Identifying Optimum Sites for locating Reservoirs employing Remotely Sensed
Data and Geographical Information Systems.
K. Wan Yusof1 and Serwan M. J. Baban 2
1Email: apx158@coventry.ac.uk
GRRU Group, Geography,
School of Natural and Environmental Sciences,
Priory Street, CV1 5FB. U.K.
Tel. no: 44 024 76 838444
Fax. no: 44 024 76 838409
2Email:sbaban2001@yahoo.com
Department of Surveying & Land Information,
The University of the West Indies, St. Augustine, Coventry University, Coventry,
Trinidad, West Indies
Tel: 001 868 662 2002 ext. 2108
Fax: 001 868 6624414
Abstract
Langkawi Island in Malaysia, faces the possibility of having water shortages in the future, building reservoirs have been promoted as a possible solution to meet future demands for water supply. In this study, a criteria was developed to locate reservoirs taking into consideration all relevant factors including; topography, geology, hydrology, location in relation to both abstraction and supply points, land use/cover types and settlements.
A satellite imagery and digitised geological and elevation maps were analysed and used to generate the necessary data layers to satisfy various conditions within the established criteria. Then, IDRISI, a raster based GIS was employed to implement the criteria using two different methods to combine the information layers. First, the Boolean method which considered all the layers as being equally important to the process and gave them an equal weight. Second, theWeighted Linear Combination (WLC) method which grouped the layers and graded them according to their perceive importance. The Boolean method produced five reservoir sites located at the northern, southern and eastern of the Island. Whilst, the WLC method produced five sites located mainly towards the central area of the Island.
Comparing these outcomes with a field based study with a similar objective on the Island, which identified six suitable reservoir sites, showed that two of the sites located using the Boolean method and four of the sites identified using the WLC method have corresponded well with the field-based study sites.
This study indicates that the developed criteria for locating reservoirs are sensitive to the physical, environmental and economical settings on the Langkawi Island. Furthermore, GIS and remote sensing can be useful tools for generating, manipulating and handling relevant data layers, leading eventually to identifying a number of optimum sites for locating reservoirs and ultimately providing options and, assisting with the planning process.
1. Introduction
A study was conducted in Langkawi Island which faces the possibility of having water shortages in the future as a result of rapid development. The study concluded that the total water demand may increase three times greater in 2010 compared to 1993 (Syed, 1992). Building reservoirs has been promoted as a possible solution to meet the future demand of water supply (Baban and Wan Yusof, 2000).
