Abstract
Cost-benefit analysis of landuse regulation strategies was performed to evaluate their applicabilities. The study basins were Osaka and Tokyo regions, Japan’s two largest cities. In this research, two different kinds of landuse regulation strategies were considered: landuse regulations that prohibit use of area predicted to be inundated under or above floor level with a design rainfall event. The former is called a strict regulation and the latter a weak regulation. It was deemed from results that the weak regulation had broader applicability than the strict one for both regions because net benefit of the weak regulation tended to be positive for a wide range of design rainfall events. However, for Osaka region, the strict regulation based on a design rainfall of 5 years return period was shown to be the most effective because it gave the largest net benefit in all regulations. For Tokyo region, results showed that the weak regulation had some applicability while the strict one did not; this is because economic damages in this region are mainly expected to be caused by flooding above floor level.
