What factors affect the rates of landform change?
Factors that affect the rate of landform change in a river are:
- Geology – such as hard and soft rocks in the formation of a waterfall.
- Climate – in the UK this varies with seasons, and affects the discharge amounts in a river and the level of energy it has to erode and deposit.
- Human activity – intended and unintended consequences, such as building a dam which traps sediment and controls the flow of a river.
The River Severn
The The place where a river starts in its upper course. of the River Severn is located in the Cambrian Mountains of Mid Wales, and it flows east and south to its The place where a river meets the sea. where the river joins the Bristol Channel underneath the Severn Bridges.
The area receives excessive rainfall due to depressions from the Atlantic. The Severn swiftly grows and forms a V-shaped valley. The river transports a large load, which allows rapid erosion to take place. Waterfalls and gorges have been formed in the upper course. As the gradient decreases, meanders can be found. As the river nears the lower course, flooding is a threat.
Upper course
- The The highest section of a river located in the mountains. has hard impermeable rocks. Here, When the land is eroded or worn away in a downwards direction, eg a river that is high up will erode vertically because gravity pulls the water downwards. has formed a V-shaped valley.
- The River Severn has many waterfalls in its upper course.
Middle course
As the River Severn starts to erode sideways (The wearing away of the landscape when a river erodes sideways.), it forms A bend in a river.. These can be identified in the The middle section of a river which has sloping land. near Kempsey in Worcestershire.
Lower course
Near Tewkesbury in Gloucestershire, the meanders in the The final section of a river located on flat land. are much larger. In this area there are also Ridges or banks formed by deposits of alluvium left behind by the periodic flooding of rivers. Can also be artificially constructed banks or walls. which have formed when the river has flooded.
The River Severn has a very large mouth with mudflats and sandbanks which support wildlife in the area. Many of the sites are protected areas.
