B120UP (05/10/12 1146)
DEPARTMENT OF WATER RESOURCES
California Cooperative Snow Surveys
WATER SUPPLY FORECAST UPDATE
2012 April-July Unimpaired Runoff (1,000 Acre-feet)
May 1 %Avg May 8 %Avg
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Shasta Lake, Total Inflow average = 1806
90% Exceedance 1480 82% 1520 84%
50% Exceedance 1670 92% 1700 94%
10% Exceedance 2070 115% 2060 114%
Sacramento River, above Bend Bridge (near Red Bluff) average = 2485
90% Exceedance 2010 81% 2060 83%
50% Exceedance 2240 90% 2270 91%
10% Exceedance 2770 111% 2750 111%
Feather River at Oroville average = 1758
90% Exceedance 1210 69% 1200 68%
50% Exceedance 1400 80% 1370 78%
10% Exceedance 1810 103% 1730 98%
Yuba River near Smartsville average = 996
90% Exceedance 730 73% 730 73%
50% Exceedance 840 84% 820 82%
10% Exceedance 990 99% 960 96%
American River, below Folsom Lake average = 1231
90% Exceedance 780 63% 790 64%
50% Exceedance 910 74% 900 73%
10% Exceedance 1110 90% 1080 88%
Mokelumne River, Inflow to Pardee Reservoir average = 461
90% Exceedance 230 50% 230 50%
50% Exceedance 260 56% 260 56%
10% Exceedance 310 67% 310 67%
Stanislaus River, below Goodwin Res. (blw New Melones) average = 699
90% Exceedance 330 47% 330 47%
50% Exceedance 370 53% 360 52%
10% Exceedance 500 72% 480 69%
Tuolumne River, below La Grange Res. (blw Don Pedro) average = 1221
90% Exceedance 590 48% 590 48%
50% Exceedance 660 54% 650 53%
10% Exceedance 830 68% 800 66%
Merced River, below Merced Falls (blw Lake McClure) average = 636
90% Exceedance 295 46% 295 46%
50% Exceedance 320 50% 310 49%
10% Exceedance 430 68% 400 63%
San Joaquin River, below Millerton Lake average = 1258
90% Exceedance 550 44% 550 44%
50% Exceedance 680 54% 660 52%
10% Exceedance 850 68% 810 64%
Kings River, below Pine Flat Reservoir average = 1236
90% Exceedance 550 44% 550 44%
50% Exceedance 650 53% 640 52%
10% Exceedance 770 62% 740 60%
Kaweah River, below Terminus Reservoir average = 290
90% Exceedance 150 52% 145 50%
50% Exceedance 175 60% 170 59%
10% Exceedance 230 79% 220 76%
Tule River, below Lake Success average = 64
90% Exceedance 36 57% 39 61%
50% Exceedance 45 71% 45 71%
10% Exceedance 67 105% 64 101%
Kern River, inflow to Isabella Lake average = 465
90% Exceedance 190 41% 180 39%
50% Exceedance 230 49% 220 47%
10% Exceedance 300 65% 280 60%
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.
