Groundwater Modelling to Predict Management Options for Vavuniya Region Aquifer

The problems in sustainable groundwater management are of major and vital importance in the areas that comprise shallowly weathered and rarely fractured rocks with thin soil mantle, as recharge and yield are relatively low in these areas due to low porosity and permeability. In order to find out better ways and means to evaluate, develop and manage groundwater resources in these regions, an attempt Was made to understand the groundwater system of Vavuniya region aquifer through numerical modelling and to examine the behaviour of the aquifer under various operating conditions. The results reveal that the groundwater usage has already reached its optimum level in this region and immediate action is required not only to control further expansion of groundwater exploitation but also to regulate groundwater withdrawal especially in low rainfall years. Further, the influences of the river and subsurface dams in groundwater system were examined and the results show that the non-perennial river has less influences and the subsurface dams certainly have an impact on groundwater system but this has to be studied further in detail, in order to minimize the negative impact and utilize the merits.