Geography - Rivers + coasts

Describe the long profile of a river

what are some landforms you can find in the upper course

• V shaped valleys

• waterfalls + gorges

• interlocking spurs

what are some landforms you can find in the middle course

meanders + oxbow lakes

what are some landforms you can find in the lower course

• flood plains and levees

• Estuary + salt marshes + mud flats

what is a river’s discharge

The amount of water flowing past a point in 1sec

what are the cross profile like in the 3 courses of a river

what is a drainage basin

a geographical area where all surface water, such as rain and snowmelt, collects and drains into a single point, like a river, lake, or ocean

what is a tributary

a river or stream flowing into a larger river or lake

what is a water shed

an area or ridge of land that separates waters flowing to different rivers, basins, or seas.

what is a confluence

where the tributaries meet the main river

what are the 4 types of erosion

1) Abrasion → rocks scraping land

2) solution → rocks dissolving in water e.g water is acidic/ rock is soluble

3) Hydrolic action → water smash against bed/bank

4) Attrition → rocks banging together

what’s one of our case study about rivers called

The River Tees

what’s the gradient like in a river

• UC → steep

• MC → less steep

• LC → flat

what’s the bed load like in a river

• UC → Angular rocks

• MC → rounded small rocks (due to erosion)

• LC → silt

what’s the velocity like in a river and state why

• UC → medium bc the channel is shallow and small + friction from big rocks slows down flow

• MC → fastest bc the channel becomes wider and deeper + less friction from rocks in river beds + more discharge from tributaries

• LC → slowest bc flatter gradient + inc of friction on river bed 

when does vertical (downwards) and lateral (side ways) erosion happen in a river

• vertical → upper course, why it forms V-shaped valleys

• Lateral → middle course, why it forms river cliffs 

what’s the largest river in the UK

River severn

what are the 4 types of transportation in rivers

1) Traction → rolling

2) saltation → bouncing

3) suspension → carried e.g salt

4) solution → dissolved

What are info abt case study - River Tees that i do not know how to put in question so like just remember it + watch video

explain the formation of a waterfall + gorge

1) Where you find hard rock over soft rock, differential erosion occurs causing soft rock to erode faster

2) making a plunge pool where hydraulic action and abrasion happen

3) causing a cave to form behind the waterfall, this then causes the rock above to become unsupported 

4) which will then eventually collapse and the waterfall will retreat as this process repeats 

5) Eventually leaving behind a gorge 

explain how V-shaped valleys are formed

through vertical erosion where due to the potential difference, the river erodes downwards

explain how interlocking spurs are formed

differential erosion occurs as the river meets both hard and soft rock so the river erodes the soft rock faster, causing the river to bend

explain how meanders and oxbow lakes are formed ( EXAMINERS FAV Q)

1) River flows faster on the outside than inside of a river bend

2) Therefore river cliffs form outside of bend through hydrolic action + abrasion

3) On the inside bend you get deposition which forms a river beach

4) as the bends grow, the neck of the meander slowly joins leaving behind an oxbow lake

describe the cross section of a meander

1) the channel is asymmetrical meaning one side is steep and the other gentle

2) steep side is outside bend = river flows fast + lateral erosion + deeper = river cliff

3) gentle side is inside bend = river flows slower + deposition = river beach

what are flood plains and how are levees formed

• Floodplains is the area of flat land on both sides of a river that regularly floods

1) when river flood they carry sediments 

2) larger sediments are deposited closer to river

3) as water flows away from river they lose energy = becomes slower 

4) smaller sediments deposites further away from river

5) so sediments left behind are called levees 

what is a method to make use of floodplains

do pastoral farming e.g cows + sheeps

what is an estuary and how are salt marshes and mud flats formed

Estuary is the mouth of the river where fresh river water meets salt water from the sea

1) As water constantly moves from high to low tide, sediments like silt is deposited by the banks or bed → bc water flows at low energy = mud flats

2) overtime salt resistant vegetation will grow on the mud flats e.g halophytes = salt marshes

describe the water cycle

1) Water evaporates from the sea

2) condenses to form clouds, which are carried by wind 

3) When clouds become heavy, water falls back to Earth as rain, snow, sleet, or hail

4) water flows overland into rivers and streams

5) Some water infiltrates into the ground bc of permeable rocks, e.g lime limestone → eventually back to rivers, lakes, or sea

6) Some are intercepted by trees, reducing surface runoff into rivers/streams 

7)  Eventually, the water collects in oceans, lakes, and rivers — and the cycle repeats.

what are the physical factors effecting flood risks

• precipitation → heavy + prolonged rain can lead to floods

• melting ice at mountainous areas

• saturated ground → raises risk 

• geology → impermeable rock = likely to flood

• relief → steeps slopes lead to surface runoff

what are the human factors effecting flood risks

• deforestation → reduces interception, inc. surface runoff

• urbanisation → more impermeable surfaces e.g roofs, streets, car parks → this is a change in land use

what are hydrographs

A graph which shows how river discharge changes in response to rainfall

is the river cam a flashy river

NO bc:

1) permeable rock

2) land use - mainly farming

3) relief is flat - little surface runoff

4) small drainage basin

What are the different hard engineering flood defenses

• dams + resevoirs

• embankments 

• flood relief channel

• channel straightening 

what are the different soft engineering flood defences

• flood warning and prep

• afforestation

• floodplain zoning

• river restoration

what are the positive + negatives of dams and resevoirs

positive

• hydroelectric power → green energy

• can regulate flow of river → reduces flood risks

• reliable water supply 

negative

• uses concrete which releases CO2 when produces 

• expensive → high maintenance + opportunity cost

• can break if not maintained well and burst

what are the positive + negatives of embankments

positive

• inc. rivers capacity → uses soil from bottom of river

• cheap 

negative

• may disrupt aquatic life in river e.g newt

what are the positive + negatives of flood relief channel

positive

• river discharge is reduced

negatives

• There will be an increased risk of flooding where the flood relief channel re-joins the river. If bankfull capacity is reached in the flood relief channel, it will flood the surrounding area.

what are the positive + negatives of channel straightening

positive

• inc. river capacity

• less water flow in river

negative

• moves problem downstream

• made from concrete

what are the positive + negatives of flood warnings

positive

• flood maps can be produced → allows ppl to plan for floods 

• local authority + emergency services can plan their responses to floods

negative

• cannot be 100% certain of how an area will respond to flooding

• areas at high risk of flooding can see house properties lose their value, insurance premiums can become very expensive

what are the positive + negatives of afforestation

positive

• inc. interception/transpiration/root uptake → reduce surface runoff

• it’s natural

negative

• not possible to cover the whole drainage basin of a river with trees 

• most trees lose leaves during autumn + winter → reducing interception in those months

what are the positive + negatives of floodplain zoning

positive

• Buildings are not constructed in areas at risk of flooding

• Impermeable surfaces are not constructed on the floodplain → so the risk of flooding is not increased.

negative

• might be too late to change location of the town e.g London

what are the positive + negatives of river restoration

positive

• Discharge in the river reduces, meaning there is less risk of flooding downstream.

• Little or no maintenance is required, which makes this a low-cost solution.

• Biodiversity is maintained along the river.

negative

• flooding is reintroduced to the area. those with valuable land/housing/properties will now be significantly effected

Give an example of a hard engineering in the UK

Thames Barrier (London)

• big investment

• going to rebuild in future → bc of rising sea lvl due to: melting ice at Antarctica + greenland and thermal expansion 

Give an example of a river restoration

Using beavers 

• builds mini dams for free

• reduce velocity of river

• however they chop down trees and eats lots of fish

who manages flood risk in the UK

Environmental Agency