The weir, the water can be normal irrigation, flood drainage, when can a foreign River, but also ranked the role of gravel, and sometimes a lot of stones can roll away from the weir.

• 这个堰，平时可以引水灌溉，洪水时则可以排水入外江，而且还有排砂石的作用，有时很大的石块也可以从堰上滚走。