Abstract
The following are shown to be fundamental and essential flood damage mitigation measures in basins: (a)reduction of the damage by increase in the ability of flood control facilities (structural measures), (b) damage control by reduction or curbing of the damage potential (non-structural measures), and (c) integrated flood damage mitigation measures which comprise a combination of (a) and (b), this is based on the basic theory of flood damage mitigation measures in basins. Concrete examples to conduct post-evaluation of the effects of the implementation of the integrated measures under this fundamental theory of integrated flood damage mitigation measures are those taken in the Naka/Ayase river basin in Japan, the Bangkok metropolitan area, and the entire Chaophraya river basin in Thailand. All the target basins belong to gently flowing rivers on low-lying plains, where flood damage has increased due to the recent rapid progress of urbanization. As the results, the followings are shown: (1) as structural measures, appropriate measures have been planned against the cause of flooding by taking into consideration the hydraulic and hydrological characteristics of each basin, and these measures are being slowly but steadily implemented; (2) non-structural measures, which include curbing of the flood damage potential (adjustment and regulation of land use) as an important component, are implemented but under varying degrees of scale according to each country's situation; (3) based on the above-mentioned facts, the integrated flood damage mitigation measures can be estimated to be effective in the basins of gently flowing rivers on low-lying plains, which have undergone rapid urbanization.
