Keywords:flood management, Sacramento–San Joaquin Delta
Sea level rise, large-scale flooding, and new conveyance arrangements for water exports may increase future water salinity for local agricultural production in California’s...
Sea level rise, large-scale flooding, and new conveyance arrangements for water exports may increase future water salinity for local agricultural production in California’s Sacramento–San Joaquin Delta. Increasing salinity in crop root zones often decreases crop yields and crop revenues. Salinity effects are nonlinear and vary with crop choice and other factors including drainage and residence time of irrigation water.
Here, we explore changes in agricultural production in the Delta under various combinations of water management, large-scale flooding, and future sea level rise. Water management alternatives include through-Delta water exports (current conditions), dual conveyance (through-Delta and a 6,700 Mm3 yr?1 [or 7500 cfs] capacity peripheral canal or tunnel) and the flooding of five western islands with and without peripheral exports. We employ results from previous hydrodynamic simulations of likely changes in salinity for irrigation water at points in the Delta. We connect these irrigation water salinity values into a detailed agro-economic model of Delta agriculture to estimate local crop yield and farm revenue losses.
Previous hydrodynamic modeling work shows that sea level rise is likely to increase salinity from 4% to 130% in this century, depending on the increase in sea level and location. Changes in water management under dual conveyance increase salinity mostly in the western Delta, and to a lesser extent in the north, where current salinity levels are now quite low. Because locations likely to experience the largest salinity increases already have a lower-value crop mix, the worst-case losses are less than 1% of total Delta crop revenues. This result also holds for salinity increases from permanent flooding of western islands that serve as a salinity barrier.
Our results suggest that salinity increases could have much smaller economic effects on Delta farming than other likely changes in the Delta such as the retirement of agricultural lands after large-scale flooding and habitat development. Integrating hydrodynamic, water salinity, and economic models can provide insights into controversial management issues.
Pursuant to numerous Board decisions (D-1485, D-1641, Order 2001-05), the Projects are required to release stored water to meet water quality standards in...
Pursuant to numerous Board decisions (D-1485, D-1641, Order 2001-05), the Projects are required to release stored water to meet water quality standards in the Delta (including flow and salinity standards) where natural flows are insufficient. The obligation was originally placed on the Projects as an interim measure pending future studies of how the obligation to meet water quality standards would be shared with other appropriators. In return for resolving Project protests on subsequent applications to appropriate water, Term 91 was developed and made a condition to permits issued after 1965. Term 91 prohibits diversions by these Permittees when natural and abandoned flows to the Delta are insufficient to meet the water quality standards and the Projects are supplementing such flows with previously stored water to meet the standards.
The purpose of this report is to explore the enhanced use and more vigorous enforcement of diversion curtailments as a means to achieve flow standards. This subject matter is relevant to the Delta even through the Projects are under a present and legal obligation to meet existing flows standards.
This report proposes a reconciliation approach for addressing 160 years of accumulated problems and for managing the Delta’s ecosystem in the future. Reconciliation...
This report proposes a reconciliation approach for addressing 160 years of accumulated problems and for managing the Delta’s ecosystem in the future. Reconciliation ecology seeks to improve conditions for native species while recognizing that most ecosystems have been altered irrevocably by human use and will continue to be used to support human goals. Improving ecosystem conditions for native species must, therefore, happen in a context of continuing use of land and water by humans and continuing physical and biological change.
The report focuses on the State Water Board’s responsibility to enforce water rights and to prevent unauthorized diversions of water in the state...
The report focuses on the State Water Board’s responsibility to enforce water rights and to prevent unauthorized diversions of water in the state of California.
Pursuant to the Water Code, the State Water Board is responsible for enforcing the terms and conditions of water right permits, licenses, and registrations, as well as investigating diversions of water. As addressed in the Strategic Workplan for Activities in the San Francisco Bay / Sacramento-San Joaquin Delta Estuary, the State Water Board is directed to investigate illegal diversions and violations of permit and license conditions and take action when violations are occurring in the Bay-Delta Watershed.
The report discusses how the State Water Board began an investigation of illegal diversions of water, focusing on the Delta. For instance, the State Water Board has investigated two islands in the Delta to establish whether the landowners possessed any water rights. Most did, though some individuals were subject to more review, the majority of which concerned validating riparian claims for severed parcels.
The report notes that the State Water Board has also investigated diverters within an area of the southern Delta and resolved all cases resulting from that investigation. The report also discusses how the State Water Board has begun an investigation of water diverters, statewide, who have failed to file required reports, which include the annual reports for permit and license holders, and the supplemental statements.
Finally, the report suggests a new approach of looking at districts in the Delta who serve water to individuals, in addition to looking at compliance issues related to individual diverters.