PHOENIX (CN) - Fifty-five southern Arizona subdivisions have been illegally siphoning water from federally protected wetlands since at least 2006, conservationists say in a new lawsuit. 

The Center for Biological Diversity and San Pedro 100 are challenging 100-year water supply designations for Sierra Vista subdivisions, citing a 2023 ruling that quantified water rights for the San Pedro National Riparian Conservation Area in response to Congress's 1988 protection of the San Pedro River. The lawsuit urges the Arizona Department of Water Resources to reassess whether the developments can proceed without draining the Southwest's last free-flowing river.

"Governor Hobbs and Director Buschatzke refuse to acknowledge that over-pumping in Sierra Vista is violating the San Pedro River's water rights," Robin Silver, co-founder of the Center for Biological Diversity, said in a Thursday press release. "They refuse to act despite laws requiring review of inaccurate water adequacy designations and consumer protections requiring full disclosure of those facts. So we're taking Arizona to court."

Conservationists say the San Pedro River is vital for millions of migratory birds and endangered species, but groundwater pumping for housing and a U.S. Army base is depleting it. Water levels in six of 13 court-monitored wells and gauges have dropped below mandated levels, the lawsuit claims.

Along with demanding a reevaluation of water certificates, the plaintiffs accuse the department of violating the Arizona Consumer Fraud Act by assuring developers access to water that may not be legally available, claims they say Arizona Governor Katie Hobbs and Department Director Tom Buschatzke have ignored for two years.

Only after the center's August 2024 lawsuit did Buschatzke and the department agree to review the water-supply designation of one of the local subdivisions, a 7,000-home development called Pueblo Del Sol. The department settled the suit and agreed to reexamine the matter.

That was the second time in recent years that the center sued Arizona over the San Pedro. In June 2024, it sued to demand that Hobbs declare the riparian area an active management area, in which the state would closely monitor and record groundwater pumping. A state judge dismissed that challenge in January. 

Thursday's lawsuit centers around water rights assigned to the San Pedro in 1988. Though Congress reserved the water, the rights were never quantified in statute, allowing the state to give those water rights to developers. The state supreme court affirmed the transfer in a 4-3 decision in 2018, leaving the decision to reserve them for the San Pedro up to the department's interpretation. 

Dissenting justices noted that "this interpretation defeats the adequate water supply provision's manifest purpose to proactively protect consumers in Arizona before they purchase property."

The winds shifted in the San Pedro's favor in August 2023, when Maricopa County Judge Mark H. Brain issued a ruling quantifying water rights for the conservation area. Now, plaintiffs say that the ruling nullifies the granting of water rights to the 55 subdivisions named in the suit. 

The Arizona Department of Water Resources has not replied to a request for comment. 

Source: Courthouse News Service