NUMERICAL SIMULATION OF SALT WATER TRANSPORT TOWARDS A PUMPED WELL

Abstract

A numerical model for the simulation of salt water transport and subsequent entry into the pumped well in the coastal aquifer is presented. Model accounts for both convective and diffusive components of salt water transport. The convective component is evaluated by the method of charcteristics. The necessary velocity distribution is computed by solving the differential equation governing two dimensional axi-symmetric ground water flow equation by iterative alternating direction implicit method. The hydraulic conductivity and storage coefficient are defined in terms of salt water concentration. The diffusive component is estimated at each time step by solving the equation governing the diffusive transport of salt water explicitly, knowing the distribution of the salt water concentration arrived at by considering only the convective component. The model permits the estimation of,amongst others, the time variation of salt water lifted into suspension and of salt water concentration in the pumped well. Thus, the model can be used for the design of geometrical dimensions of well i.e. radius, degree of partial penetration etc. and its operating schedules.