2011 could turn out to be the second-best year ever for Lake Powell inflows
By Summit Voice
SUMMIT COUNTY — Flooding in the high country in early spring and summer may have been a nuisance for some, but in the big picture, it helped push Colorado River inflows into Lake Powell to near record levels. At times, Powell was rising at the rate of about 12 inches per day, bringing the water level up by 50 feet for the runoff season so far.
The Bureau of Reclamation reported that July inflow along totaled about 4.5 million acre feet (278 percent of average), the second-best year since Glen Canyon Dam was completed in 1963. Only 1995 was wetter, with a total inflow of 4.41 million acre feet in July. Total inflows for the runoff season, April through July, reached 12.9 million acre feet, which is 162 percent of average. June inflow was even higher, totaling 5.4 million acre feet.
Lake Powell, a key reservoir for the entire Colorado River Basin, has seen below average inflows, and the water level has been on a downward trend for about a decade, with only a few exceptions. The lowest level ever was recorded in the spring of 2005, when Powell was only at 33 percent of capacity.
Powell’s storage, which provides irrigation and municipal water in Arizona, Nevada and Southern California, provides a buffer against calls for more water from the Upper Colorado River Basin.
As of late July, the reservoir was 76 percent full, storing 18.6 million acre feet. The last time Powell was at this level was in October 2001. The Bureau of Reclamation expects that the water level in Powell will peak in early July as the inflow from the Colorado River dwindles. The outflow is currently at about 24,100 cubic feet per second, which is very near the full capacity of the Glen Canyon power plant.
Higher-than-average inflows are predicted through the rest of the summer, with a total projected inflow of 16.7 million acre feet, about 139 percent of average. That’s good news for Lake Mead, the downstream reservoir that’s critically important for Las Vegas. Lake Mead is 20 feet higher than it was last year this time, and projected to climb another 30 feet in the next 12 months with continued releases from Powell.
The last time Lake Powell was close to being completely full was in the summer of 1999, at 97 percent of capacity (18.6 million acre feet). From 2000 to 2004, inflows were well below average and storage dropped to 8 million acre feet, just 33 percent of capacity, in April 2005. Above average runoff in 2005 and 2008 brought some relief, but the Bureau of Reclamation noted that the current level in Lake Powell is still somewhat below the desired operating level for this time of year. Overall storage capacity in the Colorado River Basin as of late July was 65.9 percent of capacity.
Filed under: climate and weather, Colorado, Environment, rivers, Snow and weather, Summit County news, water Tagged: | Colorado River, Colorado River Basin, Environment, Glen Canyon Dam, Lake Powell, Lake Powell water levels, NASA, Summit County News, United States Bureau of Reclamation, water