Risk-Based Early Warning System for Pluvial Flash Floods: Approaches and Foundations

Abstract

In times of increasing weather extremes and expanding vulnerable cities, a significant risk to civilian security is posed by heavy rainfall induced flash floods. In contrast to river floods, pluvial flash floods can occur anytime, anywhere and vary enormously due to both terrain and climate factors. Current early warning systems (EWS) are based largely on measuring rainfall intensity or monitoring water levels, whereby the real danger due to urban torrential floods is just as insufficiently considered as the vulnerability of the physical infrastructure. For this reason, this article presents a concept for a risk-based EWS as one integral component of a multi-functional pluvial flood information system (MPFIS). Taking both the pluvial flood hazard as well as the damage potential into account, the EWS identifies the urban areas particularly affected by a forecasted heavy rainfall event and issues object-precise warnings in real-time. Further, the MPFIS performs a georeferenced documentation of occurred events as well as a systematic risk analysis, which at the same time forms the foundation of the proposed EWS. Based on a case study in the German city of Aachen and the event of 29 May 2018, the operation principle of the integrated information system is illustrated.

Algorithm to Predict the Rainfall Starting Point as a Function of Atmospheric Pressure, Humidity, and Dewpoint

“…Taken together, these results suggest that current early warning systems could be based on measurements of rainfall intensity. Those systems could be combined with monitoring of water levels [62,63]. These findings suggest several courses of action to record, send, and monitor floods using a new generation of smart water level gauges [64].…”

Investigation of Flash Floods on Early Basis: A Factual Comprehensive Review

“…Risk based early warning system case study was carried out at the German city of Achen. Georeferenced files consisted the following data for GIS design, precipitation velocity, timings, precipitation intensity, affected area, video and images of flood with time and actual depth of the flow rate [70]. Flash flood event was estimated which was caused by the severe rainfall eighty millimeter per day in northern Morogoro and Tanzania.…”

Geomorphology of landslide–flood-critical areas in hilly catchments and urban areas for EWS (Feltrino Stream and Lanciano town, Abruzzo, Central Italy)

“…Early Warning Systems (EWSs) are one of the methods and tools to increase urban resilience to geomorphological hazards. These systems are fundamental for disaster management and adaptation, and the preparation of response strategies, and are becoming increasingly used at the national and regional scales (Chikalamo et al, 2020;Corral et al, 2019;González-Cao et al, 2019;Harilal et al, 2019;Hofmann & Schüttrumpf, 2019;Krzhizhanovskaya et al, 2011;Ma et al, 2019;Parker, 2017;Rosi et al, 2015;Segoni et al, 2018). To be useful at the urban scale, EWSs should be implemented incorporating (1) geomorphologically based mapping; (2) an assessment of landslide-flood critical areas at the basin and local scales; (3) an integrated geodatabase for the management of base data and critical area mapping; (4) IOT (internet of things) networks of urban gauge-sensors, realized by taking into consideration the overall features of the specific catchments or urban areas (e.g.…”