2010 Lake Powell Water Level Forecast – Part 1 April

It appears that Lake Powell has bottomed out for the year at 3618 feet above sea level putting the lake 82 feet below full pool of 3700 feet above sea level.

This is been a wet year for Southern Utah however the water in the Colorado River comes from the Colorado River Basin and their snowfall has been below normal, of the 30 year average.

As of April 9, 2010 snowfall in the Upper Coloroado River Basin is 88% of normal. A 24 month study completed in April, which is probably the most reliable data, suggests that Lake Powell will peak out at 3631 feet above sea level bringing the lake to 69 feet below full pool.

This translates to an inflow of @ 5 million acre feet (maf) of water. One maf is 325,826 gallons and is roughly enough for a family of 4 or 5 for a year. The 1922 Colorado River Compact requires that Lake Powell (storage facility for the upper states of UT, CO, NM and WY) release 8.23 maf of water to the lower states of AZ, NV, CA and Mexico. This means we are looking at a 3.23 maf shortage in Lake Powell for the coming year.

Lake Powell usually peaks out around the first week of July, which is when we should hit the 3631 mark. From there the lake slowly draws down until the next spring runoff beings, usually around the end of April.

Below is a graph from the Bureau of Reclamation showing project inflows to Lake Powell. The best case scenario is we would peak about above 3645 however, more likely is the projection of just above 3630. Runoff depends on spring moisture as well as temperatures. A slow warming spring with not much moisture leads to less runoff, as the water has time to sink into the ground. Quickly warming temps usually indicate fast melting snow with not much time to absorb into the ground.