A setback dike is a dike that is built inland, or set back further from the riverbank or coastal shoreline than a traditional dike. Having more land between the water body and the dike protects the dike from erosion and seepage. In the case of a dike set back from a river, there may also be more room for water flow during a flood. Depending on size, the land in front of a dike can be used for public recreation, natural wetland and habitat, or potentially other uses, provided there are reduced flood consequences.
If there is an existing dike on the bank or shoreline, it can remain to provide some protection for smaller flood events, or it can be lowered or removed entirely. Existing infrastructure and development in the exposed land might be encircled by ring dikes or floodproofed.
In BC/Lower Mainland
In the Lower Mainland, some of the dikes along the lower Fraser River gravel reach (e.g., Chilliwack, Kent and Abbotsford) are set back some distance from the riverbank.