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Bill Williams River, Arizona - Managing rare ecosystems in a unique natural setting

The Bill Williams River flows through the wild Arizona desert. Most of the river below Alamo Dam, the only major dam and reservoir in the watershed, runs through wholly undeveloped lands. This makes the Bill Williams a river of critical ecological importance and unique scientific opportunity in the Southwestern U.S., where most rivers are highly engineered for human uses. The Corps, Conservancy and numerous partner organizations are working together to better understand the connections between water and nature as part of an ongoing and collective effort to promote science-based stewardship of this rare oasis.

Alluvial valley of the Bill Williams River, Arizona. The Bill Williams River channel is characterized by a series of relatively narrow bedrock gorges separated by wider, alluvial reaches.
Bill Williams River - Alluvial valley of the Bill Williams River, Arizona. The Bill Williams River channel is characterized by a series of relatively narrow bedrock gorges separated by wider, alluvial reaches (USACE photo).
Bill Williams National Wildlife Refuge, Arizona. The Bill Williams River drains more than 5,200 square miles of rugged, mountainous terrain in west-central Arizona. It is the largest tributary of the Colorado River (in the background here) between the Virgin and Gila Rivers.
Bill Williams River - Bill Williams National Wildlife Refuge, Arizona. The Bill Williams River drains more than 5,200 square miles of rugged, mountainous terrain in west-central Arizona. It is the largest tributary of the Colorado River (in the background here) between the Virgin and Gila Rivers (photo by Greg Bedinger/LightHawk).
The Bill Williams River and floodplain during a time of high release from Alamo Dam. High flows in the Bill Williams are critical for renewing riparian forest and maintaining channel habitat. The river and its aquifer support conservation projects managed by federal and state partners, including ponds (lower right) for rearing native fish.
Bill Williams River - The Bill Williams River and floodplain during a time of high release from Alamo Dam. High flows in the Bill Williams are critical for renewing riparian forest and maintaining channel habitat. The river and its aquifer support conservation projects managed by federal and state partners, including ponds (lower right) for rearing native fish (photo by Greg Bedinger/LightHawk).
The Bill Williams National Wildlife Refuge is downstream of Alamo Dam and is home to more than 300 species of birds and an array of native riparian flora.
Bill Williams National Wildlife Refuge - The Bill Williams National Wildlife Refuge is downstream of Alamo Dam and is home to more than 300 species of birds and an array of native riparian flora (USACE photo).
Alamo Dam is managed by the U.S. Army Corps of Engineers Los Angeles District. In the 1990’s, the Corps entered an innovative partnership with state and federal agencies to facilitate open communication and promote the use of science in resource management decision making.
Bill Williams River below Alamo Dam - Alamo Dam is managed by the U.S. Army Corps of Engineers Los Angeles District. In the 1990’s, the Corps entered an innovative partnership with state and federal agencies to facilitate open communication and promote the use of science in resource management decision making (USACE photo).
Understanding relationships between reservoir outflows and downstream physical processes and natural communities is key to effective science-based decision-making. Photo shows survey equipment used to collect land surface elevations along the Bill Williams River.
Management decisions supported by science - Understanding relationships between reservoir outflows and downstream physical processes and natural communities is key to effective science-based decision-making. Photo shows survey equipment used to collect land surface elevations along the Bill Williams River (photo by John Hickey, USACE).
Scientists, engineers, and other professionals from a variety of organizations have nurtured the investigation of ecological dynamics related to flow management for the Bill Williams River. The rich scientific understanding produced by these efforts helps inform operations of Alamo Dam.
Connecting science and operations - Scientists, engineers, and other professionals from a variety of organizations have nurtured the investigation of ecological dynamics related to flow management for the Bill Williams River. The rich scientific understanding produced by these efforts helps inform operations of Alamo Dam (photo by John Hickey, USACE).
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Story

The Bill Williams River watershed includes Alamo Dam and Lake, a U.S. Army Corps of Engineers reservoir constructed in 1968 and located in southwest central Arizona. Alteration of natural river flows resulting from the construction and operation of dams can result in substantial changes to downstream aquatic and bottomland ecosystems and undermine the long-term health of native species and communities.   Read More

Partners
  • Arizona Game and Fish Department
  • Arizona State Parks
  • The Nature Conservancy - Arizona Chapter
  • U.S. Army Corps of Engineers - Los Angeles District
  • U.S. Bureau of Land Management
  • U.S. Bureau of Reclamation
  • U.S. Fish & Wildlife Service
Resources
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