Folsom Lake was at 26 percent of capacity as of Nov. 19. And it’s shrinking. The South Fork of the American River below Salmon Falls Bridge looks more like a creek or a canal. The 400-500 cubic feet of water flowing into Folsom Lake from the North and South forks is only because of releases from the Sacramento Municipal Utility District’s “Stairway of Power” series of dams. Without that it would be like the 1950s when in the late summer and early fall people could walk or wade across the South Fork.
We understand that water needed to be released for the fall salmon run. The trouble was the U.S Bureau of Reclamation incompetently managed the water it had from last season. It reserved excess space for flood control, by letting out too much water early in the rain season. The 2012-13 rain year was a low water precipitation year at 33.12 inches recorded in Placerville, following 29.51 inches in 2011-12.
Last year was not a dry year, just a below-average precipitation year. The average over 139 years is 39.57 inches.
Folsom Lake is now the lowest reservoir in the federal Central Valley system. It is nice that people can tour the ruins of old dams, old canals, old bridges and the site of the old town of Salmon Falls. Interesting views, but we’d prefer water.
Folsom is the only reservoir reduced to such a pathetic level. With nearly a million acre-foot capacity, in mid-November Folsom Lake had only 251,300 acre-feet.
Other federally operated reservoirs were at more normal levels for this time of years: 42 percent of capacity for New Melones, 49 percent for Trinity, 48 percent for Millerton. Shasta was at 37 percent of capacity, but it has started rising; Folsom has not.
Among state reservoirs the only one as low as Folsom is San Luis Rey in Merced County, but it is mainly a rain-fed reservoir depending on a drainage area that comes from San Benito and Santa Clara counties.
Though we are baffled why the 1-million acre-foot Pine Flat Reservoir in the Sierra foothills east of Fresno is at 17 percent.
The latest report from NASA is that when high pressure systems set up over the Arctic they provide a funnel for atmospheric rivers that will bring heavy rain to California. They can also send more than the usual amount of rain to Great Britain. This information gleaned from new satellites has extended forecasting ability to two weeks, with the possibility of even longer-range forecasts in the future.
The USBR should tune into this new forecasting and its associated technology to better calibrate reservoir levels during the rainy season.