Article from Calaveras Enterprise.
http://www.calaverasenterprise.com/news/article_9173226c-659c-11e6-8bfe-4b787c68bce4.html
By Dana M. Nichols dana@calaverasenterprise.com
Aug 18, 2016
The population of rainbow trout in the lower Stanislaus River plummeted to its lowest level in six years in 2015 and will likely decline further this year, according to a study released this week by Fishbio.
The Fishbio report blames overly warm water temperatures for the sharp decline. The water in the river was warmer because New Melones Reservoir, which normally holds a large pool of cold water to release downstream, was drawn down in 2015 to less than 12 percent of its capacity, leaving only warmer surface water to be released from New Melones Dam into the lower river. The low water followed four years of drought.
The report said scientists found about 5,000 trout in the river between Goodwin Dam and Oakdale. That is a quarter of the average of 20,000 fish found from 2009 to 2015. In 2012, scientists estimated there were more than 35,000 trout.
“Although conditions improved in 2016, the water year is still classified as dry, and O. mykiss (rainbow trout) abundance is expected to decline even further in the summer of 2016,” the report said.
The fate of the trout has repercussions for human users of the river.
Rainbow trout and steelhead are the same species. The fish are considered steelhead when they migrate to the ocean. The steelhead eventually return to spawn in the river.
State and federal laws require releases of water into the Stanislaus River for a variety of purposes, including diluting saltier water in the San Joaquin River downstream, maintaining minimum flows through the San Joaquin River Delta and helping steelhead to survive, including efforts to allow young steelhead to migrate to the ocean. Steelhead are listed as a threatened species under the federal Endangered Species Act.
But representatives of the water agencies that serve farms and cities generally would prefer to see as much water as possible held behind dams during the winter and spring for use by their customers later in the year. Fishbio, the firm that issued the report, is hired to study the Stanislaus River by South San Joaquin and Oakdale irrigation districts.
The districts this week issued a joint statement saying that the Fishbio study shows that “flawed science” in a 2009 biological opinion issued by the National Marine Fisheries Service causes federal dam operators to release water in ways that do not benefit steelhead and trout.
“The current flow standards are destroying the fisheries that they are intending to protect and doing so at the expense of Central Valley agribusiness and urban interests, who also depend upon a healthy and sustainable river,” the statement said.
Representatives for the National Marine Fisheries Service and for the California Sportfishing Protection Alliance disagreed. They noted that irrigation districts still get the lion’s share of the water from the river and water is released from New Melones Dam to protect a wide variety of interests, including San Joaquin River Delta farmers who can’t irrigate their crops if water in the Delta is allowed to become too salty.
“The reality is there are a lot of demands on the water in the Stanislaus,” said Rhonda Reed, the San Joaquin River Basin branch chief for the National Marine Fisheries Service. “We work very hard to do it in a way that addresses the population and agricultural businesses at the same time.”
Reed said that the biological opinion is based on science and that an appellate court that considered a water district suit challenging the biological opinion agreed with the National Marine Fisheries Service scientists.
Still, she applauded the Fishbio research and said that the work appears sound. “It will be useful the next time we are required to consult on an action on the Stanislaus,” she said.
Still, she acknowledged that it is “a challenge” to provide cold water flows in the river below New Melones Reservoir during long droughts. “If the rain doesn’t come, we don’t have water to deliver.”
When water agencies next negotiate over how to manage New Melones Reservoir releases, expect water districts to push for rule changes that reduce mandated flows early in the year in favor of keeping cold water available later in the year. Such a policy would also potentially benefit Calaveras County Water District, which uses Stanislaus River water to serve customers in the Copperopolis area.
Early last year, officials with the South San Joaquin and Oakdale irrigation districts announced that low water in New Melones Reservoir might force them to draw down the level of water in Tulloch Reservoir. Tulloch is a much smaller reservoir just downstream from New Melones Reservoir that the water districts operate. District officials said they might need to take water from Tulloch in order to provide water to customers.
That provoked an uproar from people living around the lake. It also prompted CCWD to build a new, deeper intake in Tulloch that could still provide water to customers should drought force a drawdown of that lake. Ultimately, the drawdown never happened. But it alerted Copperopolis residents to the fact that distant farms and cities and even fish are all competing for a limited amount of water.
Bill Jennings, executive director of the California Sportfishing Protection Alliance, noted that in fact federal dam operators in the last several drought years have several times asked and received permission from the California Water Resources Control Board to relax environmental rules so they could reduce flows and hold more water behind New Melones Dam.
“I suspect that the farmers in OID and SSJID have fared probably better than any other group of farmers in the state as far as getting water supply,” Jennings said. “The problem is once OID and SSJID take their water out of the river, there is not much left.”
Another problem is that little, if any, water is released from Millerton Dam on the San Joaquin River. What water flow the lower San Joaquin gets is largely salty irrigation runoff from farms on the west side of the San Joaquin Valley. Federal water managers release water into the Stanislaus River to improve conditions in the lower San Joaquin River. The Stanislaus River flows into the San Joaquin River where the San Joaquin River enters San Joaquin County near Vernalis.
Jennings notes that if the twin tunnels conveyance is built to take Sacramento River water from the north side of the delta to pumps on the south side of the delta near Tracy, then there will no longer be fresh Sacramento River water in the Delta, something that could put even more pressure on water managers to use Stanislaus River water or San Joaquin River water for that purpose.
“The San Joaquin side is going to have to pick up some of the burden; more of the burden,” Jennings said.