TerraTruth

The California Delta provides water to millions of people and scores of farms. The Delta is home to fish, animals, birds, and bugs. Consequently, the delta is subject to many conflicting demands and is currently under a lot of stress. Fish populations are collapsing and water transfers through the delta have been reduced by the courts. One of the solutions to the Delta problems is the peripheral canal. Here is a map of the proposed routes of the peripheral canal.

Potential Benefits

Proponents of the peripheral canal believe that the canal would help restore the delta to its natural state by sending water around the delta instead of through it.  This change may allow the delta to return to its natural state as a saline-freshwater tidal estuary. Ever since the construction of large dams in California (e.g. Shasta Dam), the Delta has been maintained as a, for the most part, freshwater lake. A peripheral canal may harm agricultural users and some water districts (e.g. Contra Costa Water District) that use Delta water. However, reducing agricultural use of Delta water may not be a bad plan as farms in the Delta discharge untreated, nutrient, and pesticide laden runoff to the Delta without regulation.  In fact, by constructing a peripheral canal, the Delta may be exposed to a larger variance in salinity that more closely matches conditions prior to human intervention (e.g. levee construction). Allowing the Delta to function as an estuary may help restore the ecosystem of the Delta.  This paper by Jay Lund et al. has more information on Delta salinity.

The agricultural firms that run the large farms in the Delta have been polluting the Delta for decades. DDT from the 50s and 60s is still present in large quantities in the Delta sediment. Pesticides that farmers are currently using, such as pyrethroids and organophosphates, are present in toxic levels throughout the Delta. These pesticides are sprayed on the fields and then carried off by irrigation and rain runoff to drainage ditches on the islands. The agricultural firms then pump the untreated runoff directly to the Delta. The pesticides , nitrogen, and phosphates contained in the runoff negatively affect the water quality in the Delta. It is reasonable to assume that these pollutants are responsible for killing significant quantities of fish and other organisms in the Delta. See this report for details on the pesticide concentrations in the Delta.

Costs

The construction costs for a peripheral canal have been estimated by many different agencies (CALFED, USBR, etc) over the last fifty years. The most recent, comprehensive cost estimate we have found is a 2006 report titled "Isolated Facility, Incised Canal Bay-Delta System: Estimate of Construction Costs." The cost estimate, which estimates the total construction cost of a peripheral canal to be $3.3 to $3.7 billion, was prepared by Washington Group International (now part of URS Corp) for the State Water Contractors. The report presents a detailed assessment of costs for two possible canal alignments. In order to prepare the estimates, canal alignments were updated, hydraulic profiles were generated, and pumping requirements were refined. Because it is not currently available on the internet, we have posted the report here in several pieces (due to the large size of the document).

-Main Body of the Report (18.9 MB)

-Maps of Canal Alignments (26.6 MB)

-Hydraulic Profiles, Levee Sections and Siphon Details (5 MB)

- Appendix A: Quantity Takeoffs (email us if you would like this file - it is approximately 80 MB)

-Appendix B: Cost Estimate Tables (email us if you would like this file - it is approximately 60 MB)

More Information

Additional maps of conceptual peripheral canal routes are available on the California Department of Water Resources website. In our opinion, this canal route is most likely to be implemented.

Click on these links to learn more about Shasta Dam and the Central Valley Project. The Central Valley Project was constructed by the Federal Government. the State Water Project was constructed by the State of California