砂防堰堤の最適解（位置と高さ）の探査ツール開発 －Kanako を活用して－

抄録

Debris flows often cause severe and tragic damages to human life and the economy. Sabo dams are effective protection against debris flow. Planning and estimation using numerical simulation are important to determine the type and size of sabo dam, and the installation location required to achieve the most effective solution. However, non-experts involved in sabo work or debris flow planning often find it difficult to conduct simulations to determine the best sabo solution because the existing simulation systems do not have efficient user interfaces. Furthermore, they find it difficult to define and measure damage indices. Therefore, a system that estimates the best sabo solution based on a user-supplied set of initial landform and debris flow conditions would be useful.
We developed a method to estimate the best sabo solution. We selected that moved sediment volume can be used as valid indices of the damage scale. Simulations of several cases of recent disasters showed that sabo dams installed on the lower reaches of river reduced damage more than sabo dams installed on the upper reaches. Higher dams can be more effective, but only up to a certain value. Placing dams on the upper reaches of a river has very little effect in reducing damage. We then combined our method with the KANAKO GUI-equipped debris flow simulator that provides good visualization and simple explanations. This enabled users to simulate and find the best solutions easily.