Spatial and Temporal Analyses of Land Use and Land Cover Changes in Negombo Lagoon-Muthurajawela Marsh Areas

Abstract

In the present study, an investigation has been carried out to identify and assess the spatial and temporal changes of land use/land cover in the Negombo lagoon and Muthurajawela marsh areas from 1987 to 2001. The paces of changes of land use and land cover in this area keep rising due to urbanization and industrialization. Time-series satellite images of Landsat TM and ETM+ which covered the time frame from 1987 to 2001 were used in this study. Interpretation of images and analysis of data was accomplished through integrated use of ERDAS imagine [version 9.2) and ArcGIS (version 9.2) software packages along with Microsoft Excel analytical tool. The results revealed that there are nine different major land use categories namely, built-up areas, coconut lands, home-gardens, marshy lands, paddy fields, sandy covers, shallow water areas, vegetation areas and water bodies. More than 28% of the total area has been covered by both deep water and shallow water bodies throughout the 14 year period. Paddy lands, coconut plantations, sandy covers and marshy lands have been considerably decline during the 14 year period. Apparently those lands were converted to home gardens and built-up areas due to urbanization and industrialization; residential occupation has significantly increased during 1987 and 2001. In 2001 the home garden and built up areas constituted 41% of the total land extent. An Increasing trend has been detected in built up areas and home gardens while decreasing trend is observed in all other cases. Extent of built-up areas seems to expand in eastern and southern part due to industrial development. Built-up area expansion in the western part is associated with tourism, where as in the northern part it relates to urbanization.