By Tyler Clarke, Lake Cowichan Gazette, September 20, 2010
Those around the Cowichan River on September 8 were witness to an unusual sight, when six truck loads of gravel were shot out of a truck and into the Cowichan River.
Of the loads, 5.5 were put into the river next to the Lake Cowichan Municipal Offices, with a half load put in at the trestle footbridge site near Duck Pond.
During the day, a group of workers created three parallel mounds of gravel extending from the bank, between a third and half way across the channel. These mounds are separated by about five meters, and provide ideal spawning habitats for coho and chinook salmon.
“We will be doing an “as built” survey to document the elevations of the mounds relative to previous (2008 and 2009) survey datum,” Living Rivers Senior Fisheries Biologist Craig Wightman wrote in an e-mail to the Gazette.
A Victoria-based engineering firm will review the new elevation survey data in relation to the overall channel geometry and river hydrology in the reach between the Catalyst weir and the Greendale Trestle.
“We expect some gravel movement this winter, but our experience to date (based on the 2008 gravel placements) is that this site is remarkably stable and highly suitable to salmon and steelhead spawning success,” Wightman wrote.
This depositing of gravel is the second for the Cowichan River. The first deposit took place in 2008, also done courtesy of the Living Rivers program.
The deposits were done in response to low levels of chinook salmon in the Cowichan River, with numbers declining since 1999 to an all-time low of an estimated 1,069 spawners in the river in 2006.
It’s hoped that these new gravel deposits will provide abundant spawning habitats for their winter spawning.