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Upper Colorado Mainstem: Lake Powell. CRFS March 30, 2010. Lake Powell. 65%. 85%. 85%. 95%. 110%. 3650/78%. 1730/55%. ESP GUIDANCE March 1 March 29 no qpf – qpf Green R. 1782 1522 – 1587 Colorado R. 3475 3177 – 3235
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Upper Colorado Mainstem:Lake Powell CRFS March 30, 2010
Lake Powell 65% 85% 85% 95% 110%
3650/78% 1730/55% ESP GUIDANCE March 1 March 29 no qpf – qpf Green R. 1782 1522 – 1587 Colorado R. 3475 3177 – 3235 San Juan R. 972 831 – 824 1150/93% • Average contribution to Lake Powell Apr-Jul inflow: • Green River-Green River, UT 34% • Colorado River-Cicso, UT 50% • San Juan River-Bluff, UT 13%
March 1 March 15 March 29 NWS-SWS: 5425 NWS-ESP: 51154910 4480 NRCS daily: 510251704930 NRCS statistical: 54404550-4950 Coordinated: 5400/68% 5300/67% Model Guidance & Forecast
Lake Powell Probability of Equalization Forecast CBRFC uses ESP to create a forecast probability distribution of regulated (observed) inflow volumes for the rest of the water year (Oct - Sep): Water Supply forecasts are for unregulated volumes; this is what would be observed if there were no upstream reservoirs and diversions. ESP knows how the reservoirs and diversions operated in past years and uses this information and reservoir rule curves to make (rough) assumptions about how they will operate in the future based on the forecast flows/volumes. USBR provides the threshold observed inflow volume for the rest of the water year that would trigger equalization from the latest 24-month study. CBRFC plugs that threshold value into the forecast probability distribution to determine the probability of equalization.
After October the water year to date observed volume is include in all numbers This is the forecast of the chance that Lake Powell will reach the equalization level by the end of the water year – not the chance that equalization will be triggered.