The Peninsula of Jaffna has the greatest concentration of dug wells in the Island. It is the only part in the entire country where no perennial rivers exist. Hence the area does not get accounted in the standard 103 River Basins. The surface beneath abounds in Karstic Limestone, at times, from almost surface level. This assists in storing the moderate rainfall, which runs to the sea or inland lagoons relatively slowly, due to its flat terrain.For centuries this region has been self sufficient in water to grow its own food and for consumption of a large population, without any water imports from outside. This paper investigates how this water can be preserved and enhanced for the future,, by creating internal freshwater lagoons.