Delta-Mendota Canal/California Aqueduct Intertie Project
Crews worked throughout the year toward completion of the Delta-Mendota Canal/California Aqueduct Intertie Project, which will link the two Central Valley canals to improve water supply reliability south of the Sacramento-San Joaquin Delta.
Although the $28 million project is relatively small compared to many other water infrastructure improvements, the benefits are significant. U.S. Senator Dianne Feinstein of California, Secretary of the Interior Ken Salazar, Bureau of Reclamation Commissioner Mike Connor and other leaders attended the groundbreaking ceremony in October 2010, emphasizing that the project adds operational flexibility and more efficient delivery of water in an area with a limited supply.
Reclamation provided nearly $16 million in ARRA funds, which combined with other funding sources, made it possible to begin construction. Reclamation’s partners in the project are the San Luis and Delta-Mendota Water Authority and the California Department of Water Resources.
The Intertie, located in Alameda County, west of Tracy, will potentially increase average annual deliveries to theCentral Valley Project (CVP) by as much as 35,000 acre-feet by addressing conveyance conditions in the Delta-Mendota Canal (DMC) that restrict use of the nearby C. W. “Bill” Jones Pumping Plant to less than its design capacity.
The DMC receives water pumped by the Jones plant and is the primary federal delivery facility sending water to CVP contractors south of the Delta. The State Water Project’s California Aqueduct operates in much the same way.
The Intertie is being constructed at a point where the canals are just 500 feet apart. They will be linked via two 108-inch diameter pipelines. The tie will allow more conveyance to storage south of the Delta, provide redundancy in the distribution system in case of emergency, and make maintenance and repair work less disruptive to water deliveries.
During 2011, workers removed a section of the DMC’s concrete liner, installed a cofferdam, and constructed an underground sump structure to collect and channel water from the canal. Above ground, workers erected a pump house and installed four sets of 1,000-horsepower motors and pumps, each with a capacity of 117 cubic feet per second (cfs). Crews also constructed a 4.5-mile overhead 69-kilovolt power transmission line from a Tracy substation to the site.
On the California Aqueduct side of the project, workers installed a cofferdam in May 2011, then removed a section of concrete liner and excavated about 25 feet for a turnout structure. Crews completed the structure’s two reinforced concrete bays and began laying twin pipes to connect the canals.
The state canal is 50 feet higher than the federal canal. When the Intertie is complete in 2012, operators will be able to pump 468 cfs of water uphill from the federal canal to the state canal. In reverse operation, up to 900 cfs of water can be conveyed from the state canal to the federal canal via gravity flow.
More information: http://www.usbr.gov/mp/intertie/index.html
Shows construction of the pump station at the Delta-Mendota Canal end of the Intertie Project
Shows construction of the turnout at the California Aqueduct end of the Intertie Project
Motors and pumps are installed in the pumphouse
A view from inside the Intertie pumphouse looking out at pipe support structures
April 20, 2012