The Finance Ministry has proposed building a legal framework to limit where people may live in areas that hazard maps show are at risk of flooding and other disasters, arguing that Japan cannot keep rebuilding in the path of increasingly severe weather.
The ministry presented the proposal at a meeting of a subcommittee of the Fiscal System Council, an advisory body to the finance minister, on Thursday. It said river improvement plans drawn up by river managers should be revised to take land-use regulation and the steering of residents away from danger as their premise, so that public safety is protected.
It also called for hard infrastructure to be rationalized and concentrated, for example by narrowing the stretches of levee that are reinforced to match limited funding.
The proposal follows a run of severe disasters across the country, including the heavy rain in Chiba in August.
A shrinking hazard-zone population
Regulating land use and housing is not without precedent. The ministry cited work carried out in the lower reaches of the Arakawa River in Tokyo, and used it to model what nationwide restrictions would do.
Under that estimate, the population living in hazard zones would fall from about 20 million in 2020 to as low as 436,000 fewer by 2050, a drop of roughly 20%. The ministry presented the figure as a projection based on the earlier case.
Overlapping infrastructure
The ministry also said the value of roads, railways and ports should be assessed for the way overlapping routes compete for the same users.
In one case in the Hokuriku region, an expressway was built along a section already served by a conventional railway line. Rail ridership roughly halved, leaving the service dependent on large subsidies to keep operating.
To prevent a repeat, the ministry said projects should be evaluated against each other and the infrastructure network optimized as a whole.