River Flashcards
What is a source
the beginning of a river
What is a course
The route a river takes
What is a confluence
The point at which two rivers or streams join together
What is a tributary
A stream or smaller river that flows into a larger stream or river
What is the mouth of the river
The point where a river comes to its end, usually when entering the sea
What is a drainage basin
The area of land drained by a river
What is watershed
The edge of highland surrounding a drainage basin.It marks the boundary between two drainage basins
What is a Estuary
The part of a river mouth that is tidal
What are the three stages of a river
Upper or youthful stage,middle or mature stage and lower or older stage
What is the river at the upper or youthful stage
Steep, fast-following river Little water Lots of erosion Steep,V-shaped valley Narrow, shallow channel High bed load(larger rocks) FEATURES:V-shaped valley,interlocking spurs,waterfalls
What is the river at the middle or mature stage
River starts to slow down More water Still eroding Open, gently slopping valley with flood plain Wider deeper channel More suspended sediment FEATURES:meanders,oxbow lakes
What is the river at the lower or old stage
Slow-moving water Much more water Depositing here not eroding Open, gently slopping valley with flat and wide flood plain Very wide and very deep channel High levels of suspended sediment FEATURES:Flood plains levees
What is erosion
The river water wears the landscape away
What is transportation
The river carries the materials that it has eroded
What is deposition
The river drops off material that it is carrying
What is hydraulic action
The force of the moving water wears away the banks and bed of the river
What is abrasion
Small stones carried by the river wear away the banks and bed of the river
What is attrition
The small stones in the river are worn down and broken up as they hit off each other
What is solution
ps hydraulic action,abrasion,attrition and solution are methods of erosion
Rocks such as limestone, and soil are dissolved by acids in the water
What is rolling
The larger rocks are rolled along the bed of the river.This process is known as traction
What is bouncing
The smaller pebbles are bounced along he bed of the river.The process is known as saltation
What is suspension
Light materials such as sand and slit float along the water
What is solution
ps rolling,bouncing,suspension and solution are all methods of transportation
Materials dissolve in the water and are carried along be the rive r
What is river deposition
Deposition can shape the land by leaving sediment in new places, making new land or adding to existing land
What are the causes of river deposition
- Reduction to the river’s speed.This can happen when a river enters a sea or a lake, or during a period of dry weather
- Increase load size.This can happen when a tributary joins a river, or after a period of heavy rain fall
- Reduction to rivers volume.This can happen during of dry weather
- When the gradients levels off.This occurs when the river reaches fatter land
What are V-shaped valleys
A V-shaped valley is a steep-sided valley in the shape of a V, down which the river flows from its source.It is shaped by vertical erosion:the river cuts down into the river bed making it deeper.This process is called hydraulic action.It creates an deep narrow valley.Mechanical weathering and mass movement also weathers down the sides f the valley, breaking down the rock and soil.The material that falls into the river is carried downstream.Examples of this are shown in the upper course of the river Liffey,the river Moy and driver Lee
What are interlocking spurs
Interlocking spurs are areas of high ground that jut out at both sides of a V-shaped valley.As the river erodes the landscape in the upper course,It winds and bends around any areas of hard rocks it can not breakdown down.It still erodes vertically however.This process creates interlocking spurs which look a bit like interlocking parts of a zip.Examples are seen in the upper course of the river Barrow and The River Slaney
What are waterfalls
A waterfall is a vertical drop in the course of a river in its youthful stage.When the river flows over the area of hard rock lies across a band of soft rock, the soft rock is eroded quicker than the more resident hard rock, creating a drop or vertical fall.This fall increases in size and the material it carries creates a plunge pool at the base.The plunge pool enlarges over time, and hydraulic action and abrasion cause undercutting of the waterfall.This is turn results in the creation of over hang.Pressure and the force of gravity eventually cause the overhang to collapse.This process repeats itself over time, making the waterfall retreat upstream
What are meanders
Meanders are curves or bends in the river as it flows along its course it its mature stage.(mature side)
What is an oxbow lake
An oxbow lake is a horse-shoe shaped lake that was formed when a meander was cut.When they neck of a meander becomes very tight, the river can break through.(mature stage)
formation-1.Made feom well developed meaneders
2.erosion takes place on the outer concave of the river and the neck of land between the two lands becomes narrower
3.During a flood the river may finnaly break through and continue straight ahead and vlose off the meander by depositing sediment on the edges of the meander
4.An oxbow scar is a dried up oxbow lake
eg of oxbow lake is the middle stage of the river liffey
What are flood plains
A flood plain is a wide, flat area of land on either side of a river in its old stage.
What is a levees
A levee is a build-up of alluvium on the banks of a river.Levees are caused by floods
What is a delta
A delta is a triangular or fan-shaped area of land at the mouth the river where it enters the sea.Deltas are features of deposition found in the old stage of a river
Under what circumstances might a delta form
- The river must be transporting a large amount of sediment
- The sea must have a small tidal range and weal current
- The sea must be shallow at the river mouth
What human interactions does rivers have
Transport,tourism,fishing,settlement,pollution,flooding and HEP
What doe humans have to do with transport and rivers
Since the earliest settles came to Ireland, rivers have been used as a means of transport people and goods.
What do humans have to do with tourism and rivers
Tourists use rivers for cruising and fishing
What do humans have to do with fishing at rivers
Irish rivers are popular with anglers and many are famous for salmon fishing
What do humans have to do with settlement and rivers
Many settlements develop along river banks as the location provides food water and transport
What do humans have to do with pollution and rivers
Pollution comes from man made things such as slurry and industrial waste which run into or local rivers
What do people have to do with flooding and rivers
Human interaction can be responsible for flooding.
What do people have to do with HEP and rivers
HEP stations are often build using dams.The building can have both a positive and negative effect on the rivers.A dam is a large concrete wall built across a river to provide flooding
