Delta Vision Strategic Plan

State of California | October 17th, 2008

When it was created by Governor Schwarzenegger’s Executive Order S-17-06 in 2006, the charge of the Delta Vision Blue Ribbon Task Force (Task Force) was nothing less th

When it was created by Governor Schwarzenegger’s Executive Order S-17-06 in 2006, the charge of the Delta Vision Blue Ribbon Task Force (Task Force) was nothing less than to create a vision to repair the ecological damage to the Sacramento-San Joaquin River Delta (Delta), and then prepare a strategic plan which would sustain the Delta in future decades while ensuring a reliable water supply for the two-thirds of California’s population who depend in whole or in part on water from the Delta.

Delta Vision Strategic Plan -- from Phil Isenberg, 1939-2023

State of California | October 17th, 2008

When it was created by Governor Schwarzenegger’s Executive Order S-17-06 in 2006, the charge of the Delta Vision Blue Ribbon Task Force (Task Force) was nothing less th

When it was created by Governor Schwarzenegger’s Executive Order S-17-06 in 2006, the charge of the Delta Vision Blue Ribbon Task Force (Task Force) was nothing less than to create a vision to repair the ecological damage to the Sacramento-San Joaquin River Delta (Delta), and then prepare a strategic plan which would sustain the Delta in future decades while ensuring a reliable water supply for the two-thirds of California’s population who depend in whole or in part on water from the Delta.

Delta Working Landscapes Program Final Report

Delta Protection Commission (DPC) | October 14th, 2013

The Delta Working Landscapes Program (Program) is a group of projects which demonstrate how farmers can integrate habitat restoration into farming practices. The objectiv

The Delta Working Landscapes Program (Program) is a group of projects which demonstrate how farmers can integrate habitat restoration into farming practices. The objectives of the Program are to improve the environmental quality of existing landscapes in the Delta; coordinate programs with local farmers; understand the social, economic, environmental and governmental policy hurdles and/or incentives to perform conservation practices; and communicate to farmers the advantages of implementing wildlife friendly agricultural practices. The Delta Protection Commission was awarded a three year grant to construct the program through the California Bay-Delta Program in 2005. Program partners included California Department of Fish and Wildlife Ecosystem Restoration Program, Hart Restoration (Hart) and Ducks Unlimited (DU). Hart established vegetative buffers along irrigation ditch banks and hedgerow grass plantings. These plantings were designed to provide habitat for wildlife, improve water quality by reducing runoff of pesticides and sediment, enhance levee stability, and retard levee erosion. DU coordinated restoration enhancement projects which included creating seasonal and permanent wetlands on marginal farmlands. These projects provide waterfowl brooding habitat, a food source, and additional habitat sites which promote healthier waterfowl flocks. These projects total 312 acres of seasonal and permanent wetlands and 6.5 miles enhanced levees and waterways. Project areas established native plant life, have been repopulated by wildlife, and filter agricultural drainage which improves water quality and enhances levee stability. Multiple species of waterfowl are using the restoration habitat for brooding and feeding as well as staying later into the season. No easements, MOUs, fee purchases, or eminent domain were used. Challenges to Working Landscapes projects include prior long term use of pesticides and herbicides which have created a hostile environment for native plants and wildlife. Additionally, some cultural practices are not conducive to habitat creation such as practices which rely on herbicides instead of tillage. Furthermore, economic costs are affiliated with physical land alterations, and in some cases permit requirements are cumbersome. Despite these challenges, successful public/private partnerships are possible. Working Landscapes projects can be expanded through better communication between policy and regulatory agencies and publicizing successful projects.

Development of Stage-Frequency Curves in the Sacramento-San Joaquin Delta for Climate Change and Sea Level Rise

California Energy Commission (CEC) | August 27th, 2018

Future changes in hydrologic patterns and sea level rise will impact water levels in the Sacramento-San Joaquin Delta (Delta), the hub of California’s water supply sys

Future changes in hydrologic patterns and sea level rise will impact water levels in the Sacramento-San Joaquin Delta (Delta), the hub of California’s water supply system and an important ecosystem and agricultural area. An important tool for flood management is stage frequency curves which indicate how often certain water levels (or stage) occur. The Delta poses inherent complexity in the determination of stage-frequency and requires a number of considerations. One needs to account for river flows coming into the Delta, as well as the effect of tides from the Delta’s connection to the ocean through San Francisco Bay. During storms, Delta water levels are also affected by storm surge from the advancing storm fronts coming from the Pacific Ocean. Under climate change, Delta water levels will also be affected by rising sea levels and expected changes in hydrology, such as shifts in timing and amount of precipitation and runoff and changes in how much of our precipitation falls as rain or snow (referred to as climate change hydrology in this paper). With these taken into consideration, this study lays out the assumption and method used to develop stage-frequency curves in the Delta for three different conditions: current hydrology conditions, current hydrology with sea level rise, and late-century climate change hydrology with sea level rise. In addition, water surface elevation profiles along the Sacramento and San Joaquin rivers for various magnitudes of flood events were compared to the top of levee elevations. Both the stage-frequency curves and the water surface elevation profiles comparisons to top of levee elevations provide valuable information to water resources planners and were applied to inform life and flood risk analysis for the Delta in the Central Valley Flood Protection Plan 2017 Update.

DRERIP Ecosystem Conceptual Model: Riparian vegetation

California Department of Fish and Wildlife (CDFW) | November 14th, 2008

The Sacramento-San Joaquin Delta has immense municipal, agricultural, biological and industrial importance to the economy and livelihood of California and in turn to the

The Sacramento-San Joaquin Delta has immense municipal, agricultural, biological and industrial importance to the economy and livelihood of California and in turn to the United States. Plans to improve conditions in the Delta must address both human and biological communities. The region has been altered extensively over the past 200 years from land conversion to agriculture, fluxes in sedimentation rates, levee construction, and a completely re-plumbed network of waterways and hydrology (Thompson, 1957). Remnant, native riparian and wetland plant communities are almost completely removed and there is some question of whether the natural processes that create and maintain them can be restored (Mount and Twiss, 2005). Restoration implementation will be difficult considering the extent of alteration and complexity of both the natural system and cultural setting. The scientific approach to resolve these issues needs to reflect system complexity and represent the many potential response pathways that lead from proposed alterations. Development of conceptual models to understand these potential pathways is an important first step in understanding restoration implementation (and other management actions) in light of the complexity of the natural system and existing management scheme. The CALFED program is interested in restoring the Delta ecosystem to the extent possible. Riparian Vegetation (RV2) is but one of the natural systems of interest; others include fisheries, wildlife, and other plant communities. The conceptual model presented here deals exclusively with those physical, chemical, and ecological processes relevant to riparian vegetation. Riparian vegetation is important not only for biological conservation of the plant species themselves, but also the other flora and fauna species—and the physical and ecological processes—that depend upon riparian vegetation. Although the restoration of riparian vegetation as a component of a healthy riverine landscape has cultural and economic importance, these aspects are not included in this model. The conceptual model of riparian vegetation presented here is actually a sub-model of the larger floodplain processes/habitat model (Figure 1). The RV Sub-model is general by design, and is intended to provide a framework for potential expansion or adaptation to more-refined models of individual species, habitats, and/or entire landscapes. Spatially, we focus specifically on the floodplain or land area beginning at the upper edge of the emergent vegetation zone, then moving up in elevation and inland from the water, ending when non-floodplain areas, open water, or marsh is encountered. Together, the Floodplain model and the RV Sub-model can be used to analyze various “scenarios,” ranging from potential restoration or research actions, to water management decisions, to placement of bank protection at a specific Delta levee site. In addition, to highlight key differences in conditions that occur in the Delta, we present here two specific applications of the RV Sub-model that we generalize as a being dominated by tidal processes and another dominated by more riverine processes.

Early Reclamation and Abandonment of the Central Sacramento-San Joaquin Delta

Sacramento Historical Society | September 15th, 2006

Earthquakes and High Water as Levee Hazards in the Sacramento-San Joaquin Delta

Delta Stewardship Council (Delta Council) | September 30th, 2016

Exploration of Tolerable Risk Guidelines for the USACE Levee Safety Program

U.S. Army Corps of Engineers (USACE) | January 10th, 2011

Risk assessment methodologies have been used around the world to provide decision makers with information on the likelihood of adverse outcomes and resulting consequences

Risk assessment methodologies have been used around the world to provide decision makers with information on the likelihood of adverse outcomes and resulting consequences. Governments are recently moving to broader flood risk management approaches that encompass structural measures and manage floodplain development while recognizing climate change, environmental functions and social factors. Such flood risk approaches consider the probability of a flood hazard occurring; the vulnerability of flood mitigation measures implemented to lessen flood consequences through preparation, response, recovery and mitigation; and the consequences that result from the mitigated flood event. Within that overarching flood risk management context, the U.S. Army Corps of Engineers (USACE) is considering risk management approaches for dams and levee systems in order to make better decisions, better prioritize and justify risk reduction measures, better communicate risks to decision makers and the public, and better understand and evaluate public safety risks in an environment of shared flood risk management responsibilities. USACE consideration of risk management approaches includes the potential use of a Tolerability of Risk (TOR) framework, originally developed in the United Kingdom and adapted elsewhere, as well as Tolerable Risk Guidelines (TRG). Tolerability of Risk was developed as a framework for reaching decisions with stakeholders that focuses on the most serious risks consistently, efficiently, and transparently. Tolerable Risk Guidelines categorize the nature of risks in ways that can assist in assessing their acceptability or non-acceptability, and in prioritizing actions for reducing risks. (Further information regarding TOR and TRG is available in the summary of Dr. Jean LeGuen’s presentation, in Section 3 of this report, and in his paper, included in Appendix D.) In March 2008, three Federal agencies - US Army Corps of Engineers (USACE), Department of Interior, Bureau of Reclamation (Reclamation), and Federal Energy Regulatory Commission (FERC) convened a workshop entitled “Workshop on Tolerable Risk Evaluation – A step towards developing tolerable risk guidelines for dams and levees”. With the formation of the USACE Levee Safety Program (USACE 2007), attention began to be directed toward adapting the newly developed risk-informed dam safety policies and methods for application to levee systems. The National Committee on Levee Safety (NCLS) authorized by the Levee Safety Act of 2007 published its draft recommendations in January 2009 (NCLS 2009) including Recommendation #5 that Tolerable Risk Guidelines (TRG) be developed for application in risk-informed, flood risk management (FRM) associated with levees. This March 2010 workshop constitutes one step in USACE engaging the flood risk management community to work collaboratively in developing policies, TRG, and methods to further levee safety for the nation. The workshop purpose was to examine the concepts and principles of tolerability of risk and tolerable risk guidelines and explore their application to, and use in, managing life, economic, and environmental risk associated with levee systems. The workshop scope encompassed national and international approaches to flood risk management, tolerability of risk, and tolerable risk guidelines as they would apply to the USACE levee safety program. The workshop was comprised of three parts: introductory plenary presentations that set a common base and vocabulary for subsequent discussions; three facilitated break-out sessions that deliberated on questions prepared in advance; and concluding panels and plenary sessions that would capture the sense of the participants in what was learned and how to proceed. Invited participants numbering about sixty were from USACE, FEMA, other Federal agencies, professional societies, NGO’s, and from The Netherlands, United Kingdom, Japan, and Spain.

Factors and Processes Affecting Delta Levee System Vulnerability

University of California, Davis (UC Davis) | December 1st, 2016

The authors appraised factors and processes related to human activities and high water, subsidence, and seismicity. Farming and drainage of peat soils over time has cause

The authors appraised factors and processes related to human activities and high water, subsidence, and seismicity. Farming and drainage of peat soils over time has caused a gradual sinking which contributed to internal levee failures. Although these subsidence rates have decreased with time, they still contribute to levee instability. Additional data is needed to assess spatial and temporal effects of subsidence caused by peat thinning and deformation. Since the mid-1970s large-scale, State investments in levee upgrades have increased conformance, however accounts continue to conflict on how these investments correspond to the numbers of failures. Both modeling and history suggest that the projected increases of high-flow frequency associated with climate change will increase levee-failures rates. Quantification of this increased threat requires further research. A reappraisal of seismic threats resulted in updated ground motion estimates for multiple faults and earthquake occurrence frequencies. The immediate seismic threat, liquefaction, is the sudden loss of strength due to an increase in the pressure of the pore fluid and corresponding loss of contact forces. However, levees damaged during an earthquake that do not immediately fail, may eventually breach. Consequences for future levee failure are estimated to cost up to billions of dollars. The analysis of future risks will benefit from more detailed descriptions of levee strength and upgrades, consideration of subsidence, climate change, and earthquake threats. Ecosystem benefits of levee habitats in this highly altered system are thin. Better recognition and coordination is needed among the creation of high value habitats, levee needs, costs, benefits of levee improvements, and breaches.  

Flood Risk and Management of California's Sacramento-San Joaquin Delta Levee System

University of California, Santa Cruz (UC Santa Cruz) | September 15th, 2020