Bay-Delta Conveyance Concepts
The BDCP stakeholders have put forward a number of conceptual options for getting water around, through, or under the Delta to the state and federal pumps at Old River and Clifton Court Forebay northwest of Tracy.
General options include a "through-Delta alternative", an east-side canal (40 miles long), an "all-tunnel" alignment from near Hood to Clifton Court Forebay, and a west-side canal and tunnel option. Each canal diversion would have multiple intake facilities that would be outfitted with fish screens—a "multi-headed Hydra" said one fisheries biologist at recent Delta Flow Criteria Proceeding discussions—to reduce impacts to fish.
The feasibility of such large fish screens remains to be demonstrated at this scale.
To get a sense of the scale of the canal concepts, we present cross sections from 1968 and the more recent BDCP version. In 1968, the canal's bottom width was 180 feet wide and its levee to levee width was about 440 feet. It would have had a maximum water depth of about 13.4 feet.
BDCP released a hypothetical cross section ("dimensions are preliminary and subject to change") of 340 feet at bottom with a levee to levee width of 540 feet. This canal would have a water depth of about 23.5 feet. This cross section alone is about 54 percent larger than the canal cross section considered in 1968.
And, as shown in the BDCP image at right, the BDCP conveyance canal is much larger than the already impressive California Aqueduct.
As noted above, BDCP is also considering digging tunnels under the Delta to convey water to the export pumps, and the image at right sketches conceptual cross sections for a 2-bore version. A three-bore design is also under review.
We invite you to view:
Review of tunnel concepts, 2009 (including cost estimates)