Studies on saline water intrusion in the coastal stretch of Kadalundi river basin, Malappuram district, Kerala using visual MODFLOW – A case study.
Abstract The study on simulation of sea water intrusion into the coastal aquifers using Visual MODFLOW was conducted on coastal stretch of Tanur, Tirurangadi and Parappanagadi blocks of the Kadalundi river basin and this area comprises of about 130 km2 drainage area. The base map of the study area was imported into the model in BMP format and divided into 40 columns and 40 rows (1600 cells). Water level and water quality data of observation wells maintainedby Ground Water Department, Govt. of Kerala was used as input to the model. Secondary data on hydrogeological parameters and aquifer properties were also used as the input parameters of the model. In this study, Visual MODFLOW 2.8.1 integrated with MT3D software was used for groundwater modelling and contaminant transport modelling. It was observed that there is a chance of saline water intrusion in the coastal stretch of study area. There are chances of saline water intrusion to a lateral distance of 0.5 km to 1.9 km from the coast which extents 3.2 to 4.5km along the coast from northern boundary of Kadalundi river basin. Coconut retting, lime shelling and sand mining activities in the river basin were a potential source of pollution and contaminant transport. Development of small industries, construction of buildings and agricultural activities in the coastal stretch of river basin necessitated increased rate of pumping of ground water. This increased pumping of ground water leads to the entry of salt water into the fresh water aquifer formations. Global warming and sea level rise are also threatening problems in the current climate change scenario which is also a reason for saline water intrusion in to the coastal fresh water aquifers. Groundwater replenishment through natural and artificial recharge and sustainable development activities in the area are the main countermeasures to overcome this problem.
