SIERRA VISTA, Ariz.— The Center for Biological Diversity and the San Pedro 100 sued Arizona Department of Water Resources Director Tom Buschatzke today for failing to review and revoke the designation guaranteeing a 100-year water supply for the 28,000-home Villages of Vigneto development in Benson.

The Benson homes would rely on groundwater that’s no longer available based on court rulings in 2023 and 2024. The groundwater feeds the nearby San Pedro River, the last free-flowing desert river in the Southwest, essential for millions of migratory songbirds and many endangered species. Arizona law requires that new developments guarantee a sufficient water supply for at least 100 years.

“The Villages of Vigneto development has always been predicated on the mirage of unavailable water,” said Robin Silver, a co-founder of the Center. “It’s hard to believe that we now need to file a fourth lawsuit against the state because officials continue refusing to protect the San Pedro River.”

The Arizona Department of Water Resources was required to review the Benson development’s water supply designation by July 14, 2023. It has failed to do so.

San Pedro River streamflow during the dry times of the year is already diminishing, as evidenced in three hydrology studies — Prucha (2016), Eastoe (2017) and Meixner (2018) — showing that Vigneto groundwater pumping will violate federal reserved water rights and will damage the San Pedro Riparian National Conservation Area.

Today’s lawsuit is the fourth challenging Gov. Katie Hobbs and Buschtzke for various actions failing to protect the San Pedro River.

The Hobbs administration designated the Willcox area an Active Management Area and is considering similar protections for Gila Bend.

Despite increasing signs of San Pedro River demise, including decreasing streamflows, the administration has refused to take action to protect the groundwater basin from over-pumping.