Under the terms of Judge Wanger's interim order to protect Delta smelt in 2008, the VAMP agreement (see below) began providing the flows required under the order to protect species on April 22, 2008. The VAMP provides flows for 31 days, until May 22, 2008. The court order specifies that the VAMP flows will meet the Delta smelt's needs during that period.
At the end of the 31 days, the order directs the U.S. Fish and Wildlife Service to resume its weekly determination of level of negative (upstream) flows needed in Old and Middle Rivers to protect the species. Judge Wanger's order suspended the FWS's weekly determination of upstream flows for the period when VAMP is providing water.
The VAMP (Vernalis Adaptive Management Plan) is an agreement by a group of water agencies to maintain targeted flows for 31 days each spring. Their water source is rivers flowing down into the east side of the San Joaquin Valley.
The purpose of VAMP is to help salmon smolt migrate downstream by providing enough water for them to get through the Delta. The agreement is capped at 110,000 acre-feet of water, but can be less, depending on weather and water conditions.
In 2007, VAMP delivered 33,330 acre-feet of water. The water is provided by the five irrigation districts: Merced, Modesto, Oakdale, Turlock, South San Joaquin plus the Exchange Contractors. This year's VAMP flows will be 3200 cfs, with exports at the pumping facilities of 1500 cfs.