Modelling of a Coastal Aquifer using FEFLOW

The study by National Institute of Hydrology attempts to model seawater intrusion using FEFLOW, an interactive finite element simulation system in the coastal area of Bardez taluka in North Goa and evaluate the impact of increasing groundwater development on the phenomenon. Coastal tracts of Goa are rapidly being transformed into settlement areas and the poor water supply facilities have encouraged people to develop their own sources of water by digging or boring wells.

During the last decade, there have been large-scale withdrawals of groundwater by builders, hotels and other tourist establishments. Though the seawater intrusion has not yet assumed serious magnitude, but in the coming years it may turn to be a major problem if corrective measures are not initiated at this stage. It is necessary to understand how fresh and salt water move under various realistic pumping and recharge scenarios.

The study concludes that –

  • Presently, seawater intrusion in Bardez taluka of North Goa is confined only up to 290 m from the coast under normal rainfall conditions and present draft pattern.
  • Seawater intrusion may further advance inland if withdrawal of groundwater by builders, hotels and other tourist establishments continue to increase in the coming years.
  • Groundwater salinity needs to be continuously monitored near the coastal area, especially within 2 km from the coast.
  • Corrective measures with proper planning and management of groundwater resources in the area needs to be initiated to prevent a major water quality problem in the times to come.
  • The model is very sensitive to hydraulic conductivity and dispersivity values. Field and laboratory investigations need to be undertaken for measurement of these parameters for use in further modeling studies.
Presentations from Dr. C.P Kumar : Modelling of a Coastal Aquifer using FEFLOW