Rivers and landforms Flashcards
When might a river slow down
If there isn’t any wind
What’s hydraulic action
The force of fast flowing water that breaks up the bed and banks of the river
What’s abrasion
Stones carried by the river hit against the bed and banks of the river, wearing it away
What’s traction
Larger stones are rolled or dragged along the river bed.
What’s saltation
Lighter stones are hopped along the river bed
What is alluvium
Alluvium is a fertile soil. It’s a type of river mud that helps farmers by making their fields more fertile
What’s a feature
A natural physical part of the earths surface e.g waterfall or cave
Solution
When river water dissolves the rocks over which it flows
Attrition
Stones roll along the bed or collide with each other. River stones become round and smooth over time.
3 fts and their processes of the youthful stage
V shaped valley ( erosion)
Interlocking spurs ( erosion)
Waterfall (erosion)
2 fts and their processes of the mature stage
Meanders ( erosion and deposition)
Ox bow lake ( erosion and deposition)
3 fts and processes of the old stage
Leeves ( deposition)
Floodplain ( deposit ion)
Delta ( deposition)
Explain the formation of water falls
Waterfalls form in the youthful stage of a river due to differential erosion where soft rock erodes faster that hard rock. Hydraulic action is the main force with moving water wearing away the softer rock while abrasion uses the river load to further erode the bed and banks, shaping the plunge pool. As the river carries its load over the fall, it deepens the plunge pool. Solution erodes the back wall, creating an overhang of hard rock that eventually collapses into the plunge pool. This process repeats causing the waterfall to retreat upstream forming a gorge through headword erosion e.g powerscourt
Leeves formation
Leeves are raised banks that form along the edges of rivers and help prevent flooding. They develop through the process of deposition. During heavy rainfall or snowmelt, the rivers water level rises and overflows its banks. As the floodwater spreads out, it slows down losing energy and dropping the heaviest sediments ( such as sand and gravel) closest to the river banks. Over time, repeated flooding deposits more sediment, gradually building up raised embankments
. Lighter materials like silt and clay are carried further away helping form fertile floodplains beyond the levees. Artificial levees can also be built by humans using soil, concrete, or other materials to control flooding and protect settlement. E.g the Liffey
Hydroelectric power
Rivers are used to generate electricity by building dams that harvest the energy of flowing water e.g the hoover dam in USA
Transport in rivers
Rivers serve as natural highways for boats and ships, allowing for the movement of goods and people. Historically, major cities developed along rivers for this reason.
Sport and recreation
Rivers are used for activities like fishing rafting and swimming providing leisure opportunities for local communities and tourists.
