Analysis of the flash flood occurred on 18 January 2010 in wadi El Arish, Egypt (a case study)

Wadi El Arish is the largest drainage system in Sinai Peninsula, Egypt. The wadi was subjected to severe thunderstorms on 17 and 18 January 2010 followed by extreme violent flood that had not been known in Sinai since 1980. The flood claimed six victims, injured tens and devastated vital infrastructure and hundreds of houses. Hydrologic characteristics of the wadi are not fully understood due to the great lack of the detailed hydro-meteorological information. Hence, remote sensing and geographic information system (GIS) techniques were widely used to provide better spatial understanding of storm rain characteristics and drainage basin response. The study was based on the analysis of the TRMM images and the averaged six hourly HYDIS data for storm rain analysis. Hydrological model was constructed using ASTER digital elevation models (DEMs). The empirical black model box was used depending on the curve number approach to predict stream runoff. Landcover and hydrological soil groups were identified from the Landsat ETM+mosaic using multispectral supervised classification. The curve numbers were adjusted to ARC I (dry condition) as the total rain in five-day period preceding the storm was very low (5mm). The study deduced that the wadi received a total rain volume of 665.4x10(6) m(3). Most of the rain fell on 17 January with an intensity ranged between 4-8mm/hr. The estimated total surface runoff Q was 123.3x10(3)mm and the total runoff volume was 124x10(6) m(3) that constitutes 18.8% of the total rain volume. The results are in agreement with the observed values in the wadi, and highly required for many applications related to water harvesting and flood protection studies.