Portable bamboo raft cofferdam, canal and construction method of portable bamboo raft cofferdam

The invention discloses a portable bamboo raft cofferdam, a canal and a construction method of the portable bamboo raft cofferdam. The portable bamboo raft cofferdam comprises a cofferdam framework, the cofferdam framework comprises two bamboo frames, each bamboo frame comprises a wood raft and a bamboo raft, the lower ends of wood piles are inserted into a riverbed, the upper ends of the wood piles extend out of the water surface, each bamboo raft comprises a plurality of bamboo chips, the bamboo chips are transversely arranged between the wood piles, the two bamboo frames are arranged at intervals to form a backfilling groove, and leakage-proof nets are arranged on the inner sides and the outer sides of the bamboo frames; the underwater sludge layer is arranged in the backfilling groove and located below the water surface, and sludge of the underwater sludge layer is taken from sludge of the breeding area; the overwater silt layer is arranged in the backfilling groove and backfilled on the underwater silt l