This can erode the bank and slowly increase the size of the bend to form a large curve called a meander.

How are Meanders Formed?Īt a bend in a river or stream, water flows against the outer river bank with increased force. Uvac River, Serbia and eastern Bosnia and Herzegovina What is a Meander Landform?Ī meander is where a river or stream makes a bend or curve, generally over 90 degrees. The floodplain also gets built up with the fine sediment to create alluvium which makes the floodplain very fertile.Meander Landforms Have 2 Main Characteristics: Over the years this material builds up to create a levee. During a flood the river will deposit its heaviest material first (i.e. They are formed when the river deposits material as it floods. Natural levees form beside a river’s banks. When a river floods onto the floodplain the water becomes shallow and the river’s velocity decreases leading to deposition. Lateral erosion and the formation/migration of meanders have caused the floodplain to get wider, interlocking spurs have been eroded away. It is covered with water during times of flood. The floodplain is a wide, flat area of land either side of the river in its lower course. However, as the river reaches the end of its course, energy is low and deposition occurs. The river channel is now deep and wide and the surrounding landscape is flat. In the lower course the river has a high volume. Eventually the river will break through the neck of the meander to create a new, straighter channel and an ox-bow lake will remain. Over time the meander becomes more pronounced and the ‘neck’ of the meander becomes smaller. Video on formation of meanders and ox-bow lakes On the inside of the bend the velocity is much slower and consequently, deposition occurs creating a slip-off slope. The faster water travels around the outside of the bend, eroding the banks through abrasion and hydraulic action. They are formed by a combination of erosion and deposition. Erosion is now mainly lateral and it has widened the river.

In the middle section the river has more energy and a high volume of water. Landforms resulting from erosion and deposition This process happens repeatedly which means that the waterfall gradually retreats upstream creating a gorge. Over time this creates an overhang which eventually, due to gravity, collapses under its own weight. A plunge pool is created and processes such as abrasion and hydraulic action cause further erosion of the soft, less resistant, rock. As the river flows over the hard rock onto soft rock, the soft rock will be more easily eroded. When a river flows over alternating layers of hard/soft rocks waterfalls can be formed. Interlocking spurs are created when the river has to flow around an obstruction for example, hard rock. This means that abrasion can continue to steepen the valley and the river cuts further downwards. Freeze-thaw weathering and other processes create loose material on the valley sides which are then washed into the river from the steep valley sides during times of heavy rainfall, adding to the material being carried by the river. This causes the most distinctive river feature, the V-shaped valley. In the upper course of the river, the river cuts rapidly downwards, as the main direction of erosion is verticall. In the upper course erosion is the dominant process creating V-shaped valleys, interlocking spurs and waterfalls. Each of these sections have different dominant processes resulting in different features. Rivers have an upper, middle and lower course.

Formation of a meander