Executive Update: Hydrologic Conditions in California

Executive Update

Hydrologic Conditions in California (10/01/2014)

Northern Sierra Precipitation Accumulation (1)
Rainfall & Snow Water Content (in inches)
 
Water Year Amount to Date (since Oct. 1, 2013): 31.34      
Average to Date: 50.00      
Percent of Average to Date: 63 %  
Average for the Water Year (Oct. 1 through Sep. 30) 50.00      
Percent of Average for the Water Year (Oct. 1 through Sep. 30) 63 %  

(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 ---                   --- (3)                   ---                  
Central Sierra ---                   --- (3)                   ---                  
Southern Sierra ---                   --- (3)                   ---                  
Statewide ---                   --- (3)                   ---                  

(2) April 1 is the date of normal maximum accumulation for the season.
(3) 'Percent Average to Date' is not calculated this early in the WY when the historical average is small.

Forecast of Regional Water Supply Indices (5)
Index Value Year Type
8 River Index for September (in 1000 AF)296.8       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%3.9       Critical
San Joaquin Valley Water Year Type Index (60-20-20) @ 50%1.2       Critical
San Joaquin Valley Water Year Type Index (60-20-20) @ 75%1.1       Critical

(4) 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 09/30/2014 midnight
Reservoir River Storage
(in 1000 AF)
Avg Storage
(in 1000 AF)
%
Average
Capacity
(in 1000 AF)
%
Capacity
Flood Control (6)
Encroachment
(in 1000 AF)
Trinity Lake Trinity 607   1,666   36   2,448   25   ---      
Shasta Lake Sacramento 1,157   2,725   42   4,552   25   -3,395      
Lake Oroville Feather 1,076   2,188   49   3,538   30   -2,275      
New Bullards Bar Res Yuba 419   593   71   970   43   -492      
Folsom Lake American 345   554   62   977   35   -632      
New Melones Res Stanislaus 520   1,343   39   2,400   22   -1,754      
Don Pedro Res Tuolumne 777   1,371   57   2,030   38   -995      
Lake McClure Merced 122   464   26   1,032   12   -731      
Millerton Lake San Joaquin 184   210   88   520   35   -336      
Pine Flat Res Kings 114   338   34   1,000   11   -886      
Isabella Kern 50   187   27   568   9   -254      
San Luis Res (Offstream) 464   955   49   2,041   23   ---      

(5) 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.

Selected Cities Precipitation Accumulation As of 09/30/2014
  Jul 1 to Date
2014 - 2014
(in inches)
%
Avg
Jul 1 to Date
2013 - 2013
(in inches)
%
Avg
% Avg
Jul 1 to Jun 30
2014 - 2015
Eureka 3.13               290       3.22               298       8                  
Redding 3.44               378       1.39               153       10                  
Sacramento 0.47               138       0.59               174       3                  
San Francisco 0.64               237       0.43               159       3                  
Fresno 0.19               100       0.01               5       2                  
Bakersfield 0.01               8       0.00               0       0                  
Los Angeles 0.19               66       0.03               10       1                  
San Diego 0.08               40       0.05               25       1                  

  

Comments
As of September 30, the end of Water Year 2014, statewide hydrologic conditions were as follows: precipitation, 55 percent of average to date; runoff, 35 percent of average to date; and reservoir storage, 60 percent of average for the date. Sacramento River Region unimpaired runoff, for Water Year 2014, observed through September 30, 2014 was about 7.5 million acre-feet (MAF), which is about 41 percent of average. In comparison to Water Year 2013, the observed Sacramento River Region unimpaired runoff through September 30, 2013 was about 12.2 MAF, or about 67 percent of average. On September 30, the Northern Sierra 8-Station Precipitation Index Water Year total was 31.3 inches, which is about 63 percent of an average water year (50.0 inches). During September, the total precipitation for the 8-Stations was 1.6 inches, or about 178 percent of average for the month. Last year on September 30, the Water Year 2013 seasonal total for the 8-Stations was 44.3 inches, or about 89 percent of average. On September 30, the San Joaquin 5-Station Precipitation Index Water Year total was 20.4 inches, which is about 50 percent of an average water year (40.8 inches). During September, the total precipitation for the 5-Stations was 0.8 inches, or about 114 percent of average for the month. Last year on September 30, the Water Year 2013 seasonal total for the 5-Stations was 26.5 inches, or about 65 percent of average. The latest National Weather Service Climate Prediction Center (CPC) long-range, 1-month precipitation outlook for October 2014, issued September 30, 2014, suggests no tendency for above or below average rainfall for much of California. The exceptions are the northern part of the State where below normal precipitation is indicated, and the southern portion of the State where above normal precipitation is indicated. 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 Monday, November 10, 2014, for conditions on November 1, unless there are significant hydrologic changes.


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