Spatial and structural analysis of remotely sensed –automatically extracted lineaments and geophysical survey for groundwater exploration in se bayuda desert, Sudan

Abstract

ABSTRACT The study area lies in the southeastern part of the Bayuda Desert area in the Nile State, northern Sudan. Although the River Nile great loop engulfs the Bayuda Desert, most of its parts are subjected to severe water shortage, as it is characterized by a basement complex terrain, typical desert climate and scarce rainfall. Tectonically, the area is located at the fringe of the low grade ophiolitic decorated – metavolcanosedimentary arc assemblages of the Nubian Shield (Pan African age) with the high-grade gneisses and migmatites of the Saharan Metacraton (Pre- Pan African?). The main objective of this study is utilize the remote sensing and GIS techniques to investigate the groundwater potentialities to provide water supply, especially for the construction of infrastructure utilities. The Landsat 7 ETM+ image and SRTM DEM data have been digitally processed to produce a geological map, automated extracted lineament and drainage patterns, which integrated with the GIS spatial and structural analysis to locate the optimum sites for groundwater exploration. The potential groundwater zones mapped from the density map are favoured by the open extensional and release fractures in NW –SE and ENE –WSW, respectively. Moreover, they are governed by the proximity to the highway and existence of recharging drainage system. The potential sites were authenticated by ground geophysical survey and drilling activities. 1. INTRODUCTION Sudan new development plans are based on the optimum utilization of the natural resources in sustainable manner and conserving the environment. These plans started with inauguration of the Merowe hydro-electric generating dam in the northern Sudan in March, 2009. Additionally many infrastructural projects have been established, highways and bridges and supporting industries of building material queries and mining have been established in northern region and specifically in the Bayuda Desert in the North Sudan. The essential demands for groundwater resources are crucial in developing regions especially those in barren basement terrain such as Bayuda Desert. Hydrogeological investigations and exploration for groundwater in barren basement terrains are guided by two main groups of criteria: the primary or surface indicators and secondary indicators. The primary indicators are directly related to the groundwater regime such as recharge and discharge zones, i.e. rivers, channels, lakes, which are usually genetically originated or structurally controlled, soil moisture and anomalous vegetation. Secondary indicators comprise those geological and morphological features that control the occurrence and distribution of groundwater and include the rock type, geological structures, landforms and drainage pattern (Singah and Gupta, 1999). 2. STUDY AREA The study area lies in the southeastern part of Bayuda Desert, within the River Nile State administrative boundaries in North Sudan. The area is bounded by the great loop of the River Nile between the fifth and fourth cataracts. Geographically, the area is bounded by longitudes 33° 00’– 34° 00’E and latitudes 17° 30’- 18° 00’N, respectively (Figure 1).