There is a sound reason that Cave Creek now gets all its municipal water from the Central Arizona Project (CAP) Colorado River aqueduct. Even before the Cave Creek Water Company was purchased by the Town, the switch from groundwater wells to CAP water was made by the previous owner. This was to obtain more secure, high quality water. Carefree has also reduced its dependence on groundwater in favor of Colorado River/CAP water. It is still possible that groundwater from, mostly long-abandoned town wells, could supplement CAP water for our municipal system, and that option is now being investigated by town staff.
An extensive report about our main groundwater aquifer was made by geologists at ASU, published in 1991. That aquifer gathers water from areas of North Scottsdale and Carefree. It is professionally known as the Carefree Aquifer. Compared with the Phoenix Valley aquifer it is smaller and not nearly as deep. The Carefree Aquifer seems to be capable of supporting most of our residential wells, but probably not a large portion of our municipal needs.
Furthermore, many wells in the Southwest contain arsenic in small amounts, but enough to exceed federal water standards. Arsenic can be reduced by relatively expensive treatment, or by blending with Colorado River water, That’s now being done in the Desert Hills water system that Cave Creek owns.
Probably our greatest vulnerability with CAP water is caused by climate change in the Colorado River watershed. Lakes Powell and Mead were dangerously low, about 25% of capacity, two years ago. Two years of better snowfall in the upper watershed have increased to about 35%, but that’s still uncomfortably low.
Furthermore, the river is over-allocated. Estimates of Colorado River flow were based on two relatively wet decades. Arizona has reduced its use of CAP water by cutting back water available for agriculture, mostly used to grow animal feed, much of which is exported to the Persian Gulf. Fortunately, most of our Cave Creek water has a higher priority. But Cave Creek could be asked to reduce the consumption of CAP water. Because the majority of our water is used outside our homes for irrigation and pools, more judicious use of water could extend our supplies greatly.
Although expensive, the Phoenix Interconnect was a wise choice to secure water delivery when our single aging pipeline bringing CAP water up to Cave Creek fails. It has already occurred and those events have required immediate repair. The Interconnect will also facilitate maintenance and repairs to the original pipeline.
Our staff considered joining other municipalities to explore the use of water from expansion of Bartlett Reservoir. But the cost of just “a seat at the table” was high and the likelihood of getting significant water made other ways to extend our supplies better use of our resources.
This is a small portion of what I have learned, mostly from our professional staff. If you have further questions, and there are many, they are our best source of information.
Thomas McGuire
Councilperson, Cave Creek
