Articles | Volume 12, issue 2
Nat. Hazards Earth Syst. Sci., 12, 443–457, 2012
Nat. Hazards Earth Syst. Sci., 12, 443–457, 2012

Research article 27 Feb 2012

Research article | 27 Feb 2012

An early warning system for flash floods in hyper-arid Egypt

J. Cools1,2,*, P. Vanderkimpen1, G. El Afandi3,4, A. Abdelkhalek5,6, S. Fockedey7, M. El Sammany6,**, G. Abdallah6, M. El Bihery6,***, W. Bauwens5, and M. Huygens1,**** J. Cools et al.
  • 1Antea Group, Ghent, Belgium
  • 2University of Geneva, enviroSPACE Laboratory, Switzerland
  • 3Al Azhar University, Department of Astronomy and Meteorology, Cairo, Egypt
  • 4Tuskegee University, College of Agricultural, Environment and Nutrition Sciences, College of Engineering, Tuskegee, Alabama, USA
  • 5Vrije Universiteit Brussel, Department of Hydrology, Brussels, Belgium
  • 6Water Resources Research Institute, El Khanater, Egypt
  • 7University College West Flanders, Research Group EnBiChem, Kortrijk, Belgium
  • *now at: Cool2Adapt Consult, Ghent, Belgium
  • **now at: Nile Research Institute, El Khanater, Egypt
  • ***now at: Ministry of Regional Municipalities & Water Resources, Muscat, Oman
  • ****now at: Dredging, Environmental & Marine Engineering (DEME), Zwijndrecht, Belgium

Abstract. An early warning system (EWS) for flash floods has been developed for part of the Sinai peninsula of Egypt, an hyper-arid area confronted with limited availability of field data, limited understanding of the response of the wadi to rainfall, and a lack of correspondence between rainfall data and observed flash flood events. This paper shows that an EWS is not a "mission impossible" when confronted with large technical and scientific uncertainties and limited data availability. Firstly, the EWS has been developed and tested based on the best available information, this being quantitative data (field measurements, simulations and remote sensing images) complemented with qualitative "expert opinion" and local stakeholders' knowledge. Secondly, a set of essential parameters has been identified to be estimated or measured under data-poor conditions. These are: (1) an inventory of past significant rainfall and flash flood events, (2) the spatial and temporal distribution of the rainfall events and (3) transmission and infiltration losses and (4) thresholds for issuing warnings. Over a period of 30 yr (1979–2010), only 20 significant rain events have been measured. Nine of these resulted in a flash flood. Five flash floods were caused by regional storms and four by local convective storms. The results for the 2010 flash flood show that 90% of the total rainfall volume was lost to infiltration and transmission losses. Finally, it is discussed that the effectiveness of an EWS is only partially determined by technological performance. A strong institutional capacity is equally important, especially skilled staff to operate and maintain the system and clear communication pathways and emergency procedures in case of an upcoming disaster.