Hydro Geochemical Processes of Evolution Of Ground Water In A Small Tropical Coral Island Of Amini, Union Territory Of Lakshadweep, India

In the small tropical island of Amini ground water occurs under phreatic condition and is seen as a thin lens floating over the saline water. The coral sands and coral limestone act as principal aquifers. The depth of the wells varies from 1.6 to 5.5 mbgl and depth to the water table 1.20 to 4.80 mbgl. The ground water is generally alkaline and EC varies from 465 to 999 micromhos /cm at 25o C. The ground water is under Na+-SO42- type and shallow to deep meteoric percolation types and generally alkaline in nature. The factors affecting the quality of ground water are rainfall, tides, ground water recharge and draft, human and animal wastes, oil spills and fertilizers. Water samples collected from different parts of the island during pre-monsoon and post monsoon seasons. The water sample results of chemical analysis indicate that water type ranges from Ca-HCO3 (recharge type) to Ca-Mg-Cl type (reverse ion exchange water type).