Project Description
Delta Island Adaptations
Using SDM for Landscape-Scale Scenario Planning
Over the last 160 years, the Sacramento-San Joaquin Delta in California has been transformed from the largest wetland system on the Pacific Coast into large and highly productive agricultural tracts. Extensive wetlands were drained to support agricultural operations, resulting in significant land subsidence. Many tracts in the Delta are now experiencing elevations as low as -25 ft below sea level and are protected by perimeter levees. The risks associated with continued land subsidence include increased flooding risk due to levee breaches, which would have significant impacts on freshwater supply for Southern California, ongoing commercial agriculture, and Indigenous activities and relationships to place on the islands.
The Delta Island Adaptations project aims to make progress toward improving the resilience and sustainability of the islands owned by Metropolitan Water District of Southern California (MWD) in the Sacramento-San Joaquin Delta. The planning initiative consisted of two phases:
- Phase 1: Island Selection – a Structured Decision-Making process to select which of MWD’s four islands provides the best opportunity for island-wide, landscape-scale scenario planning;
- Phase 2: Detailed Scenario Planning – a process to develop and evaluate conceptual-level, landscape-scale, multi-adaptation scenarios for the selected island.
Compass was engaged to design and deliver a two-part SDM process to guide the selection of an island in Phase 1, and the development of landscape scenarios for the chosen island in Phase 2. Collaborating with UC Davis, HydroFocus Inc., and Environmental Science Associates (ESA), Compass worked with technical and subject matter experts to identify project objectives and develop associated evaluation criteria and to characterize the opportunities and trade-offs for four islands in Phase 1, and across landscape scenarios in Phase 2.
Finally, Compass designed and facilitated a series of technical advisory committee meetings (virtual and in-person), including exercises such as preference assessments, alternative endorsements, and expert elicitation through Compass’ Decision Support Tool Altaviz.
