Risk evaluation and mitigation against flood danger in an arid environment. A case study (El Bayadh region, Algeria).

Abstract

Floods are among the most serious and devastating phenomena of natural disasters. Cities adjacent to flood-prone areas in the last decades have played a major role in increasing the potential adverse effects of flood damage. This research study aims to evaluate and mitigate the risks of flood events in the El Bayadh region, which suffers from poor infrastructure and drained networks. To achieve this, it is necessary to evaluate rainfall intensities and their limits for durations from 0.167 to 24h with return periods from 2 to 1000years. Eight different frequency analysis distributions were fit to the historical rainfall data series over 43years (1970-2012) using hypothesis-based goodness tests and information-based criteria. The most appropriate distributions were used to develop the rainfall intensity-duration-frequency (IDF) and flood risk-duration-frequency (RDF) curves for the study area. The results show that high-intensity rainfall values last for short durations, while high flood risk values last for intermediate durations. The results of the flood RDF curves can provide useful information for policy makers to make the right decisions regarding the effectiveness of the region's protection structures against future flood risks.