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Rivers and drainage basins - Coggle Diagram
Rivers and drainage basins
Main hydrological characteristics of a river
•all the landforms are found within a drainage basin
•tributary rivers
•when two tributaries join together, they form a confluence
•the area of land drained by a river is called it’s drainage basin
•the line that divides one river basin from another is called the watershed
•as more tributaries join the main river channel, the discharge will increase
Main hydrological characteristics of a drainage basin
•there are also many processes which occur in a drainage basin
•evaporation: when liquid changes to a gas
•overland flow: the movement of water across a land’s surface, not in rivers
•through flow: the horizontal movement of water through soil
•groundwater flow: the slow horizontal movement of water through underground permeable rocks
•interception: precipitation that is temporarily stored on the surfaces of plant leaves.. etc.
•infiltration: the downward movement of water into soil
demonstrate an understanding that rivers present hazards and offer opportunities for people
The causes of river hazards
•flooding:
•snow melting - rapid increase in water levels
•steep slopes - gathers water into one area
•ploughing (in straight lines) - surface runoff is faster
•impermeable rock - the land is left to surface runoff and more absorption
•urbanisation - fast drainage means more water quicker in an area
•deforestation - no water intercepted or absorbed by plants
•hot, dry wether - impermeable soil
•heavy rain - needed to cause most floods, increasing likelihood
•the hazards of rivers
•flooding
•economic: •cost of cleaning; damaged buildings; loss of stock; cost of insurance
•social: •use of services; cleaning; unemployment; death; lack of transportation
•environmental: •ruined habitats; destroys trees; ruins farmland; disease; littering
•short term: •road covered; evacuation; minor injury
•long term: •property damage; death; major stock damage; costs; disease
•river erosion
•vertical erosion of v shaped valleys can destabilize the valley sides, causing landslide
•lateral erosion and meander migration can undercut river banks and threaten development