Application of climate change projections in drainage project planning for agricultural infrastructure in Japan

Abstract

In Japan, agricultural drainage facilities such as pumping stations and drains are designed by calculating an approximately 10–30-year return period based on observed precipitation in the past. However, damage to farmlands and agricultural facilities caused by heavy rainfall has become more severe and frequent in Japan. The Ministry of Agriculture, Forestry and Fisheries of Japan (MAFF) is urged to develop new design standards in consideration of projected future precipitation, keeping in mind that MAFF needs to avoid building unnecessarily large-scale facilities. Therefore, more accurate and reasonable projection methods for precipitation are needed. Based on recent advancements and discussions of climate change projections through the Coupled Model Intercomparison Project Phase 5 (CMIP5) and the Intergovernmental Panel on Climate Change (IPCC), Japanese universities and research institutes are developing datasets for future precipitation projections, especially for assessing weather extremes in small areas. In light of the above, we conducted a case study in a model area to design drainage facilities using the latest climate change outlook. This study introduces how to apply climate change projection in drainage project planning for agricultural infrastructure in Japan and shows the result of future projections in the selected area.