Analyzing changes in the surface-subsurface hydrology in the

Abstract

Interconnective processes involving surface and sub-surface groundwater reservoirs are complex and need visualization on the spatial domain for developing systems knowledge. In this context, this investigation mainly focuses on analyzing ‘how human induced changes to the surface hydrology (i.e., in the overland flow) have impacted on the subsurface hydrology in the Vavuniya UC limits’. Due to the lack of adequate data, field based model building approach and subsequent simulations become essential for developing management scenarios. Using data gathered as such spatial mapping of terrain, geometric network modeling of water flow lines were done in Arc GIS 9.2 based on the info from Google Earth services to get a model for the estimated area of groundwater potential. For validation of the model, the actual state of groundwater’s potential was modelled using 190 point (based) data of the depth of water table gathered in-situ. It is seen that the human induced changes that have occurred in the cascade-lines of water flow have reduced the groundwater potential at present. From the data collected, it is also estimated that 17% of the wells are usually dried-out in the dry season (June – Sep) every year in which 7% of the wells have been further drilled to tap more water. For future researches in this regard, incorporation of population and meteorological data will facilitate the development of better models for the integrated (and sustainable) management of surface-subsurface hydrology.