Feisha Dam

在都江堰景区离堆公园西侧过桥跨过内江向右就是飞沙堰，这也是都江堰水利工程三大件之一。在飞沙堰向东望，内江对岸就是宝平口和离堆。飞沙堰又称 “泄洪道”、“减水河”。这个有点倾斜的堤坝修在离堆之侧、金刚堤末端，按一定高程（河床到河面2.15米高）由南向北开一道200余米宽的口子，具有泻洪、排沙和调节水量的显著功能。 作为都江堰三大件之一的飞沙堰，古时是用竹笼卵石堆砌的临时工程，即使如今已改用一劳永逸的混凝土浇铸形式，其外观看上去依然十分平凡。其实这飞沙堰的功用非常之大，可以说是确保成都平原不受水灾的关键要害。当内江水量较小时，它拦水进入内江灌区；当内江的水量超过宝瓶口流量上限时，多余的水便从飞沙堰自行溢出，排到外江；如遇特大洪水的非常情况，它还会自行溃堤，让大量江水回归岷江正流。岷江从万山丛中急驰而来，挟着大量泥沙、石块，如果让它们顺内江而下，就会淤塞宝瓶口和灌区。而由于位置设计很巧，飞沙堰具有强大的排沙石能力，能将流入内江的沙石再排除出去，所以称为飞沙堰。

在2000年前，能用物理的原理，做到分流去沙，确实有点儿水平呀！不愧是个天才，不愧是秦王看中的人才，佩服佩服，确实有水平

飞沙堰位于鱼嘴分水堤未端的侧向溢流堰，古称“待郎堰”、因排沙效果好而得名。飞沙堰发挥内江堤坝的泄洪排沙作用，既保证了成都平原用水之需，又能将进入内江的大部分沙石排出。

Flying sand is one of the three components of Dujiangyan water conservancy project. Flying sand has cleverly used the centrifugal effect of water flow, so that the dike has the ability to clean up the sediment by itself, which is unique and magical in many water conservancy projects. When the flow of the inner river exceeds 1,000 cubic meters per second, the diversion ratio of flying sand is more than 40 ％, and the ratio of sand can reach about 75 ％. The greater the flood, the higher the diversion ratio of flying sand, the more significant the sand discharge effect. After the sand discharge, the transfer of the bottle into the bottle only accounts for about of the total amount of the Lijiang River. That is to say, the wisdom of the ancients is amazing!

The role of flying sand is "flying sand", the Lijiang River from the mountains rushing, carrying a large amount of sand, stones, if they let them down the river, they will silt the bottle mouth and irrigation area. Flying sand squall cleverly uses the centrifugal effect of water flow, so that the embankment has the ability to clean up the sand by itself, which is unique and magical in many water conservancy projects.