On April 6, 2015, the California State Water Resources Control Board (SWRCB) issued an order modifying its earlier orders from February 3 and March 5 concerning operations of the State Water Project (SWP) and Central Valley Project (CVP) in the Sacramento-San Joaquin River Delta (Delta). Those orders were the result of a petition by the California Department of Water Resources and U.S. Bureau of Reclamation for a temporary, urgency change to SWP and CVP withdrawals of water in the southern Delta in response to the current drought. The SWRCB’s action applies to joint project operations between March 25 and June 30, 2015. Later operational changes will be addressed by future SWRCB action.
The primary changes to SWP and CVP operations in the latest order are: increasing authorized diversions, by reducing minimum daily Delta outflow requirements at Collinsville from 7,100 cfs to 4,000 cfs; allowing the gates at the Delta Cross Channel to remain open under certain circumstances; reducing the minimum San Joaquin River outflows at Vernalis from 710-1,140 cfs (depending on hydrologic conditions) to 500 cfs; and changing the timing of Vernalis pulse flows from April 15-May 15 to March 25-April 25. The SWRCB denied a request to increase the maximum export rate from the southern Delta, due to concerns that releases from New Melones Reservoir would not leave sufficient water in storage to protect fish and wildlife on the Stanislaus River.
The SWRCB concluded that the authorized changes in SWP and CVP operations strike a reasonable balance between fish and wildlife protection and best serving other needs for water diversions for municipal and agricultural purposes. It is clear heading into the 2015 dry season that the projects will be under extreme stress, as will all water users relying on the Sacramento and San Joaquin Rivers.