Drought threatens Lake Tahoe Cave Rock water system
Wave action is damaging pipes for Douglas County’s Lake Tahoe Cave Rock water system that are above the surface, thanks to the drought.
Lake residents get their water from the Lake, once famed for its clarity.
But with the surface continuing to drop, Douglas is looking at means to ensure the water keeps flowing.
County Engineer Nick Charles told Douglas County commissioners at a workshop on Thursday that the Lake level was about 4 inches from activating a Stage 2 drought.
According to the U.S. Geological Survey the Lake level on Friday was 6,221.84. The activation level is 6,221.5 feet.
While the pipeline has risen above the surface in places, the intake for Cave Rock is still below the surface by 17 feet.
Charles presented a plan that would install a booster pump at Cave Rock’s furthest intake. He said that if the drought continued, the booster pump could be in place by Memorial Day. If Tahoe has a good winter, the $48,953 spent on engineering the booster on Cave Rock’s water system would be available when it’s needed.
Construction on the system would cost $212,000. Charles said analysis of what that would do to the rates is still under way.
Charles said about 100 feet of the 10-inch intake pipe would also be replaced, due to the wave action.
However, even an average winter at Lake Tahoe is unlikely to help the water system much.
“We would have the plans done in February or March, and then make a determination to see if we can make it another year,” he said. “We would want to be done before Memorial Day when we see the tourist crowds. If we have a great year, we have plans on the shelf we can use.”
Charles said that projections based on an average winter would bring the Lake below its historical minimum by November 2016.
A wet May, June and July brought the Lake up to its natural rim briefly, and got the county water systems through the summer.
“When we met in May it was raining like crazy,” he said. “It really pushed this out and bought us some time.”
Charles said the four years of drought, which is so far equivalent to the one in the early 1990s, has skewed the averages for the area.
If implemented, the Lake level would have to drop another 15 feet before it would affect Cave Rock’s water intake.
Lake Tahoe received 62 percent of its average precipitation during the 2014-15 water year. The Carson River basin received 77 percent of average, thanks to the wet spring. Minden posted 82 percent or 7.29 inches for the water year. Ebbetts Pass at the top of the Carson River’s East Fork only saw 64 percent of average precipitation during the water year, that ended Sept. 30.