Assured Water Supply

What political entity only plans for 100 years? Arizona water planning, outside of areas with CAP water, is based on pumping the groundwater down to 1,000 within AMA’s and 1,200 feet outside of AMA’s. What will the state look like then—all small streams and riparian areas will be completely gone? It has been predicted that once you travel out of the line that has the CAP water, there will be nothing alive—not a tree, not a bird, not an animal. On a recent trip from Nogales to Flagstaff through Oak Creek Canyon, I saw that it is already happening. Roads and highways provide a mini-watershed for the roadside. That’s one of the reason there is grass and wild flowers along a roadway. However, there are an alarming number of dead trees visible along the Oak Creek roadside. It does seem like a warning of things to come. Pinal County gives us a good example—no riparian areas left there.

Arizona ’s Groundwater Code was passed in 1980 with arm-twisting by the Federal Government “get a groundwater code or you won’t get Colorado River water." The “Code” grandfathered and exempted every high water user in the state, which left only some 20% of groundwater to be managed statewide (only 5% in some areas). Logically, this has prompted ADWR to put their time and energy into counting on CAP water.

The Code formed the AMA’s, which were charged with verifying an “safe-yield,” which means “equal water in and equal water out,” so that groundwater pumping could not exceed recharge. This was a sensible solution since much of Arizona’s groundwater had been depleted by agriculture use for growing subsidized cotton. Therefore, the groundwater levels would not continue to lower without serious problems. Since CAP water was intended to retire the large agricultural groundwater users, water levels could be maintained in the areas of serious depletion, such as Queen Creek and Eloy areas.

In 1995, a section was added to the Groundwater Code. Within the AMA’s areas a “100-year assured water supply” certification was required for developments with six or more units. This certification held two requirements:

1) According to hydrological assessments, the water can be pumped down to bedrock or 1,000 ft. within 100 years within AMA’s. No consideration was made as to the possibility of subsidence occurring, the drawdown of nearby wells (either public or private)—well owners would just have to drill their wells down to 1,000 feet also. No cost analysis was made of the cost of drilling wells down to 1,000 feet or the price of electricity to pump from 1,000 feet. Further, hydrologist state that 1,000 feet will be very mineral-laden, so there is a likelihood there will be additional costs for filtering.

Neither does the ADWR “assured water supply” certification include the possibility of an industry, including high water users, such as mining and electric plants, which are exempt from all water laws , coming into the region and lowering the water table. [According to El Paso Electric it takes 800 gallons of water to make 1 megawatt-hour of electricity.]

2) The second requirement was that it was necessary to replenish the amount of water used. Therefore, every home built after 1995 has to pay an annual water assessment to have non-groundwater recharged for them. This was essential to create “save yield” and has worked perfectly in areas that have CAP water available to them. The CAP water is recharged into their public water system by the various providers.

Unfortunately, there are areas within the AMA’s that do not have CAP availability, so logically these areas would have had no new development because there was no method to fulfill the recharge requirement. These areas include Cave Creek, Queen Creek, Sahuarita, Vail, Green Valley and others. However, to accommodate new development in these areas, the Groundwater Replenishment District was formed. Since there could be no replenishment in the area of use, the groundwater levels continue to recede down to 1,000 feet, even though it is likely there will be serious subsidence before that depth is reached. Some have ventured to assert that the pumping should be tied to the hydrological reality of each area. Further, residents in these areas have to pay an assessment to have water recharged somewhere else.

Some think that pumping groundwater down to bedrock or 1,000 feet within AMA’s and 1,200 feet outside AMA’s is only “planned depletion.” What do you think?

USGS report on Subsidence

Return to Home Page