The lower Fraser River floodplain in BC has a complex diking system, comprised of 58 dikes, which protects more than 340,000 people living on the floodplain. When it comes to preparing mapping, for planning and emergency response and to support regulation of land use and development, assumptions tied to future upgrading of dikes and the performance of dikes during a large flood event can be critical. _x000D_ _x000D_ Northwest Hydraulic Consultants (NHC) recently completed regional hydraulic modelling and mapping for a 100 km reach of the lower Fraser River. We will discuss the dike performance assumptions selected for the project and the reasoning behind the approach. We will go over the modelling and mapping implications and limitations of the selected approach. Finally, we will share information about the results and potential uses of the new flood maps; as well as challenges, opportunities and lessons learned._x000D_
