What can we do about our diminishing water supply?
(Printed in Green Valley News Comments, February 10, 2006)
The idea has been that one way to solve the depleting water table in Green Valley is Colorado River Water [CAP]. The truth is it is highly unlikely that CAP water will be piped to Green Valley. The price tag for CAP project is likely to approach $100 million— and short of divine intervention or a billionaire sugar daddy, it’s not going to happen. The residents here don’t even want to incorporate because it would cost them tax dollars for the infrastructure.
Yet, without an infrastructure, we have no public works department that looks after our water needs. Everyone agrees depleting water levels in Green Valley are a problem. That’s why eighteen water experts, including Eric Holler, manager of Bureau of Reclamation, Ken Seasholes, manager of Tucson Department of Water Resources (DWR), Mark Cross, hydrologist from Errol Montgomery, Ann Phillips of Audubon Society Restoration, including representatives of Pima County Flood Control and Wastewater and mangers of six local water companies showed up to discuss about the problem. They know the depleting ground water in Green Valley is a crucial issue. And it’s not because of building homes, in fact, municipal use is only 5 - 6% of the total use.
Representatives from the two biggest water users, Phelps Dodge and F.I.C.O, were also present. As Ken Seasholes of State water agency pointed out, “There are historic users of water in the Green Valley/Sahuarita area that have been issued perpetual water rights—the large mining operations and the F.I.C.O. irrigation—and that has resulted in localized groundwater overdraft, there’s no question about that.” F.I.C.O. has grandfathered rights of 34,700 acre feet per year, although their normal annual usage averages something around 25,000 acre feet. Phelps Dodge Sierrita and Twin Buttes mine complex have total grandfathered rights of 30,627 acre feet annually of groundwater, and use an average of 30,000 acre feet per year. Far enough downstream that it doesn’t affect our water levels, Asarco has grandfathered rights of 17,585 acre feet annual. Why wasn’t the Public issued some water rights when they were divvying up water—even though they didn’t even know how much there was available?
How much do we need?
At the current rate of pumping, how long will the water last? When I first spoke with Ken Seasholes, over two years ago, I asked him: “How much water is in the aquifer?” His reply was something to the effect: “Well, there is a lot of water, we don’t really know how much. And it does not really matter because of subsidence. Long before all the water is gone all the houses and pavements will crack because of faults and sinkholes.” As the water level recedes (it’s now some 300 feet below ground surface), the earth compacts causing subsidence, actual lowering of the ground level. Since Green Valley is built over the aquifer, homes and walkways would begin to crack, so it is a prime area for subsidence.
Can CAP could save us?
In 1998 a study was sponsored by a group of water stakeholders in the area and funded by Department of Water Resources. The optimum plan entailed taking the CAP infrastructure from the terminal at Pima Mine Road to the Santa Cruz County line near Elephant Head. The price tag for the optimum plan to Elephant Head was some $50 million for the pipes and pumping stations. Add on to that cost, the price of treating the water. Surface water has to be treated, and has always been treated in Phoenix because they use the Salt River water. CAP water is very poor quality water (TDS = 700 to 800 mg/ltr). There must be some residual radiation from the Moab uranium tailings, but there is not data on the CAP website about radiochemical levels. [Yes, I’m checking into that issue.] Then there is the perpetual delivery cost of moving the water uphill.
All in all, the project could easily add up to a price of some $100 million dollars. It’s not that we don’t have the money, we don’t even have an entity to apply for loan—and then there’s the interest on the loan. Federal loans are available at somewhere between 3.6% and 6.0%. Frankly, the price looks too high to serve 5% of the total water use. At least that’s what was concluded in 1999, because the committee, which was formed for the study, disbanded and took no further action. This is the reason I think CAP is not coming to Green Valley, if it were, it would have happened in 1999—before six years of additional inflation of costs.
In regard to CAP, there is one important consideration—that 5% of the total water use would cover the municipal use: the residences and business—not golf courses, not pecan groves and not mining operations. Therefore, it would save us from running out of water for our homes—if the number of homes does not expand substantially—and businesses. The original plan was to recharge the CAP water in the ground and let the earth filter it as they now are doing Tucson (although they are now talking about the more expensive membrane filtering system). We can’t afford to put million-dollar water into the ground for the mining operations and agriculture to pump it out. It would have to be filtered and piped directly to the only two water companies that have CAP allocations, Community Water Company (2,858 acre feet) and Green Valley Water (1,900 acre feet), plus some Groundwater Replenishment District allocations. It could give us in our homes and residences, but it would not take care of the subsidence problem. Furthermore, this is just 5,000 acre feet against a 31,000 acre foot deficit.
Challenges of storm water recharge
Mark Cross commented that enhancing the infiltration of storm water was a possibility, but a difficult one, therefore a costly one, since the flows are so heavy for such short periods. Marie Light, recharge expert at Tucson Water Co., emphasized the problem with the dirty storm water clogging up wells intended to catch and infiltrate the water. However, she also mentioned that the heaviest sediment is in the first flush of the storm. So if you figure out how to escape that phenomenon then you could have better results.
I commented that in Chandler, the detention/retention basins are all grass lined, so the grass serves as a natural filter for the sediment. They are not having any problems at all with their dry wells clogging up. However, in Sahuarita, where the surface soil is unstable due to new construction, there is a lot of movement of silt. So selecting the sites will be crucial—an area of little sediment movement in a spot that has good infiltration capacity. U.S. Geological Survey will possibly be available for selecting sites.
Slowing the water down in the river bed or in washes with check dams, disking and spreading the bed, so that water has time to saturate into the earth is another option. However, this option is fraught with the worse kind of obstacle—of the governmental kind. The moment water hits the ground it immediately belongs to someone who has surface water rights downstream. In this area, only FICO has surface water rights, and they would not present any obstacles to a community project because they would also benefit. However, the water agency does depend on logic—maybe someone in Marana would claim it. The obvious solution is for the public to file for surface water rights. What public?—we don’t have public works, we don’t have a water district. Surely, the water companies and golf courses could file for surface water rights. Okay, here’s the next catch. To get surface water rights, you have to prove a “beneficial use.” Recharging a depleting aquifer is not deemed a beneficial use—an obstacle “of the governmental kind.”
Will endangered native fish save us?
I spoke up, “Great you can put the dikes down our way and they can serve to hold the water back, so it will have more time to percolate.” After all, this could be our excuse to put some dikes across the Santa Cruz to slow the rain flow down without having to jump the governmental red-tape barrier. Again, it will be an input of water—an unknown amount at this time—but surely it will not reach anywhere near 31,000 acre feet.
And then there is always collection of rainwater at homes and businesses. Many homes in New Zealand have their own cisterns to catch rain in the rainy season. If we had had them in place last August, they would have filled for the year. Ann Phillips of the Audubon Society Restoration said, “Before you talk about how many millions of dollars it is going to cost to extend the CAP pipeline down to Green Valley to bring in a bunch of poor quality water, with TDS of some 700 to 800 mg/ltr. Why don’t we use rainwater that has a TDS of 50 to 100 mg/ltr. It’s high quality water and we treat it like a waste product.”
Ken Seasholes wound up the meeting by asserting that there has to be several parts to the solution: CAP, wastewater, fish dams, conservation and enhancing natural storm water infiltration all need to be part of the whole—but he didn’t mention my “best” solution.
I came up with a suggestion in the meeting—on the spur of the moment. Since we are going to have to spend millions, why don’t we spend those millions on buying up the pecan groves and replacing the trees with mesquite trees and native plants? Doesn’t it make more sense to cut some 20,000 acre feet of water off our deficit, instead of just 5,000 acre feet? Stopping pumping is another way of putting money in our water reserve. And we would still have a green belt for our beautiful Green Valley.
Why didn’t somebody tell us?
The fact remains they are not giving us answers and they don’t have to give us answers. As long as the Tucson AMA—with the use of the GWRD, which I ranted and raved about in my last comments in the GV News—the AMA can be in balance on paper for the mandated assured water supply, so no one has to do anything. The mandated recharge required by new subdivisions will happen ten miles downstream from us—where it will have no impact on our water supply—and it’s only some 600 acre feet in 2003 (more recent figures not available from ADWR).
Until someone comes up with a better plan, Groundwater Awareness League is dedicated to providing technical plans to be able to construct catchment basins and dry wells to enhance storm-water infiltration. They should be used in Green Valley, plus there are many rural areas of Arizona with water depletion without any possibility of relying on CAP. First, there should be some opportunity of sharing information with Sierra Vista, which has the same situation that we have here--except they have Fort Huachuca which could bring in Federal funds there.
Even so, there is a price tag on the basin infractructure—although a lot less than CAP water. So again, the obstacle is money. Who should we expect to pay for solving our water depletion problem? The GOVERNMENT? Which government? We have no City/Town government. As a matter of fact, even though GVCCC was invited, no representative attended the important water meeting in Tucson. Pima County? Arizona State? Federal? We have no precedent of any of these entities bailing anyone out. The Federal Government gave Arizona State some relief on their huge CAP debt because of the Native Indian Settlement. Bill Lemman postulated the hope that Representative Kolbe would give us an “earmark” project before he retires.