A crew just got done dumping gravel in the Stanislaus River to help salmon about to head that way from the Pacific Ocean.
The Oakdale Irrigation District split the $1.1 million cost of the project with the U.S. Fish and Wildlife Service, which aims to rebuild a chinook salmon population laid low by various factors.
"It expands nesting habitat and rearing habitat on the Stanislaus River," OID General Manager Steve Knell said Friday.
Since June, district workers have placed about 400 tons of gravel on 2.4 acres of riverbed about five miles east of Oakdale.
Some of the gravel went in the main channel, where adult salmon lay their eggs in the fall after spending a few years at sea. The rest of the rock is in places along the banks that could be underwater in winter and spring, when the young salmon are preparing for their own journeys to the Pacific.
"Research over the last decade has shown that juvenile chinook utilize these shallow-water floodplain benches as rearing habitat because the water is a little warmer and in some cases has more food for the fish," said Doug Demko, a fishery consultant based in Oakdale.
His company, FISHBIO, helped with the project, which also could benefit steelhead trout. Also involved are River Partners, which has a branch office in Modesto; the Army Corps of Engineers, which runs parks along the river; and CBEC Inc., an engineering firm based in West Sacramento.
Conserving water for farms
The OID and other irrigation districts have been trying to show that projects such as these do fish more good than boosting river flows with water that has been going to farms.
The latest project was done at Honolulu Bar, an island in the Stanislaus that had been damaged by gold mining and other human activities.
The project involved taking gravel from the island, cleaning sediment from the rock and depositing it in the desired places.
At times, rafters drifted by the restoration site and were guided around the heavy equipment by a crew member.
The project includes removal of nonnative plants and revegetation to provide shade and other benefits.
Salmon populations are much reduced from their natural levels in rivers that flow toward the California coast. They got so sparse that fishing was suspended in 2008 and 2009, but they have improved somewhat since then.
Environmental and fishing groups contend that the main cause of the decline is the diversion of river water to farms and cities.
Other factors could include poor sea conditions, river pollution and predation in the Sacramento-San Joaquin Delta by nonnative striped bass.
Bee staff writer John Holland can be reached at firstname.lastname@example.org or (209) 578-2385.