Cl-/(CO3 2- + HCO3 -) Ratio to Evaluate Salt Water Intrusion: A Case Study of Gnanapuram Area of Visakhapatnam, AP, India

A systematic study has been carried out to evaluate salt water intrusion in the coastal aquifers around Visakhapatnam Port (Gnanapuram, Kobbarithota, Allipuram and Sevanagar) AP, India. The study area (latitude 83o17' and longitude 17o65') is at a distance of 2.5 to 3.0Km from the sea (Bay of Bengal) shore. Salt water intrusion can be one of the possible causes for ground water contamination. An attempt has been made to assess the impact of sea shore proximity on the ground water quality in the study area. Water samples have been collected from 12 open and bore wells (30-60ft deep) in the area and analysed to determine quantitatively the levels of carbonate and bicarbonate along with chloride. Cl-/ (CO3 2- + HCO3 -)ratio is considered to be one of the important criteria to evaluate salt water intrusion in the study area. Cl-/ (CO3 2- + HCO3 -)in all the samples is found to be less than 0.5. Therefore salt water intrusion is ruled out in the aquifers in the study area.