Flood Management Program

Flood Management Program

Managing where and how communities develop is an important part of managing how floods affect property and people. This initiative provides important information and tools for local governments, the development industry and property owners to help understand local flood hazards and to consider flood mitigation options to reduce flood risks today and into the future.

The following floodplain maps show where water will flow during a flood and what land could be affected. The 200-year return period flood event shown on the maps account for future climate change impacts.

River and Lake Flood Hazards

River flooding in the region generally occurs in the late fall or early winter driven by high intensity rainfall and snow accumulation at higher levels. There are three major river systems in the  region prone to annual flooding (Nanaimo River, Englishman River and Little Qualicum River) with designated floodplains and one lake (Horne Lake) with established Flood Construction Levels as shown on the maps below:

Englishman River Floodplain Mapping
Little Qualicum Floodplain Mapping
Nanaimo River Floodplain Mapping
Horne Lake Floodplain Map

Coastal Flood Hazards

Coastal flooding occurs when low banks experience high tides and/or storm surges. With over 188 kms of varying coastline, high-bank areas are not at risk of flooding, erosion may be a consideration. Low banks are most likely to experience coastal storm surges, flooding (and erosion) from high tides, king tides and wind-driven waves. Over time, global sea level rise will intensify these natural processes. The regional coastal floodplain maps (below) incorporate these changes:

Coastal Floodplain Mapping Project

Flood Mitigation 

Land use planning, particularly development controls can provide effective non-structural mitigation measures to reduce flood risks. The construction of new buildings and structures in the designated floodplains are regulated through the Flood Hazard Mitigation Bylaw 1872 (which replaces Floodplain Management Bylaw 1469)

Homeowners and builders are encouraged to refer to the RDN Sustainable Site Planning Guide. This Guide provides vital information to reduce the impact of development on the natural ecosystems (such as wetlands and shorelines) and on natural systems (water cycle), while increasing the comfort and safety of your home.

For more information contact askplanning [at] rdn.bc.ca (askplanning[at]rdn[dot]bc[dot]ca)

Other Resources