Even though there’s still plenty of snow in the Sierra and plenty of warm weather ahead, the California Department of Water Resources says it believes the annual snowmelt has peaked and should now decline. The observation came after a week in which landowners in some low-lying areas coped with flooding that resulted from a record-setting mid-June heat wave.
The eight-day heat wave rapidly melted the snowpack and filled Pine Flat Lake on the Kings River, which prompted the U.S. Army Corps of Engineers to send a surge of water into the river to make room for more runoff behind the dam. The surge tested levees along the Kings River, which runs through Fresno County and ends in the Tulare Lake Basin in southern Kings County.
Flooding resulted in the evacuation of about 90 homes, caused minor farmland damage and affected a golf course and country club in Kingsburg.
California Department of Water Resources Chief of Flood Operations John Paasch said the heat wave “really ripened the snowpack.”
“This heat event brought peak inflows into Pine Flat upwards of 20,000 cubic-feet per second. There was a peak before that in May and in June that was about 15,000 cfs,” Paasch said.
But if there is another peak in the future, Paasch said, “we expect it to be a minor peak that operators at Pine Flat and other reservoirs should be able to manage without having to adjust their flows any higher than what we’re seeing today.”
The flooding along the Kings River caused minimal agricultural damage, Fresno County Supervisor Buddy Mendes said, adding, “unless it is your place. Then, it is not so minimal.”
For example, a 40-foot breach along the south fork of the river damaged newly planted alfalfa fields at a family farm east of Lemoore.
“Four hundred to 600 acres of alfalfa were flooded, and about how much is lost is probably closer to the 400 number, but it’s dead,” said Aubrey Bettencourt of Bettencourt Farms. “The field has turned black. We should have got around 12 to 15 cuttings. It was a brand new field; we had only got one cutting.”
Bettencourt said what she initially thought was a spillage of water along the Kings turned out to be “a full-on breach of the riverbank.”
“What had happened on our breach was probably like a squirrel hole or something, and as the change of velocity and amount of debris came through, that water had nowhere else to go. It’s the power of water,” she said.
Although damage to Kings County agriculture turned out to be minor, Kings County Farm Bureau Executive Director Dusty Ference said a few other fields experienced flooding, adding, “Some of those concerns have tapered off, but levee repair work continues.”
At the Kings River Conservation District, which maintains more than 130 miles of levees along a portion of the Kings River and staffs levee patrols, spokeswoman Cristel Tufenkjian said water managers had been conducting flood releases for some time when the heat wave worsened the situation, resulting in larger volumes of water being pushed out of the system. Tufenkjian explained that water is first sent down the north fork of the Kings River and, once that tributary reaches capacity, water is then sent down the south fork.
“The system in the south had not seen water for a number of years, so it was a dry system,” she said. “The south fork became more stressed as the volume increased. We maintain all of the levees, but they get tested when they get floodwaters.”
As the water moves down the Kings River, Tufenkijian said, it is being used to recharge groundwater basins wherever feasible.
“They are putting it in every hole and ponding basin, trying to put as much water into the groundwater as possible,” she said.
Justin Fredrickson, an environmental policy analyst for the California Farm Bureau Federation, noted that if water must be released too quickly during too short a time, some groundwater recharge opportunities may be lost.
“Creating more surface water storage would give reservoir managers additional ways to control runoff, which would help maximize recharge efforts,” Fredrickson said.
On the San Joaquin River, Paasch said, inflow peaked at about 9,000 cfs at the height of the heat wave-induced snowmelt, but had returned to 5,500 cfs by the end of last week and was expected to drop even lower.
“The San Joaquin River and the flood control system downstream as you get into the Mendota-Firebaugh area, they’ve seen a lot of high water throughout the spring, but they will see flows in their system continue to decline as these reservoirs dial back flood releases,” he said. “The worst is over.”
After comparing data with fellow water managers, Paasch said, “We’re pretty confident that any future peak (flow) that we have this summer is not going to come close to that peak that we just had.”
With the new water year not due to begin until Oct. 1, he said there would likely be some pressure on reservoir operators to “top off” reservoirs, “but in a year like this when we’ve had well above average, 200-plus percent rainfall and snowpack, the system is ripe with water.”
“I suspect that towards the end of the summer you’ll see reservoirs working and making flood releases to get back into a spot where we can anticipate and manage the flood flows going into next flood season,” Paasch said.
Kings County farmer Bettencourt, who also serves as executive director of the California Water Alliance, said the flooding underlines the ongoing need for California to focus on its water infrastructure.
“It would be so easy to point fingers here, but the only finger pointing I would do is over the lack of investment in our infrastructure over the last 40 years,” Bettencourt said. “When we’re not investing at a macro and a micro level to get our technology and infrastructure up to speed, we won’t be prepared for instances like this.”
Paasch said improving and increasing water storage “not only helps water supply and in improving the economics of the state, but selfishly, from a flood management perspective.”
Christine Souza is an assistant editor of Ag Alert. She may be contacted at email@example.com. Permission for use is granted by California Farm Bureau Federation.