B120UP.201202 (02/23/12 1243)
DEPARTMENT OF WATER RESOURCES
California Cooperative Snow Surveys
WATER SUPPLY FORECAST UPDATE
2012 April-July Unimpaired Runoff (1,000 Acre-feet)
Feb 1 %Avg Feb 14 %Avg Feb 21 %Avg
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Shasta Lake, Total Inflow average = 1806
90% Exceedance 850 47% 800 44% 750 42%
50% Exceedance 1310 73% 1250 69% 1200 66%
10% Exceedance 2130 118% 2030 112% 1950 108%
Sacramento River, above Bend Bridge (near Red Bluff) average = 2485
90% Exceedance 1110 45% 1050 42% 1020 41%
50% Exceedance 1600 64% 1510 61% 1460 59%
10% Exceedance 3150 127% 2950 119% 2840 114%
Feather River at Oroville average = 1758
90% Exceedance 500 28% 410 23% 390 22%
50% Exceedance 800 46% 670 38% 610 35%
10% Exceedance 2130 121% 1870 106% 1740 99%
Yuba River near Smartsville average = 996
90% Exceedance 280 28% 210 21% 200 20%
50% Exceedance 480 48% 390 39% 340 34%
10% Exceedance 1145 115% 1005 101% 920 92%
American River, below Folsom Lake average = 1231
90% Exceedance 320 26% 280 23% 250 20%
50% Exceedance 590 48% 490 40% 430 35%
10% Exceedance 1560 127% 1370 111% 1270 103%
Mokelumne River, Inflow to Pardee Reservoir average = 461
90% Exceedance 130 28% 110 24% 100 22%
50% Exceedance 230 50% 200 43% 180 39%
10% Exceedance 530 115% 470 102% 440 95%
Stanislaus River, below Goodwin Res. (blw New Melones) average = 699
90% Exceedance 170 24% 140 20% 120 17%
50% Exceedance 350 50% 290 41% 260 37%
10% Exceedance 780 112% 690 99% 640 92%
Tuolumne River, below La Grange Res. (blw Don Pedro) average = 1221
90% Exceedance 380 31% 340 28% 310 25%
50% Exceedance 700 57% 600 49% 540 44%
10% Exceedance 1420 116% 1240 102% 1140 93%
Merced River, below Merced Falls (blw Lake McClure) average = 636
90% Exceedance 180 28% 140 22% 130 20%
50% Exceedance 340 53% 280 44% 260 41%
10% Exceedance 810 127% 680 107% 620 97%
San Joaquin River, below Millerton Lake average = 1258
90% Exceedance 390 31% 310 25% 280 22%
50% Exceedance 750 60% 630 50% 570 45%
10% Exceedance 1490 118% 1270 101% 1150 91%
Kings River, below Pine Flat Reservoir average = 1236
90% Exceedance 360 29% 300 24% 280 23%
50% Exceedance 760 61% 650 53% 580 47%
10% Exceedance 1510 122% 1310 106% 1190 96%
Kaweah River, below Terminus Reservoir average = 290
90% Exceedance 70 24% 70 24% 70 24%
50% Exceedance 170 59% 150 52% 140 48%
10% Exceedance 410 141% 340 117% 320 110%
Tule River, below Lake Success average = 64
90% Exceedance 5 8% 4 6% 5 8%
50% Exceedance 31 49% 27 43% 25 39%
10% Exceedance 121 190% 100 157% 94 148%
Kern River, inflow to Isabella Lake average = 465
90% Exceedance 120 26% 110 24% 100 22%
50% Exceedance 270 58% 240 52% 220 47%
10% Exceedance 750 161% 620 133% 560 120%
Questions regarding this forecast:
John King: (916) 574-2637 (e-mail kingjj@water.ca.gov)
Steve Nemeth: (916) 574-2634 (e-mail nemeth@water.ca.gov)
Dave Rizzardo: (916) 574-2983 (e-mail daver@water.ca.gov)
Andy Reising: (916) 574-2181 (e-mail areising@water.ca.gov)
Runoff forecasts are unimpaired (full natural) flows which represent the
natural water production of the river basin, unaltered by upstream diversions,
storage, or export or import of water to or from other watersheds.
The median (50%) forecast assumes median conditions after the date of forecast.
Runoff exceedance levels are derived from historical data.
The 90 percent exceedance level and the 10 percent exceedance level together
comprise a range about the median forecast in which the actual runoff should
fall 8 times out of 10.
Forecasts are stated in 1,000's of acre-feet and percent of (50-year) average.
The averages are for the period 1961 to 2010.
