B120 (05/08/09 1300)
Department of Water Resources
California Cooperative Snow Surveys
May 1, 2009 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 420 64% 360 - 580
Scott River near Fort Jones 130 65%
SACRAMENTO RIVER
Sacramento River above Shasta Lake 200 67%
McCloud River above Shasta Lake 310 79%
Pit River above Shasta Lake 760 71%
Total inflow to Shasta Lake 1300 71% 1130 - 1700
Sacramento River above Bend Bridge 1750 70% 1470 - 2240
Feather River at Oroville 1140 64% 870 - 1540
Yuba River at Smartsville 750 75% 610 - 900
American River below Folsom Lake 920 74% 750 - 1120
SAN JOAQUIN RIVER
Cosumnes River at Michigan Bar 76 60% 45 - 105
Mokelumne River inflow to Pardee 370 80% 340 - 420
Stanislaus River below Goodwin Res. 580 83% 490 - 680
Tuolumne River below La Grange 1010 83% 910 - 1180
Merced River below Merced Falls 480 76% 420 - 590
San Joaquin River inflow to Millerton Lk 900 72% 750 - 1070
TULARE LAKE
Kings River below Pine Flat Res. 910 74% 810 - 1030
Kaweah River below Terminus Res. 195 68% 170 - 250
Tule River below Lake Success 25 39% 19 - 45
Kern River inflow to Lake Isabella 250 54% 210 - 320
NORTH LAHONTAN
Truckee River,Tahoe to Farad accretions 170 65%
Lake Tahoe Rise, in feet 0.8 58%
West Carson River at Woodfords 39 72%
East Carson River near Gardnerville 145 78%
West Walker River below Little Walker 125 81%
East Walker River near Bridgeport 41 64%
Water-Year Forecast and Monthly Distribution
Oct Water 80%
thru Feb Mar Apr May Jun Jul Aug Sep Year Probability
Jan Range
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Trinity, Lewiston 113 77 185 138 182 80 20 7 5 807 386 - 1328
Inflow to Shasta 915 665 1040 470 385 255 190 180 180 4280 4050 - 4810
Sacramento, Bend 1215 1035 1385 595 530 355 270 240 235 5860 5500 - 6485
Feather, Oroville 475 475 775 410 405 215 110 80 70 3015 2705 - 3470
Yuba, Smartville 205 230 380 255 310 150 35 15 10 1590 1435 - 1750
American, Folsom 185 240 455 325 385 170 40 10 10 1820 1635 - 2030
Cosumnes, Mich.Bar 18 34 77 33 33 8 2 1 0 206 170 - 240
Mokelumne, Pardee 45 40 100 105 175 80 10 2 1 558 520 - 610
Stanislaus, Gdw. 95 75 170 190 220 135 35 10 5 935 840 - 1045
Tuolumne, LaGrange 200 115 230 260 380 300 70 15 10 1580 1470 - 1760
Merced, McClure 85 60 105 150 180 115 35 10 5 745 680 - 860
San Joaquin, Mil. 155 80 140 230 310 265 95 30 15 1320 1160 - 1500
Kings, Pine Flat 130 65 110 215 360 255 80 30 15 1260 1150 - 1390
Kaweah, Terminus 39 23 33 54 80 49 12 4 2 296 260 - 360
Tule, Success 10 9 11 11 9 4 1 0 0 55 45 - 75
Kern, Isabella 70 25 40 65 90 70 25 15 10 410 360 - 490
Notes:
50 year averages are based on years 1956 to 2005.
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 at (916) 574-2637 kingjj@water.ca.gov
Steve Nemeth at (916) 574-2634 nemeth@water.ca.gov
Dave Rizzardo at (916) 574-2983 daver@water.ca.gov
Andy Reising at (916) 574-2181 areising@water.ca.gov
Adam Schneider at (916) 574-2208 aschneid@water.ca.gov
