Spatial Hydrological GIS Analysis and Estimations of Runoff in Khor Gowb Drainage Basin in the Red Sea State –Sudan

Abstract

The magnitude and availability of surface waters in Khor Gwob of the Red Sea State was examined
using spatial hydrological analysis in Geographical Information Systems (GIS). As a system with advanced geo-
modelling capabilities, GIS is used to integrate spatial analysis with hydrological modelling. Several levels of
spatial hydrological modelling such as parameterization, spatial integration, regionalization and assessment of
hydrologic problems were made. Four physical / deterministic and stochastic models were developed and applied
at both catchment‟s and regional scales to estimate the water volume of many drainage basins in the area. The
results evaluated using the general error term to compute the differences between the estimated areal runoff and
the observed runoff in the Khor Gwob drainage basin in Erkowit area of the Red Sea State. Accordingly, one
stochastic model has been tested and regionalized. The significance of the catchment and regional runoff estimates
was evaluated in relation to errors inherent in the spatial database, GIS analysis, and hydrological modelling (e.g.,
the Rational Formula). Finally, it is concluded that Khor Gwob basin and the Red Sea State at large, contributes an
annual surface runoff that exceeds the human and animal needs with a considerable surplus that can be used for
agriculture (i.e., the region is water sufficient). Conversely, this sufficiency is limited by the problem of spatial
distribution and related storage difficulties. With regard to human, animal and agricultural water supply, only few
catchments can support the proposition of water sufficiency in the State.