RIVERS Flashcards
What is a drainage basin?
The area of land which is drained by the river and its tributaries.
What is a watershed?
Each drainage basin is separated by a watershed. A watershed is usually an area of high land, such as a mountain range.
What is the long profile?
It shows how a rivers gradient changes as it flows from its source to its mouth.
What is the cross profile?
It shows the shape of the river channel.
What type of erosion happens in the middle course?
Lateral erosion.
What type of erosion happens in the upper course?
Vertical erosion.
What are the characteristics of the upper course?
Vertical erosion, Narrow channel, Waterfalls
What are the characteristics of the middle course?
Lateral erosion, Rounded rocks, Meanders
What are the characteristics of the lower course?
Very wide channel
What are the 4 types of erosion?
Attrition, Abrasion, Hydraulic action, Solution.
What is Hydraulic Action?
When the force of water forces water and air into cracks in the bedrock. The repeated changes in air pressure cause the riverbed to weaken.
What does the long profile of a river refer to?
The gradient.
What is deposition and when does it occur?
It is the dropping of material and it occurs when the water in the river channel no longer has sufficient energy to move the material.
What is a waterfall?
A geological formation where flowing water rapidly drops in elevation as it flows over a steep region or a cliff.
What is a gorge?
A narrow, steep-sided valley, with bare, rocky walls where a waterfall once was.
What is capacity?
The maximum number of things a river can carry. Overall weight of the load.
What is competence?
The largest individual particle size that a river can carry.
What is an artificial levee?
Created as a flood defence they increase the maximum volume of water the channel can take and so reduce the likelihood of flooding.
What is a delta?
A flat area of sand and silt built out into the sea.
What are the impacts of flooding socially, economically, and environmentally?
Social- damage to properties, injury of loss of life.
Economic- cost of repairs, reduced income/crops/tourism.
Environmental- loss of habitat, destruction of crops.
What is flooding?
An overflow of water onto normally dry land and it normally occurs when a river bursts its banks and overflows onto the surrounding land.
