Runoff modeling of Sebou watershed (Morocco) using SCS curve number method and geographic information system

Abstract

The Sebou watershed is considered as one of the most important drainage basins in Morocco. This basin had been exposed to frequent flood hazards which were responsible for many damages in several areas of the basin. In the present study, the curve number method was implemented to assess the runoff based on hydrologic modeling method. The use of geographical information system allow us facility in the mapping and geo processing of spatial data for the factor affecting runoff such as land use, hydrologic soil group, digital elevation model and rainfall. The average annual rainfall is 582 mm, and we distinguish two hydrological soil groups with the dominance of group D, the largest land use found in the area is agriculture class. The average curve number is 85. This high value means a high degree of runoff and a low degree of infiltration. The average annual runoff depth for Sebou watershed is 543.6 mm which represents 91.5 % of the total annual rainfall. These results revealed that hydrologic model can be used efficiently to support integrated watershed management.