LINEAMENT MAPPING FOR GROUNDWATER EXPLORATION USING REMOTELY SENSED IMAGERY IN KARST TERRAINS

Developing methods for analyzing remote sensing data to delineate fractures and discontinuities in hard-rock terrains could be used to improve well-sitting strategies. Groundwater recharge/discharge zones might also be delineated using remote sensing techniques that are sensitive to temperature, vegetation, and water content differences Meijerink (2006). Most features, such as bedding planes, foliations, and faults, occur as linear features called lineaments. Bruning (2008) demonstrated how lineaments could be mapped using remotely sensed imagery by identifying patterns based on color, tone, and texture in a small volcanic region. A similar approach is being used for karst terrains. A common application of remote sensing images in karst terrains is the mapping of features as indicators of the solubility of the rock. Other applications include mapping faults, lineaments and discontinuities that can be associated with cavern/fissure conduits and mapping regional faults that can be associated with zones of high permeability and concentrated groundwater flow Meijerink (2006). The study focuses in the Tanamá river catchment located in the North Coast Tertiary Basin of Puerto Rico, where groundwater is the main supply of drinking water for inhabitants and also contributes to base flow for surface water bodies. This aquifer region is a karst platform of carbonate rocks and clastic beds with one confined and another unconfined aquifer Renken et al (2002). Imagery to analyze includes an ASTER, a Landsat, a SRTM DEM and its hillshade (30 m), and a Lidar DEM (2 m). In addition to the Remote Sensing and lineament coincidence analysis, field verification, Isotope, rainfall, wells, and available tracer test data will be analyzed to better understand the influence of fracturing and dissolution features on groundwater in karst terrain in the region. Because of the high vulnerability to transport contaminants karst aquifers posses, having a better understanding of topographic, hydrological and tectonic relations is crucial to address environmental issues.