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On the River
SALMON SONG & DANCE
The tactic that worked in legend for the Pied Piper of Hamlin and seems to save some baby salmon doesn't seem to hurt adult fish either, a new federal study shows. Underwater music played in the correct key, which keeps fish away from nuclear power plants on the East Coast, has succeeded at Georgiana Slough but failed at Grimes in leading endangered Sacramento River salmon to safety.
A $1.7 million study by State Water Resources and BurRec is showing adult salmon are not distracted from swimming up river by underwater speakers designed to warn baby salmon away from Georgiana Slough, says the Department's Darrel Hayes.
The study began in April and will conclude in December, but its early portion indicates that 50 percent of the baby fish that might have entered the slough were successfully chased away by underwater sound. The study's more recent portion shows that adult winter-run salmon aren't distracted by the sounds. Research involved netting, tagging and tracking adults, as well as scanning the river with radar for every object over 17 inches long for 10 days at the end of November. None of these experiments indicated any negative effects on adult fish, says Hayes.
The news hasn't been so good for Reclamation District 108 near Grimes on the Sacramento River, which has also been experimenting with a musical fish screen, according to Cal Fish & Game's Dan Odenveller. District officials have said high river velocities may have kept tiny fish from avoiding the mound, whether they want to or not. Others blame the velocity rather than the technology for the screen's poor performance. "The problem is when something doesn't seem to be working, they change it rather than taking the time to prove it doesn't work." says Odenveller. "That doesn't leave us with a lot of usable data at the end of the year."
Because RD 108 water goes into a rice field, says Odenveller, the musical screen must have a success ratio of 95% or better. "At Georgiana Slough a success ratio of 50% may be good, but it's not enough here." Contact: Dan Odenveller (916)654-2731 6/93
SUBMERGED SCREENS SUCCEED
Despite a mystery over how a fish screen could become a fish incubator and a tangle with a floating 65-foot-tall cottonwood tree, the experimental Pelger Mutual Water Company fish screen is working, federal and state officials say. These submersible tank screens stuck in a deep-water hole at the end of a giant tube are now being studied along the Sacramento River. This year, irrigation water for Pelger's tomato and rice farmers was successfully diverted through the screen, says screen engineer Gilbert Cosio. Meanwhile, farmer Scott Tucker says a cottonwood tree that fell into the river was snagged by underwater deflector piles designed to keep floating debris away from the screens. When the tree cleared, divers from three agencies checked the screen but found no damage.
Baby fish were found in the ditch where the water that flows through the screen dumps out, says Cosio. He believes the squawfish eggs may have grown inside the Volkswagen-sized tank while it was shut off but that the fish may have entered the ditch from somewhere else. "We know there is no way the fish could have gotten through the mesh," says Cosio. Contact: Gilbert Cosio (916)456-4400 6/94
TASK FORCE PLUGS BANK PROTECTION
A 34-member public-private task force will meet on January 10 to complete its recommendations for how best to stave off a Sacramento flood. The task force's job is to provide the Sacramento Area Flood Control Agency with a locally preferred alternative for managing 26 miles of the American River upstream from the city. The alternative soon-to-be ratified by the task force is a river-mile-by-river-mile plan for state-of-the-art bank and levee improvements, riparian habitat restoration, and mitigation for construction activities and for flood impacts that may be referred downstream by the improvements.
"This is a chance to undo a 15-year-old adversarial relationship between flood control agencies and advocates for resource protection," says task force facilitator Scott McCreary of CONCUR. "It's also a chance to save a lot of money." Bank protection generally costs less than dam construction and requires far less mitigation. Indeed dams figure in the flood control agency's two other alternatives, one of which is to build a dam at Auburn Canyon and the other to undertake a "reoperation" of Folsom Dam (i.e., putting aside more reservoir space for flood protection, which could in turn mean less space for water supply). The flood control agency will decide between the three alternatives this February, or may choose a hybrid (see calendar). Contact: CONCUR (510)649-8008 6/94
RIVERS MEASURE UP
Eighteen months of sampling Sacramento and American River waters had three area agencies breathing easier, as levels of most of the metals, solids and other constituents monitored measured low enough to comply with EPA water quality criteria. The three city and county agencies launched the monitoring program in 1991 in the hopes of developing better information about actual ambient water quality conditions to help guide policy and regulatory decisionmaking. Since the program began 18 months ago, consultants have compiled data on 12 trace elements, cyanide, suspended solids, organic carbon and water hardness at six sites along the two rivers. Much of this information was recently published (see Now in Print) and made available through a data base clearinghouse containing over 23,000 result records. The only result of concern, according to Malcolm McEwen of Larry Walker Associates, was that mercury occasionally exceeds criteria in the Sacramento River. Contact: Malcolm McEwen (916)753-6400 8/93
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