我省山区河流特点,是比降大、流速急、岩石露头较多,另外河流短,洪峰历时短,下游尾水不足水跃要求。据对15个岩基水坝的调查,大部都带有鼻坎,其中溢流5年以上的有6个,12年以上有2个,二百年以上的有1个,除二百年老坝外,其余各坝并未发现河床有明显冲刷现 The characteristics of mountainous rivers in our province are larger than those of large ones. The flow velocity is acute and there are many rock outcrops. In addition, rivers are short, flood peak lasted for a short time, and the tailrace water shortage is insufficient. According to the survey of 15 rocky basins, most of them have nose cocks, of which 6 are over five years old, two are over 12 years old, and one is over two hundred years old, except for two hundred years old Outside the dam, the remaining dams did not find any obvious erosion in the riverbed