Integrated Exploration methods for Groundwater Occurrence in basement terrain, Southern Hamissana area, Red Sea Region, Sudan.

Abstract

The study area lies in the Hamisana area at the westem flank of the Red Sea Hills in northeastern Sudan. lt represents one of the largest basement structures in Northeast Africa. The arca is mostly covered by crystalline basement rocks. where water supply is very limited and affected by the climatic degradation in which the annual precipitation is less than 50 mm/year. Acute water shortage is experienced. To achieve the main goal to explore the groundwater in the weathered/fractured basement, multi-disciplinary methods such as GIS, Remote sensing, Structural geology, geophysical and hydrogeological techniques were applied. Remote Sensing and Geographic Information System (GIS) techniques were used for effectual groundwater resource exploration and management In addition to that the investigations aim to reveal the geological, topographical and structural aspects ofthe area. as well as to extract. delineate and decode the main lineaments (features) were statistically analyzed to show their potential lineament map and frequency density map which are important guides to detect suitable site for groundwater occurrence. According to the structural analysis accompanied classification of potential fractures in the study area are; the extensional fractures trending North west-South east and the release fractures in north east -south west in the first collision and east west as extensional fractures and the release fractures in North-South direction in Second collision phase. Two geophysical methods were applied in this investigation including; Electrical resistivity method notify as Geo-electrical profiling and Vertical Electrical sounding techniques and the electromagnetic method frequency domain (FDEM). To provide more reliable results \~ hen combined together and integrated with geoinformation technologies. These techniques gave comprehensive information on the vertical and lateral lithological variations that govern the water bearing zones. The ultimate distribution of geophysical measurements can be achieved when based on satellite image interpretation and structural analysis disclosing the promising sites for groundwater occurrence. The outcome of the present investigations revealed that the area consists of two types of aquifers: the alluvial aquifers at depths range from 5 to 15 meters below the ground surface with resistivity values range from I90 ('Qm) to 570 (Om); and the weathered/fractured basement rocks aquifers that range in depth between 20-60 meters below the ground surface with resistivity values range from 51 (Om) to ('Qm) 242.