Cooler weather prompts lower water outflows
May 18, 2017
The cooler-than-normal May weather may have provided some relief — and maybe a few prayers — as agencies continue to monitor the melting snowpack in the Sierra Nevada and the flow in area rivers.
Rusty Jardine, general manager of the Truckee Carson Irrigation District, said the weather forecast issued earlier this week, prompted agencies to reduce the flow (cubic feet per second) in the Carson River below Lahontan Dam.
"In looking at the forecast, we thought it was appropriate to ramp down," Jardine said. "We need to balance the flood operation with the irrigation operations."
According to information released from the county's Emergency Operations Center, "The reduction will be approximately 300 cfs. It began on May 17 and will continue until June 1 when another evaluation will be made. Due to the saturation along the Carson River corridor, it is uncertain if the reduction of flows will be immediately apparent. It will take time to drain back areas where water has migrated over the past months."
A change in weather patterns or a significant warming trend, however, could alter flood mitigation in the Lahontan Valley. Although the long-range forecast models plan for runoff and flow increases, Jardine said local, state and federal agencies are also prepared for the unexpected.
"We have plenty of areas where excess water can go," he said. "If we encounter increased flow into the reservoir, then we need to release more water below Lahontan."
Jardine said the weir and spillway off the V-line canal can channel thousands of acre-feet of water down the valley and across U.S. Highway 95 about 12 miles south of Fallon. From there the water travels to Carson Lake and to Stillwater National Wildlife refuge and the Carson Sink in a 60-foot wide, 15-foot channel called the "Big Dig."
The National Weather Service in Reno expects the Carson River to peak at Fort Churchill at 5,000 cfs, the same gauge measurement recorded on May 8.
The EOC said about 567,000 acre-feet of water has entered Lahontan Reservoir this season and of that amount, 361,000 acre-feet has passed into the river and canals to mitigate flood potential.
Silver Springs residents who live near the Carson River east of Fort Churchill have mentioned on their Facebook pages that the river has flooded some roads. Jardine said some Churchill County residents who live near the river have reported minor flooding.
"The message is we're not out of the woods yet," Jardine said. "People should continue to protect their property."