First, water pollution is becoming more and more prominent. As sewage from life, industry, agriculture, catering services, livestock and poultry breeding has been directly discharged into rivers for a long time, the water quality of rivers is deteriorating day by day. According to the data released by Wenzhou Environmental Protection Bureau, in 2000, only 15.0% of the reach of Wenruitang River met the requirements of Grade IV water quality, and 85.0% of the reach was Grade V or worse. Second, the riverbed is seriously silted. Due to the long-term lack of river bed dredging, coupled with soil erosion in the basin, garbage and silt flow into the river from the coast, leading to river bed siltation. The average siltation layer of riverbed reaches 0.8m, and the deepest reaches 2.2m The water storage and overflow capacity is greatly reduced, which seriously affects flood control and drainage, and also causes a lot of endogenous pollution. Third, the phenomenon of river surge is very common. For a long time, the phenomenon that urban construction, industrial parks and real estate development occupy rivers is very common. River landfill has affected the flood control, drainage and ecological environment of the city, and the water towns in the south of the Yangtze River have gradually lost their survival foundation.