Background & History

Salt River

The Salt River runs 200 miles from the White Mountains in eastern Arizona to the Gila River.  Despite the dry appearance you see it in today, it was once a source of frequent flooding and loss of property. 

Construction

In 2000, the U.S. Army Corps of Engineers (ACOE) received approval from Congress for the Tres Rios Ecosystem Restoration and Flood Control Project. The city of Phoenix partnered with the ACOE to improve and enhance a seven-mile long, almost 700-acre section along the Salt and Gila Rivers in southwestern Phoenix. The project received 65 percent of the funding from the ACOE, with 35 percent coming from the local sponsor, the city of Phoenix and the Sub-Regional Operating Group Members (Scottsdale, Tempe, Glendale, and Mesa.)  Technical and financial assistance was also provided by the Flood Control District of Maricopa County.  Construction lasted from 2007 through 2012.  

Wetlands in the Desert

Former agricultural fields were graded and contoured into the wetlands you see today.  Once the depths were just right, plants including rushes, sedges, arrowhead, cattail, and floating aquatics were installed to recreate wetlands of the southwestern United States.  

Restoring Riparian Habitat

Most of the rivers in the southwestern United States have become choked with a non-native plants including the salt cedar and the tamarisk. These plants were originally brought to this country in the 1800s as ornamental vegetation and for stream bank stabilization. However, in the 20th century Arizonans started to realize the danger of importing foreign plants into our fragile desert environment. Sonoran Desert wildlife has lived with the native plants for millions of years.

The plant and animal communities have evolved together, with the animals using the plants for shelter and food, and the plants exploiting the animals for seed dispersal. Native plants are perfectly suited to sustain native animal populations. Now, the salt cedar has displaced many of our native plants their invasions have thrown off the natural balance between plants and animals, making survival much more difficult for our native wildlife.

To reverse this process, Tres Rios removed large tracts of salt cedar and replaced it with native cottonwood/willow riparian corridors. In some areas, where the salt cedar is very dense and would be impossible to replace, the river sediment will be dug down and filled with water. This will prevent regrowth of the salt cedar, provide habitat for waterfowl, and offer a cleared channel for flood flows to utilize.

trmapclickon2013a

Click on the map to view and print a larger version (in Adobe Acrobat)