Swamp refers to the place where the surface is very wet or there is a thin layer of ponding, the soil moisture is almost saturated and there is peat accumulation.
The formation of swamp is inseparable from its vegetation. There are a large number of wet and water loving biogenic plants in the swamp. Due to the large amount of water and the lack of oxygen in the swamp soil, under anaerobic conditions, the decomposition of plants after mildew is slow, only in a semi decomposition state, and finally form peat. Coupled with the massive accumulation of sediment, it will gradually evolve into a swamp. Therefore, the swamp looks like a plush green carpet, but below it is a bottomless mud, into which people or animals will fall once they step in. People call it "green trap".