Comparing Futures for the Sacramento-San Joaquin Delta (PPIC II)

One of the goals of the CALFED Science Program is to provide authoritative and unbiased descriptions of scientific knowledge. To fulfill this goal, the Science Program holds workshops designed to provide a forum for discussions and the exchange of information among Scientists, Stakeholders, Agency Staff, and the public about topics important to the region. These workshops synthesize the science related to complex problems and provide advice for undertaking specific complex tasks in support of Delta planning and decision-making.

Workshop Archive

Comparing Futures for the Sacramento-San Joaquin Delta (PPIC II) - A Conversation with authors of the recent Public Policy Institute of California Report Appendices

November 12 & 13, 2008

Workshop Purpose
The Public Policy Institute of California recently released an on-line edition of its report “Comparing Futures for the Sacramento-San Joaquin Delta,” by Jay Lund, Ellen Hanak, William Fleenor, William Bennett, Richard Howitt, Jeffrey Mount, and Peter Moyle. Much of the core technical information and reasoning behind the comparison of potential futures in the Sacramento-San Joaquin Delta is contained in Appendices available with the report (

This two-day workshop featured presentations and question-and-answer sessions focusing on material contained within each appendix. After the appendix presentations and discussions, a concluding panel featuring CALFED Science Program advisors discussed the best use of science for the Delta’s future, given the results of the PPIC report and ongoing planning processes.

Links to the workshop presentations are provided below. Webcast archives of the workshop are provided here:

If you have questions or comments on this workshop or its content, please contact Steven Culberson, CALFED Science Program, (916) 445-0584;


Notable Points of Discussion

  • There are still fundamental gaps in our basic data needs – for example, there is no high-resolution collection of Delta-Suisun bathymetric profiles for use in various hydrodynamic models, and no directed periodic update to existing profiles.
  • It would be useful to know what assumptions are critical to our conceptual models of the Bay-Delta ecosystem, how robust these assumptions are, and what resources have been identified to increase our confidence in the underlying data upon which these assumptions were built. Who is ultimately responsible for upkeep of such models and critical datasets?
  • Drinking water supply quality is now marginal system-wide, and is likely to get worse if nothing is done to change the source of the supply.
  • A mass-balance accounting of dissolved salts in water applied to San Joaquin Valley soils via Central Valley Project-irrigated agriculture shows a future of reduced productivity on existing farmlands is inevitable.
  • Reduced salinity of irrigation water delivered to farm fields may have significant effects on water use efficiency of various crops and the amount of water that must be applied to achieve optimal crop yields. Less water per acre for irrigation may be required if salinity levels are reduced.
  • Precise prediction of individual species’ response to water management is an unrealistic expectation given the dynamic, adaptable, self-organizing nature of Delta ecosystems. Guild-based or energy-balance approaches to ecosystem characterization and future function show promise for informing management decisions and policy outcomes.
  • Our understanding of flow requirements must improve beyond discussing simply the amount of flow needed to sustain healthy fish populations. These requirements must also consider the timing, duration, rate of change, and frequency of flows that might be required. An analysis of these needs should be linked to the historical hydrograph (for ecological reasons, not romantic ones).

The workshop announcement and two-day archive is available at the following link: