MCRI dike realignment will expand channel width by almost 400 percent
Phase 1 of the Mission Creek Restoration Initiative (MCRI) is officially underway, meaning that the south dike between Casorso Road and Gordon Drive is closed, environmental and archaeological monitoring is underway, and trees and vegetation that hinder project design are being removed. Slated for completion next spring, dike relocation and floodplain enhancement will increase the creek’s channel width from 40 to 150 metres, thereby reducing flood risks while expanding fish and wildlife habitat.
REMOVING THE EXISTING DIKE
To prepare for the dike realignment, the existing dike within the construction area will be scalped to an average elevation of 40cm above the creek’s current water level. Three ‘meander’ notches, each 30 metres long and level with the creek bed, will be carved out as the existing dike is removed. The resulting meander pools will be lined with logs and root wads during fisheries enhancement work being done next spring following dike realignment. Over time, these pools will help naturalize flow patterns and provide enhanced fish spawning and rearing habitats.
BUILDING THE NEW DIKE
Designed to accommodate a one-in-200-year flood, the 570-metre section of new dike will reflect government standards and design specifications outlined in the MCRI Dike Setback Design Report. Assuming a mild winter, construction will take place during the low-water period between now and next spring, with no harmful impacts on creek water quality.
The site of the new dike will initially be stripped down to mineral soil, with the excess top soil being stored for future use. Construction will start from both upstream and downstream ends, allowing for faster removal of material from the existing dike. The new dike requires about 9,000 cubic metres of sand, clay, and gravel. To reduce material and hauling costs, all of the needed gravel will come from the old dike.
Construction is being undertaken by City of Kelowna workers, which MCRI project coordinator Steve Matthews says ìs an ideal arrangement. “Being a key MCRI partner, the City has a strong vested interest in getting the job done right… on time and within budget. It`s also a project that provides extra work for the City`s seasonal crews. I`m looking forward to watching it all unfold over the next six months.”
But watching it unfold in the short term may concern residents who don`t understand that MCRI is a long-term project with uncertain outcomes. For example, a walk along the four-metre crest of the new dike “won`t be what people are used to, at least not for a few years,” says Matthews. “But as nature takes its course over time, and native trees and vegetation take hold, the view from the new dike across the naturalized creek will be stunning.”
For more information visit www.missioncreek.ca or contact Joanne de Vries at 250-766-1777 or use our contact form.