Floods and Reservoir Safety 3rd and 4th Edition Flood Freeboard Estimates Compared

The paper provides a short summary of some of the changes introduced in the 4th Edition such as the introduction of the Safety Check Flood in conjunction with the Design Flood and the move away from wave freeboard to a permissible wave overtopping discharge. The freeboard estimate in both editions is based on the significant wave height and the paper outlines the differences in approach after the significant wave height has been determined.

The variation of the flood freeboard estimates derived from both editions as a function of fetch and other parameters will be examined. Examples of the application of the two approaches to existing dams in the UK are provided.