In 1992, Metropolitan entered into an agreement with the Central Arizona Water Conservation District that allowed for the storage of unused Colorado River water in central Arizona. The program’s basic goal is to store Colorado River water underground in Arizona aquifers to reduce the potential for future flood control releases from Lake Mead. The Southern Nevada Water Authority also participated in the program.

When Metropolitan wishes to recover the stored water, CAWCD will reduce its Central Arizona Project (CAP) diversions. The Secretary of the Interior will allocate the unused CAP apportionment to Metropolitan. This can be exercised in a year when Arizona’s Colorado River supply is at least 2.8 million acre-feet. The maximum amount recoverable is 15,000 acre-feet per month. When Metropolitan recovers any of the water stored under this program, Metropolitan’s water balance will be debited by 110 percent of the water recovered. This factor is applied to conform to Arizona state law, which requires that a portion of any stored water be left underground.

The maximum amount that could have been stored under the agreement was 300,000 acre-feet through December 31, 2000. As of December 2000, Metropolitan had stored 89,000 acre-feet in this program. Metropolitan paid the cost of transporting the water through the CAP aqueduct. CAWCD is responsible for the costs of recovering the water.