Presentation on theme: "Oxbow Lakes By Cara. What is an Oxbow Lake? An oxbow lake is a crescent shaped lake lying beside the middle course of a river. It is formed when a bend."— Presentation transcript:
Oxbow Lakes By Cara
What is an Oxbow Lake? An oxbow lake is a crescent shaped lake lying beside the middle course of a river. It is formed when a bend in the river is cut off from the main channel by forces of erosion.
Due to greater volumes of water carried by the river in low land areas, lateral erosion becomes more dominant than vertical erosion. This causing the channel to cut into the banks forming meanders.
A river moves fastest on the outside banks.
Meanwhile, on the inside bank of the river, the water flows more slowly, leading to the deposit of sediment.
Gradually the inside banks are filled in with accumulated deposits and the outside bends extend further and further, forming a wide loop in the river.
. As the outer banks of a meander continue to be eroded through processes such as hydraulic action the neck of the meander becomes narrow and narrower.
Eventually the two outer bends meet and the river cuts through the neck of the meander. The water now takes its shortest route rather than flowing round the bend.
Deposits gradually seals of the old meander bend forming a new straighter river channel. Leaving the old meander bend is isolated from the main channel as an oxbow lake.