Analysis and Classification of Channel Network Types for Intermittent Streams in the United Arab Emirates and Oman

Abstract

The mountainous region in the north of the United Arab Emirates (UAE) and Oman features intermittent streams called wadis which are generally dry but flow seasonally or temporarily. This region is characterized by high peaks and carbonate rocks. The main objective of the present study is to identify drainage network types for fifteen wadis in this northern region of the UAE and Oman. The slope of preexisting surfaces (preexisting slope) is also estimated to determine whether the preexisting slope affects the development of wadi networks. Drainage network types are determined by using three scaling-invariance measures: the drainage area increments, the channel course irregularity, and the tributary junction angle. The slope of preexisting surfaces is estimated based on small drainage areas and Laplace curvatures that are close to zero. In this study, thirteen wadis are classified as rectangular networks and two wadis are classified as parallel networks. Parallel networks are found to occur on steep preexisting slopes similarly to other regions in the world. Rectangular networks are also found to develop on steep preexisting slopes, whereas in other locations, such as in the USA, the same network type occurs on gentle preexisting slopes. This indicates that the development of rectangular networks in the region may be unaffected by preexisting slopes.