人口減少地域における社会資本管理の課題とその原因

～北海道の自治体へのインタビュー調査結果～

抄録

Japan has been depopulating since 2008. An official projection indicates we will lose 10 percent of the population by 2035 and 30 percent by 2055, based on the population recorded in 2005. Impacts of population decline are expected to occur on infrastructure management; however, previous research projects in Japan have not analysed the situation or numbers in detail.

This survey was conducted in municipalities of depopulated regions in Hokkaido to explore actual impacts on infrastructures. Public officers in the municipalities provided details concerning the occurrence of impacts, the history of infrastructure developments and other related factors.

Main findings of this research show the importance of factors other than population decline itself, such as geographical factors, the financial situation of depopulated municipalities, and the speed and causes of population decline. Characteristics specific to Japan, such as severe geographic features and the local public financial support system, seem to mitigate the impacts on infrastructures. In other words, it can be considered that the public finance system supporting depopulated municipalities is key to controlling the impacts of population decline on infrastructure management.