Author(s): Muto Yasunori; Kotani Sayaka; Miyoshi Manabu; Kamada Mahito; Tamura Takao
Linked Author(s): Yasunori Muto
Keywords: Retarding effect; Paddy fields; Inundation simulation; Housing land development; Disaster risk reduction
Abstract: Inundation processes and retarding capacity of wetland paddy fields were evaluated using a commercial inundation simulation software, AFREL, based on a 2-D shallow flow model. How housing land development in the fields will change the flooding characteristics there is of particular interest. Several scenarios of the housing land development were considered, based on a prediction of land-use change by an urban development model, and on adopting a better policy of disaster risk reduction resulting from the inundation simulation for the current situation. Financial advantages of keeping paddy fields as a retarding basin rather than applying new river improvement works were also examined. The results clearly show that both the total area and the arrangement of the housing area strongly affect the inundation process and retarding capacity. Housing land development indicates to need further river improvement works to enhance drainage capacity from the inundation volume analysis. In addition, capable land development based on a viewpoint of withdrawing from the exposure of flooding was quantified. The results indicate that wetland paddy fields have an advantage as green infrastructure in flood alleviation measures from both technical and financial points of view. As a result, land use planning including wetland preservation and land development restriction is necessary in order to establish the best strategy in flood risk management. Such a land use situation is quite common in most monsoon Asian countries, thus the idea deduced in the paper can also widely be applicable to those countries.
Year: 2018