The question is not whether managing the rivers and coasts is a "necessary evil." The problem is that widespread concretization not only does not offer control, it cuts away at the natural environment and exacerbates disasters.
不論水泥化的河川整治、海岸護堤、消波塊，是否真是「必要之惡」，問題是，全面水泥化不但沒有達到治山防洪效果，反而侵蝕了自然環境，造成更大的災難。