Thesis (M.Sc.)--Chulalongkorn University, 2006

Numerical simulation of groundwater flow and contaminant transport often involves managing large input and output data sets. Geographic Information systems (GIS) are used to store, manipulate and visualize both spatial and non-spatial data. Because of these data manipulating capabilities, GIS have been linked to different simulation models in different research areas and are commonly used for groundwater modeling. LGGM.NET is a program for linking GIS and groundwater model that is created in the Visual Basic.NET language to take full advantage of GIS capabilities. The Arc view 3.3 and Visual MODFLOW 3.0 were selected to investigate the method of integrating the GIS and groundwater model. A real contamination scenario of the sanitary landfill of the Pattaya municipality was chosen as the project area for this study. The predicted groundwater level and lead contamination were calibrated with historical data from the period 1999 through 2003 obtained from the Pollution Control Department. Statistical measures indicated a good fit between the predicted and observed concentrations. The root mean square error (RMSE) showed that errors were approximately 1.66 m for simulation of groundwater levels and 0.029 mg/L for simulation of lead transport. The advantages of linked GIS and groundwater model are represented in the application studies which resulted in the analysis of affected area of contamination using GIS analysis tools. It was found that remediation by pump-and-treat systems gave the highest treatment efficiency while the natural attenuation and vertical cutoff wall gave almost the same results.