Balancing the needs of rivers, riparian habitat, and housing while ensuring environmental protections and sustainability for Arizonans

How a recent ruling by the Arizona Supreme Court fails to protect the San Pedro River and current and future residents in southeastern Arizona.

The Arizona Supreme Court recently ruled that the Arizona Department of Water Resources (ADWR) does not need to consider the impacts of groundwater pumping from a proposed large development on the not-yet-finalized water rights of nearby federal public lands.

This ruling does not resolve the uncertainty for the San Pedro River and its connected system of groundwater. And it does not protect prospective homebuyers in the area who may not have water indefinitely.

The water rights in question are for the San Pedro Riparian National Conservation Area (SPRNCA). The federal Bureau of Land Management (BLM), who manages SPRNCA, claims that to protect and fulfill the purposes of the conservation area, it is entitled to 44,000 acre-feet of water annually. The BLM is currently waiting to have these water rights quantified and legally secured, as part of a long-running Arizona lawsuit called the Gila River General Stream Adjudication.

In 2000, the Arizona Supreme Court rightly decided surface water and groundwater were hydrologically connected in specific geologic circumstances. This means that groundwater pumping can be cut off if it is determined that someone is affecting a higher priority user.

The recent ruling determined that ADWR could say there is adequate water to build Tribute, a proposed 7,000-unit residential and commercial development, despite the possibility the development could eventually be found to be pumping underground “subflow” of the nearby San Pedro River through SPRNCA. SPRNCA’s water right, once quantified, will be of higher priority than the development. If it is determined that the large housing development is affecting BLM’s (and by extension, the public’s) water rights, it could affect the continued development, other homes in the community, and of course, it could have environmental consequences for birds and other wildlife that rely on the San Pedro.

In 2008, Cochise County, where a major stretch of the San Pedro River lies, voluntarily adopted provisions to ensure that development within its boundaries has enough water for the subsequent 100 years. In doing this, the County demonstrated how water supply planning was critical to its long-term economic future.

Yet the Arizona Supreme Court ruling greenlights this specific development despite the uncertainty in future water rights claims for the San Pedro River. In his dissent Chief Justice Bales wrote, “The majority would allow ADWR to ignore the legal inadequacy of a proposed water supply until the problem becomes a reality. This interpretation defeats the adequate water supply provision’s manifest purpose to proactively protect consumers in Arizona before they purchase property.”

This decision underscores the urgency in resolving questions about water allocation on the San Pedro River, as well as other rivers and streams within Arizona. It also highlights the need for better laws that protect surface water and groundwater and acknowledges their hydrologic connection.

We need certainty to solve these worrisome water problems – for people, and for the birds and wildlife that depend on Arizona’s rivers.