As millions of migratory birds begin arriving at the San Pedro River on their annual journey north, local, regional and national conservation groups today notified the U.S. Army Corps of Engineers and the U.S. Fish & Wildlife Service that they are poised to file a lawsuit to protect the San Pedro River and its surrounding wildlife habitat from a sprawling residential and commercial development. An Army Corps permit for the development is in violation of the Endangered Species Act.

The San Pedro River, the Southwest’s last free-flowing river, is one of the most biodiverse areas in the region.

The groups’ letter explains that the Villages at Vigneto, a 12,324-acre residential and commercial community planned in the desert landscape along the San Pedro River in southeastern Arizona, could further imperil a variety of species dependent on the last major free-flowing river in the Southwest. 

The project is forecast to increase demand on groundwater resources from approximately 800 to as high as 13,000 acre-feet per year, depleting San Pedro streamflows. It also would increase stormwater runoff, flooding and destructive sediment accumulation in the river.

“The Villages at Vigneto will be stealing water from the adjacent San Pedro Riparian National Conservation Area, degrading habitat for hundreds of migratory bird species. It will be contributing to more unmitigated sprawl in a watershed with some of the most impressive species diversity in Arizona,” said Robin Silver, co-founder and board member of the Center for Biological Diversity.

The San Pedro River watershed is one of the most biodiverse areas in the arid Southwest. It is a critical nesting and resting area for migratory birds with nearly 45 percent of the 900 bird species in North America using the habitat corridor at some point in their lives. This watershed also sustains intact stands of cottonwood/willow riparian forest and is home to 84 species of mammals and 41 species of reptiles and amphibians.

Recognizing its importance, Congress designated 36 miles of the river as the San Pedro Riparian National Conservation Area in 1988.

Among the San Pedro species threatened by the development are the western yellow-billed cuckoo, the northern Mexican gartersnake, the southwestern willow flycatcher and the Huachuca water umbel.

“The San Pedro River is this incredible asset to our state, providing habit for a diversity of species, a flyway for migratory birds, a wildlife viewing paradise for people from around the world,” said Sandy Bahr, director for Sierra Club’s Grand Canyon Chapter.

“Several species that are dependent on the river are also threatened or endangered due to habitat loss. Arizona has allowed development and other diversions to dry up and destroy several important rivers. We cannot, we must not, allow the San Pedro to join that list.”

Numerous conservation easements—including mitigation land for the proposed development—are located downstream and would be affected by the development, many of which were specifically established to offset impacts to endangered and threatened species from other developments in Arizona.

“The lower San Pedro watershed supports the last intact desert river ecosystem in the Southwest,” said Peter Else, chair of the Lower San Pedro Watershed Alliance, a landowner-based conservation association.

“Our members are aware of the rapid loss of water resources and habitat that has taken place in every river valley of Arizona’s growth corridor. Preserving this critical resource as required under the Endangered Species Act will protect wildlife habitat and migration corridors, sustainable rural lifestyles and valuable recreation opportunities.”

“What is most alarming about this proposal for those along the Lower San Pedro River is that a new upstream city of 70,000 people will be pulling water from the ground in an unsustainable way. Most of that water will never be replaced. It’s a potential death sentence for the Lower San Pedro,” said Mick Meader, co-president of the Cascabel Conservation Association.

The adjacent Whetstone Mountains also provide habitat for endangered and threatened species, such as the jaguar and ocelot, which could be adversely affected by construction of a massive development at the foot of the range.

“The San Pedro River Valley supports two Globally Important Bird Areas. The valley is a critical migratory corridor for millions of birds, including the threatened western yellow-billed cuckoo. Despite prodding by the U.S. Fish and Wildlife Service and numerous conservation organizations, the Army Corps has failed in its duty to formally consult on the potential impacts the Villages at Vigneto mega-development could have on numerous threatened and endangered species. Apparently the threat of litigation is required for the Corps to meet its obligation to fully gauge and minimize the impacts of this development,” said Karen Fogas, executive director of the Tucson Audubon Society.

The developer, El Dorado Benson, LLC, is relying on a Clean Water Act permit issued by the Corps of Engineers in 2006. Since then, the plans have been altered to make the development 50 percent larger, and new information has surfaced on the impacts to endangered and threatened species that inhabit the watershed. Under the Endangered Species Act, these new scientific data trigger mandatory consultation with the Fish and Wildlife Service before any development can proceed. 

“The Endangered Species Act requires federal agencies to look before they leap to ensure they aren’t putting any endangered or threatened species in jeopardy, but here the Army Corps has chosen to turn a blind eye to the potentially serious effects this development could have on a number of at-risk species and their habitats,” said Chris Eaton, an attorney with Earthjustice representing the groups.

The Center for Biological Diversity, Sierra Club, Maricopa Audubon Society, Tucson Audubon, Lower San Pedro Watershed Alliance and Cascabel Conservation Association are working together to warn the federal agencies that they are in violation of the Endangered Species Act. The groups will bring suit within 60 days if necessary to force the required consultation.

Read the letter.