Is it possible to plan new housing that makes sustainable use of groundwater? Why should we care? Can we have our cake and eat it too? Certainly, the members of the Friends of the San Pedro River have concerns in this regard. This article attempts to identify what sustainable use of groundwater might look like.
Current water supplies and future prospects are in the news frequently these days. There are local issues in Cochise County and wider issues of statewide concern like the low level of Lake Mead. The local issues in Benson and Sierra Vista in recent years pit those residents who desire the economic development promised by large master planned communities against those who wish to preserve scarce natural resources like those of the San Pedro River and surrounding Sky Islands. Is that conflict inevitable or is there another way forward? Is it possible to plan new housing that makes sustainable use of groundwater? Can we have our cake and eat it too? Certainly, the members of the Friends of the San Pedro River have concerns in this regard.
This article attempts to identify what sustainable use of groundwater might look like. But before doing so, there is another question to address. Why should we care now and not kick the can down the road? One reason can be found in the state to our west. Arizona should not follow the path to a water resources crisis like the one California has on its collective hands. How did it happen? Aggressive growth over the past hundred years is certainly a contributing factor. But how is it that farmers in the central valley of California are pitted against the massive populations of the metropolitan areas like Los Angeles to compete for scarce water resources from the snowpack of the Sierra Nevada? Can’t farmers just irrigate their crops with groundwater instead? Well, they could if they hadn’t depleted the aquifer, but that has occurred in many areas unfortunately. In the past hundred years, pump technology has made it possible to withdraw vast amounts of groundwater from deep underground. But natural recharge is typically a very slow process. The water underground accumulated over thousands or millions of years. The key to avoiding such a crisis is sustainable use of groundwater. A sustainable water supply might be achieved by enhancing recharge – ideally to recharge as much water as is withdrawn through groundwater pumping.
Background on proposed developments near the San Pedro for the next decade
The Villages at Vigneto in Benson, Arizona is a roughly 12,000-acre development proposed by El Dorado Benson, LLC on private property south of Interstate 10 and just north of Kartchner Caverns State Park accessed from State Route 90. The development would increase the population of Benson significantly from its current 5,100 residents to as many as 75,000 residents after completion of the final phase. Nearly 28,000 new homes would be built along with commercial businesses, infrastructure and amenities. A substantial utility and road network would be constructed to serve these residents. To support this population, 12,000 acre-feet (AF) would be pumped annually from deep in the regional aquifer once built out. Eventually, such groundwater pumping has the potential to deplete the aquifer west of the St. David Cienega in the San Pedro Riparian National Conservation Area, not to mention the existing communities of Benson and St. David. The Benson City Council recently approved a development agreement with El Dorado Benson, LLC and will vote soon on the Final Community Master Plan.
So does the Vigneto plan look sustainable with regard to groundwater resources. No, or at least not yet. The Stormwater Management Plan — contained in the Final Community Master Plan — addresses only flood control, but does not propose any enhanced stormwater recharge. This is certainly one area where there is untapped potential. But the developer would need to acknowledge the scarcity of local water resources – this finite underground resource is not limitless. The developer has not done so. Nor does the Benson City Council seem interested in sustainable use of groundwater. For them, there is plenty of water now, so no need to worry, right?! Dollar signs are obscuring their view of the future. But they have it in their power to require sustainable groundwater use if they wanted.
Meanwhile, Castle & Cooke Arizona, Inc. plans to build nearly 7,000 homes in Sierra Vista, Arizona east of State Route 92 and north of Buffalo Soldier Trail according to the Tribute Specific Master Plan. However, a lawsuit was filed by local property owners and later joined by the Bureau of Land Management, the federal land manager of the San Pedro Riparian National Conservation Area. That lawsuit contends that the Arizona Department of Water Resources (ADWR) failed to account for groundwater needed by the river when ADWR issued a certificate of 100-year water adequacy for Pueblo del Sol Water Company to serve prospective residents of the Tribute development.
The judge’s decision in the lawsuit held that ADWR must include the federal reserve water right for the San Pedro Riparian National Conservation Area in a re-analysis of the legal availability of water over the span of the next 100 years before concluding that there is adequate water for Tribute. Any appeal in that case will take a while to play out.
How to get to sustainable use of groundwater
The importance of basin groundwater to surface water, including base flows of rivers, and to alluvial aquifers under them, is emphasized in the presentation “Natural Tracers of Source Water to Critical Wetland Habitats for Endangered Species” (J. McIntosh, R. Tucci, R. Tiller, A. Salywon, and J. Haney) at the recent symposium “Science on the Sonoita Plain” last June 4 at the Appleton-Whittell Research Ranch near Elgin, Arizona. This is a significant reason to protect our regional aquifer from depletion if we want to ensure the river continues to flow in the future.
Current efforts to protect the San Pedro River include the San Pedro Recharge Network land acquisitions and the Palominas Recharge Facility (85 AF capacity) operated by Cochise County. But in the face of the proposed developments, is that sufficient? Not likely…. more projects are needed. The developer could incorporate recharge into the stormwater management plan and leverage the presence of heavy equipment not just for flood control, but also to construct recharge facilities while earth-moving bulldozers are on site.
If we insist on sustainable use of groundwater, how might we fund potential recharge facilities? Our local politicians can seek appropriations and grants to help pay for such infrastructure. It is difficult in the current budget environment for cities like Benson and Sierra Vista, or Cochise County, or the state to budget for such projects out of their general funds. Taxes? Obviously, levying taxes would be very unpopular at present. Only if people understood the importance of securing our water resources for the future is there any hope of that. Could the developer be required to fund recharge facilities as a condition of approval? Would they run from the project? The only way to find out is to ask. Developers might cover some of those costs as they do with the costs of roads and flood control. Ultimately, a combination of the above funding sources is probably necessary.
Is there the political will to require stormwater and effluent recharge in development plans to balance groundwater withdrawals? Perhaps, especially if we take the long view: Don’t be California! Economic development at all costs seems short-sighted given the consequences of being on the wrong side of history. So the question remains, how do we balance economic prosperity with sustainable groundwater use? Can it be done? The jury is still out on this one….
Finally, to get an idea of the challenges Arizona faces in managing its water resources in the future, see the program Beyond the Mirage: http://