Author : Dr.N.Sridhar 1
Date of Publication :22nd February 2018
Abstract: The groundwater model is used to predict the effects of hydrological changes like groundwater extraction or irrigation developments on the behaviour of the aquifer and is often named as groundwater simulation model. Visual MODFLOW is the U.S. Geological Survey modular finite-difference flow model, which is a computer code that solves the groundwater flow equation. In this study, the Visual MODFLOW is used to simulate the flow of groundwater through aquifers in Lower Ponnaiyar watershed, Tamilnadu, India. The three-layer model is run with four phases that are model design, calibration, validation and prediction. The model is calibrated in two stages, which is involved a steady state calibration and transient state calibration using observed groundwater levels from 2005 - 2014. The validation is done by using observed groundwater levels from 2014 - 2016. The spatial distribution of hydraulic conductivity and storage properties are optimized using a combination of trial and error method. The simulation results showed that the fluctuations of hydraulic heads are dependent on seasonal variation in recharge from natural infiltration of precipitation and irrigation. The different scenarios are developed to predict aquifer system response under different conditions of the study area. The calibrated parameters are very useful to identify the aquifer properties and to analyze the groundwater flow dynamics and the changes of groundwater levels in the study area. The study suggests that from the prediction the recharge rate must be improved in the villages like Tiruppanambakkam, Karaimedu, Agaram, Kavanippakam, Anangur, Pillur, Tiruppachanur, Pedagam and Perangiyur which are located nearer to the river course. Also, this study concluded that the water level is high in central western part and declining towards the south Ponnaiyar River.