Complex sentence: A new river bank then starts to accumulate, sealing off the meander and leaving another oxbow la a wide meander from the main stem of a river is cut off, creating a free-standing body of water.
Split into simpler sentences: A new river bank then starts to accumulate, sealing off the meander and leaving another oxbow lake. An oxbow lake is a U shaped body of water that forms when a wide meander from the main stem of a river is cut off, creating a free-standing body of water.