English

H Kulkarni N

doi:10.5897/ijwree2015.0572

Abstract

This paper presents the numerical simulation of groundwater recharge from a point source, that is, injection well using Explicit Finite Difference Model (FDFLOW) and Galerkin Finite Element Model (FEFLOW). The proposed model aims at simulation of groundwater flow in two-dimensional, transient, unconfined aquifer for a chosen synthetic Test Case. These models are validated with reported analytical solutions for a test run period of 210 days. It is found that the FEFLOW model performed better than FDFLOW model in terms of conservation of mass and oscillations in numerical solutions. For simulation of recharge from an injection well test run period of 1500 days is considered. The accretion in groundwater volume from an injection well is analyzed. Further the effect of injection rate of a well and aquifer parameter is analyzed on model results. It is found that both the model solutions are highly sensitive to injection rate and moderately sensitive to transmissivity whereas the specific yield has negligible effect on numerical solutions.   Key words: Explicit Finite Difference Model (FDFLOW), Finite Element Model (FEFLOW), model validation, mass balance, courant number, sensitivity of models to recharge rate, transmissivity and specific yield.&nbsp

Highlights

Due to global warming it has become the need of the hour that ever depleting groundwater resources are to be continuously replenished using modern artificial recharging techniques
The mass balance error analysis for the flow models used in numerical experiments for Test Case 1 showed that both the FDFLOW and FEFLOW conserves the mass satisfactorily and the average mass balance error in both the models is well within the limit i.e. up to 0.69%.The FDFLOW and FEFLOW model solutions are found to be stable for the Courant number of 0.14 for the chosen time step of 1 day
Validation of FDFLOW and FEFLOW model for Test Case 1 shows that there is a close agreement between computed and analytical solutions in the initial stages of the pumping, after 210 days of pumping the difference between drawdown obtained by FDFLOW and FEFLOW model and analytical solution are 10 and 7% respectively

Summary

Introduction

Due to global warming it has become the need of the hour that ever depleting groundwater resources are to be continuously replenished using modern artificial recharging techniques. It is found that Explicit Finite Difference Model (FDFLOW) and Finite Element Model (FEFLOW) models provide meaningful simulations of recharge from injection well to aquifers than available physical and electricanalog models; these models provide ease in simulating complex aquifer geometry and varying aquifer parameters. Because these are quite so, numerical models of groundwater flow are properly conceptualized version of a complex aquifer system which approximates the flow phenomenon.

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