Rivers Flashcards
Precipitation
When water falls down from the clouds. (eg. Rain, Snow, Hail)
Condensation
Water all binds together to form a cloud. (Gas out of water vapour)
Evaporation
A liquid evaporates and forms into a gas.
Surface Runoff
When water trickles down from a mountain.
Ground Water
When the water gets transported from underneath the ground.
Transpiration
Water gets evaporated off of the leaves of trees.
9 Stages of the waterfall formation
1) Hard rock and soft rock
2) Soft rock erodes quicker
3) Notch develops
4) Erosion makes the notch deeper
5) Plunge pool
6) No Support
7) Hard rock collapses
8) Process repeats, waterfall retreats
9) Gorge carries on being formed
Hydraulic Action
Small cracks trap air inside to create pressure and make the crack bigger. (Erosion)
Solution
Sand or salt dissolves when it mixes into the water to create a solution (Erosion)
Attrition
When big rocks collide into each other to create smaller rocks (Erosion)
Abrasion
Rocks scraping across the bed like sandpaper creating friction (Erosion)
Hard engineering
Dams:
Trap and store water
Reduces surface runoff
Expensive but effective
Upstream of the dam flooded, changes the eco system and will cause people to move out from that area
Traps sediment and won’t flow downstream, leads to farmers not having enough fertile soil for their crops
Flood Walls: Quite expensive Don't look very natural VERY effective at stopping flooding Placed in areas where locals are
Soft Engineering
Afforestation: Greenery Interception prevents flooding on wildlife Takes up a lot of space Cannot prevent serious flooding
Washlands: Can't be built on Parts of a floodplain (Small hills of sediment in ponds or lakes) Mostly used for sports Space is left empty, no injuries
Formation of an Oxbow Lake
1) Fast water erodes the outside curve, bigger meander
2) Fast water still crashing onto curves, erosion happens (Abrasion)
3) Slow moving water deposits sand and mud on the inside bend
4) Steep river cliff is created where river bank is being eroded, deposited sand creates slip-off slope or river beach
5) Meanders come close, continues overtime, deposition and erosion carry on, meanders change shape and size
6) River creates a thin barrier, eventually peaks through it, after it leaves the bottom meander and carries on as a straight river
7) Called an oxbow lake when it is cut off from the meander
8) Oxbow lake dries out
9) Process repeats
Upper course
The slowest because of traction and abrasion
Not very many tributaries, not enough water to make the river move faster
Hydraulic action does not occur
