Columbia River low near Tri-Cities for chinook salmon eggs

You may notice that the Columbia River level has gone down this month.

This is the annual flow adjustment to help chinook salmon lay their eggs at Vernita Bar, a large gravel bank in the river, four miles downstream of the Priest Rapids Dam.

There and in three other places in Hanford Reach, just above Richland, in the Columbia, nests dug by salmon, called redds, nest in the gravel to lay their eggs.

Every year, as the Chinook returns, the levels of the rivers below the Priest Rapids Dam are reduced mid-October during the day, says the Bonneville Power Administration.

The chinook spawns especially during the day.

The lowering of the river's level encourages them to dig swirls further down the riverbanks to make sure that when the water level drops, the nests do not end on the mainland.

The nests must remain underwater until the fish emerge in the spring.

The salmon use their powerful tails to keep the rocks away from nests about 20 feet apart.

Once the eggs have been laid, the salmon will move up the rocks, bringing them back up to eight inches wide. Each swirl can have up to 4,500 eggs.

At night, flows are increased to release any excess water downstream of the river.

Historically, scientists thought that a relatively small number of chinook were born in the Vernita Bar area.

However, river operations in some seasons have increased the number of salmon to 250,000, according to BPA.

Salmon spawning is fed by maintaining low river levels during salmon spawning, but higher in winter and spring in order to keep as many eggs and fry as possible under the sea. 39; water.

It's more profitable that dams release water during the day and produce electricity when people use it. But that's not the best thing for salmon in the fall.

Water levels are also adjusted in the Columbia River downstream of the Bonneville dam for chum salmon spawning in November.

Called "salmon" because of their canine teeth, chum salmon is the last salmon of the year to return to Colombia to spawn and its young are the first to leave for the ocean in the spring.

Chum salmon generally spawn in the lower Columbia River downstream of the Bonneville Dam in areas where warm water rises through the soil in the gravel where salmon nest.

According to the BPA, the hatchery programs for which it paid and the construction of new spawning grounds allowed 20,000 chum annually to return to the Columbia River.

The federal government listed Columbia ketan as endangered under the Endangered Species Act in 1999.

Annette Cary; 509-582-1533