Istanbul is the most populated city of Turkey with a population of around 10.58 M (2000) living on around 5,750 km2. In 1980, the population was only 4.7 M and then it has been more than doubled in only two decades. The population has been increasing as a result of mass immigration. An urbanization process continues and it causes serious increases in urban areas while decreasing the amount of green areas. This rapid, uncontrolled, and illegal urbanization accompanied by insufficient infrastructure has caused degradation of forest and barren lands in the metropolitan area, especially through the last two decades. The watershed basins inside the metropolitan area and the transportation network have accelerated the land-cover changes, which have negative impacts on water quality of the basins. Monitoring urban growth and land cover change will enable better management of this complex urban area by the Greater Istanbul Metropolitan Municipality (GIMM). A temporal assessment of land-cover changes of Istanbul has been documented in this study. The study mainly focuses on the acquisition and analysis of Landsat TM and Landsat GeoCover LC satellite images reflecting the significant land-cover changes between the years of 1990 and 2005. Raster data were converted to vector data and used in Geographic Information Systems (GIS). A database was created for Istanbul metropolitan area to plan, manage, and utilize statistical attribute data covering population, water, forest, industry, and topographic position. Consequently an overlay analysis was carried out and land use/cover changes through years have been detected for the case study area. The capability of Landsat images in determining the alterations in the macro form of the city are also discussed.

Istanbul is one of the largest metropolitan cities in the World. The city has experienced rapid industrialization and urbanization in the second half of the twentieth century. Between 1950 and 2000, the city has grown by an average of 4.5% annually. Given the scale of the growth, neither local nor the central governments have shown capability of controlling the influx of migration, most of which settled illegally on public lands. Most of the settlements lack the basic sewerage facilities, and a significant portion of which are on the major water resource basins. As of today, Istanbul Metropolitan Municipality (IMM) not only has to cope with the infrastructure problems, but also has to find ways of solving the problem of illegal occupations of public lands and water resource basins. This paper presents the land use changes in the water resource basins providing water to the Istanbul Metropolitan Area. Using four consecutive Landsat images between 1990 and 2005, the changes in 12 different land use categories are obtained via overlay operations by GIS for water resource basins surrounding the City of Istanbul. It has been observed that the most critical land use changes are in the nearest basins to the city. The capability of Landsat and IKONOS images in determining the alterations in the macro form of the city are also discussed. Finally, possibility of utilization of new technologies in policy making regarding environmental management in Istanbul is discussed.

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Istanbul, one of the largest metropolitan cities in the world, experienced rapid industrialization and urbanization in the second-half of the 20th century. The City grew at an average annual growth rate of 4.5 per cent between 1950 and 2000. Growth of settlements and the transportation system have damaged the natural environment. Istanbul is located on both sides of the Bosporus Strait that divides Europe from Asia. Recently an alternative to the planned third bridge for the Istanbul metropolitan area has been selected. The transportation infrastructure which has been constructed has drastically changed the land use profile and caused negative impacts on the environment. The proposed third bridge route threatens agricultural areas, forests, waterbodies and water collection areas that form the open-space systems of Istanbul.The aim of this study was to analyse the effects of existing Bosporus bridges on the spatial development and the natural resources of the metropolitan area of Istanbul. With the new transportation axis focused on the bridge route, the potential impacts on vital open spaces such as the northern forest regions, the existing agricultural lands and the waterbodies and catchments are evaluated. These changes are explored using a geographical information system and five sets of Landsat satellite images from 1975, 1990, 1995, 2000 and 2005. This should provide a better understanding of the main reasons for the effects and will support city administrators planning similar projects.