Vanderhoof’s Nechako River hosted more than just trumpeter swans and a Ford pickup truck this spring.
A Spyder Walking Excavator, hired by the Nechako White Sturgeon Recovery Initiative, raked and sifted the Nechako River bed by Burrard Bridge in Vanderhoof from Apr. 6 to 8.
It’s an attempt to shake off fine sediment that filled the coarse cobble-gravel bed laid by the Ministry of Forest, Lands and Natural Resource Operations in 2010 to provide spawning beds for sturgeon egg and larvae, explained Wayne Salewski from NWSRI.
According to recent research, gravel, as opposed to packed fine sediment, was shown to increase sturgeon early survival rates by providing pockets for baby sturgeon to hide from predators.The excavator’s mechanical cleaning would move coarser material towards the surface of the river bed, while finer sand would move downstream.
As stirred up silt travelled down the river, master’s student Simon Gauthier-Fauteux from the University of British Columbia deposited a sensor into the water west of the bridge to measure the cloudiness of the water.
His research explores how sediment and silt move down and are deposited through the Nechako River, as well as their effects on the sturgeon habitat, Gauthier-Fauteux explained.
As the first time that the artificial river bed was shaken, re-suspending packed clay, it’s also an opportunity to collect silt and examine the organic pollutants, such as pesticides, that bind to the material, explained Todd French, research associate from the University of Northern British Columbia’s geography department.
French and fellow research associate Barry Booth is taking part in a project to determine the Nechako River’s historical sediment sources, such as where and when certain pesticides were deposited in the agricultural region, Booth explained.
“It’s a really good opportunity to partner with local groups,” French said.