DEVELOPMENT OF GIS BASED MODEL FOR LOCATING SUSTAINABLE CONSTRUCTION AGGREGATE MINING SITES: CASE STUDY FROM SRI LANKA

摘要

Major raw material for the construction industry in Sri Lanka is rock aggregates. During the last decade construction industry has boomed in Sri Lanka and the mining for the construction materials increased dramatically. Though, Sri Lanka has rules and regulations imposed to manage and control the mining activities, several social and environmental issues are encountered at most rock quarrying sites. Most of the issues faced by quarry mining industry are due to prevailing heterogeneous land use pattern in Sri Lanka. As mining activities always cause some negative impacts on the environment, it is important to find a solution to minimize such impacts. Present study aimed to develop model to locate most appropriate sites for sustainable quarry mining where impact on the surrounding environment is minimum. GIS model was developed to locate most suitable and sustainable quarry mining sites. The model was tested using two districts, Anuradhapura and Gampaha in Sri Lanka representing rural and urbanized areas respectively. Five Land use classes such as Home-Land, Cultivated-Land, Forest-Land, Scrubs/Bare-Land and Rocks were used for the model giving weights based on the distance to the site and their impacts on the environment. From the developed model, cumulative weighted indexes calculated in 14 locations in Anuradhapura district show minimum score of 250 and maximum score of 394. However, in Gampaha district from 10 locations studied, it shows 116 as minimum value and 591 as maximum. Anuradhapura district has relatively low population density, and mining locations scored higher weighted indexes within a narrow range whereas Gampaha district where population density is higher and mostly covered by urbanized areas, some locations scored very low weighted indexes from the model and few locations show very high scores. Most of sites scored higher average weighted indexes from the developed GIS model operating with less social and environmental issues. Thus the developed model can be used to locate new mining sites with minimum impact to the environment.