This paper gives an overview of the geophysico-chemical groundwater conditions in Sri Lanka and the associated contemporary management challenges. Groundwater is extensively used in Sri Lanka today, for agriculture, domestic use and industry/tourism. Groundwater access, availability and vulnerability are governed by six major types of aquifer systems of which the most prevalent is the regolith aquifers in the central hard rock areas of the island. Uncontrolled groundwater use and contamination or natural poor quality are leading to access limitations and health concerns. The tsunami severely affected groundwater in the coastal areas and functioned as a wake-up call to further emphasize the importance of groundwater for life-supporting functions. Despite an emerging awareness, groundwater management is in its infancy, with the attitude of groundwater development still not converted into an approach of active management. The role of groundwater in achieving sustainable development and in the development of appropriate water management institutions needs to be highlighted and specifically addressed in policy discussions.

The Valigamam region is underlain by a Miocene limestone formation and a highly porous soil cover. The region is totally dependent on groundwater to meet its agricultural, industrial and domestic needs, since other sources of water are seasonal. Recharge from rainfall is limited by high run-off and evapotranspirational losses. The region experiences water supply problems due to high concentrations of chloride, total hardness and nitrate in groundwater. The spatial distribution of chloride varies from year to year, with maximum concentrations experienced during or after the wet season. The major factor explaining high chloride concentrations is the excessive extraction of groundwater that results in saline intrusion from the sea or tagoonal areas. In a large proportion of wells sampled for nitrate, levels exceed the WHO standard due to intensive agricultural practices involving very high inputs of artificial and natural fertilizers and the improper construction of latrine soakaway pits. To improve groundwater quality in the Jaffna Peninsula will require controls on the location of new wells, a revision of existing and future pumping rates and a change in agricultural practices. It is imperative that future work in the region should focus on combining groundwater management and sustainable agricultural practice.

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