RIVERS

rivers

by Carlotta Medioli

Start

Index

waterfalls

the water cycle

river landforms

drainage basins

hazards and opportunities

the work of rivers

floods

river valleys

rivers in the water cycle

Evaporation + evapotranspiration – condensation – interception – overland flow. Water reaches the sea to continue the cycle by rivers. Discharge: amount of water flowing in a channel.

drainage basins

- Areas drained by a river and its tributaries, the river’s catchment areas - Watershed: the drainage basin’s border or edge, found on hills or mountains.

the work of rivers

erosion of valleys

erosion

transport

deposition

- Hydraulic action - Corrasion/abrasion - Attrition - Solution/corrosion

- Solution load - Suspension load - Saltation load - Traction load

It occurs when the river’s energy dicreases. The first material deposited is the heaviest, followed by the lighter ones. Alluvium: the finest material which may be transported to the sea and it’s very fertile.

- Vertical erosion - Lateral erosion

river valleys

Factors influencing river valleys: rate of vertical erosion, rate of lateral erosion, geology , climate, time. Ex: Gran Canyon

waterfalls

- The water is fast-flowing, vertical erosion. - It can be found over horizontal hard rocks or vertical ones. - The movement back of the water forms gorges

river landforms

deltas

flood plains

meanders

Created by continuous overflowing and flooding by the river onto the flat valley either side of its main channel and deposition.

As rivers flow towards lower land there is less vertical erosion --> meanders

Over the time deposited material builds up and outwards into the sea to form deltas which can block the main channel.

OPPORTUNITIES

HAZARDS

- water for domestic use- water for industrial use- water for irrigation- water for transport - water for generating electricity - water for leisure and tourismValleys: - flat plain for building - fertile soils for farming - flat transport route for roads and railways

- loss of housing - lower house prices and higher insurance costs - loss and diversion of transport routes - loss of social, environmental and economic amenities - stress, injuries and death

floods

Hydrographs: graphs used by hydrologists to advise the authorities on flood management. Stores of sands and sandbags, systems of sirens and warnings, evacuation procedures and temporary metal barriers that can be put up quickly are used to protect people and properties from floods. To prevent floods hard and soft engineering techniques can be used.

Thank you!