How are waterfalls formed BBC Bitesize GCSE?
A waterfall is a sudden drop along the river course. It forms when there are horizontal bands of resistant rock (hard rock) positioned over exposed, less resistant rock (soft rock). The soft rock is eroded quicker than the hard rock and this creates a step. This process continues and the waterfall retreats upstream.
How are waterfalls formed GCSE geography?
Waterfalls often form in the upper stages of a river where it flows over different bands of rock. It erodes soft rock more quickly than hard rock and this may lead to the creation of a waterfall. The soft rock erodes more quickly, undercutting the hard rock. A steep-sided gorge is formed as the waterfall retreats.
Are waterfalls found in the middle course?
Waterfalls can usually be found in the upper and middle course of a river. They are found when a river runs over alternating layers of hard and soft rock. As the water moves over the hard rock it will be able to erode any exposed softer rock.
What processes of erosion undercut a waterfall?
When the river plunges over a waterfall it forms a deep and turbulent plunge below. Here the processes of erosion (hydraulic action and abrasion) are active and they undercut the waterfall.
How is a waterfall formed ks2?
Waterfalls are formed as the river flows downstream. The river can flow over different rocks- some are hard and some are softer. As water flows it erodes the rocks. However, it erodes layers of softer rock more quickly and easily than the layers (or strata) of harder rock.
Which course are waterfalls found in?
upper course river
Waterfalls are upper course river landforms. In the upper course of a river gradients are steep and river channels are narrow. Vertical erosion is greatest in the upper course of a river. As the result of this typical features include steep valley sides, interlocking spurs, rapids, gorges and waterfalls.
How a waterfall is formed?
Often, waterfalls form as streams flow from soft rock to hard rock. This happens both laterally (as a stream flows across the earth) and vertically (as the stream drops in a waterfall). In both cases, the soft rock erodes, leaving a hard ledge over which the stream falls.
What type of erosion is a waterfall?
A waterfall is a feature of erosion found in the youth stage of a river. The river erodes the soft rock by the main processes of erosion including Hydraulic Action (the force and power of the moving river) and Abrasion (the scraping of the load against the bed and banks).
Why are waterfalls temporary features of rivers?
waterfalls are temporary features of rivers because stream erosion is greatest at waterfalls and rapids. Specifically, streams erode at waterfalls by undermining. The water that falls at the base of the waterfall erodes rock there, leaving the rock at the tops of the waterfalls to overhang.
How do waterfalls form quizlet?
Waterfalls form where a river flows over an area of hard rock followed by an area of softer rock. The softer rock is eroded more than the hard rock, creating a step in the river. 3. As the water goes over the step it erodes more and more of the softer rock.