Increasingly chaotic mixtures of urban and rural land uses are being created in the suburbs of the mega-cities located on Asia’s deltas. This chaotic land use is causing serious environmental problems and, in particular, serious flooding, and dynamic urban growth controls are urgently needed. In this case study, we examined land-use changes in the suburbs of Bangkok, a good example of an urban mega-city, and focused on the landform transformation by man which is inevitable on deltas where the land use is shifting from paddy fields to urban dwellings. The research was conducted through an aerial photograph interpretation and field measurements. GIS was used for data analysis. As a result, we confirmed that the present pattern of urban land use has been profoundly influenced by past agricultural land uses, which, in turn, were adapted to the natural local environment. The area covered by agricultural land readjustment is occupied by apartment houses, whereas the area not covered is occupied by slum-type housing. The transect figures indicated that the local people have responded to flooding expertly through artificial landform transformation. There was a statistical association between land level and land-use type. The volume of landform transformation that has occurred over the last half-century was calculated at 3.2 × 107 m3; this volume would be equivalent to the creation of 64 km2 of newly flooded area with an average depth of 50 cm. Thus we cannot separate horizontal land-use changes from vertical landform transformation. From these results, it is clear that past patterns of agricultural land use and landform transformation will be the keys to sustainable landscape planning for mega-cities on the deltas of Asia.
>>Takeuchi Lab., Landscape Ecology & Planning
Delta, Asian mega-cities, Land use changes, Landform transformation, GIS