Identification of groundwater potential zones in the Machuca River in the Central Pacific of Costa Rica using a GIS-Multi-criteria analysis

Abstract:

Water supply systems in the Machuca River basin in the Central Pacific of Costa Rica are subject to fluctuations in their production capacity at the end of the dry season; especially in the lower part of the basin. The urban development – and water demand -- is expected to increase because of a newly build highway. In order to understand the actual water resources and to asses new ones, the identification of groundwater potential zones is done using a geographical information system (GIS) based on thematic raster using fixed score and weight computed by the multi influencing factor (MIF) technique.

The thematic layers used in the analysis are lithology, slope, land-use, lineament, drainage, soil and rainfall. The results were compared with the results of the Modified Thornthwaite-Mather model used to perform the water balance on a monthly scale. The groundwater potential was divided into three categories: no suitable, suitable, and very suitable zones. The resulting map is a decision support tool for the planning and management of groundwater resources in the Machuca River basin.