Friant’s Class 1 Supply Increased To 62%
A Little More Water
Despite what is shaping up to be a drought year’s long and very hot, dry summer, the U.S. Bureau of Reclamation has been able to squeeze a little more San Joaquin River runoff into the Friant Division’s Central Valley Project Class 1 supply.
Reclamation officials on July 15 increased Friant’s Class 1 declaration to 62% of contract amounts ― a total of 496,000 acre-feet.
THIRD HIKE SINCE JUNE 5
The supply increase is the third since early June and has resulted from natural San Joaquin River flows that remained modestly higher than had been expected as runoff began to wane from much below normal snow accumulation totals this past winter.
Unimpaired natural flows, calculated as they would have occurred at Friant if there were no dams, have dropped off considerably as July has advanced. On July 14, the full natural flow was only 256 c.f.s.
Friant’s supply availability has remained far below what would be necessary for Reclamation to make available any water to Class 2 contract users. Class 2 water becomes available only when all of the 800,000 acre-feet of Class 1 (firm supply) water is available for distribution.
When June began, the Class 1 supply was set at only 45%, which would have provided 360,000 acre-feet. That was increased by Reclamation on June 5 to 50% (400,000 acre-feet) and on June 13 to 55% (440,000 acre-feet).
The increased supply is based on conservative projections and takes into account water user demands, San Joaquin River Restoration interim releases and downstream riparian demands, and natural flows.
Another consideration involves scheduled hydroelectric releases into Millerton Lake from upstream power company reservoirs which have been accelerated somewhat by Southern California Edison Company.
Reclamation officials project that Millerton Lake storage, which is now declining, will remain above its “dead storage” pool of 135,000 acre-feet when the reservoir’s storage reaches its low point. That is now projected to be in January and February.
It is not unusual for Millerton Lake to be drawn down to low levels even in bigger water years because of the reservoir’s relatively small capacity, 520,500 acre-feet. The lake behind Friant Dam has only 385,000 acre-feet of “active capacity,” below which water cannot be released into the Friant-Kern and Madera canals.
As of July 14, Millerton Lake held 393,238 acre-feet, 75% of capacity.
LITTLE RAIN AND HIGH HEAT
Meanwhile, the National Weather Service’s precipitation year came to a hot, dry conclusion on June 30 in the midst of a brutal heat wave gripping the valley and much of the West.
At press time, the string of maximum temperature days over 100 degrees F was nearing three full weeks. For a few truly miserable days, high readings soared over 110 degrees in several valley areas.
Although the state’s water year will continue through September 30, most precipitation figures are reported on a fiscal year basis. Between July 1, 2012-June 30, 2013, most valley floor weather stations within the Friant Division had less than 5 inches of rain with a number of south valley locations ending up with less than 2.5 inches. It is the second consecutive much below average water year.
Most valley locations had their driest-ever January-through-May period.
Ron Milligan, Central Valley Project Operations Office Manager, told a special July 15 meeting of the Friant Water Authority board in Visalia that it wasn’t much better in the mountains where a big snowpack that had been building from October through December was mostly melted by May 1.
The San Joaquin Five-Station Index – covering the San Joaquin and its main tributaries – averaged only 6.8 inches of precipitation in 2013’s first five months, far lower than the previous record, Milligan said
Southern San Joaquin Valley river runoff during the key April-through-July peak snowmelt period is expected to end up between about 37% on the San Joaquin River and just 11% of normal on the Tule River.