Longhu Lake in Huaiyang is formed by yellow water. For thousands of years, Huaiyang City has been repeatedly harmed by the Yellow River. Every time the Yellow River invades the city, thousands of people are mobilized to build dikes. When the Yellow River recedes, the sediment it carries will accumulate outside the city wall. Over time, dams will get higher and higher, dams will gradually sink, water will be stored in low-lying places, and more water will become lakes. In addition to a large area of Puwei and lotus root growing in the lake, Euryale ferox, Zizania latifolia, water chestnut, duckweed, water chestnut and water hyacinth are floating on the water surface. The lake is also rich in fish and shrimp, including carp, herring, silver carp, crucian carp, eel, catfish, shrimp, crab and other fish, and the aquatic resources are quite rich.