The Service has determined that the following recommendation will be protective of delta smelt. The projects will implement a 7-day average OMR target of -2,000 cfs, and to maintain the flap gates on the agricultural barriers in the open position.
These actions are needed to protect delta smelt for the following reasons:
1. Delta water temperatures are about 22 degrees C (three station average of Mossdale, Rio Vista and Antioch) which is above the range of peak delta smelt spawning, which is 12-18 degrees C. Most spawning has likely concluded, although a recent Spring Kodiak trawls caught pre-spawned delta smelt, meaning further spawning is possible. Temperatures in the delta remain below the lethal temperature of 25 degrees C.
2. Delta smelt caught at the salvage facilities have increased over the past week. Expanded salvage at the CVP was 24 on 5/12, 3 on 5/14, 4 on 5/15 and 72 on 5/18 and 60 on 5/19. Expanded salvage at the SWP was 10 on 5/15, 40 on 5/16 and 8 on 5/17. The total delta smelt salvage for the past week was 161 and a total of 578 delta smelt have been salvaged this year.
3. Delta smelt were found in the most recent 20 mm survey (Survey 5, May 12 to May 16) in the central Delta. Delta smelt were found in the Sacramento ship channel at station 719 as well in the central Delta at stations 809, 901, 902, 906, and 914. Smelt continue to be within the influence of the pumps in the central and south Delta.
This action is needed to help reduce delta smelt entrainment in the south Delta and to reduce risks as water temperatures are increasing in the south Delta.