Browsing by Author "Jayawickrama, N.T."

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    Identification of suitable landfill sites for solid waste disposal in the Matara District using Geographical Information Systems and the Analytic Hierarchy Process
    (Sri Lanka Association for the Advancement of Science, 2011) Jayawickrama, N.T.; Weerasinghe, V.P.A.
    Improperly placed solid waste dumping sites have created numerous environmental and social problems in the society. Such impacts could be minimized by implementing proper landfills in suitable locations. Even though Matara is a highly populated district, it lacks properly planned landfills. The objective of this study was to select suitable sites for solid waste landfills in the Matara District using the Geographic Information System and the Analytical Hierarchy Process. Existing national and international landfill site selection regulations and guidelines were reviewed to prepare eleven landfill site criteria namely; surface water body, forest reserve, wetland, coastal zone, rainfall, town centre, residential area, important building, major road and railway, slope and soil. These criteria were divided into two parts, constraint criteria and factor criteria. Constraint criteria divide the district into suitable and unsuitable areas for landfill site placement. Factor criteria classify the suitable areas for landfill placement into high, medium and low suitable areas. Each constraint criterion was mapped using GIS. All eleven constraint criteria maps were overlaid to prepare the final constraint map. From the total area of Matara district, 1100.16 km2 (85.7%) is unsuitable for landfill placement. The remaining 182.34 km2 (14.2 %) land area of the district was further evaluated using factor criteria and was classified into three groups of high, medium and low suitability. When determining the relative importance of each factor criterion Analytic Hierarchy Process was utilized. The resulting final factor map revealed that 112.4 km2 (8.8%) of land in the Matara District is highly suitable for placing landfills. Field investigations within the Matara Divisional Secretary Division were carried out to validate the data obtained from the final factor map. It was found out that one site at Thalpawila, one site at Parawahera and two sites at Kekanadura were suitable for landfills in Matara Divisional Secretary Division. The final decision for landfill site selection will require more detailed field studies.
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    Locating Suitable Sites for Solid Waste Landfills in Matara District Using GIS and AHP
    (Department of Zoology, University of Kelaniya, Kelaniya, Sri Lanka, 2014-06) Jayawickrama, N.T.; Weerasinghe, V.P.A.
    Landfill site selection in highly populated areas is a critical issue in today‘s society because of its enormous impact on the economy, ecology and the environmental health of the region. Present study was conducted to find suitable locations for landfills in Matara district, which is a highly urbanized area. Geographic Information Systems and Analytic Hierarchy Process were integrated in this study to solve the landfill site selection problem. Waste collection and population data of the study area were used to estimate the cumulative waste amounts up to the year 2020 and the minimum effective area needed for landfill sites. Eleven landfill siting constraint criterion maps including surface water, forest reserves, wetlands, coastal zone, rainfall, town centres, residential areas, important buildings, major roads and railways, slope and soil were prepared and unsuitable areas for landfills were determined according to the existing regulations. Further evaluation of the remaining suitable areas in three categories of high, medium and low priority for being suitable for landfill sites was done using factor criteria. Depending on the relative importance of the identified criteria, weights were calculated by Analytic Hierarchy Process and were incorporated in to the analysis. The maps prepared for each criterion were then overlaid in Geographic Information Systems environment to obtain the final suitability. The resulting final factor map shows a land area of 112.4 km2 from Matara district as highly suitable for landfill areas. Field investigations show that Thalpawila, Parawahera and Kekanadura have most suitable areas for landfill sites at Matara district.