REMOTE SENSING INDICATIONS OF RECENT DRAINAGE REVERSAL OF WADI WATIR, EASTERN SINAI PENINSULA

The transformed sinistral Gulf of Aqaba-Dead Sea strike-slip fault occured due to the Neogene tectonic movement along the eastern margin of the Sinai sub-plate. The movements were associated with uplifting forces and some volcanic activities during the Pleistocene. Evidence from structural features and recent seismic activities indicate that this phase is still active along the Dead Sea rift. The tectonic activity influenced the slope direction of El Hazim plateau in the eastern Sinai. Consequently, this phase affected Wadi Watir that has two major branches, Wadi Zeleqa toward the south and Wadi El-Heisi toward the north. The two branches are connected in Bir El-Saura area and flow to the SE on the Gulf of Aqaba. The present research aims at using remote sensing data, including ETM+, SRTM and Radarsat-1 to provide clear evidences to confirm the slope reversal of Wadi Watir. The watershed of Wadi Watir and its drainage patterns were extracted from the DEM (SRTM) data. Thus, several morphological features are noticed, indicating the reversal slope of Wadi Watir. First, the channels of the upstream are wider than the downstream, and the effluents emanate from vast flatlands. Second, the junction between the side wadis and the main stream of Wadi Watir is points to the Gulf of Aqaba, instead of pointing downstream. Third, the v-shape of the conjunction appears abnormal; the obtuse angle is toward the upstream, while the acute angle is directed toward the downstream of Wadi Watir. Data fusion of Radarsat-1 and the synchronous ETM+ satellite images were conducted to classify the texture roughness of wadi deposits. The results show existence of small disconnected paleolakes at upstream of the two branches. The northern system covers 150 km² and consists of two paleolakes. This system seems to be connected with the mega paleolake at the upstream of Wadi El Gerafi, which fans eastward toward the Negev Desert. The southern system covers 160 km² and consists of three paleolakes. These results indicate that both fluvial systems of Wadi Watir developed in depressions surrounded by highlands, prior the uplifting.