Executive Update: Hydrologic Conditions in California

Executive Update

Hydrologic Conditions in California (11/01/2016)

Northern Sierra Precipitation Accumulation (1)
Rainfall & Snow Water Content (in inches)
 
Water Year Amount to Date (since Oct. 1, 2016): 12.57      
Average to Date: 3.20      
Percent of Average to Date: 393 %  
Average for the Water Year (Oct. 1 through Sep. 30) 50.00      
Percent of Average for the Water Year (Oct. 1 through Sep. 30) 25 %  

(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)1,168.7       n/a
Sacramento Valley Water Year Type Index (40-30-30) @ 50%7.1       Below Normal
Sacramento Valley Water Year Type Index (40-30-30) @ 90%6.8       Below Normal
San Joaquin Valley Water Year Type Index (60-20-20) @ 50%2.5       Dry
San Joaquin Valley Water Year Type Index (60-20-20) @ 75%2.4       Dry

(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 11/01/2016 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 1,038   1,591   65   2,448   42   ---      
Shasta Lake Sacramento 2,784   2,675   104   4,552   61   -1,086      
Lake Oroville Feather 1,563   2,128   73   3,538   44   -1,437      
New Bullards Bar Res Yuba 651   541   121   966   67   -145      
Folsom Lake American 361   497   73   977   37   -354      
New Melones Res Stanislaus 509   1,340   38   2,400   21   -1,461      
Don Pedro Res Tuolumne 1,328   1,309   101   2,030   65   -362      
Lake McClure Merced 381   449   85   1,025   37   -294      
Millerton Lake San Joaquin 210   196   107   520   40   -184      
Pine Flat Res Kings 188   346   54   1,000   19   -666      
Isabella Kern 90   164   55   568   16   -80      
San Luis Res (Offstream) 599   1,085   55   2,041   29   ---      

(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.

Daily Precipitation (in inches) for Selected Stations as of 11/01/2016

Station
Oct 1 to Date
2016 - 2016
%
Average
Season to Date
2015 - 2016
%
Average
% Average
Oct 1 - Sep 30
Mount Shasta11.845170.522327
Eureka9.564271.205424
Redding6.222960.271318
South Lake Tahoe7.304061.277136
Sacramento Executive Airport4.644880.121325
Santa Rosa (Sonoma Co AP)5.162540.07314
San Francisco2.352100.00010
Stockton2.322830.212617
Yosemite6.583273.2116017
Monterey2.823030.141517
Paso Robles1.342160.061010
Fresno0.671060.49786
Bakersfield0.24800.14474
Death Valley0.03431.081,5431
Los Angeles0.51770.45683
Riverside0.863070.16577
Palm Springs0.07160.13301
San Diego0.0350.43750
Updated Information and Data
Daily Drought Information Summary
Daily Statewide Hydrologic Update(Interactive)
Weekly Update to Unimpaired Runoff Forecast (Feb - Jun)
Unimpaired Forecast Discussion (Weekly/Monthly, Dec - June)
Bulletin 120, Water Conditions in California (Monthly, Feb - May)
Water Supply Indices Forecast (Monthly, Dec - May)
Comments
 
Statewide Hydrologic Conditions (As of October 31)
As of October 31, statewide hydrologic conditions were as follows: precipitation, 305 percent of average to date; runoff, 255 percent of average to date; and reservoir storage, 85 percent of average for the date.
 
Sacramento River Unimpaired Runoff
Sacramento River Region unimpaired runoff, for Water Year 2017, observed through October 31, 2016 was about 0.9 million acre-feet (MAF), which is about 188 percent of average. In comparison to Water Year 2016, the observed Sacramento River Region unimpaired runoff through October 31, 2015 was about 0.3 MAF, or about 63 percent of average.
 
Northern Sierra 8-Station Precipitation Index
On October 31, the Northern Sierra 8-Station Precipitation Index Water Year total was 12.6 inches, which is about 420 percent of the seasonal average to date and 25 percent of an average water year (50.0 inches). During October, the total precipitation for the 8-Stations was also 12.6 inches, or about 420 percent of average for the month. Last year on October 31, the Water Year 2016 seasonal total for the 8-Stations was 1.2 inches, or about 40 percent of average.
 
San Joaquin 5-Station Precipitation Index
On October 31, the San Joaquin 5-Station Precipitation Index Water Year total was 6.4 inches, which is about 305 percent of the seasonal average to date and 16 percent of an average water year (40.8 inches). During October, the total precipitation for the 5-Stations was also 6.4 inches, or about 305 percent of average for the month. Last year on October 31, the Water Year 2016 seasonal total for the 5-Stations was 1.9 inches, or about 90 percent of average.
 
Tulare Basin 6-Station Precipitation Index
On October 31, the Tulare Basin 6-Station Precipitation Index Water Year total was 1.6 inches, which is about 133 percent of the seasonal average to date and 5 percent of an average water year (29.3 inches). During October, the total precipitation for the 6-Stations was also 1.6 inches, or about 133 percent of average for the month. Last year on October 31, the Water Year 2016 seasonal total for the 6-Stations was 1.5 inches, or about 125 percent of average.
 
Long-Range Weather Forecast
The latest National Weather Service Climate Prediction Center (CPC) long-range, 1-month precipitation outlook for December 2016, issued November 17, 2016, suggests average precipitation for all of California.
 
Next Update
Updates to the Executive Summary will generally be issued 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, December 15, 2016, for conditions on November 30, unless there are significant hydrologic changes.

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