creates a steep sided V- shaped valley.
Downward erosion is the dominant
process.
In The Middle Course, the river starts
to flow slowly because it starts to
transport lots of sediment, as rivers
look muddy. As a river moves down its
valley, a number of changes occur.
The river gets wider, as more tributaries join together.
- The valley sides become less steep, giving the shape of a open V.
- The river begins to erode sideways, into its banks. This opens out the valley floor and a flood plain that starts to develop.
- Erosion and deposition occur.
- The edges of the floodplain are marked by bluffs.
The lower Course, is when the valleys
V shape is so wide that he valley
sides have been disappeared. The
river approaches its mouth. The river
now winds its way slowly across a
large floodplain. Deposition is now
dominant process.
Landforms located on The upper Course
Waterfalls and Gorges are located on The Upper Course.
A waterfall can occur when the water tumbles over a ledge of hard rock. The softer rock is eroded more easily. This leaves the harder rock over hanging. Eventually after the under cutting has occurred, the harder rock collapses into the river. The water fall retreats to a position further upstream.
A waterfall is a sign meaning that there are layers of different rocks under the river. If the same process happens several times, then a steep sided Gorge is left, downstream of the waterfall. This can be seen at the diagram of high force waterfall on the river tees.
The famous waterfall Niagara Falls
Niagara Falls is on the border between the United States and Canada. It actually consists of two waterfalls, the American Falls in western New York and the Horseshoe Falls in Ontario. Bridal Veil Falls and the Cave of the Winds, shown here behind a curtain of water, are part of American Falls. Every year millions of tourists visit the falls.
The falls may be viewed from parks located on either side of the river, from observation towers, from boats, from Goat Island, and from the Rainbow Bridge, located a short distance downstream. The bridge connects the town of Niagara Falls in Canada with the town of the same name in the United States.
Niagara Falls was formed about 12,000 years ago. Erosion has slowly pushed the waterfall upstream, forming the Niagara Gorge.
Gorge
The Grand Canyon is a famous Gorge. It is very deep; it is almost a vertical Gorge. This is created by the erosive action of a powerful river.
The famous Grand Canyon
The Grand Canyon stretches across the state’s Colorado Plateau and averages 16 km (10 mi) in width. Beautiful rock formations of layered limestone, sandstone, shale, and other rock rise from the canyon floor. This formation is known as “The Alligator”.
Grand Canyon is exceptionally deep, steep-walled canyon in north-western Arizona, United States. It was formed by the eroding action of the Colorado River.
The entire canyon is extremely beautiful, containing towering buttes, mesas, and valleys within its main gorge.
Grand Canyon, United States
The Grand Canyon is relatively young in geological terms; the river began its work of erosion about 10 million years ago. Coupled with the downward cutting of the river has been a general rising or up warping of the Colorado Plateau, which has added its effect to the action of the river.
