Analytical probabilistic flood routing for urban stormwater management purposes

The main purpose of flood routing calculations conducted in urban stormwater management studies is to determine the flood frequency distribution at a downstream location knowing the upstream catchments, channel reaches, and detention ponds. As the current state of practice, the design storm approach is widely used for this purpose and for the planning and design of related stormwater management facilities. Building upon previous work, methods and procedures are proposed here so that flood routing for stormwater management purposes can be completed probabilistically using analytical equations. Results from the proposed methods and procedures are compared with design storm modeling results for a number of routing scenarios. The comparison study not only establishes the credibility of the proposed methodology, but also highlights potential problems associated with the application of the design storm approach.