The City will be hosting a second Flood Mitigation Program open house a=in City Park tomorrow, Tuesday, August 24, at 9:00 am. We’ve prepared a list of frequently asked questions from last Thursday’s open house.
Q: What is the width of the dike, both the top width and base
- Dikes will be 4m across the top in almost all locations. Depending on how low-lying the ground is, the footprint of the dikes will be 10-15m across. (30-45 ft)
- For example, a dike where the Flood Construction Level is 2m above ground would be 12m across the base (dike top of 4m + 2:1 slope x height). A dike on higher ground, with Flood Construction Level is only 1m above the ground, would be 8 m wide at the base (2m per side plus the 4 m top)
Q: What material will the dike be made out of
- Earth berm dikes are a mixture of sand, gravel, silt and clay according to engineered specifications. Layers or courses of these materials are laid down and compacted. If it is next to the river, the dike will have large rocks (rip-rap) and geotextile fabric to prevent erosion from the river.
- Some areas do not have room for earth berm dikes, so engineers have specified reinforced concrete or sheet pile flood walls. Concrete walls are specially engineered with deep, wide footings. Sheet pile walls are long sections of interlocking steel sheets that are driven by hydraulic pounding or vibration, then capped with concrete.
Q: When will these dikes begin construction.
- Depending on permitting, dike construction and other flood protection works such as stormwater mains will begin this winter.