Floodplain Management Bylaw Guide for Residential Construction

Floodplain Management Bylaw Guide for Residential Construction

Much of the City of Chilliwack lies in the floodplain of the Fraser River to the north, the Vedder River to the south, the Sumas River to the west or one of several creeks entering the valley from hillside areas.

In order to reduce the potential damage which would occur should one or more of these rivers overtop their banks or protective dykes, the Province of British Columbia developed appropriate floodproofing guidelines for various forms of development. These guidelines form the basis of the City of Chilliwack's Floodplain Regulation Bylaw No. 4519. This Bylaw, adopted by Council, regulates construction elevation requirements for new development in the floodplain.

1. HIGHLIGHTS:

  • Floodplain elevation requirements consist of the applicable 'Flood Construction Level' (FCL), plus 0.6m Freeboard;
  • The 0.6m Freeboard requirement may be waived provided the owner registers a Section 219 Covenant against the title of the property, and provides a Qualified Professional's report indicating that the property may be safely used for the intended purpose;
  • FCL's within the Agricultural Land Reserve, on properties protected by standard dykes, have generally been standardized at 1.2m above the natural ground elevation. The owner is required to register a Covenant with respect to the flooding of the property or flood damage.

2. RESIDENTIAL DEVELOPMENT:

  • General Floodplain Area (not special cases)
    • The underside of the lowest habitable floor or the pad height for a mobile home must be constructed to Flood Construction Level (FCL) plus 0.6m Freeboard;
    • Garage, carport, entrance foyer are exempt;
    • No basement (maximum 1.5m deep crawlspace permitted subject to local drainage requirements);
    • The 0.6m Freeboard requirement may be waived provided the owner registers a Covenant against the title of the property and provides a Qualified Professional's report indicating that the property may be safely used for the intended purpose; and
    • The area below the FCL as applied to a residential use, may be used for utility room, workshop or indoor recreation uses provided that:
      • the floor level of these areas is at least 0.3m above the crown of the road and;
      • the owner enters in to a Covenant absolving the City of liability with respect to the flooding of the property or flood damage
  • Non-ALR areas in Greendale and Yarrow
    • The underside of the lowest habitable floor may be constructed to not less than 1.2m above natural ground elevation or 0.3m above the crown of the adjacent road, whichever is greater, provided:
      • the owner provides a report from a Qualified Professional that the land can be used safely for the intended purpose, and;
      • the owner enters in to a Covenant absolving the City of liability with respect to the flooding of the property or flood damage.
  • Dwellings on parcels within the ALR:
    • The underside of the lowest habitable floor may be constructed to not less than 1.2m above natural ground elevation or 0.3m above the crown of the adjacent road, whichever is greater, provided:
      • the property is protected by a standard dyke, and;
      • the owner enters in to a Covenant absolving the City of liability with respect to the flooding of the property or flood damage.
  • Alluvial Fan Areas
    • A site specific assessment by a Qualified Professional is required to determine building setback and elevation requirements;
    • An engineered concrete foundation shall extend to a minimum of 1.0m above grade at any point on the perimeter of the building
  • Building Size Exemption
    • The elevation requirements in the Bylaw do not apply to a renovation or addition to a building that would increase the size of the building, at the original non-conforming elevation, by less than 25% of the floor area that existed at the time of the adoption of the previous Floodplain Bylaw. (March 1997)

Consult Floodplain Regulation Bylaw No. 4519 for additional details and for further information please contact:

City of Chilliwack
Development and Regulatory Services Department
Telephone:  604.793.2905
Fax:  604.793.2285
8550 Young Road
Chilliwack, BC   V2P 8A4

This brochure has been prepared to provide guidance only.  It is neither a bylaw nor a legal document.  Please consult the Local Government Act and its regulations, and the City of Chilliwack Floodplain Regulation Bylaw and applicable reference for definitive requirements and procedures.

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