Estimation of groundwater recharge potential using MIF techniques in the Tatacoa desert, Huila, Colombia

Abstract

The Tatacoa desert, in the department of Huila, Colombia, is located between the Magdalena River and the Eastern Mountain Range. It is an arid zone, with a lot of erosion, classified as a tropical dry forest with maximum temperatures of 40 °C. The climatic and hydrogeological conditions produce problems related to water resources in the area, since, during the summer, 90 % of the streams dry up, causing a problem of drought in the municipality of Villavieja; however, there is underground water, but it is exploited in an empirical and not scientific way. The little hydrogeological knowledge comes from the Institute of Hydrology, Meteorology and Environmental Studies (IDEAM) studies, where it is made clear that the area belongs to the Neiva-Tatacoa-Garzon aquifer system, but there is not enough information to develop studies that allow the sustainable use of groundwater resources. For this reason, it was decided to carry out this study, which is part of a larger project of the EAFIT University, which seeks to expand the hydrogeological knowledge of this aquifer system. The objective of this work was to make a map of potential groundwater recharge zones, using geographic information data and satellite images of six geological factors: lithology, drainage density, slope gradient, land use/cover (LULC), guidelines and type of soil; these were chosen by the work team. The thematic layers of the factors were also transformed into raster and reclassified, according to a weight calculated from the multiple influence factor (MIF) methodology. The groundwater recharge potential (GWRpot) map obtained was divided into five categories: very poor, poor, moderate, high and very high. Finally, the results indicate that 83 % of the study area has moderate to very high potential and it is mainly located between the western and central zones.