Tetsuo Nakaya

Functions and Cost of Irrigation Service at the Aichi Irrigation Scheme

Because of externalities, it is difficult to study an irrigation service segmented into service receivers. The case study of the Aichi IS shows that irrigation services combine a private good-type service and a public good-type service. This complexity causes problems with cost-benefit relations and the flexible supply of services. The authors propose analyzing functions and cost of actual irrigation services to solve these problems. To achieve a staged solution to these problems, first, core services are selected and, including private–public relations, the benefits of functions and the cost of functions should be well balanced.

Reducing Tsunami Damage to Drainage Pump Stations in Coastal Areas

Measures to mitigate tsunami disaster damage to drainage pump stations in coastal areas were studied by conducting a field survey of drainage pump stations that suffered a great deal of damage from the 2011 Tohoku Pacific Ocean Tsunami, and by performing an experiment with a hydraulic model. The field survey showed that the spatial relationship between the pump house and the water discharge tank greatly affected the level of damage suffered by the drainage pump station from the disaster. The ability of the water discharge tank to dissipate the tsunami energy was examined in a hydraulic model experiment. The result showed that even if the tsunami wave height exceeded the height of the water discharge tank, the wave force in the direction of movement of the tsunami wave was reduced.