Background

The Gila Gravity Main Canal is a component of the Arizona Gila Project constructed by the U.S. Bureau of Reclamation in the late 1930’s. The canal delivers Colorado River water for irrigation and domestic purposes to approximately 100,000 acres in an area located east of the City of Yuma. The primary irrigation districts that depend on the canal for water are the North Gila Valley Irrigation and Drainage District, Wellton-Mohawk Irrigation and Drainage District, Yuma Irrigation District and Yuma Mesa Irrigation and Drainage District. The canal also supplies domestic water to the City of Yuma and the area known as the “Foothills” east of Yuma. The city is expected to eventually rely on the canal for delivery of a substantial portion of its domestic water supply.

Water is discharged from the Imperial Dam through a desilting basin into the Gila Gravity Main Canal, which consists of two tunnels, the Gila River Siphon, 19 miles of open unlined canal and 10 turnouts to divert water to agricultural and domestic users.

Several sections of unlined canal are not susceptible to concrete lining and have been identified as areas of substantial seepage. In addition, sediment deposits have raised the bottom of the canal by as much as four feet, which has not only reduced the canal’s operability, but has apparently also increased seepage by adding pressure to seeping areas.

Description

The project consists of five elements:

1. removal of sediment from canal;
2. canal efficiency enhancement to provide real-time data to better gauge water requirements;
3. water measurement improvement structure to measure water flows;
4. remote control of all canal gates which will allow for hourly water orders, thus reducing and/or eliminating the diversion of excess water; and
5. canal sealing to prevent seepage.

Benefits

The project will reduce water losses from seepage, increase control of water usage and improve overall operational efficiency of the canal. Total water savings from all five project components is estimated at 45,000 acre-feet a year. This project will also improve the availability and delivery of water to domestic and agricultural water users.