-feet. But it’s not enough, and competition is growing.
CAGRD has identified several potential sources of water that are problematic. Excess water results from municipal providers not ordering their full CAP allocation; it will decline as providers serve more customers and recharge the rest. Both excess and NIA water will disappear with the first declared shortage on the Colorado River, maybe as early as 2016. Reclaimed water is increasingly used by municipalities for non-potable purposes and recharge, and will not likely be available to CAGRD for the next 20 years. Importing groundwater from distant basins poses water quality issues. Desalinization of brackish groundwater could help, but hasn’t been tried yet. The Inter-Tribal Council has made it clear that Indian water is not a potential source. So where is the replenishment water to come from?
There are no safe answers to this question of imbalance. And that leaves major risks built into the proposed Plan.