Dam‐Break Solution

A closed‐form solution is obtained for a dam‐break problem in which the reservoir, dam breach, and downstream channel all have different widths. The reservoir outflow is calculated by using a quasi‐steady flow approximation, and downstream flood depths are calculated by using the kinematic‐wave approximation. An investigation into the validity of these two approximations leads to constraints that must be placed upon applications of the solution. A numerical example shows that maximum downstream flood depths decay relatively slowly because of storage contained within the upstream reservoir.