Executive Update: Hydrologic Conditions in California

Executive Update

Hydrologic Conditions in California (08/01/2014)

Northern Sierra Precipitation Accumulation (1)
Rainfall & Snow Water Content (in inches)
 
Water Year Amount to Date (since Oct. 1, 2013): 29.07      
Average to Date: 48.80      
Percent of Average to Date: 60 %  
Average for the Water Year (Oct. 1 through Sep. 30) 50.00      
Percent of Average for the Water Year (Oct. 1 through Sep. 30) 58 %  

(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 July (in 1000 AF)366       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 07/31/2014 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 865   1,954   44   2,448   35   ---      
Shasta Lake Sacramento 1,575   3,234   49   4,552   35   -2,977      
Lake Oroville Feather 1,253   2,579   49   3,538   35   -2,285      
New Bullards Bar Res Yuba 513   750   68   970   53   -453      
Folsom Lake American 406   691   59   977   42   -571      
New Melones Res Stanislaus 626   1,467   43   2,400   26   -1,794      
Don Pedro Res Tuolumne 898   1,548   58   2,030   44   -1,132      
Lake McClure Merced 212   627   34   1,032   21   -813      
Millerton Lake San Joaquin 276   327   84   520   53   -244      
Pine Flat Res Kings 140   509   28   1,000   14   -860      
Isabella Kern 59   274   22   568   10   -302      
San Luis Res (Offstream) 457   996   46   2,041   22   ---      

(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 07/31/2014
  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 0.02               10       0.00               0       0                  
Redding 0.09               90       0.00               0       0                  
Sacramento 0.01               0       0.00               0       0                  
San Francisco 0.08               0       0.00               0       0                  
Fresno 0.01               100       0.00               0       0                  
Bakersfield 0.00               0       0.00               0       0                  
Los Angeles 0.17               567       0.03               100       1                  
San Diego 0.07               233       0.05               167       1                  

  

Comments
As of July 31, 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 July 31, 2014 was about 6.9 million acre-feet (MAF), which is about 39 percent of average. In comparison to Water Year 2014, the observed Sacramento River Region unimpaired runoff through July 31, 2013 was about 11.5 MAF, or about 66 percent of average. On July 31, the Northern Sierra 8-Station Precipitation Index Water Year total was 29.1 inches, which is about 60 percent of the seasonal average to date and 58 percent of an average water year (50.0 inches). During July, the total precipitation for the 8-Stations was 0.2 inches, or about 100 percent of average for the month. Last year on July 31, the Water Year 2013 seasonal total for the 8-Stations was 44.3 inches, or about 91 percent of average. On July 31, the San Joaquin 5-Station Precipitation Index Water Year total was 19.6 inches, which is about 49 percent of the seasonal average to date and 48 percent of an average water year (40.8 inches). During July, the total precipitation for the 5-Stations was 0.4 inches, or about 133 percent of average for the month. Last year on July 31, the Water Year 2013 seasonal total for the 5-Stations was 26.2 inches, or about 66 percent of average. The latest National Weather Service Climate Prediction Center (CPC) long-range, 1-month precipitation outlook for August 2014, issued July 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 Thursday, September 11, 2014, for conditions on September 1, unless there are significant hydrologic changes.


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