Dr Robert Pyke has a wealth of geotechnical and water resources engineering experience from all over the world, including the Delta, and he has some sensible suggestions for addressing our water management problems. Among them
1. Restoration of floodplains on the Sacramento and San Joaquin rivers and their tributaries, which provides three significant benefits: stretching out floods to allow export pumping over a longer time; reducing peak flows as floods pass by the major urban areas and through the Delta; and restoring complexity and nutrients to the ecosystem.
2. New pumping facilities somewhere in the west Delta to allow flows to pass through the Delta in a natural way before surplus flows are extracted; these facilities might include some temporary storage.
3. One or more tunnels that can move the extracted water to a large temporary storage facility until the existing pumps can move it south; this storage facility would likely be adjacent to and might incorporate the existing Clifton Court Forebay.
4. Additional south-of-Delta storage, much of it likely as groundwater but also including new west-side surface storage.
Said Dr. Pyke in a Stockton Record op-ed last month, “Any well-thought-out plan for getting out of this stalemate has to start by recognizing both the need for more natural flows through the Delta and that precipitation in California is extremely variable.
Thus, natural flows through the Delta should be restored to the maximum practical extent; and much more water should be extracted at periods of high flow and much less at periods of low flow.”
Other suggestions from Dr. Pyke:
- Put in place a rational plan for maintaining and improving Delta levees and a mechanism for funding these improvements.
- Be sure that Delta levee and water conveyance policies allow for adaptive management to adapt to sea level rise as necessary.
- Encourage growth of native vegetation on the water side of all Delta levees. (This engineer insists that it can be done safely, and we agree.)
- Preserve the tradition of agriculture in the Delta to the maximum extent possible but encourage habitat-friendly agricultural practices.
- Encourage development of recreational and tourism facilities on broadened levees that provide positive flood protection as well as access to the water.
- Emphasize the interconnectedness of conveyance, ecosystem restoration, flood management, and water quality.
The Delta never had large stretches of open water. Dr. Pyke recommends restoring five sunken Delta islands (including Franks Tract) as tidal wetlands or tule marsh. Allowing tule marsh would allow soil level to rebuild to sea level. Open water, he says, does nothing for the ecosystem, is hard on levees, and can’t be used by boaters.
Dr. Pyke notes that the Delta Conservancy is the primary state agency responsible for ecosystem restoration in the Delta.
For the BDCP or anyone else to prioritize ecosystem restoration efforts, including possible conversion of agricultural lands to habitat, is premature until the Conservancy’s strategic plan is complete.