2012 headed for 3d-driest year on record
By Summit Voice
SUMMIT COUNTY — In a blunt reminder of the severity of this year’s drought, the Colorado River for the second month in a row delivered less than 15 percent of its average flows to Lake Powell.
Water managers are now forecasting a total inflow for water year 2012 of about 5.15 million acre feet, which is less than half (48 percent) of average. That would make it the third-driest year on record, but still much wetter than 2002, when total inflow was only 2.64 million acre feet (24 percent of average).
The water level in the key reservoir — which helps balance competing demands from the upper basin and lower basin states — has dropped fast, to 24 feet below the maximum 2011 level.
The U.S. Bureau of Reclamation is reporting that July inflow was about 154,000 acre feet, with almost 900,000 acre feet released downstream. At the end of July, Lake Powell was at 60.4 percent of capacity, storing about 14.7 million acre feet. Read the full report on the Bureau’s Upper Colorado/Lake Powell web page.
For April through July, the peak of the runoff season, inflow was just a little more than 2 million acre feet, which is about 20 percent of average. The four-month season was the third-driest on record, behind 1977 and 2002.
For July through September, water managers expect inflow to be about 40 to 68 percent of average, for a total inflow of abaout 800,000 acre feet during the three-month period, based on averages dating back to 1981.
The currently projected water year unregulated inflow volume of 5.15 maf would rank as the 3rd driest year on record since the closure of Glen Canyon Dam (1963).
Following an extended drought in the early 2000s, water conditions in the Upper Colorado River Basin have been close to average since 2005, with annual inflows averaging 10.98 million acre feet per year (about 101 percent of average).
Overall storage in the Colorado River Basin has dropped from about 65 percent at the start of the current water year (Oct. 1, 2011) to 59 percent of capacity as of Aug. 9.