Importance Of Hydrogeology

1000 Words2 Pages

HYDROGEOLOGY
4.1 Introduction

The hydrogeology of a particular area is mostly determined by geology, geomorphlogy and climatic conditions. The document compiled by MWIE (2003)indicated that the hydrogeology of a country is characterized by regional factors such as geological processes (the swell, rifting and volcanism), the stratigraphy of alternating pervious and impervious formations, the development of secondary porosity and permeability through the fracturing and jointing of rocks and, the development of thermal groundwater and steam,mostly associated with rift valley. These factorsare ground to be putting serious impact on characterizing the challenges and problems in the catchments and the hydrogeological conditions of the study area. …show more content…

The main hydrogeological properties that have been used to characterize the catchments areporosity, yield and hydraulic conductivity. Due to the differences in mineralogy, texture and structure of volcanic rocks, water bearingpotential also varies. Groundwater circulation and storage in the volcanic rocks depend onthe type of porosity and permeability formed during and after the rock formation. All rockstructures possessing a primary porosity may not have necessarily permeability. In other words,without the original interconnection, the primary porosity may not give rise to the primarypermeability, but the latter’s connection, by means of weathering or fracturing may give rise to asecondary permeability(Alemayehu, 2006). The spatial distribution of the hydraulic conductivity of the area is highly variable due to the differences in geological settings. This section discusses the hydrological and hydrogeological features of the catchment so as to characterize and understand the hydrogeological conditions of the catchments. In addition to this purpose, the hydrogeological characterization of the catchments was used in determining the groundwater inputs of the SWAT …show more content…

A number of small streams and few perennial rivers drain the area. Wabe river, one of the major tributaries of Omo-Gibe river basin,joins this river in the vicinity of Welkite town. Among the main tributaries of Wabe river, Kereb, Demekash, Gogn, Cheika, and Legedima rivers are perennial rivers that sustain the Wabe flows during dry period. The main source of these rivers is from the northern and eastern parts of the catchment. Both the majority of large discharge springs and these rivers are being used for irrigation purpose in recent times. When compared to tributaries of Meki(Weja, Irenzaf, Atamuja), the tributaries of Wabe river are less affected by human and natural conditons and hence higher discharges are observed at Wabe catchment(Figure 4.1). Based on data from baseflow analyzed for river discharges of the catchments, it was observed that there exists significant interactions between surface water and groundwater(section 2.3) in both catchments. In turn, this condition has significant effects in the determination of the groundwater related parameters of SWAT model

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