Impact of Rainfall Movement on Flash Flood Response: A Synthetic Study of a Semi-Arid Mountainous Catchment

Abstract

Rainfall is a spatiotemporally varied process and key to accurately capturing catchment runoff and determining flood response. Flash flood response of a catchment can be strongly governed by a rainfall’s spatiotemporal variability and is influenced by storm movement which drives a continuous spatiotemporal change throughout a rainfall event. In this work, the sensitivity of runoff and flooded areas to rainfall movement are assessed in the Kan catchment (Iran). The allochthonous nature of floods in the catchment and how they interact with the effects of rainfall movement are investigated. Fifty synthetic rain hyetographs are generated and traversed over the catchment under different velocities and directions and used to force a 1D/2D hydrodynamic model. The results suggest rainfall movement affects the runoff response in different degrees. Peak discharge, hydrograph shapes and flooded areas are affected. Storms with higher velocities result in higher peaks and faster onsets of runoff and consequently higher flooded areas in comparison to slower storms. The direction of the movement also plays a role. Storms moving along the average direction of the stream result in higher peaks and flooded areas. The relevance of storm direction is greater for slow moving storms. Additionally, the influence of rainfall movement is modulated by hyetograph structure, and the allochthonous behavior is greatly dependent on the location within the drainage network at which it is assessed.

Integrating Critical Infrastructure Networks into Flood Risk Management

“…In this paper, "probability", "hazard" and "consequences" are used as terms where the consequences are a combination of exposure and vulnerability [39]. This paper describes catchment-based flood risk analyses based on Bachmann and Schüttrumpf [40]. The focus on entire river catchments ensures that hydraulic responses of potential measures up and down the river are considered.…”

“…Inundation maps are used to derive the water level at CI structures during flooding events. Hydrological and hydraulic modelling are the state-of-the-art tools to achieve this identification for operational and strategic flood risk analysis, from a local to a global scale [22,[40][41][42][43].…”

Development of Pod-Based Reduced Order Models Applied to Shallow Water Equations Using Augmented Riemann Solvers

“…Shallow flow numerical modelling has been a very active field of research recently, supported by the increasing availability of laboratory and field data. Developments in numerical methods in recent years have led to a series of models applicable to a wide variety of geometries and flow types [4][5][6][7].…”