Modelling of Seawater Intrusion in Munroe Island, Kollam District, Kerala, India

Abstract

Munroe Island is an island situated at the meeting point of Ashtamudi Lake and the Kallada River in Kerala's Kollam district. It has been confronted with a substantial issue of salinity intrusion, which has been adversely impacting the groundwater's quality on the island. To combat these, it is necessary to develop a groundwater management model. The present study aims the modelling of seawater intrusion using FEFLOW. The main objectives of this study are to develop a numerical model using FEFLOW for groundwater flow and contaminant transport, as well as to identify the affected areas and the extent of seawater intrusion. From 2015 to 2021, the ingress of saline water into the island was assessed, and a forecasted simulation of seawater intrusion was conducted for normal conditions and due to 1% increase in pumping conditions until the year 2050. The study revealed that Edachal South is the area most susceptible to seawater intrusion. In normal conditions, the extent of saline water intrusion is around 1.123 km, and under increased pumping scenarios, it is expected to rise by 3.3%. The study's findings highlight that a significant portion of Munroe Island will be at risk of seawater intrusion by the end of 2050.