CHAPTER 8: FLUVIAL PROCESSES, PATTERNS AND LANDFORMS
2. Oxbow lakes Main processes: flooding, erosion, deposition Example: RiverMoy, CountyMayo Oxbow lakes are the remains of meanders that have been cut off from the river’s course. They are often called cut-offs for this reason. They are found in themature stage of a river.
IN DEPTH – Oxbow lakes
Oxbow lakes formwhenmeanders become so developed that the bend is very tight and there is only a narrow neck of land separating the two sides of the meander bend. In times of flood the water flows across the neck of land rather than going around the bend. By doing this, hydraulic action and abrasion erode a new path for the river, straightening it in the process. Because the river is not confined between its banks as it flows across the meander
loop, it slows down and loses energy. This leads to deposition which, over time, seals off the old meander bend. The old meander loop is now cut off from the new course. Slowly it dries out because of evaporation and seepage through the ground and becomes a dead lake or amortlake.Mortlakes are also known asmeander scars.
Deposition
Oxbow lakes Erosion 1 2 3
Weblinks Oxbow lake
River erodes River deposits
Fig. 32 Exam Diagram: The development of oxbow lakes 119