From Longman Dictionary of Contemporary Englishburst its banksburst its banksif a river bursts its banks, water from it goes onto the land → burst
Examples from the Corpus
burst its banks• Residents were evacuated from the town as the waters rose and the Ouse threatened to burst its banks.• The River Frome had burst its banks after torrential rain and the Rovers' ground was absolutely waterlogged.• The River Deben had burst its banks and people's homes were getting flooded.• Denied its usual egress, the river had burst its banks and was pouring down the fire-ravaged streets. 