This Technical Report supplements the Sacramento and San Joaquin Basins Study Report (Summary Report) by providing greater detail on the technical approach employed in this analysis, including assumptions, methodologies and results not included in this Report. See the Summary Report for a discussion of the Basin Study program context (Section 1), basin settings (Section 2), and historic and projected climate (Section 2). Figure P-1 shows the geographic area included in the study.
The Central Valley and regions that depend on the Sierra Nevada and Coast Range mountains for water have been facing rising demands for water from rapidly increasing populations, changes in land use, and growing urban, agricultural and environmental demands. These demands already exceed the capacity of the existing water management system to supply adequate water—especially in droughts like the one California is now experiencing. Future climate changes are likely to increase the challenges that have already occurred in the 20th century. This Basins Study builds on previous climate impact assessments and addresses both the potential impacts of climate and socioeconomic changes and explores how these challenges might be addressed (see Section 1. Introduction of the Summary Report).