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5-Mile-Long Habitat Testifies to Nature's Resiliency : Return of River Life

July 04, 1985|VICTOR VALLE | Times Staff Writer

A great blue heron stood motionless at dusk, its long pointed beak poised to strike a tadpole or minnow in the shallow green water. Behind the elegant long-legged bird, red-winged blackbirds flitted up and down in the wind, bending the tall cattails. The heron, between sandbars thick with mulefat and young willows, waded in a river carpeted on its banks by clover-like weeds.

One might expect to stumble upon this solitary wetland scene in the wild, perhaps behind a duck blind in some wildlife preserve. But the roar of cars passing above on the Pomona Freeway is a noisy reminder that this riverine landscape is part of a five-mile-long habitat that has gradually sprung back to life along the San Gabriel River over the last 15 years.

Running southeast from the confluence of the river and Walnut Creek near Baldwin Park through a patchwork of south San Gabriel Valley cities down to Pico Rivera, this greenbelt of sandbars and slow-flowing water is a paradox of nature's resiliency hemmed in by concrete banks, housing tracts and factories.

Some of the contrasts--an abandoned shopping cart sitting amid reeds in the water, a rusted bumper in the river mud--are obvious. Others, including an occasional bicyclist or jogger traversing the miles of man-made paths and trails, are subtler reminders that civilization is not far away.

The present-day lushness of the river habitat belies a dramatic cycle of transformations that began in the 1950s when the once-wild river, historically known for overflowing its banks and causing floods, was tamed.

Men using heavy equipment cleared the river of life-sustaining plant life, creating a flood-control channel with a sandy bottom and concrete banks. Thus began a continuing struggle in which plants would spring up,

only to be periodically stripped clear by bulldozers, then rise again. The habitat that flourishes today was created gradually and accidentally as the San Gabriel River became a conduit for replenishing stores of underground drinking water further downstream.

This still-youthful habitat may be about to undergo another transformation. About half of the wetlands area may soon be destroyed as part of a clearing operation by the Los Angeles County Department of Public Works (DPW), which manages the channel upstream from the river's confluence with San Jose Creek near Industry.

The DPW says that its portion of the channel must be cleared of vegetation to control the growth of brush and trees that might undermine bridges and cause flooding downstream.

Negotiations Under Way

However, the state Department of Fish and Game, which oversees fisheries along the river, has been alerted to the threat by environmentalists and has asked that the DPW save a 10-foot swath of vegetation at the channel's edges to ensure that the wildlife now thriving there will survive the operation. A DPW spokesman said the agencies are negotiating and are expected to reach an agreement next week.

In contrast to the county, the Army Corps of Engineers, which manages a 2-mile section of the channel south of San Jose Creek in the 1,400-acre Whittier Narrows Recreation Area, says it will allow the portion of the habitat it controls--surrounded by South El Monte, El Monte, Rosemead, Montebello and Pico Rivera--to flourish in a way that will not damage the channel.

David Drake, a fisheries biologist for the state Department of Fish and Game who supports the corps' concept of channel management, believes the habitat is a valuable wildlife resource that should be protected.

"In Southern California, we realize that we have very limited riparian (river) habitats," said Drake, who monitors the health of the river's fisheries. "So it's very important to protect those few areas that remain" for waterfowl, fish and other animals.

The view that such habitats are in themselves endangered species is supported by a report prepared last year for an Assembly subcommittee that concluded that more than 90% of the state's coastal and inland wetland areas--estimated at 3 million to 5 million acres--has been destroyed. Along the state's 1,100-mile coast, the report said, only one-fourth remains of the 300,000 acres of wetlands that once existed.

Links in Food Chain

Drake said that the San Gabriel River habitat's aquatic plants provide the links of a complex food chain, beginning with fresh water plankton, snails, crawfish, aquatic insects, several species of fish and amphibians.

Anglers who have found their way back to this spot say they regularly hook carp, channel and bullhead catfish, and, on occasion, red-eared sunfish and trout. Drake said fish enter the river after escaping from dams upstream. Once in the river, he said, some of the fish like carp and catfish reproduce, making it a popular urban fishing ground that must be patrolled by state fish and game wardens.

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