General situation of sand bar

The development history of sand bars around the world is related to the management of barren rivers. As early as the14th century, countries in the Alps of Europe built sand dams to trap solid materials in debris flow in barren streams, so as to ensure the safety of buildings and facilities such as villages, roads and churches located on alluvial fans of barren streams. At that time, limited by technical and economic conditions, simple log sandbars, wooden frame sandbars, dry masonry sandbars and steel wire gabion sandbars were mainly built of trees or stones. With the development of water conservancy science and civil construction science, new dam types have emerged, such as orifice sand dam, slit sand dam, grid sand dam, grid sand dam and metal cable sand dam. Japan began to build sand bars in the17th century. In the practice of developing and utilizing land resources and soil and water conservation in mountainous areas, farmers in rocky mountainous areas of China have generally built a large number of dry masonry sand dams to intercept sediment, and built farmland or orchards in ditches. In order to prevent debris (such as quartz sand) and soil sand from flooding the downstream farmland, farmers in mountainous areas in southern China also built sand dams in ditches.