From the winter of 1977 to the spring of 1978, Nanhui County carried out the Dazhi River Regulation Project. Dazhi river starts from the Yagang town of Shanghai County in the west and ends in Jiuzao Port of Nanhui County. With a total length of 37.5 kilometers, it is the fundamental project for the basic construction of farmland in the suburbs, which can completely reform the saline-alkali land in Nanhui County. The video recorded the entire process of this project.