B120 (05/08/12 1330)
Department of Water Resources
California Cooperative Snow Surveys
May 1, 2012 FORECAST
OF UNIMPAIRED RUNOFF
(in thousands of acre-feet)
April-July Forecast
April Percent 80%
thru of Probability
July Average Range
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NORTH COAST
Trinity River at Lewiston Lake 720 111% 680 - 790
Scott River near Fort Jones 240 133%
SACRAMENTO RIVER
Sacramento River above Shasta Lake 310 103%
McCloud River above Shasta Lake 420 107%
Pit River above Shasta Lake 820 78%
Total inflow to Shasta Lake 1670 92% 1480 - 2070
Sacramento River above Bend Bridge 2240 90% 2010 - 2770
Feather River at Oroville 1400 80% 1210 - 1810
Yuba River at Smartsville 840 84% 730 - 990
American River below Folsom Lake 910 74% 780 - 1110
SAN JOAQUIN RIVER
Cosumnes River at Michigan Bar 100 78% 87 - 140
Mokelumne River inflow to Pardee 260 56% 230 - 310
Stanislaus River below Goodwin Res. 370 53% 330 - 500
Tuolumne River below La Grange 660 54% 590 - 830
Merced River below Merced Falls 320 50% 295 - 430
San Joaquin River inflow to Millerton Lk 680 54% 550 - 850
TULARE LAKE
Kings River below Pine Flat Res. 650 53% 550 - 770
Kaweah River below Terminus Res. 175 60% 150 - 230
Tule River below Lake Success 45 71% 36 - 67
Kern River inflow to Lake Isabella 230 49% 190 - 300
NORTH LAHONTAN
Truckee River,Tahoe to Farad accretions 150 59%
Lake Tahoe Rise, in feet 0.8 58%
West Carson River at Woodfords 29 55%
East Carson River near Gardnerville 90 48%
West Walker River below Little Walker 75 48%
East Walker River near Bridgeport 20 32%
Water-Year (WY) Forecast and Monthly Distribution
Oct Water 80% WY
thru Feb Mar Apr May Jun Jul Aug Sep Year Probability %
Jan Range Avg
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Trinity, Lewiston 116 65 190 308 240 130 42 21 15 1125 1060 - 1195 82
Inflow to Shasta 950 260 830 775 405 270 220 205 195 4110 3860 - 4580 69
Sacramento, Bend 1415 350 1190 1125 505 345 265 250 235 5680 5360 - 6330 65
Feather, Oroville 515 155 680 695 410 185 110 80 70 2900 2685 - 3350 64
Yuba, Smartville 190 55 425 465 275 75 25 15 15 1540 1420 - 1700 66
American, Folsom 205 65 440 570 270 60 10 0 5 1625 1485 - 1840 61
Cosumnes, Mich.Bar 21 7 53 75 20 4 1 0 0 181 168 - 225 47
Mokelumne, Pardee 45 15 60 140 95 20 5 0 0 380 350 - 440 51
Stanislaus, Gdw. 100 25 90 200 120 45 5 5 0 590 550 - 730 51
Tuolumne, LaGrange 115 35 105 290 240 110 20 5 0 920 850 - 1100 47
Merced, McClure 55 15 45 150 120 40 10 5 0 440 410 - 560 44
San Joaquin, Mil. 135 35 75 210 270 155 45 15 10 950 810 - 1150 52
Kings, Pine Flat 160 30 65 210 260 145 35 15 10 930 825 - 1060 54
Kaweah, Terminus 50 12 26 69 70 30 6 1 1 265 240 - 330 58
Tule, Success 21 7 12 27 13 3 2 0 0 85 76 - 110 58
Kern, Isabella 120 30 35 65 80 60 25 10 10 435 390 - 520 59
Notes:
50 year averages are based on years 1961 to 2010.
Unimpaired runoff represents the natural water production of a river basin,
unaltered by upsteam diversions, storage, or by export or import of water
to or from other watersheds.
Forecasted runoff assumes median conditions subsequent to the date of forecast.
Runoff probability ranges are statistically derived from historical data.
The 80% probability range is comprised of the 90% exceedance level value
and the 10% exceedance level value.
The actual runoff should fall within the stated limits eight times out of ten.
Forecast point names are based on USGS gage names.
For more information please contact:
John King (916) 574-2637 kingjj@water.ca.gov
Steve Nemeth (916) 574-2634 nemeth@water.ca.gov
Dave Rizzardo (916) 574-2983 daver@water.ca.gov
Andy Reising (916) 574-2181 areising@water.ca.gov
