Executive Update: Hydrologic Conditions in California

Executive Update

Hydrologic Conditions in California (07/01/2015)

Northern Sierra Precipitation Accumulation (1)
Rainfall & Snow Water Content (in inches)
 
Water Year Amount to Date (since Oct. 1, 2014): 35.98      
Average to Date: 48.60      
Percent of Average to Date: 74 %  
Average for the Water Year (Oct. 1 through Sep. 30) 50.00      
Percent of Average for the Water Year (Oct. 1 through Sep. 30) 72 %  

(1) Northern Sierra (Sacramento, Feather, Yuba, and American River Basins)

Snowpack Water Content
Region
Water Content
(in inches)
%
Avg to Date
%
April 1 Avg (2)
Northern Sierra 0.00                   0                   0                  
Central Sierra 0.00                   0                   0                  
Southern Sierra 0.00                   0                   0                  
Statewide 0.00                   0                   0                  

(2) April 1 is the date of normal maximum accumulation for the season.

Forecast of Regional Water Supply Indices (3)
Index Value Year Type
8 River Index for June (in 1000 AF)547.2       n/a
Sacramento Valley Water Year Type Index (40-30-30) @ 50%4.0       Critical
Sacramento Valley Water Year Type Index (40-30-30) @ 90%3.8       Critical
San Joaquin Valley Water Year Type Index (60-20-20) @ 50%0.7       Critical
San Joaquin Valley Water Year Type Index (60-20-20) @ 75%0.7       Critical

(3) For more information see Sacramento & San Joaquin Valley Water Year Type Index forecast: Latest | Previous
    (Issued monthly from December 1 through May 1)

Key Reservoir Storage As of 06/30/2015 midnight
Reservoir River Storage
(in 1000 AF)
Avg Storage
(in 1000 AF)
%
Average
Capacity
(in 1000 AF)
%
Capacity
Flood Control (4)
Encroachment
(in 1000 AF)
Trinity Lake Trinity 930   2,086   45   2,448   38   ---      
Shasta Lake Sacramento 2,198   3,650   60   4,552   48   -2,354      
Lake Oroville Feather 1,395   2,887   48   3,538   39   -2,143      
New Bullards Bar Res Yuba 515   830   62   930   55   -451      
Folsom Lake American 438   810   54   977   45   -539      
New Melones Res Stanislaus 401   1,532   26   2,400   17   -2,019      
Don Pedro Res Tuolumne 756   1,618   47   2,030   37   -1,274      
Lake McClure Merced 130   732   18   1,025   13   -882      
Millerton Lake San Joaquin 179   416   43   520   34   -342      
Pine Flat Res Kings 266   691   39   1,000   27   -734      
Isabella Kern 36   313   12   568   6   -325      
San Luis Res (Offstream) 813   1,293   63   2,041   40   ---      

(4) Temporary encroachment into seasonally reserved flood storage space; requirements can vary considerably on a daily basis due to numerous variables: rainfall amounts, anticipated snowmelt, time of year, soil moisture, etc.

Daily Precipitation (in inches) for Selected Stations as of 07/01/2015

Station
Oct 1 to Date
2014 - 2015
%
Average
Season to Date
2013 - 2014
%
Average
% Average
Oct 1 - Sep 30
Mount Shasta33.718012.062977
Eureka29.947617.234474
Redding23.086816.124867
South Lake Tahoe12.876813.177063
Sacramento Executive Airport15.43858.924983
Santa Rosa (Sonoma Co AP)22.276213.703861
San Francisco17.557511.965174
Stockton10.66777.005176
Yosemite16.294416.604543
Monterey14.51918.325290
Paso Robles8.39674.913966
Fresno6.43574.914356
Bakersfield5.29832.413882
Death Valley1.05541.025244
Los Angeles8.40575.743956
Riverside4.83401.871639
Palm Springs2.19460.921938
San Diego8.78874.904885
Comments
As of June 30, statewide hydrologic conditions were as follows: precipitation, 70 percent of average to date; runoff, 45 percent of average to date; snow water content, 0 percent of average to date (0 percent of the April 1 average); and reservoir storage, 55 percent of average for the date. Sacramento River Region unimpaired runoff, for Water Year 2015, observed through June 30, 2015 was about 8.4 million acre-feet (MAF), which is about 50 percent of average. In comparison to Water Year 2014, the observed Sacramento River Region unimpaired runoff through June 30, 2014 was about 6.6 MAF, or about 39 percent of average. On June 30, the Northern Sierra 8-Station Precipitation Index Water Year total was 36.0 inches, which is about 74 percent of the seasonal average to date and 72 percent of an average water year (50.0 inches). During June, the total precipitation for the 8-Stations was 0.8 inches, or about 80 percent of average for the month. Last year on June 30, the Water Year 2014 seasonal total for the 8-Stations was 28.9 inches, or about 59 percent of average. On June 30, the San Joaquin 5-Station Precipitation Index Water Year total was 17.7 inches, which is about 45 percent of the seasonal average to date and 43 percent of an average water year (40.8 inches). During June, the total precipitation for the 5-Stations was 0.3 inches, or about 50 percent of average for the month. Last year on June 30, the Water Year 2014 seasonal total for the 5-Stations was 19.2 inches, or about 48 percent of average. The latest National Weather Service Climate Prediction Center (CPC) long-range, 1-month precipitation outlook for July 2015, issued June 30, 2015, suggests equal chances of wet or dry conditions for most of California, except for the eastern third portion of the State where above average precipitation is suggested. Updates to the Executive Summary will generally be issued approximately weekly, biweekly, or monthly (depending on conditions) through the wet months of winter and spring. Beginning about June 1, this product is updated monthly through the dry seasons of summer and fall. The next update of this product will be issued about Wednesday, August 12, 2015, for conditions on August 1, unless there are significant hydrologic changes.


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