LINEAMENT ANALYSIS FOR THE GROUNDWATER IN KARST FRACTURED ROCKS IN THE SUOIMUOI KARST CATCHMENT

Abstract. Vast areas of the world consist of hard rocks (basement complexes), where water is restricted to secondary permeability, and thus to the fractures and the weathered zones. Most of such areas have a shortage of water. As the success ratio of drilling in hard rock terrain may be low, and the use of geophysics is often judged as too expensive, the study of lineaments from remote sensed imagery is an attractive alternative. High production areas in hard-rock aquifers are generally associated with conductive fracture zones. An effective method for defining the fracture zone is based on lineament indices, which are extracted from satellite imagery. Together with a detailed structural analysis and understanding of the tectonic evolution of a given area it provides a useful tool for hydrogeologists for studying groundwater in fractured rock and developing water resources. The relationship of lineaments, fractures and groundwater is studied by Mabee et al. (1994), Kresic (1995), Sander (1997), Magowe (1999), Krishnamurthy et al. (2000). They agree that a high density of lineaments indicate in general the presence of groundwater. Hung et al. (2002) suggested that fractured rocks could be analysed by studying lineaments with the help of lineament indices. An application of the proposed methodology, on basis of Landsat ETM images, is given here for the tropical Suoimuoi karst catchment, NW-Vietnam.