River Flood Mapping

We have completed detailed flood hazard studies and mapping for the Englishman and Little Qualicum rivers as part of the Sea Level Rise and Climate Adaptation Program. This work is an essential step in better understanding and managing flood risks as the maps show where water will flow during a flood event under current and future climate change conditions. They are also an important tool for land use and emergency planning and future infrastructure investment. Residents can use this information to check if they live in the Englishman River or Little Qualicum River floodplain areas and what regulations apply before they build a new home.

An updated floodplain map for the Nanaimo River and amendments to the existing floodplain bylaw is in development. Both are scheduled to be completed in 2023. Future details will be made available on this project page and in the local media.

The overview reports of the studies and floodplain maps can be found online at rdn.bc.ca/sea-level-rise-adaptation-program. For those who live in or near flood prone areas, the RDN has a wide range of emergency preparedness resources available at rdn.bc.ca/flooding.

Due to storm events in November 2021, the river projects (Little Qualicum River and Nanaimo River) experienced some delays. Our engineering consultants from Kerr Wood Leidal were engaged in supporting Provincial flood efforts in the lower main land and the high water flow levels delayed the field survey team on the Nanaimo River.

With improved weather and river conditions the project teams have resumed and we've happy to announce we've back on track! The projects are scheduled to be completed as proposed; Little Qualicum River in March 2022 and Nanaimo River later in 2022. Once the project report has been finalized for the Little Qualicum River, staff will be preparing a update to the RDN's Flood Management Bylaw No. 1469. The bylaw update will include the new mapping information for the Englishman River, Little Qualicum River and the coastal zone. This information will be presented to the RDN Board of Directors and residents with a request to proceed with consultation on the draft amendment bylaw.

Future updates will continue to be posted here, on the project's Get Involved webpage and through local media, as applicable.

Integrated flood management applies a systems approach to flood risk reduction that considers all natural flood hazards - river, overland (e.g., culverts) and the sea.

The Province of British Columbia advises coastal communities to plan for at least one metre of sea level rise by the year 2100, and two metres by 2200. To better understand the implications of sea level rise and future land use, the RDN retained Ebbwater Consulting Inc. along with Cascadia Coast Research Ltd. in 2018 to develop flood mapping for the coastal area. The mapping information was released in June 2020. Revised mapping information followed in October 2021. The revised documents and supporting information are located on the RDN webpage here: Sea Level Rise Adaptation Program

As we learn more about coastal flooding and sea level rise it is anticipated that the coastal maps will be reviewed and periodically revised along with the applicable land use plans and regulations.

The Nanaimo River is part of the Georgia Basin drainage network located on central Vancouver Island. The Nanaimo River watershed ranges from the Island Range to sea level, draining through Jump Lake into the Strait of Georgia within the boundaries of the City of Nanaimo, Snuneymuxw Reserve Lands and the RDN, Electoral Area A.

As with other rivers in the region, the Nanaimo River is primarily a rain-driven hydrologic system, influenced by heavy fall and winter rain or snow. The majority of the flow occurs in the fall and winter with low discharge in the summer period. The Nanaimo River floodplain has been designated by the Government of BC as a “high risk” floodplain. The river has a long-standing history of flooding, with extreme events due to a combination of rainfall and high tide, such as in 1949, 2007and 2014. The most recently extreme event was in January 2020, triggering the temporary displacement of on-reserve and Electoral Area A residents.

The existing floodplain map for the Nanaimo River, issued by the Province of BC in May 1984, are considered outdated because the hydrologic model used to create the map does not consider upstream and downstream changes in the watershed, regional climate allowances nor the influence of rising sea levels. This project is designed to address this issue by conducting a hydrologic analysis, including climate change forecasting and subsequent hydraulic modeling. The key output of this work will be up-to- date riverine floodplain regulatory map and to complete a risk assessment informed by these findings and key stakeholder including the City of Nanaimo and Snuneymuxw First Nation.

The project timelines are October 2021 to March 31, 2022.

The Little Qualicum River is part of the Georgia Basin drainage network located on central Vancouver Island. The Little Qualicum River watershed ranges from Mt. Arrowsmith to sea level, draining through Cameron Lake into the Strait of Georgia just north of Qualicum Beach. The Little Qualicum River is primarily a rain-driven hydrologic system, influenced by heavy fall and winter rain or snow. The majority of the flow occurs in the fall and winter with low discharge in the summer period. Flooding is not uncommon along the Little Qualicum River.

The current floodplain map for the Little Qualicum River were prepared by the Province of BC in September 1997. These maps are considered outdated because the hydrologic model used to create the map does not consider regional climate change and sea level rise on the floodplain of the Little Qualicum River and estuary area.

As part of modernizing the RDN's approach to flood management, the existing riverine floodplain maps are being updated for the Little Qualicum River. This work commenced in April 2021 and is anticipated to be completed in March 2022.

The Englishman River Flood Hazard Mapping project wrapped up in May 2021, following the completion of the technical study and the high-level risk assessment. Stakeholder engagement played an important role in this project. Twenty-two key stakeholders in the study area participated in a online workshop on March 25, 2021 to share their priorities for flood management. The workshop serviced as an opportunity to start the conversation about flood hazards and management along the Englishman River as an early stage of hazard analysis.

RE: RDN News Release July 13, 2020

The Regional District of Nanaimo (RDN) is launching a new flood hazard study of the Englishman River. The study and resulting maps will replace the existing floodplain maps produced by the provincial government in 1985 to provide better information to support land use and emergency planning in reducing the risks of flooding. Developed for the RDN’s Sea Level Rise and Climate Adaptation Program, when complete the maps will be used by engineers and the development industry to plan construction projects near the Englishman River and estuary and will inform updates to the RDN’s land use bylaws.

Using the latest approaches in science and engineering, along with applicable climate change data, the flood hazard maps will provide a visualization of predicted water levels and location to help communities adapt to our changing environment. The results of the recently completed coastal flood hazard study will be incorporated to determine the flood extent under combined influences.

“The RDN recognizes the importance of gather the required information and making it available to communities to help them proactively plan for and increase our resiliency to flooding. Updating the Englishman River flood hazard maps is an essential step that will help to inform better decision making, now and into the future, said RDN Chair Ian Thorpe”.

Under the RDN’s Sea Level Rise and Climate Adaptation Program, the Englishman River Flood Hazard Mapping project is partly funded through a grant from the Province of BC’s Community Emergency Preparedness Fund. The RDN is currently inviting proposals from engineering professionals through the Request For Proposals process until July 23, 2020. It is anticipates that the project will be completed in the Summer of 2021.