Two new reports from the provincial government predict extreme flooding events along the Fraser River will become more frequent and warn all but one of 15 dikes from Hope to Mission are too low.
One report entitled Fraser River Design Flood Level Update says many of the 146 kilometres of dikes were built in the 1970s and 80s to withstand the largest floods on record dating back to 1894.
But it says new modelling calibrated with data from Fraser River flooding in 2012 found most of the dikes to be too low and confirmed they need to be upgraded.
The second report, Simulating the Effects of Sea Level Rise and Climate Change on Fraser River Flood Scenarios, looked at 170 kilometres along the Fraser from Hope to the river mouth including the densely populated Metro Vancouver and Fraser Valley regions.
It concluded that by the end of this century, the size of flood that used to occur only once every 200 to 500 years will be more likely to take place once every 50 years.
The ministry says the reports are issued to assist in flood risk management, floodplain development and dike upgrade planning.
It recommends governments use the information to develop a regional flood protection strategy prioritizing high risk areas.