(Phoenix, Ariz.—July 31, 2012) The Bill Williams River is the fifth "River of the Month" in a year-long series celebrating Arizona's centennial year. The series is produced by Environmental Defense Fund, Sierra Club, Grand Canyon Trust, Sonoran Institute, and Western Resource Advocates.
According to the profile, available here, the Bill Williams River is formed by the confluence of the Big Sandy and Santa Maria Rivers in the mountains of west-central Arizona. The river flows almost immediately into Alamo Reservoir, formed by the 283-foot-high Alamo Dam.
"As with many Southwestern rivers, the modern story of the Bill Williams River centers around the often unanticipated consequences of human activity," say the conservation organizations in the River of the Month profile.
The Bill Williams, and the wildlife it supported, were severely impacted by the 1968 construction of Alamo Dam. In response to the loss of rich riparian habitat, the Army Corps of Engineers and others developed strategies to operate the dam in a more natural way. Water is now released from Alamo Dam in a pattern imitating pre-dam conditions; ecosystems are monitored and releases are adjusted accordingly. As a result, much of the river corridor has been revitalized, and it contains some of the most extensive cottonwood-willow riparian forest remaining in the Lower Colorado River Basin.
According to the River of the Month profile, the cottonwood-willow riparian forest of the Bill Williams supports over 350 species of birds including the endangered Southwestern willow flycatcher and Yuma clapper rail. It also supports endangered fish and other animals including bald eagles, peregrine falcons, big-horn sheep, javelina, at least 14 bat species, mountain lions, bobcats, ringtail cats, foxes, and beavers.
Previous River of the Month profiles have featured the Colorado River, the Salt River, the Little Colorado River, and the Santa Cruz River. Next month the groups will celebrate the Gila River. The University of Arizona’s Water Resources Research Center has provided assistance in creating the profiles.