Guest View-Hector Conde: About Oro Valley's Water

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Hector Conde is a preeminent expert when it comes to water in Oro Valley. We wanted to share some of his expertise with you. In this posting, Hector poses some of the questions to ask the incumbents on the issue of water use, planning and conservation. Hector has been working on water issues and also on the Falcon Valley toxic dump-site since 1995. He believes that our 4 term year incumbents should be answering long-term water planning questions.
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The diagram on the left is a cross section of the Oro Valley aquifer. The most important part of the water flow comes from the north in Pinal County. The other flows north from the south and even if it is significant, it will be affecting us less. The reason is that Pinal County is not that interested in protecting the aquifer. When their water is gone, our supply from the north is gone.

Notice that the graph is not to scale, to make it user friendly. It shows the location of Oro Valley and Avra Valley, an important point.

The aquifer, the blue section in the diagram, made of sand and water, flows slowly (a drop of water may take two years to traverse OV) and goes from Falcon Valley, in southern Pinal County, to the Santa Cruz River in Marana. The location of the aquifer varies from 3000 feet in the north to 1800 feet in Marana relative to sea level and is roughly 200 feet below the surface.

The Arizona Legislature has created a category of water users called “per capita per day” that makes towns responsible for fines if they use more water than the average user is allowed. If the town exceeds the limit, it is fined and made to pay to recharge water to compensate for the deficiency. Water is now legally recharged in Avra Valley, 600 feet below Oro Valley’s sea level altitude and 12 miles away. The aim should be to pump water into the aquifer in Oro Valley, but since water does no flow uphill, one wonders if a requirement for a HS diploma for legislators would solve the problem.

Other than that, there are no enforceable requirements in Title 45 of the Az. Statutes to provide for a stable aquifer. That does not preclude towns to protect their aquifer, like Prescott, that told developers clearly: “bring your own water”. So far, the town succeeded.

The greatest user of water are golf courses. They serve a minority (8%) of the population. Of that minority, a large percent (40%) are snowbirds. Of those a large percent pay taxes in their home in another state. I made a study in 2003 that shows that golf courses used about a third of the town’s general population use. Golf courses pay an agricultural rate of property tax, which is about 14 dollars per acre per year.

I worked for a year on a OV citizen's committee on renewable water. We recommended bringing CAP water and recharging the aquifer accordingly. Instead, the town decided to bring reclaimed water in at a great cost, to water golf courses instead. Probably because of the unknown number of golf courses to be built in the proposed Arroyo Grande development. The Town has regulations against watering any new golf courses with water from the aquifer. The residents, in turn, had to pay for the pipes to water golf courses.

BIBLIOGRAPHY

• Carruth, Pool & Anderson Land subsidence and Aquifer-system compaction in the Tucson Active Management Area 1987-2005 USGS Sci. Inv. Rept 2007-5190
• Gelt, J. Land  subsidence -  http://ag.arizona.edu/azwater/arroyo/062land.html
• Mason D., Bota L. Regional groundwater flow model ADWR Publ 2006
• Hanson R.T. & Benedict J.F. – Simulation of ground water flow and potential land subsidence …Rept 93-4196
• Megdal S.B. Water resource availability for the Tucson metro area Jul 2006 UA
• OsterkampW.R. - Map showing ground water velocities USGS map I-844-k
• Oppemheimer J.M. & Sumner J.S. - Depth to bedrock map UA Lab of Geophysics 1980
• Conde, H www.azwater.us
• Fonseca, J. Cañada del Oro recharge and recovery project Pima Co 1998