Rivers Flashcards
Where is the river most steep?
At the top (in the mountains).
What are the three stages of a river called?
The upper course, the middle course and the lower course.
What is the start of a river called, and where is it found?
The mouth, the upper course.
What is a river or stream flowing into a larger river or lake called, and where would you find it?
A tributary, in the upper course mainly.
What are V-shaped valleys?
Areas around the upper course where the river is shallow and narrow but the hills around it are raised in a V-shape.
What are the five types of transportation in rivers?
Traction (where the boulders roll along the river bed), saltation (where small pebbles bounce along the river bed), floatation (where small pieces of plastic and other float along the river’s surface), suspension (where sediment is suspended in the river), and solution (when material is dissolved in the river, and carried along in solution).
How is a waterfall and gorge formed?
There is a layer of hard rock above the soft rock. Over time, the soft rock begins to erode, forming a plunge-pool at the base. However, the now overhang still remains. Over time, the plunge-pool becomes bigger, until eventually, the overhang collapses, forming a gorge. The waterfall retreats back upstream.
How is a meander formed, and where would you find them?
A river rarely flows in a straight line – it will bend around something in its course, e.g. a tree or hard rock. This results in areas of slower and faster water movement. The river flows faster on the outside and erodes the outside bends of the river channel by the processes of hydraulic action and abrasion – this forms a river cliff. Continuous erosion on the outer bank and deposition on the inner bank forms a meander in the river. Over time, meanders become larger and more recognisable. They form in the middle course.
How is an oxbow lake created?
Due to erosion on the outside of a bend and deposition on the inside, the shape of a meander will change over a period of time. Erosion narrows the neck of the land within the meander. In time and usually during a flood, the river will take a new shorter route. The new route will be fastest down the middle and therefore deposit material across the old meander. In time this will cut off the bend creating an oxbow lake.
Why might a river flood?
Sometimes after heavy rainfall or a fast snow melt there may be too much water for the river to hold. The river will then overflow its banks and flow out onto the land either side of it. This is called a river flood. Usually when it rains the water will soak into the ground. However if it is unable to soak into the ground it will flow downhill and into the river. This is the most common cause of flooding
What is an estuary?
An estuary is the area where something meets the ocean or sea.
What is the mouth of the river?
Where the river meets the sea
