DISASTER RISK REDUCTION METHOD SUBSTITUTING COLLAPSE RISK OF LARGE DAM WITH NUMEROUS SMALL DAMS OR BANKS, AND STATIONARY BANK/BREAKWATER CAPABLE OF BEING INSTALLED AT LOW COST AND IN SHORT TIME AND TO BE EMERGENCY WATER SOURCE AND EMERGENCY SMALL-SIZED POWER SOURCE

摘要

PROBLEM TO BE SOLVED: To solve the problem that, in the case where an earthquake whose epicenter is directly below a dam or a recurrence long-period earthquake of Great Kanto earthquake or Tokai/Nankai earthquake occurs, a large total flood control dam collectively including basin-wide flood control/water use/power generation functions may collapse, a dam lake may be choked by sector collapse to incur flooding in the downstream, tsunami may sweep and all infrastructures may not be recovered for several months.SOLUTION: In the invention of a disaster preventive construction method, in the downstream of a large dam, a number of small dams or banks are installed from the upstream to the downstream and branches of the basin. Therefore, in the case where the large dam collapses or a dam lake is choked by the sector collapse, the torrent is stopped by the existent small dams or new banks in the midstream/downstream of the basin. By installing sectional banks added with water intake/catchment pipe/sedimentation basin/generator/exhaust port in the dams or the like in a short time, the flood control/water use/power generation functions can be substituted in the case of emergency. This is constructed as a tsunami breakwater and connected with a drainage system, thereby returning tsunami to the sea.