Abstract

The Geological and Geochemical Examination of Ground Water Resources in a Small Tropical Coral Island of Amini, Union Territory of Lakshadweep, India has carried out. The Map Info 6.5 techniques have been used for preparation of various layers and ground water resource of Amini has been computed based on the methodology recommended by the GEC 1997. The various hydrogeological parameters collected during the field study and water level data observed during low and high tide. The pre-monsoon (PRM) and post-monsoon (PSM) groundwater samples analysed for pH, EC, F^-, Cl^-, NO^3-, HCO^3-, SO4 ^2-, Ca²⁺, Mg²⁺, Na⁺, and K⁺ as per standard procedures and the in-situ measurements of EC and pH were carried out by using EC and pH meters. At 16 sites Vertical Electrical Soundings (VES) had carried out by Wenner electrode spacing up to a maximum spread length (AB) of 120 m and IPI2 Win v2.0 used for the interpretation of the VES data. The purpose of the study is to examine geological and geochemical characteristics of ground water resources of the Amini. In Amini ground water occurs under phreatic condition and floats as lens over the marine water and the principal aquifers in the area are coral sands and coral limestones. The depth of the wells is 1.6 - 5.5 meters below ground level (mbgl) and depth to the water table 1.20 - 4.80 mbgl. The ground water is under Na+-SO42- type, shallow to deep meteoric percolation types and alkaline (EC variation 465 - 999 micromhos /cm at 25o C). The water samples are Ca-HCO3 (recharge type) to Ca-Mg-Cl type (reverse ion exchange water type).The hydrochemistry in the area is mainly controlled by evaporation, water–rock interaction and aquifer materials. The evaporation process played major role in the evolution of water chemistry. The ground water in the study area is suitable for irrigation in all types of soil.