Prospects For Warm Rain Atop MassiveSierra Snowpack Raise Kings River Concerns
March 7, 2023
F O R I M M E D I A T E R E L E A S E
For More Information, Please Contact:
STEVE HAUGEN, Kings River Watermaster, (559) 217-5249
RANDY McFARLAND, Public Information Consultant, (559) 260-2775
PREDICTIONS FOR AN ATMOSPHERIC RIVER event Thursday through Saturday that is likely to unleash tropically-spawned warm rain atop the huge Sierra Nevada snowpack up to above the 8,000-feet level are causing concerns among the Kings River Water Association and other agencies. Their biggest and most immediate uneasiness, however, isn’t with potential valley-bound high Sierra water surges but with foothill streams over which there is no way to regulate high flows entering the Kings River’s valley reaches.
Although predictions of potential rainfall timing and intensity are still preliminary, Kings River Watermaster Steve Haugen said today that KRWA and other river agencies, including the U.S. Army Corps of Engineers, are busy with projecting what sort of runoff and potential flooding with which they may have to deal.
The federal agency most concerned with flood management — the U.S. Army Corps of Engineers — is already acting. Fairly small flood releases were started by the Corps last month from Pine Flat Dam in response to earlier repeated major snowfall events. Those discharges have been increased. At noon Monday, the Corps boosted the flood release from Pine Flat. Another flood release increase was scheduled at midnight last night. A third is to take place at 12 noon today with an objective of boosting the downstream Kings River flow at Crescent Weir south of Riverdale from 1,500 cubic feet per second to 3,000 c.f.s. Water releases from Pine Flat Dam over the next few days are likely to increase up to about 5,200 c.f.s. Many districts and canal companies are diverting river flows for much-needed groundwater recharge. However, property owners and residents need to monitor nearby river water levels and be alert for any flooding warnings.
Haugen said Pine Flat Reservoir and upstream power company reservoirs have more than 600,000 acre-feet of available capacity. Pine Flat has 558,000 acre-feet of water stored.
“Mill Creek and the other foothill streams that enter the river downstream from Pine Flat Dam are our biggest concern right now,” Haugen said. “There is no way to control or store the flows in those streams.” Advance forecasts suggest that the peak flows in the largest such stream, Mill Creek, may produce a range from 4,500-14,500 c.f.s. Mill Creek, which carries only a trickle for much of most years, has recently carried flows of a few hundred c.f.s. Releases from Pine Flat would be limited to minimal fish flows if very high unstorable downstream flows occur.
Forecasters indicate the greatest amount of rainfall from the coming storm is likely to hit Friday and Friday night, possibly preceded and followed by lighter amounts.
The KRWA and its 28 member irrigation agencies that serve more than one million acres on the valley floor have been working with the Corps of Engineers for the past two months on longer-range plans for handling what was already expected to be a big snowmelt runoff year. A March 1 report based upon snow surveys measured from aircraft indicated the Kings River snowpack on the ground contained a water equivalent of 2,808,000 acre-feet. More snow has since accumulated over the watershed with some to low elevations.
Snowpack totals registered for the March 1 Kings River watershed on-the-ground California Cooperative Snow Survey show snow depths averaging 152.8 inches, 234% of the historical record average for March 1. Average snowpack water content of 53.7 inches was measured; that is 238 percent of the historical average. Both average readings are far greater than those of historical April 1 average. April 1 is the date upon which Sierra snow accumulations typically reach the season’s maximum.
The deepest snow depth measured was 196.5 inches at Rattlesnake Creek, a snow course at the 9,900 foot elevation. The snowpack at Rattlesnake Creek and Rowell Meadow (elevation 8,850 feet) each had 66 inches of water content, the most found among the 17 courses measured.
Meanwhile, along the Kings River, sheriff’s departments and other emergency officials in Fresno, Kings and Tulare counties are preparing as best they can for emergency situations that may arise. The Kings River Conservation District, which manages and maintains Kings River flood control and protection downstream from south of Kingsburg to near Stratford on the South Fork and McMullen Grade on the North Fork system, has its levees and facilities in top condition.