Area: Chilliwack
Works at this site includes sediment removal to re-establish creek bed levels. A new channel is being created to redirect the creek toward a deeper section of the Nicomen Slough. This will divert flows away from Highway 7 to protect existing infrastructure.
Deroche Creek flows through Lakahahmen IR 11 where it enters Nicomen Slough. The Slough is a historical side channel of the Fraser River . It has had its inflow from the river regulated by diking and the “Bell Dam” since the 1930s. Lakahahmen IR 11 is next to the Deroche Creek alluvial fan approximately 22 km east of the City of Mission, BC. The project location is the mainstem of Deroche Creek. The project site starts to the west of the intersection of North Deroche Road and Cooper Road then runs southeast to Taylor Road. It ends at the downstream edge of the alluvial fan within Nicomen Slough.
Total Budget:
$2.95 Million
Projected Completion Date:
October 2024
Public Health and Safety
The settling of sediment results in a higher potential for overbank flow. It may result in flooding of private property east of the Creek, and/ or flooding of Taylor Road. These effects could be caused by late spring or summer floods with recurrence intervals of 10- to 50-years.
River Capacity
The settling of sediment results in a higher potential for overbank flow and flooding of adjacent land and Taylor Road. These effects could result from late spring or summer floods with recurrence intervals of 10- to 50-years.
Environmental
The bank soil along this lower reach tends to be loose. The sediment may leave the banks and vegetation more vulnerable to erosion and loss. The sediment also further degrades already declining habitat values in Nicomen Slough.
Infrastructure
The moved sediment creates a higher potential for flooding and erosion damage along Taylor Road and at Kelly Deroche Bridge. Potential damages to the road or bridge may force the closure of both for several days. The capacity of the CP Rail and North Nicomen Rd. Bridges will also be affected, but is less likely due to more robust defences there.
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