AQA Geography Unit 2

The following cards will give a brief overview of an investigation carried out for the AS Level Geography Unit 2 Course.
It will run over a few example questions of what may appear in the exams
***NOTE*** Any questions asked will be answered on the following cards. This gives you the chance to answer the question and then compare your answer to the example answer 

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The Area of Study (1)

The investigation was carried out in the Lake District (North-West England). It contains mainly rural characteristics (such as country roads). It also has an older, more sparsely populated area with its main employment in agriculture or tourism.

Our investigation, more specifically, will be carried out on the Torver Beck River. Which has an altitude of 600m in the highlands and drops by 550m as you near the coast. 

There are many human influences onto the river; mainly the slate quarry, the regions sheep farming and Coniston Town's Settlement

Question - Describe the location of your fieldwork and explain why it was suitable for your investigation

Why was it suitable for our investigation?

1) Relatively safe to access the river, 2) Relatively short long profile, 3) Relatively easy to reach the river, 4) Torver Beck shows significant change in its channel characteristics from source to mouth and 5) Torver Beck provides an oppurtunity to see what impact human influences and a glaciated landscape has on channel characteristics

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The Area of Study (2)

Answer:
The location of our fieldwork is in the Lake District and we are studying the Torver Beck, the river found in the south of the Lake District. The long profile of the river is 600m and falls by 550m after 5km from source to mouth. The area was formed by glaciation 18,000 years ago which has left a U-Shaped Valley. This means it was suitable for our investigation because it has a relatively short long profile (5km) and making it easier to access the river. Due to the Torver Beck's natural history and its surrounding human influences, it is good to see what these factors have on channel characteristics 

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Aim of our Study (1)

To investigate the changing channel characteristics from source to mouth along the Torver Beck and to consider the factors which cause these changes

The theory that we based our aim on was Bradshaw's Theory and Model. The idea is that as you move downstream, certain characteristics such as Width, Depth, Velocity, Wetted Perimeter, Roundness of Bed Load, River Capacity (amount of load a river can carry), River Competence, Cross-Sectional Area, Hydraulic Radius and Discharge will increase and other characteristics such as Gradient and Bed Load Size decrease. 

Question - Outline the aim and describe the theory, idea or concept from which your aim was derived


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Aim of our Study (2)

Answer:
Our aim was to investigate the changing channel characteristics from source to mouth along the Torver Beck and to consider the factors which cause these changes. This aim was created from understanding the Bradshaw Model. His theory suggests that channel characteristics will change as you move downstream. This is because channel characteristics are inter-related, for example velocity increases due to bed load size becoming smaller through the process of attrition. This will result in the river having a greater kinetic energy which will allow the river to erode through abrasion, and therefore a larger Cross-Sectional Area (CSA) 

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Our Hypotheses

As velocity increases along the long profile, so to will the CSA

This is expected because as the volume of water increases within the river, potential energy (energy of a river that cannot be released until friction has been overcome) is converted into kinetic energy. 

This increases the rivers ability to erode as the energy within the channel is greater than the energy required to overcome friction and the energy used to transport bed load

At this point, the river is able to create, through abrasion, a larger CSA

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Data Collection - Selecting Our Sites

The possible options are random, systematic and stratified sampling

We will not use random sampling because it may lead to a disproportionate number of sites in one course of the river, this would not be a representative sample

We will not use systematic sampling (e.g. every 100m) as there are areas that we cannot access due to safety reasons or private land, thus not giving us a representative sample

We will use stratified sampling. Using our own knowledge of the river to choose sites where known variations in channel characteristics exist. This will demonstrate the expected downstream changes in channel characteristics

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Data Collection - Collecting Data from Each Site

We will then use systematic sampling. This will help to eliminate bias in our sampling. For example, at each site to measure the depth, we will divide the width by 10 and then take the reading at those 10 different points

Data Collection Technique: Measuring the Depth
Description: Measuring tape to measure the width. The width divided by 10 at each site and readings taken every 1/10 interval. Then use a metre ruler to measure the depth in cm's 
Justification: 1) Depth measurements are required to calculate the CSA, 2) Depth is an important channel characteristic which can cause other factors such as velocity to change. Therefore the depth measurements will help us to understand the dynamics of the river channel
Limitations: The fast flowing water often made it difficult to read the depth of the channel on the metre ruler. This could lead to an error of up to 2cm/reading. This is significant in relatively small river channels 

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Data Presentation Techniques (1)

River Cross Profile
Construction:  drawn to scale so comparisons can be made. The depths were plotted at every 1/10th along the measured width of the cross-profile. A sharp pencil was used to ensure accuracy. The channel and bedrock coloured differently to allow for clear shape of the channel. X and Y-Axis' plotted
Justification: to show the difference in channel shape as you move downstream/ Shows a clear visual representation. Helps us to understand why other factors such as velocity increases downstream, therefore helping us to investigate the hypotheses
Limitations: it does not show a correlation between the factors in the hypotheses. We have assumed the depth between each interval

Scatter Graphs
Construction: a sensible scale drawn to be able to see the trend and anomalies clearly. X-Axis contained the independent variable (CSA) while the Y-Axis contained the dependent variable (velocity). A sharp pencil used to ensure accuracy. Each point was labelled with the correct site number
Justification: to show the correlation in the downstream changes between CSA and velocity. Clear visual representation of trend/correlation and easy to spot anomalies. This allows us to test our hypotheses
Limitations: CSA and velocity are both dependent variables so difficult to decide which one should be placed on the X-Axis. The strength of the correlation displayed is subjective and requires statistical testing 

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Data Presentation Techniques (2)

Spearman Rank
Construction: two sets of data ranked. The distance between ranks is d2 - ∑d2
The end value is put against the critical value of significance
Justification: it provides a numerical value for the strength of the correlation and allows us to test hypotheses
Limitations: just because a correlation is found, it does not necessarily mean that the two factors are linked
 

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Risk Assessments

Question - Describe and justify the risk assessments that you did

Mountain environment, including cold weather, rain and steep slopes. The risks were minimised by: all students had to wear fleeces and waterproof clothing, also had to wear appropriate footwear such as walking boots

Unsafe slopes on either side of the river. The risks were minimised by: stratified sampling technique used so that hazardous parts of the Torver Beck could be avoided. This includes the slate spoil heaps which was liable to collapse. Geography Information Systems (GIS) used to identify hazardous locations before the trip

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Spearmans Rank in More Detail

This tests the strength of a correlation between two ranked sets of data

The strength of the correlation is referred to as the significance level. If there is a greater than 5% possibility of the relationship occuring by chance, it is not significant. This means that the relationship could have occurred by chance more than 5 times in a 100, and this is an unacceptable level of chance (critical value)

However, if there is less than 5% possibility, the relationship is significant and meaningful

The level of significance becomes even greater if there is a less than 1% chance

22 Pairs of Data

0.05 (5%) 0.359

0.01 (1%) 0.508

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Anomalies Affecting Channel Characteristics

Geology of River Bed: upper course was Borrowdale Volcanic Rock (resistant) whereas the middle course was Coarse Slate (less-resistant)

Glacial Till: creates resistance and decreases channel efficiency

Gradient of the Channel: a stepped profile which creates variations in velocity

Mountains Create Relief Rainfall: high rates of precipitation create high discharge and therefore a large drainage basin

Human Influence: Slate Quarry creating resistance and decreasing channel efficiency

Tributaries: adds more water to the river channel

Steep-Sided Valley: creates a short lag time, high river discharge therefore high energy for erosive processes (abrasion/attrition) and a limited range of vegetation

Open Moorland in Upper Course: a natural landscape. In the lower course, human influence as the banks are reinforced

 

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Analysis (1)

Hypotheses: there will be a positive correlation between CSA and velocity with increased distance from the source

Expected Results: positive correlation because as the discharge increases, potential energy converted to kinetic energy giving the river greater power to flow fast and erode (abrasion/attrition). This will erode a larger CSA

What Our Results Showed: 1) Scatter Graph showed a positive correlation,
2) Spearmans rank significance test shows over 99% significance, and 3) River profiles show channel size (CSA) increase with distance downstream

Found These Results Because: 1) River energy sufficient to overcome friction/resistance to maintain increasing levels of velocity, and 2) Tributaries of the Torver Beck add discharge/energy to the main channel

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Analysis (2)

Anomalies:

1) Stepped profile of the Torver Beck; site 9 the CSA is ranked 21 but the velocity is ranked 11. This is because site 9 was located on a step with a steep gradient

2) Glacial Boulders; site 15 the CSA is ranked 14 but velocity ranked 13, but both should be ranked 9. This is because the river channel was heavily influenced by large glacial material slowing down velocity and reducing the rivers energy and ability to erode

3) Slate Spoil Heaps and Quarry; site 19 CSA ranked 15 and velocity ranked 19.5, but both should be ranked 4. This is because waste slate has slipped into river channel and increasing the resistance. Also, discharge from the river dropped at this point as it has been diverted into slate quarry 

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Evaluation (1)

Did We Prove It: Yes

Two Reasons Supporting the Data: scatter graph shows a positive correlation and spearmans rank is above a critical value and achieved greater than 99% significance

What Went Well:

 1) we selected a hypotheses that could be easily measured and collected
2) stratified sampling technique gave a broad range of results successfully
3) systematic sampling at each site led to reliable data
4) range of data presentation and statistical techniques used and the results thoroughly analysed
5) our understanding of the factors affecting channel characteristics has improved
6) a limitation of the Torver Beck, and most rivers, is that the lower course is difficult to access due to safety. We have assumed in out findings that this stage of the river increases as predicted by the Bradshaw Model


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Evaluation (2)

Improvements:

1) must be tentative about our findings and any conclusions drawn from the data collected should be made with caution

2) to have a greater confidence in our findings we could carry out spatial andtemporal comparisons, e.g. sample river at different times of year or compare to woodland river

3) carry out a different sampling technique on the Torver Beck, e.g. systematic just to see what influence site selection had onto the results

4) we could practice the data collection techniques to improve the quality of data 

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Comments

Hannah

This is absolutely brilliant as the investigation we did was very similar and your model answers are very good. Thank you very much.

Emma

Thank you very much- this has helped a lot!! 

Ruth Butt

Very good. :)

Ruth Butt

Very good. :)

maryaaaaaa

Very helpful

hamzah97

splendid

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