Abstract
To protect against large-scale earthquake disasters, there is an urgent need to strengthen the disaster-response capabilities of main irrigation channels. In this study, the authors identified the causes of disaster response incapability for the typical irrigation facility consisting of a head work and open channels. This identification was done by applying fault tree analysis (FTA) to the disaster response process from the initial reaction immediately after a large-scale earthquake to the closing of intake gates for safety. The effectiveness of measures to prevent disaster response incapability was quantitatively evaluated. It was found that for earthquakes with seismic intensities of 6 or lower on the Japanese scale, some effectiveness in preventing disaster response incapability could be expected through measures that are workable by facility managers. In other words, disaster response can be generally carried out as planned. However, it was shown that such effectiveness can hardly be expected for earthquakes with maximum seismic intensities of 7 on the Japanese scale and that such earthquakes make it difficult for facility managers to close the intake gates. This suggests the necessity of a business continuity plan in preparation for a maximum-scale earthquake.
