website “River Disaster Prevention Information (Kawa Boh) Note $ ^{1} $ ” to be utilized in issuing warnings and evacuation during floods.

Also, the data broadcast function of digital terrestrial television is being used in cooperation with broadcasters for efforts to provide river water levels and rainfall volume information and by March 2015, 51 broadcast stations nationwide are providing such services. For the observation of rainfall volume, to deal with floods and sediment-related disasters due to the increased frequency of heavy storm (so called sudden showers) in recent years, XRAIN (MLIT X-band MP radar network) Note $ ^{2} $ is being developed, which makes more detailed and real-time rainfall volume observation possible, for more appropriate river administration and disaster prevention activities in addition to the conventional radar (C-band radar) and rain-gauge network. Rainfall information is also available on the Internet and an observation system consisting of 38 radars was established as of the end of March 2015.

### f. Designation of Areas Vulnerable to Inundation

To raise awareness of the dangers from flooding, work to ensure the effective evacuation of residents, and guide appropriate land use, districts that are likely to be inundated when the river floods (inundation forecast districts) are designated and information such as the depth of inundation is publicized in accordance with the “Flood Control Act”.

Also, so that residents can smoothly and rapidly initiate evacuation measures even when flood inundations occur, the method of distributing flood forecasts and the technical support for the creation and communication of hazard maps indicating evacuation areas are offered to municipalities. In addition, a portal site Note $ ^{3} $ is opened on the MLIT homepage where all domestic hazard maps can be viewed.

Inundation forecast areas are already designated and publicized for roughly 97% of the rivers concerned and 98% of municipalities within inundation forecast areas already created flooding hazard maps (as of the end of March 2015).

The MLIT not only allows for tax subsidies for inundation prevention facilities obtained by the underground malls, etc. in inundation forecast areas in accordance with inundation prevention plans and supports voluntary flood defense initiatives carried out by underground malls, facilities for people with special needs, and large-scale factories, etc. via the disaster information dissemination office established within the river-related office of Regional Development Bureaus and others across the nation as a contact point for businesses and others.

### g. Strategic Maintenance and Management of Rivers

The condition of river channels and facilities are assessed and appropriate maintenance and management is carried out in accordance with any changes to ensure that the river administration facilities developed function as intended during floods and other situations.

In the course of river development carried out, the number of facilities such as levees, weirs, floodgates, and drainage pump stations under management greatly increased and the age degradation of these facilities is also advancing. Also, for river infrastructure, migration to condition-based maintenance is being implemented where degradation conditions and its progress is monitored through inspections so that measures are taken at appropriate moments to as move to extending facility life cycles and renewal in a planned manner. In addition, the Priority Plan for Social Infrastructure Development states that major river infrastructure administered by the nation will have lifetime extension plans by FY2016. In addition, necessary technological development for extending lifetime will be furthered and technical standards for middle to small rivers will be studied in cooperation with prefectures for appropriate maintenance and management. In addition, technical support is provided through permanent consultation services made available by regional development bureaus.

The “River Law” revised partially in 2013 clarifies the need for the administrator of river management facilities or authorized structures to maintain river management facilities or permitted structures in good condition through maintenance and repair, stipulates the absolute minimum technical standards that must be adhered to by all administrators regarding the maintenance and repair of river management facilities and others by decree, and also revise the “Technical Criteria for River Works: Maintenance (River)” for promotion of appropriate maintenance.