Delta Conveyance Project Alternatives Screening Process


Aerial view looking South at the S Bacon Island road bridge over Middle River, connecting the eastern side of Bacon Island (right) and Jones Tract, both part of the Sacramento-San Joaquin River Delta in San Joaquin County, California. Photo taken March 08, 2019.Ken James / California Department of Water Resources, FOR EDITORIAL USE ONLY

Aerial view of the Sacramento-San Joaquin Delta. DWR/2019

Selection of alternatives to evaluate in an Environmental Impact Report (EIR) is an important component of public agency project planning and is typically a required as part of the environmental review decision-making process. The Department of Water Resources (DWR) has initiated this process for the proposed Delta Conveyance Project and is currently preparing a Draft EIR in compliance with the California Environmental Quality Act (CEQA).

With regard to alternatives, CEQA directs that an EIR must analyze a reasonable range of potentially feasible alternatives that meet most of the project’s objectives and avoid or reduce potential significant environmental impacts of the proposed project. An EIR is not required to consider alternatives which are infeasible or do not meet most of the project objectives.

For the proposed Delta Conveyance Project, the alternatives screening process involves identifying and studying in greater detail in the EIR alternatives that would restore and protect the reliability of State Water Project (SWP) water deliveries, consistent with the state’s Water Resilience Portfolio, in the face of many challenges (such as climate change, sea level rise and earthquake risk), while avoiding or minimizing potential significant impacts of the proposed project.

To determine the alternatives to be evaluated in detail in the EIR, DWR uses a multi-step screening selection process to filter alternatives based on whether they 1) meet most of the basic project objectives and 2) avoid or substantially lessen expected significant environmental effects of the proposed Delta Conveyance Project. For an alternative to be carried forward it must meet both screening filters.

DWR started the process by reviewing the alternatives considered for previous Delta conveyance efforts and also assessing and screening alternatives received from the public during CEQA scoping for the proposed Delta Conveyance Project, and then organized alternatives into the following category types, among others:

  • Dual Conveyance: Includes new points of diversion in the Delta and facilities to move water from those new points of diversion to the existing pumping facilities in the south Delta.
  • Isolated Conveyance: May include new points of diversion in the Delta but would not use existing pumping facilities in the south Delta.
  • Through-Delta Conveyance: No new intakes in the Delta but could include new infrastructure in the Delta to ensure continued/improved conveyance capacity through existing Delta waterways.

The Draft EIR will document alternatives considered. The following are samplings of alternatives summary descriptions (additional detail on the description and results of screening will be included in the EIR).

  • Bethany Reservoir Alternative: Water would be conveyed in the tunnel (consistent with the proposed project’s eastern alignment) but continue further south and pumped directly into the existing Bethany Reservoir.
    • Screening outcome – met both filters so it will be carried forward for additional evaluation in the Draft EIR. Specifically, it could result in fewer surface impacts because construction of a new terminal forebay and additional south Delta conveyance facilities are not needed.
  • Continued Through-Delta Conveyance with Levee Improvements: Use of existing conveyance facilities with improvement to Delta levees in several locations.
    • Screening outcome - filtered out for failing to meet most of the basic project objectives. Specifically, this alternative would not address the water quality component of climate change and sea level rise for the SWP and continued use of the existing system (even with upgrades) as a long-term plan does not address seismic resiliency and the associated water supply reliability concerns.
  • “A Water Plan for All of California” (Congressman Garamendi Plan): Construction of a new north of Delta diversion structure and pump station in West Sacramento into the Sacramento Deep Water Ship Channel (DWSC), intake near the southern end of the DWSC, boat lock to prevent water from flowing into the Delta and a 12-mile pipeline to convey water through the western Delta to the existing pumping plants in the south Delta.
    • Screening outcome – filtered out for failing to avoid or lessen impacts. Specifically, significant construction, noise, transportation, visual, air quality and other impacts associated with construction activities in West Sacramento and potential habitat disturbances at various proposed construction locations.
  • Western Intake Concept (Pyke Proposal): Use of Sherman Island as an intake forebay, construction of a pumping plant and one or more tunnels to convey water to a new reservoir near Clifton Court Forebay with connections to existing south Delta pumping plants, an enlarged Los Vaqueros Reservoir and a boat lock at the Delta Cross Channel.
    • Screening outcome – filtered out for failing to meet most of the basic project objectives. Specifically, this alternative does not address SWP water supply reliability or operational resiliency. Additionally, water quality regulations could constrain water quantities and use of the Sherman Island reservoir.

In addition to the “action” alternatives analyzed in the EIR, a “No Project” alternative will also be included. The No Project alternative will describe likely conditions if the project is not implemented, including potential actions that may be taken absent a project, such as conservation, recycling and desalination, and the EIR will present the potential effects of not approving an action alternative. Although these alternative actions that may be implemented if the proposed Delta Conveyance Project or alternative is not implemented, several of which were proposed during scoping, don’t address the fundamental project purpose and were therefore screened out as standalone alternatives, the EIR will identify and analyze the effects of these additional actions that local water agencies may consider taking in the absence of the Delta Conveyance Project.

The alternatives selection process for the proposed Delta Conveyance Project is ongoing and the alternatives formulation process and detailed evaluation and analysis will be documented in the Draft EIR.

For more information on the proposed Delta Conveyance Project alternatives selection process, see this presentation from the July 2020 Delta Conveyance Design and Construction Authority Stakeholder Engagement Committee meeting.