Endangered steelhead about to hatch in the American River could soon be killed by low flows and warm temperatures caused by the drought, a sign of the ongoing struggle over scarce water supplies.
The fish, which are protected by the Endangered Species Act, are beginning to hatch from eggs in riverbed gravel. They require water cooler than 57 degrees to survive. Temperatures are already warmer than that due to record-breaking heat this month and low river flows caused by a fourth year of drought in California.
As hatchlings – also known as alevins – the fish have not yet matured into fully formed fish and are unable to swim.
“It’s the most sensitive life stage. They can’t go elsewhere and they’re highly sensitive to flows,” said Tom Gohring, executive director of the Sacramento Water Forum, a coalition of Sacramento water agencies and environmental groups that monitors the river. “If things continue to be bad … they will perish in the gravel.”
The problem is a shortage of water in Folsom Reservoir caused by the drought. Although the reservoir now holds more water than at this time last year, it is expected to be in worse shape by the end of summer.
That’s because the Sierra Nevada snowpack is at its lowest level in recorded history – just 8 percent of average as of Thursday. As a result, it will provide little runoff to refill the reservoir in the months ahead. Weather patterns diverted storms away from California most of the winter, leaving January and March as the driest in more than 100 years of record keeping.
The U.S. Bureau of Reclamation, which operates Folsom and Nimbus dams on the American River, dropped water flows in the river to 500 cubic feet per second on Thursday. That falls below a flow standard negotiated with the Water Forum to protect the river environment, but it is allowed in cases of severe drought, Gohring said.
“That was primarily an effort to help conserve water based on the persistent drought conditions,” said Reclamation spokesman Louis Moore. “Everything is being done to make sure the water supply we have is being used to the best of our ability, and we’re working with others to stretch it.”
Water stored in Folsom Reservoir serves a number of urban water suppliers in the Sacramento region, as well as farm irrigation districts in the San Joaquin Valley.
Reclamation has a limited ability to monitor temperatures in the river on its own. So the Sacramento Water Forum, which is funded mainly by local water agencies, hired a consultant to install temperature probes at strategic locations in the river. Those revealed that water temperatures have already exceeded 57 degrees, Gohring said.
The problem has been aggravated by record-breaking heat in the Sacramento area last week. On Friday, Sacramento Executive Airport saw a high of 83 degrees, breaking the previous record of 79 degrees set in 1986. Downtown reached 85 degrees, which tied the record from 1923.
Reclamation responded by boosting water releases from Folsom Dam. The water is being released from gates in the face of the dam – a rare occurrence – in order to access cold water deeper in the reservoir. That cooler water is expected to reach the lower American River, where steelhead spawn, starting Sundaymorning.
The additional water flows will be temporary, lasting only into the afternoon on Monday. But officials hope it will be enough to help the emerging steelhead. Sacramento temperatures are expected to cool down to a more seasonable 70-degree range on Tuesday.
“If water temperatures become a detriment to fish, they will make an adjustment to try and cool the water a bit,” Moore said. “We are conserving as much as we can, and every little bit counts.”
The tight scheduling of water flows indicates how precious supplies have become.
If Reclamation lets too much water out of Folsom Reservoir to help steelhead, it could mean Sacramento’s urban areas won’t have enough when demand peaks this summer and fall. Reclamation projected last week that the reservoir will fall below 200,000 acre-feet by October, based on current water demands. At that level, Sacramento’s urban water suppliers get concerned about accessing water stored behind the dam, because their intakes are not much lower.
In case that happens, Reclamation has a contractor on standby to install temporary pumps to lift water into the intakes if necessary.
Avoiding that kind of problem will require area residents to continue working hard on water conservation, said Shauna Lorance, general manager of San Juan Water District, one of the agencies that could be affected if the lake level falls too low.
“Without the snowpack, we have less water for fish, we have less refill of the reservoir,” Lorance said. “It’s going to be more difficult this year.”
The conflicts are expected to intensify this summer, when winter-run Chinook salmon – also an endangered species – begin migrating downstream on the Sacramento River. An estimated 95 percent of the run perished last year because there wasn’t enough cold water to protect the fish.
Officials hope to avoid a repeat this year, so Reclamation is under pressure to preserve even more cold water in Shasta Reservoir. In the interim, this may mean it will use even more water from Folsom Reservoir to meet demands, which include its customers downstream and to satisfy state water quality rules that regulate salinity in the Sacramento-San Joaquin Delta.
Reclamation and the California Department of Water Resources have asked for an exemption to those water quality rules. That request is now being considered by the State Water Resources Control Board. Depending on how the request is granted, it could cause Folsom Reservoir to be drawn down much faster.
“Folsom could go dangerously low this year – potentially much worse than last year,” Gohring said.
Call The Bee’s Matt Weiser at (916) 321-1264. Follow him on Twitter @matt_weiser.