PHYSICAL - Water on the Land

Question 1

Drainage basin

Answer 1

The area of land drained by a river

Question 2

Source

Answer 2

The beginning/start of a river

Question 3

Tributary

Answer 3

A stream/smaller river which joints a larger stream/river

Question 4

Watershed

Answer 4

The area around a drainage basin, it marks the boundary between 2 drainage basins

Question 5

Confluence

Answer 5

The point at which 2 rivers meet

Question 6

Mouth

Answer 6

Th point at which the river ends, usually going into the sea

Question 7

River

Answer 7

A river is a flow of water flowing across the surface of the land, usually to the sea. It flows in a channel and the bottom of the channel is called the bed and the sides are called the banks

Question 8

Traits of the upper course river channel?

Answer 8

• Large boulders
• Slowest velocity
• Steep gradient
• V shaped valley
• river erodes vertically

Question 9

Traits of the lower course of the river channel?

Answer 9

• Rocks and smooth and there are fine sand materials
• Meanders
• Fastest velocity
• River is the widest
• Gradient is lowered
• U shaped valley
• River erodes laterally

Question 10

Diagram of the river channel in its 3 stages?

Question 11

The long profile is?

Answer 11

The sidewards view of the river course

Question 12

The cross profile is?

Answer 12

The river channel itself

Question 13

Name the 4 types of erosion?

Answer 13

• Hydraulic action
• Attrition
• Absrasion
• Soltuion

Question 14

Hydraulic Action

Answer 14

The force of the water against the banks, the pressure weakens the banks and gradually wears it away

Question 15

Abrasion

Answer 15

Rocks carried along the river wear down the bed and banks

Question 16

Attrition

Answer 16

Rocks being carried by the river smash together and break into smaller, smoother, rounder particles

Question 17

Solution

Answer 17

When river flow over certain types of soluble rock eg limestone, these become part of the water and their dissolved by it

Question 18

Name the processes of transportation?

Answer 18

• Traction
• Saltation
• Suspension
• Solution

Question 19

Traction

Answer 19

Heavy rocks and boulders and rolled along the river bed. Happens most in times of flood, when the current is the strongest

Question 20

Saltation

Answer 20

Small stones and pebbloed are ‘bounced’ along the river bed. This can take place when the river flow is less that needed for traction to take place

Question 21

Suspension

Answer 21

Vey small particles of sand/clay that are ‘suspended’ in the water

Question 22

Solution

Answer 22

Takes place with material in the water which is now invisible and doesnt colour the waters, occurs often in limestone landscapes where the water is acidic

Question 23

When does the river drop its load?

Answer 23

• When theres a fall in the speed of the water
• When the amount of warer is less
• When the gradient changes and near the mouth as it enders the sea

Question 24

Waterfall

Answer 24

A steep vertical drop of a river along its course

Question 25

Give an example of hard and soft rock

Answer 25

Hard rock = winestone, granite Soft rock = limestone

Question 26

Describe the formation of a waterfall

Answer 26

* Water flows over less resistant rock and therefore eroded more quickly than the harder, more resistant rock and is undercut by abrasion, hydraulic action and solution * Eventually the unsupported overhang collapses due to gravity. * Some of the debris us swirles around by the river, eroding into smaller pieces bt attrition. * The swirling rock also forms a deep plunge pool by abrasion * The process will be repeated, cuasing the river to retreat upstream, levaing a steep sided gorge

Question 27

The diagram for the formation of a waterfall?

Answer 27


Question 28

Gorge

Answer 28

A narrow, steep sided valley

Question 29

Meander

Answer 29

A bend/curve in the river channel

Question 30

Formation of a meander?

Answer 30

* As a river flows downstream over flatter land, (whilst still eroding vertically) more lateral/sideways erosion becomes significant resulting in a meander

Question 31

Formation of an Oxbow Lake?

Answer 31

* Continued erosion on the outer bends of a meander results in the neck becoming narrower * Eventually the neck will be cut throguht (often during floods) creating a straight channel * Depostion along the banks where the current is slowist will seal off the old meander to form an Oxbox Lake * Gradually these lakes dry up leaving a meander scar

Question 32

Picture formation of an oxbow lake

Answer 32

 

Question 33

Give 2 examples of landforms created by depostion?

Answer 33

Floodplains and leveés

Question 34

The picture formation of floodplain and leveés?

Answer 34


Question 35

Formation of a floodplain

Answer 35

 

Question 36

The Hydraudrical cycle

Answer 36

An closed system where no water is ever added or lost Water is constantly moving aorund the cycle and the amount of water stays the same 

Question 37

Discharge

Answer 37

The volume of water which flows through the river at a given time

Question 38

FACTORS AFFECTING DISCHARGE: Percipitation

Answer 38

* Less rainfall results in lower river levels * A lot of rain causes high river levels * High amounts of rain saturates the soil and underlaying rok, were as drizzle there is time for the water to infiltrate the soil and rocks, freeing up space for more water

Question 39

FACTORS AFFECTING DISCHARGE: Relief

Answer 39

* Steep s;p[es encourage fast runoff * Gentle slows allow time for infiltration to occur Relief affects the rate at which the water runs off the land surface and into rivers

Question 40

FACTORS AFFECTING DISCHARGE: Land Use

Answer 40

* The effect of people * Deforestation, Urbanisation * Concrete all over cities, water does infiltrate so it stays on the surface (eg LA always floods when it rains) * If trees are removes, water gets to the river fastes and trees dont intercept water from the ground

Question 41

FACTORS AFFECTING DISCHARGE: Rock type

Answer 41

Determines how the water infiltrtrates and how much stays on the surface * Granite = impermeable * Chalk = porous * Limestone = pervious

Question 42

FACTORS AFFECTING DISCHARGE: Temperature

Answer 42

Affects the loss of water from the drainage basin * Higher temperature = greater warer loss (via evaportion and transpiration)

Question 43

FACTORS AFFECTING DISCHARGE: Previous Weather Conditions

Answer 43

If it has been dry it willl take longer for the water to reach the river and less amount of time than if there had been many wet days

Question 44

Lag time

Answer 44

The time between the peakr rainfall and the peak discharge

Question 45

Base flow

Answer 45

Normal conditions of a river

Question 46

Flashy

Answer 46

A hydroraoh that responds quickly to a period of rain

Question 47

Subdued

Answer 47

Flood events that occur at a slower pace

Question 48

Rising Limb

Answer 48

How quickly the river reaches its peak discharge

Question 49

Falling Limb

Answer 49

How quickly the river reaches its base level

Question 50

Peak Rainfall

Answer 50

The highest level of rainfall

Question 51

Storm Hydrograph

Answer 51

A special type of graph which show river discharge over a given time in response to a rainfall event

Question 52

FLOODING: Prolounged Rain?

Answer 52

Long continuous periods of rainfall, leading to saturated ground

Question 53

FLOODING: Heavy Rain?

Answer 53

A cloudburst in a thunderstorm, which causes larg amounts of run-off in a short time eg Boscastle

Question 54

FLOODING: Snowmelt

Answer 54

A sudden increase in temperature that rapidly melts snow and ice. In winter water cannot seep into the ground because it is frozen

Question 55

FLOODING: Building on floodplains

Answer 55

Building on floodplains and impermeable surfaces so then more water runs off the surface (and faster). Rainwater falling on hard surfaces (building on roads) is led rapidly into underground drains and straight into rivers, with little chance of evaporation into the atmosphere or infiltration into the ground

Question 56

FLOODING: Deforistation

Answer 56

This reduces interception by the trees and rates of transpiration back into the atmosphere. More rainwater reaches the surface quicker, thereby increading rates of run-off

Question 57

Examples of major flooding events?

Answer 57


Question 58

MEDC flood: Boscastle - Causes?

Answer 58

* **The Weather **- 70mm of rain fell in 1 hour between 11am and 6pm 133mm feel (double the monthy rate) * **Steep Sided Valleys - **Faster surface run-off in the Jordan and Valency rivers * **Clay rich soils -** Kepp more water out so there is more surface run off * **Saturated ground and heavy rainfall - **Water cant infiltrate if the saturation level is reached, moves at great speed and has tremendous momentum

Question 59

MEDC flood: Boscastle - Primary effects?

Answer 59

* ** **155 cars were swept by the water * 60 people injured * Buildings destroyed * 58 properties were flooded, 6 destroyed outright * 4 bridges collapsed * Possesions lossed

Question 60

MEDC flood: Boscastle - Secondary effects?

Answer 60

**Happen as a result of primary effects** * Tourism decreased * Loss of business (restaurants, bakerys, hotels) * Jobs lost * Cost of insurances rised * People in debt * Trauma for people

Question 61

MEDC flood: Boscastle - other information?

Answer 61

* Happened on the 1th August 2004 * A year later things still werent back to normal * Over £200,000 needed to rebuild some bussinesses * 3.5" of rain in 1 hour - rainfall occured because moist warm air was travelling quickly upwards * Extreme case of the 'Brown Willy' effect * Some debts werent able to be paid * Physical effects such as stress

Question 62

MEDC flood: Boscastle - Primary responses?

Answer 62

**Occur during or in the days and weeks after** * 150 people were airlifted to safety * 7 helicopters sent to save people * Emergency services deployed to Boscastle to help people in the crisis

Question 63

MEDC flood: Boscastle - secondary responses?

Answer 63

**Months and years after the incident** * Water and flood supply restored * Defences improves/increases eg escape roots, car parks moved, flood defence systems, deepened river (10ft deeper), tree management scheeme * Power system renewed * Boscastle rebuilt * Bridges rebuilt (higher) * Ships and businesses re-opened within 12 months

Question 64

LEDC flood: Bangladesh - causes?

Answer 64

* H:Deforestation * H:High population density * H:Buildings near Frakka dam * P:Country is 1 huge flood plain * P:70% of land is 1m above sea level * P:10% of land is rivers, lakes and swamps * P:Bad previous weather conditions * P:Tropical cyclones

Question 65

LEDC flood: Bangladesh - Immidiate effects?

Answer 65

* Floods covered more than half of Bangladesh * 760 people were killed * 8.5 million people became homeless * over 35 million people were effected * Rice growing and fishing were disrupted * Roads and bridges were destroyed and damaged

Question 66

LEDC flood: Bangladesh - secondary effects?

Answer 66

* Over 1 million children suffered from malnutrition and disease * Rebuilding estimates to coast $2-3billion * Food supplied needed until the following years harvest

Question 67

River restoration

Answer 67

River engineers seek to restore rivers to the 'natural' state by taking out previous hard engineering and replacing this with what should have been there in the first place This involved putting swamps back in, reinstating meanders, encouraging depostion by using ediment traps and wooded groynes in the channel, adding reed beds etc

Question 68

Flood Warnings

Answer 68

* By environment agency over radio, tv, internet * Can be direct to home by text for registered users - floodline warnings direct

Question 69

Advantages of flood warnings?

Answer 69

* Gives people more time to prepare by gathering possesions upstairs, turing off gas and electric * It reduces the impact * Its relitavley cheap

Question 70

Disadvantages of flood warnings?

Answer 70

* Damage potention still remains high * Relies on the response of the community * Requires accurate and continuos information * If several false alarms occur, false fear and later reluctancy when the real situation actually happens may occur

Question 71

SOFT ENGINEERING: Afforestation

Answer 71

This occurs when trees are planted near to the river, this means greater interception of rainwater and lower river discharge. This is a relitivley low cost option which enhances the environmental quality of the drainage basin

Question 72

SOFT ENGINEERING: Flood plain zoning

Answer 72

Thi is where the areas closest to the rivers are only used for lost cost uses such as grazing and playing fields Higher cost land uses are kept away from the river on higher land 

Question 73

Hard enginerring

Answer 73

(Technology) eg Dams, Leveés * Involves building of **artificial **structures using various materials such as rock, concrete and sleet to reduce or stop the impact of river processes

Question 74

Soft engineering

Answer 74

eg forestation, flood plain zoning and reed beds * Involves managing a river using natural materials and mimicking natural processes to protect more vulnerable areas

Question 75

Hard engineered pros and cons?

Answer 75

+ Immediate results +Control the river and stops floods + Lowers insurance costs - Expensive - May cause future problems and be unsustainable - Have to be maintained (costly) - False sense of security - Environmental damage

Question 76

HARD ENGINEERING: How do dams prevent flooding?

Answer 76

Dma block rivers and cause the water carried by rivers to back up ad flood the valley upstream of the dam eg 3 gorges dam, China

Question 77

HARD ENGINEERING: straightening rivers

Answer 77

Straightening meanders - this involves digging a straighter, shorter channel in areas where rivers meaner **Why? **- Faster flow of water, reaches the mouth faster **Example? **- the Mississipi river and in York **Negative effect? - **Can cause flooding further down stream

Question 78

HARD ENGINEERING: Floodwalls

Answer 78

These raise the banks of rivers so that it can hold more water, this therefore reduces the rosk of a flood (It was a failure in floodwalls which causes further damage in New Orleans during Hurrican Katrina)