Author(s)

L. G. Castillo & M. D. Marin

Abstract

It is known that in semiarid regions with steep morphology and irregular rainfall regime areas floods present with a high proportion of solid material transport. Furthermore, climate change will increase flash flood phenomena, and will make it necessary to control them to minimize their destructive effects. In order to design effective control and intake systems in semiarid regions, it is necessary to know the hydrologic and hydraulics characteristics of ephemeral rivers. According to the results in Las Angustias Gully (Isla de la Palma-Spain), and based on their similarity to the semiarid watersheds of the Region of Murcia (Spain), the first results of Mergajón, Intermedia Gully and Hoya de España Gullies (Murcia) were studied in order to establish a general criteria of calculation in these regions. Based on the results obtained with distributed and aggregated hydrologic models, in this paper the authors try to analyse the principal hydrologic properties and sediment transport in ephemeral streams. Keywords: semi-arid region, sediment transport, resistance coefficient, ephemeral river, hyperconcentrated flow. 1 Introduction Semi-arid regions are characterized by an irregular rainfall which confers on them, among other characteristics, reduced, or almost absent, vegetation coverage. In addition, a direct effect on the frequency and intensity of precipitation is being caused by climate change, so the precipitation is less frequent and more intensive. The combination of these two elements, heavy rains and potentially erodible areas, explains the fact that hyperconcentrated flows are

Keywords

semi-arid region, sediment transport, resistance coefficient,ephemeral river, hyperconcentrated flow