Mother Nature, in the form of a big log flushed down the Columbia River by high early spring flows, served to stall the release nearly 6 million subyearling Spring Creek National Fish Hatchery “tule” fall chinook – but by only two days much to the relief of everyone involved.
The release of 6.2 million juvenile fish into Bonneville Dam’s reservoir was planned Wednesday with the hatchery’s rearing facilities bursting at the seams because of the fishes’ growth. The young salmon’s biological output was beginning to tax the capacity of the filtration system that cleans the water in the hatchery’s recycling system.
More than 900,000 young fish had been flushed into the river Wednesday morning before the U.S. Army Corps of Engineers realized that the log had become lodged across the front of the Bonneville Dam’s Powerhouse 1 ice and trash sluiceway, which along with the dam’s spill bays are the primary and safest routes of down passage for the tule chinook headed toward the Pacific. The Corps operates the dam.
The U.S. Fish and Wildlife Service, which operates the hatchery, was quickly notified and suspended the salmon releases. The Spring Creek NFH’s produce, after grown to adulthood in the ocean, is an important component of salmon harvests along the coasts of Washington and British Columbia as well as in the Columbia River.
After an initial failed attempt Wednesday to “pick” the log, which had become lodged across the front of the Bonneville Dam’s Powerhouse 1 ice and trash sluiceway, with a crane, U.S. Army Corps of Engineers officials, as well as fishery managers had become resigned to a longer term solution. High flows made hands-on work, the cutting up and removal of the log, unsafe. So the plan was to build bulkheads, a two-day process, upstream of the ice and trash sluiceway to shunt the river flows and allow workers safe access.
The Corps’ Doug Baus said his agency estimated that the removal work would then take about a half day and would be followed by about a two-day bulkhead removal process, making it five days total before the fish could access that passage route.
“We’d rather have all passage routes available” before releasing the fish, the USFWS’ Dave Wills said.
But in a last attempt, Corps crews managed to “pick the log” with crane and cable Thursday afternoon even as crews were launching into the bulkhead work, Baus said.
As a result, the April hatchery releases were to be completed today in about four hours, according to Speros Doulos, head of the USFWS’ Columbia Gorge complex hatcheries – Spring Creek, Little White Salmon, Carson and Willard. Each hatchery also has an on-site manager.
Doulos said that the Spring Creek filtration system could potentially have maintained reasonable good water quality conditions for the fish until Monday, and possibly even until next Wednesday, if the bulkhead work was needed to shut off flows, and the ice and trash sluiceway. As it turns out, there was no need to hold the fish past today.
Ironically, passing debris is exactly “what it was intended to do,” Baus said of the sluiceway. But the crossways log proved too much to handle.
Wills said that fish managers expect about 30-40 percent of the young fish to pass the dam through the sluiceway, a more surface oriented and benign route than the Powerhouse 1 turbines. Most of the fish will pass through the now active spillway.