Hydrology of Overland Flow at Halaylb and Shelatin Watersheds, Eastern Desert, Egypt

Authors: Samir Anwar AL-GAMAL

Abstract: Potential surface runoff of ten watersheds in Halayib area, southern Egypt is estimated for the tirst time. The hydrological response of the watersheds studied to single storm events is tested. Base flow source areas and major recharge areas were delineated by infiltration, and stable isotope data were expressed in terms of \delta 0-18 and deuterium (D). It is observed that these watersheds are frequently subjected to local floods, associated with short periods of high intensity thunderstorms, due to local convection in periods of excessive heating in the winter and fall seasons. Potential surface rainfall is controlled by some key hydromorphometric parameters such as weighted channel gradient (S_o), length of main channel (L_b), length of the center of gravity of the watershed (L _c) and catchment area (A). Because of the paucity of the runoff data for all of the studied watersheds, it was necessary to estimate pCotential runoff yields by means of the empirical formulae developed by Snyder (1938) and SCS (1957) in addition to the local functional relationships that are developed for these watersheds.

Keywords: Hydromorphometrical analysis, peak flow, synthetic hydrograph, lag-time, base flow, stable isotope.