Flood mapping in ungauged basins using fully continuous hydrologic–hydraulic modeling

SummaryIn this work, a fully-continuous hydrologic–hydraulic modeling framework for flood mapping is introduced and tested. It is characterized by a simulation of a long rainfall time series at sub-daily resolution that feeds a continuous rainfall–runoff model producing a discharge time series that is directly given as an input to a bi-dimensional hydraulic model. The main advantage of the proposed approach is to avoid the use of the design hyetograph and the design hydrograph that constitute the main source of subjective analysis and uncertainty for standard methods. The proposed procedure is optimized for small and ungauged watersheds where empirical models are commonly applied. Results of a simple real case study confirm that this experimental fully-continuous framework may pave the way for the implementation of a less subjective and potentially automated procedure for flood hazard mapping.

► A fully-continuous approach (FCA) for flood hazard mapping is introduced.
► The FCA overcomes the concept of design hyetograph and design hydrograph.
► The FCA may lead to the implementation of automated procedure for flood hazard mapping.
► The FCA may lead to the implementation of less subjective models for flood hazard mapping.
► Standard event-based approaches may significantly underestimate inundated areas.