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It All Starts With Bugs : Trout Fishermen Glad San Gabriel River Insects Coming Back

March 27, 1988|ASHLEY DUNN | Times Staff Writer

Reaching into the chilly waters of the West Fork of the San Gabriel River, Jim Edmondson turned over a slippery rock and gazed at the crawling collection of bugs underneath.

Half-inch caddis flies squirmed for cover and dropped into the water; smaller mayflies crawled away from Edmondson's fingers as he probed the underside of the stone.

These aquatic insects, a primary food for wild trout, spend almost all of their lives underwater, but come out once a year to mate, sending hikers swearing down the trail as they swat away swarms of the mosquito-sized bugs.

But for Edmondson, the insects were a welcome sight.

"It's just awesome," said Edmondson, the Southern California manager for California Trout Inc., a nonprofit statewide group dedicated to the preservation of wild trout.

The rising number of insects found in the stream is one of the first signs that the West Fork of the San Gabriel River is making a comeback.

Since 1981, the West Fork, one of the most heavily fished streams in the state, has endured a man-made flood, fire, drought and a destructive release of mud from Cogswell Dam that reduced the fish population.

"It has been hit with every disaster possible," Edmondson said. "It has been so beaten down. This stream is a real underdog."

But due to a joint effort by California Trout, the county Department of Public Works, the state Department of Fish and Game and the U.S. Forest Service, a slow recovery has begun.

The increase in the number of insects has been largely credited to the Department of Public Works, which agreed in 1986 to restrict valve testing at Cogswell Dam to prevent large, sudden releases of water that can flush aquatic insects down the river.

"It's out of intensive care and on its way. There is no question this river is rebounding," Edmondson said.

"We must be doing something right because the river is recovering," said William J. Brown Jr., a biologist with the U.S. Forest Service in the Angeles National Forest.

Increasing the insect population is only the first step the four groups have taken to rehabilitate the trout habitat along the river.

A yearlong study on managing the river and Cogswell Dam, located seven miles upstream, is scheduled to be finished in June.

The study will recommend ways to control the release of water from the dam to protect the dwindling population of wild trout, according to E. Woody Trihey, the hydraulic engineer conducting the $60,000 study funded by the Department of Fish and Game.

Edmondson said the plan, if accepted by all four parties, would be a major step toward protecting the wild trout for future generations.

"This will be the most important study for this stream for the next 100 years," he said. "It will never be a wild and scenic river that makes the cover of fishing magazines, but it can be one of the best in Southern California."

The West Fork, located off Highway 39 in the San Gabriel Mountains north of Azusa, has fallen a long way since its glory days in the 1800s when anglers could pull hundreds of wild trout out of it each day.

In those days, local writers extolled the tremendous fishing along the stream, which was filled with steelhead trout that began life in the San Gabriel River, swam to the Pacific Ocean and returned years later to spawn.

But the completion of the Morris Dam across the San Gabriel River in the 1920s blocked the path to the spawning ground, ending the steelhead run.

The number of rainbow trout, which remain in the river all their lives, also decreased as cities sprang up, bringing in thousands of anglers. By 1979, the Department of Fish and Game estimated that there were about 20,000 trout in the West Fork.

In 1981, the first of a series of disasters struck.

While repairing Cogswell Dam, the county Flood Control District (now a subdivision of the Department of Public Works), released an estimated 200,000 cubic yards of silt into the stream, killing thousands of fish and burying their spawning ground.

The Department of Fish and Game sued the district for $2 million. Settlement of the suit is still pending.

Five years later, a fire ravaged 3,900 acres around the West Fork, destroying vegetation that prevented soil erosion. In the aftermath of the fire, tons of mud washed down the mountain, again covering spawning grounds.

Just a year after that, the Public Works Department released tons of water while testing valves at the dam during the spawning season, flushing away much of a generation of trout in 70 minutes, Edmondson said.

It was the valve test that brought the four groups together.

To avoid more problems, the Public Works Department, the Forest Service, the Fish and Game Department and California Trout agreed to hold regular joint meetings, begin a water flow study and reschedule the valve testing.

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