Back in February, when the rainfall for the entire season was less than four inches, there was not a water-watcher in Kaweah Country who could have imagined that three months later Lake Kaweah would be full to the brim. “Full” at Lake Kaweah means an elevation of 715 feet above mean sea level and a capacity storage of more than 185,000 acre feet.
Since the basin was enlarged in 2004, the lake has only been full once. That was in 2006 when the basin was so full the water breached the spillway.
Phil Deffenbaugh, general manager at Lake Kaweah, said that full-to-the-brim level could be reached this year as soon as May 11 or 12.
As of Thursday, May 3, the lake elevation reached 704.14 feet. Storage has eclipsed 162,937 acre feet and is steadily on the rise. The current mean inflow to the reservoir is 1,297 cubic feet per second; outflow is 317 cfs.
Dam tenders could actually release less and fill the basin sooner. But downstream users can better use and store more water if the flows are less over a longer period of time.
Deffenbaugh said all that incoming water is remarkable and underscores how much is unknown about high-elevation snowpack/snowmelt and how it makes its way down the Kaweah drainages.
“The basin never came close to filling in 2017 and that was in a 200 percent water year,” Deffenbaugh said. “But there was a large pool for a longer period. On June 28, 2017, the storage was still 172,443 acre feet, quite a bit more than is currently in the pool.”
There have been other exceptional years since 2004 — when the basin’s storage was enlarged from 145,000 acre feet to its current 185,000 acre feet. In fact, Deffenbaugh said, one year the lake level came within a few inches from the top of the spillway.
So what happens to the basin when it’s brimming with water? Most noticeable is a lack of shoreline and the reduced recreational facilities. The Horse Creek Campground is already closed to vehicles but limited boat-in and walk-in sites are still available.
“We were all set to open the disk golf course but now it is underwater,” Deffenbaugh said. “The lake will remain full or close to full for Memorial Day weekend.”
It all comes down to how the snow melts and the demand down below, Deffenbaugh said.
“The full basin is expected to only last a few weeks,” Deffenbaugh said. “Stay safe, and don’t forget to wear your life jacket.”