VICTORIA - Two new reports released today will help planners and engineers in developing strategies to manage increased flood risk along the Fraser River.
The report, Fraser River Design Flood Level Update - Hope to Mission, provides diking authorities with updated design flood levels in comparison with crest levels of 15 dikes in the Hope to Mission reach. All but one dike are too low.
Many of these dikes were originally constructed in the 1970s and ‘80s to design levels established to meet the largest flood flow on record from 1894. Some sections of the 146 kilometres of dikes were upgraded over the years, but new modelling calibrated with data from the 2012 freshet found most of the dikes to be too low, and confirmed that renewed efforts are needed to protect the upper Fraser Valley from flooding.
The report, Simulating the Effects of Sea Level Rise and Climate Change on Fraser River Flood Scenarios, uses models to replicate possible effects of climate change-related sea level rise and increased flows on Fraser River flood levels.
The study area includes 170 kilometres along the Fraser from Hope to the river mouth, including the densely populated Fraser Valley and Metro Vancouver regions. The report indicates the magnitude and frequency of large floods will significantly increase due to sea level rise and climate change. The report notes that by the end of this century, a 50-year flood could be similar in magnitude to floods that currently have a return period of 200 or 500 years.
The ministry last released a report on the potential effects of sea level rise and climate change in December 2012. The ministry regularly releases studies and updated modelling information as it becomes available to assist those involved in infrastructure planning and flood mitigation.
Results from the two reports can be used to support flood risk management, and floodplain development and dike upgrade planning. Important next steps involve all levels of government working together to develop a regional flood protection strategy that prioritizes high-risk areas.
To view or download copies of the latest reports, visit the Ministry of Forests, Lands and Natural Resource Operations’ Flood Safety Section web page at: http://www.env.gov.bc.ca/wsd/public_safety/flood/fhm-2012/draw_report.html#8
Ministry of Forests, Lands and Natural Resource Operations