Siltation dam refers to soil and water conservation engineering measures built in ditches at all levels in soil erosion areas for the purpose of flood detention, mud retention and reclamation. The specific method is to select a narrow part in Ogawa-CHO, a medium-sized small ditch on the Loess Plateau (with a drainage area of more than 20 square kilometers), borrow soil from two hills, build a dam with the same height as the hills, and completely lock the whole ditch. After that, the flood is allowed to deposit in the ditch until the whole ditch is deposited into a small plain and basin.
The earliest warping dams were formed naturally and have a history of more than 400 years. In the third year of Qin Long in Ming Dynasty (A.D. 1569), the loess depression in Zizhou County, Shaanxi Province formed a "natural dam" due to natural landslide. After artificial renovation, a warping dam with a height of 60 meters and more than 800 mu of silt was formed. The fertile soil on the dam has always been the basic farmland for the local people to protect their crops in drought and flood.
Documented historical records of artificial construction of warping dams were first found in Fenxi County, Shanxi Province during the Wanli period of the Ming Dynasty (A.D. 1573- 16 19). According to "Fenxi County Records", during the Wanli period of the Ming Dynasty, "the wet place under the river ditch is easy to harvest high fields, and the drought can be used to pay rent, so it can be built for the diligent people." Mao Jiong, then the magistrate of Fenxi County, made a notice to encourage farmers to build dams and silt fields, and proposed that "anyone who can build dams and farmland to varying degrees is a good citizen, not allowed to participate in grain, and is granted a permanent career".
Since then, the dam-building and silting in Fenxi County have been developing continuously. On the eve of the founding of New China, there were thousands of acres of dam land in the county.
After the founding of New China, the warping dam construction has developed rapidly through the summary, demonstration and popularization of water conservancy and soil and water conservation departments. It has gone through four stages: experimental demonstration in the 1950s, popularization in the 1960s, development and construction in the 1970s, and dam system construction based on the backbone project of gully control since the 1980s. According to the investigation and statistics, after more than 50 years of construction, there are more than 450 million mu of silt dams 1 10000 in the Loess Plateau, which can retain 2654.38 billion cubic meters of silt.
Mainly distributed in Shaanxi (368 16), Shanxi (37820), Gansu (6630), Inner Mongolia (178 19), Ningxia (4936), Qinghai (3877) and Henan (465438).