GIS MODELLING APPROACH FOR ENVIRONMENTALLY SUSTAINABLE URBAN LAND USE PLANNING IN COLOMBO URBAN AREA

Abstract

Rapid urbanization is proceeding and pushing up the demand for various land uses mainlyresidential, commercial industria; etc. Land is an essential ingredient in this process, as in allurban growth. This growth has been associated with increasing pressure on land for humansettlements and related urban services. The problem in Sri-Lanka like most developingcountries, is not a shortage of developable land, but the ineffective and unplanned mechanismsthe use to ensure supply of suitable land for urban expansion. The trend of the development ofthis nature bears a heavy impact on the urban land development as evident from the horizontalexpansion of urban centres. As a result of that increased development pressure on agriculturallands in immediate surroundings of urban centres as further aggravated the problem ofconservation of the natural environment. The above shows that in the past insufficient attentionhave been paid to the land use planning for identification of conservation and development. As aresult of that ecologically valuable lands are converting to urban development withoutconsideration of the environment With in this contex, present land use planning necessitates topay attention of environmentally sustainable land use land use planning. When considering thesustainable development of land, land use change management is an important phenomenon.The content of land use change management can be described in terms of three value sets(ecological, social and market values) that must be brought into by land planningThe rapid population growth in Colombo Urban Area has been associated with increasingpressure on land for human settlements and related urban services. As a result, adhocdevelopment which has been taken place in the past due mostly to unplanned land usesinappropriate use of land in Colombo Urban Area. Therefore increased development pressure onagricultural lands in immediate surroundings of urban centres has further aggravated theproblem of conservation of the natural environment .The above shows that in the pastinsufficient attention has been paid to the planning for conservation and development.GIS is a powerful tool for land use planners in their effort to make land development processesmore efficient and attractive. Conventional geographic database design is based on Booleanlogic, and it created so many shortcomings. Fuzzy logic screen as the basic for representing andmanipulating in exactness in a relational geographic database hence, recent developments ofmodels in geographic information systems have been drawn upon concepts of fuzzy set theoryand multi-criteria methodology. Saaty's Analytic Hierarchy Process (AHP) (1980) is compatiblewith both these research directions, This paper demonstrates the application at Fuzzy set theoryin GIS for environmentally sustainable land use planning .The results indicate the future landrequirements and allocations in case study area so that planner can make sound judgment onland allocation.