Resource Management

Prescribed burn ignited from boat / USFWS

At one time, the banks of the Colorado River were lined with cottonwood and willow forests, sustained by the river's natural periodic flooding.

Wildlife depended on this green oasis found in the desert landscape for breeding, resting, feeding, and shade. But woodcutting during the steamboat era, clearing for agriculture, wild fire, exotic plants like salt cedar, and use of dams for flood control devastated cottonwood and willow stands along the lower Colorado River.

In an effort to maintain this important ecosystem, refuge managers and wildlife biologists depend upon and utilize a variety of tools to actively protect and manage it for the benefit of wildlife.

Marsh Management
The marshes of the Lower Colorado River are characterized by specific water depths and plants that have adapted and evolved with the river. With the constructions of dams, more than 60 percent of the river’s backwaters have been lost. The natural flooding regime has been tamed and with it is lost the processes critical for marsh vitality. To mimic this historic flooding and maintain the health of these important wetlands, Imperial National Wildlife Refuge actively manages more than 150 acres of refuge marsh. Using prescribed burning and through the removal of dead vegetation, the refuge is ensuring this important habitat continues to serve the needs of native wildlife like the endangered Yuma clapper rail and other secretive marshbirds.

Imperial Ponds
In partnership with the Bureau of Reclamation, Imperial National Wildlife Refuge has developed and currently maintains six ponds specifically for the benefit of two endangered fishes: the Razorback Sucker and the Bonytail Chub, both native to the Colorado River. The refuge’s ponds are isolated from the Colorado River to prevent the introduction of non-native fishes, and are managed by monitoring water quality and fish populations.