The water model behind California’s Bay-Delta plan

This SEI fact sheet describes the development and application of the Sacramento Water Allocation Model (SacWAM), a WEAP-based tool used by California’s State Water Resources Control Board to update the Bay-Delta Plan and balance water needs for 25 million people and 3 million acres of farmland with ecosystem restoration.

• The Sacramento Water Allocation Model (SacWAM) was developed by the Stockholm Environment Institute (SEI) using the Water Evaluation And Planning (WEAP) system for California’s State Water Resources Control Board. The model is designed to simulate the current operations of the Delta's complex water system as well as its 'unimpaired state', which represents water flow in the absence of infrastructure such as dams and diversions.
• SacWAM is being utilized to update the Water Quality Control Plan for the San Francisco Bay/Sacramento-San Joaquin Delta Estuary (the Bay-Delta Plan). The model helps the Board evaluate the impact of proposed policies on fisheries, water supply, and agriculture to determine how much water can be diverted from Sacramento River tributaries while maintaining enough flow to restore the ecosystem.
• The Board is using the model to assess several proposed changes to improve ecosystem health, including new flow requirements for the Sacramento River and its eastside tributaries (the Cosumnes, Calaveras, and Mokelumne rivers), as well as new requirements for cold water habitat, interior Delta flow, and Delta outflow.
• Following a 2016 peer review, SacWAM underwent improvements including the incorporation of additional climate data, modifications to groundwater representation, and an extension of the simulation period to cover September 2009 through September 2015.

APA

Stockholm Environment Institute (2019). The water model behind California’s Bay-Delta plan. https://www.sei.org/wp-content/uploads/2019/05/the-water-model-behind-the-bay-delta-plan.pdf

Chicago

Stockholm Environment Institute. The water model behind California’s Bay-Delta plan. 2019. https://www.sei.org/wp-content/uploads/2019/05/the-water-model-behind-the-bay-delta-plan.pdf.

Wikipedia

{{cite report |author=Stockholm Environment Institute |title=The water model behind California’s Bay-Delta plan |date=May 2019 |url=https://www.sei.org/wp-content/uploads/2019/05/the-water-model-behind-the-bay-delta-plan.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{stockholmenvironmentinstitute2019water, author = {{Stockholm Environment Institute}}, title = {{The water model behind California’s Bay-Delta plan}}, institution = {Stockholm Environment Institute}, year = {2019}, month = may, url = {https://www.sei.org/wp-content/uploads/2019/05/the-water-model-behind-the-bay-delta-plan.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }