The District of North Vancouver has pulled more than three dozen truckloads of gravel from Mosquito and Lynn creeks this month to lower flooding risks.
As erosion deposits vast quantities of gravel on the creek floor, the borders of the creek
are tested, according to district public safety section manager Michelle Weston.
"Each river has a certain storage capacity, so as the river gets filled up with gravel the area that can support water shrinks," she said. "When it gets to a certain level it'll overflow."
The district wrapped up the $110,000 project Sept. 18, after taking approximately 2,650 cubic metres of gravel, or 43 truckloads, out of the creeks.
The work is critical given that many district residents live on flood planes, said Weston.
One of the challenges of the work is making sure to minimize the effect on the fish population.
Before any gravel is removed an environmental monitor surveys the area, according to Weston.
"They'll either create a storage channel and corral them there or they'll actually capture (the fish) and move them to a different location," she said.
As quickly as the gravel is removed it's transferred, according to Weston.
District workers have already trucked 14 loads to the lower reaches of Mosquito Creek in order to create a habitat conducive to fish there.
Debris in the higher elevations of the Mosquito Creek corridor had interrupted the natural downstream movement of sand and gravel, according to district environmental protection officer Richard Boase.
"As a result the lower reaches of Mosquito Creek tend to be deficient in the sands and gravels that are important for growing benthics (bugs) that feed the other organisms in the stream," he stated in an email. "To help alleviate this the (district) will deposit sand and gravel, excavated from the basin during maintenance, lower down the stream."
The gravel that doesn't go to fish habitats is being stored and will be used for utility and park projects, said Weston.
"We were able to take all the gravel and re-use it instead of having to buy gravel."
