Executive Update: Hydrologic Conditions in California

Executive Update

Hydrologic Conditions in California (11/01/2014)

Northern Sierra Precipitation Accumulation (1)
Rainfall & Snow Water Content (in inches)
 
Water Year Amount to Date (since Oct. 1, 2014): 2.74      
Average to Date: 3.00      
Percent of Average to Date: 91 %  
Average for the Water Year (Oct. 1 through Sep. 30) 50.00      
Percent of Average for the Water Year (Oct. 1 through Sep. 30) 5 %  

(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 October (in 1000 AF)362       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 10/31/2014 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 561   1,591   35   2,448   23   ---      
Shasta Lake Sacramento 1,109   2,674   41   4,552   24   -2,783      
Lake Oroville Feather 954   2,127   45   3,538   27   -2,209      
New Bullards Bar Res Yuba 390   541   72   970   40   -406      
Folsom Lake American 305   498   61   977   31   -419      
New Melones Res Stanislaus 513   1,340   38   2,400   21   -1,457      
Don Pedro Res Tuolumne 756   1,309   58   2,030   37   -934      
Lake McClure Merced 90   449   20   1,032   9   -584      
Millerton Lake San Joaquin 175   195   90   520   34   -260      
Pine Flat Res Kings 113   345   33   1,000   11   -646      
Isabella Kern 45   164   28   568   8   -125      
San Luis Res (Offstream) 394   1,080   36   2,041   19   ---      

(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 10/31/2014
  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 7.87               237       3.27               98       20                  
Redding 5.59               186       1.40               47       16                  
Sacramento 0.89               69       0.59               46       5                  
San Francisco 1.10               79       0.43               31       5                  
Fresno 0.19               23       0.04               5       2                  
Bakersfield 0.01               2       0.03               7       0                  
Los Angeles 0.19               22       0.05               6       1                  
San Diego 0.08               10       0.30               39       1                  

  

Comments
As of October 31, statewide hydrologic conditions were as follows: precipitation, 75 percent of average to date; runoff, 65 percent of average to date; and reservoir storage, 55 percent of average for the date. Sacramento River Region unimpaired runoff, for Water Year 2015, observed through October 31, 2014 was about 0.3 million acre-feet (MAF), which is about 68 percent of average. In comparison to Water Year 2014, the observed Sacramento River Region unimpaired runoff through October 31, 2013 was about 0.3 MAF, or about 68 percent of average. On October 31, the Northern Sierra 8-Station Precipitation Index Water Year total was 2.7 inches, which is about 90 percent of the seasonal average to date and 5 percent of an average water year (50.0 inches). During October, the total precipitation for the 8-Stations was 2.7 inches, or about 90 percent of average for the month. Last year on October 31, the Water Year 2013 seasonal total for the 8-Stations was 0.7 inches, or about 23 percent of average. On October 31, the San Joaquin 5-Station Precipitation Index Water Year total was 0.1 inches, which is about 5 percent of the seasonal average to date and 0.2 percent of an average water year (40.8 inches). During October, the total precipitation for the 5-Stations was 0.1 inches, or about 5 percent of average for the month. Last year on October 31, the Water Year 2013 seasonal total for the 5-Stations was 0.9 inches, or about 43 percent of average. The latest National Weather Service Climate Prediction Center (CPC) long-range, 1-month precipitation outlook for November 2014, issued October 31, 2014, suggests no tendency for above or below average rainfall for all of California. 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, December 10, 2014, for conditions on December 1, unless there are significant hydrologic changes.


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