Groundwater flow and particle tracking model for Nileshwar basin using modflow

Abstract

Groundwater is an important source of drinking water and its availability is getting reduced as the population grows. Moreover, the groundwater, as other water supplies, is more and more exposed to pollution which results in the contamination of the groundwater. Transport path of subsurface water is the major pathways for contaminant spreading from contaminated areas. The study of this require information such as the average rate and direction of movement of ground water and contaminants The groundwater flow modelling is a vital tool for obtaining the information regarding the groundwater resources and contaminant transport in the study area. With rapid increases in computational ability and wide availability of computers and softwares , groundwater modelling has become a standard tool for effective groundwater management. The study proceeded with the development of the conceptual model of regional groundwater flow. The main objective of the present study was to set up a groundwater and contaminant transport model for the Nileswar basin in Kasaragod district of Kerala. The study presented herein used visual MODFLOW to construct a groundwater flow model in the basin. The drainage area of Nileshwar is about 190 sq kms. All the three physiographic regions, such as highland, midland and lowland of Kerala are represented in the drainage basins. A conceptual model of the study area was created based on the available input data such as topographical, climatic and well data of the area. The recharge in the area was taken as 10% of the average rainfall of the area during the period of study. A study state model was developed on the basis of average groundwater heads for 3 year period. The calibration of the model parameters was conducted under steady-state flow conditions. The model predicted the flow of the groundwater and velocity in magnitude and direction. The river, drain and constant head are taken as the boundary condition. The migration of the plume was also predicted by assigning some forward particle at different location and to remove the particle, the effect of the pumping well was studied. The model created during our study provides a clear idea of groundwater characteristics of Nileshwar river basin and it will help in the future studies and development of the groundwater management in the area. The groundwater and particle tracking model developed can be used to get a good knowledge of the groundwater availability and the risks of contaminant transport and how to mitigate its effect in the study area. A good use of the modelling software visual MODFLOW was used in this study.