Geomorphology and the urban tropics: building an interface between research and usage

The developing countries, located almost entirely within the tropics, are currently undergoing urbanization at a rapid pace. Many of these cities are not more than a few centuries old, having been established to function as regional trading posts or administrative centers by either colonial or regional powers. It is doubtful that the site conditions were taken into consideration, and consequently, many of these cities were established in hazardous or environmentally sensitive areas. As these cities developed over time, they spread across a wide range of terrain conditions much of which are unsuitable, such as floodplains, coastal swamps, steep slopes, or sand dunes. For a number of these cities, which are located near active plate margins and tropical cyclone belts, such problems are magnified. Increased demand for water has required subsurface extraction, leading to problems of subsidence and quality. mine the range of these cities with reference to (1) their site-related problems, (2) the nature of geomorphological information required for specific ameliorating actions, and (3) the level of management required for city maintenance. Management requires interfacing geomorphology with engineering practices and urban planning. We present case studies of cities ranging from those with limited problems and possible engineering and land-zoning solutions (Singapore) to cities where the hazards (either natural or anthropogenic) are so acute and widespread that a practical solution is difficult to achieve (Kingston, Bangkok). Precise geomorphological and geological information and long-term data sets are not available for most of the cities. Furthermore, it is necessary to present the information in formats appreciated by the engineering and planning communities. Often a set of specialized maps are extremely useful. We complete the discussion with several examples and suggestions for collection of geomorphological information and inventory preparation for communicating geomorphological data to city engineers and planners.