The two years of really bad drought since you spoke with your friend have had an effect on his estimate. None of the major upstream reservoirs will fill this year- Flaming Gorge, Blue Mesa, and Navajo all have too much space. Some of the smaller ones may fill, but the Animas and Colorado head waters don't have as much snow as the Great Basin drainage. Even the Green doesn't have as much snow as the Wasatch front does. And the Wasatch drainage all ends up in the Great Basin, not Powell.