This tool allows the user to determine when a dam failure wave will first impact all areas. Similarly to the People at Risk tool, analysis can be carried out using a single dam failure surface, or a dam failure surface in conjunction with a no failure surface of the same event (eg PMF with/without dam failure).
For a single failure surface analysis, at all locations on the floodplain the time of arrival of the dam failure wave is defined as the time that water levels (or depths) increase by more than a tolerance above their initial values (first time step values). In the image below, this represents a travel time of 15.75hrs.
For a paired failure/no failure analysis, it is the time at which dam failure water levels (or depths) first start to exceed the no failure levels (or depths), within the specified tolerance.
Dam Failure Scenario File: Flood surface for the dam failure model results
No Failure Scenario File: Flood surface for the no dam failure conditions for the specified flood event. Leave blank to to a single surface analysis.
Pre-warning Time: Added to the travel time to provide effective warning time (eg if it takes 1 hour from notification of pending failure before failure occurs then use a value of 1. If it takes 1 hours after failure before failure is known, use -1)
Tolerance: The minimum difference between values to be considered the influence of the dam failure wave
Calculate using depth: Tick to use depth rather than water level in the analysis.