Watershed Characterization of Wadi Aurnah, Western Arabian Peninsula

Abstract

The Western part of Arabian Peninsula constitutes a shield-like mega-structure, in which mountain chains are oriented in the NW-SE direction. Along this mountainous region, surface runoff is almost diverted to-wards the Red Sea in the west. Thus, several catchment topographic units exist to capture rainfall water among them. Even tough, the precipitation rate in the Western part of Arabian Peninsula is low (i.e. <200mm), yet a number of drainage systems occur and reveal empirical stream networking. However, stud-ies belong to the watersheds located in the Western part of Arabian Peninsula are still rare and sometimes they show erroneous morphological characterization, notably in the catchments delineation. This is attributed mainly to the complicated drainage pattern, which is structurally-controlled. Thus, related morphological and hydrological studied obtained on these drainage systems reveal discreditable results and measures. This study aims to characterize Wadi Aurnah Watershed (~3113 km2), which comprises a typical catchment in the Western part of Arabian Peninsula. In addition to topographic maps, remotely sensed data (ASTER and IKONOS satellite images) were utilized to delineate water divides with the most precision. Consequently, relevant morphological and hydrological characteristics of Aurnah watershed were obtained.