1 “INCOPERATING GIS IN WATER RESOURCES MODELLING: Application of SWAT 2005 Model in Sungai Kurau, Perak and CCHE2D Model in Tasik Harapan USM, Penang” Zorkeflee Abu Hasan 1 , Nuramidah Hamidon 2 , Norazazi Zakaria 3 , Aminuddin Ab. Ghani 4 and Leow Cheng Siang 5 1 ZORKEFLEE ABU HASAN, Senior Lecturer, River Engineering and Urban Drainage Research Centre (REDAC), Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, 14300 Nibong Tebal, Penang, Malaysia. Email: redac04@eng.usm.my 2 NURAMIDAH HAMIDON, M.Sc Student, (REDAC), Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, 14300 Nibong Tebal, Penang, Malaysia. Email: redac26@eng.usm.my 3 NORAZAZI ZAKARIA, Director, (REDAC), Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, 14300 Nibong Tebal, Penang, Malaysia. Email: redac01@eng.usm.my 4 AMINUDDIN AB. GHANI, Deputy Director, (REDAC), Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, 14300 Nibong Tebal, Penang, Malaysia. Email: redac02@eng.usm.my 5 LEOW CHENG SIANG, Research Officer, (REDAC), Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, 14300 Nibong Tebal, Penang, Malaysia. Email: redac21@eng.usm.my ABSTRACT Geographical Information Systems (GIS) is a collection of computer hardware, software, and geographic data for capturing, managing, analyzing, and displaying all forms of geographically referenced information. GIS is gaining its popularity with the water and environmental related applications. Many mathematical models have incorporated or integrate the GIS application to generate inputs and display output or as interface for the entire modelling processes. This paper is to demonstrate the use of ArcView as the interface for the mathematical modelling at the river basin level using Soil and Water Assessment Tools (SWAT) 2005 and as a tool to assist the data input for the two dimensional modelling using CCHE2D. The SWAT models with GIS interface were used to predict the impact of land management practices on water, sediment and agricultural chemical yields in Sungai Kurau basin in term of water quality and water quantity. From the calibration and validation results of SWAT show the observed and predicted data are close to each other in terms of magnitude and timing. Meanwhile for CCHE2D, the GIS software was used to assist the modeller in finding the locations of areas having potential instability problem that might occur in Tasik Harapan. The results show that GIS is a versatile tool for water resources management, either as an interface as for SWAT or as an aid for the modelling as for CCHE2D. Keywords: GIS, Hydrology, SWAT2005, Mathematical modeling CCHE2D, and ArcView GIS