Exam-style Questions: Coastal Processes
a) Describe the main differences between constructive and destructive waves.
b) Referring to a named stretch of coastline, explain how marine, physical and human processes interact to produce a variety of landforms.
(Marks available: 18)
Answer outline and marking scheme for question: 1
a) Once again, a diagram should be used to support your answer without it the maximum marks available will be 4. For maximum marks you should include:
- Constructive Waves:
These are depositional waves as they lead to sediment build up, and are most common where a large fetch exists. They tend to have a low gradient, a larger swash than backwash, low energy, elliptical orbit and a low frequency of 6 - 8 per minute.
- Wave period is high in contrast:
Destructive waves act as agents of erosion, because backwash is greater than swash. They are most common where fetch is short, have a mainly circular orbit, a steep gradient, and "plunge" onto the beach. Frequency is height 10 - 12 per minute, but wave period is low, on average 16 -18 seconds between crests.
So, the question requires 2 definitions (2 marks each and a diagram 2 marks).
b) Important Points!
- Name only 1 stretch of coastline it is what the question asks for!
- 10 is the maximum mark if no human processes are included
- If the account is general and the coast not located maximum marks will be 5
The examiner will expect you to have written about:
- Marine processes combining with sub-Ariel processes
- Marine processes combining with human processes
- Erosional features
- Depositional features
You gain credit in your answer for:
- Naming and locating specific features along your stretch of coastline, for example, Spurn head
- Explaining in depth how marine processes interact with human and other physical processes (a diagram would be a good idea)
- Using a variety of features
An answer that includes only a few limited statements, imprecise locations, is very descriptive and only relates to 1 or 2 landforms would not be getting above 5 marks.
A top level answer would have good structure, reference to a range of physical and human interactions, show a sound understanding of the formation of a number of precisely located features and have accurate well labelled maps / diagrams.
(Total = 18 marks)
a) Outline 2 of the processes by which coastlines are eroded.
b) Briefly outline the key stages in the formation of a stump.
c) Explain how urbanisation at the coast impacts on coastal processes.
(Marks available: 16)
Answer outline and marking scheme for question: 2
a) Again, really another question requiring 2 good full definitions of the processes you choose.
- Hydraulic Pressure:
Cliffs and rocks contain many lines of weakness in the form of joints and cracks. A parcel of air can become trapped / compressed in these cracks when water is thrown against it. The increase in pressure leads to a weakening / cracking of the rock.
b) A fully labelled diagram would help you obtain good marks. In order to have a high level answer be sure to include:
- Mention of joints or faults being attacked and made larger by marine erosion. Caves occur where the weakness is at the base of the cliff, and can become a blowhole if the crack extends all the way to the surface.
The followng sequence:
Cliffs, caves, arch, collapsed arch, stack stump.
c) This question cannot be answered properly unless you show some understanding / appreciation of both coastal and river processes interacting at the coast.
For example, "urbanisation and artificial channelisation of rivers speeds up river flow. It can also reduce sediment available to beaches, starving coasts of sediment. Rates of beach erosion are increased as at Barton on Sea that may require human intervention in the form of concrete coastal management strategies. This can then cause problems further down the coast within the same sediment cell."
Marks: What to look for in your answer: 7 - 8 A diagram to illustrate the points you have made that is accurately labelled. Clear demonstration of the impact on coastal and river processes. Good use of examples. 4 - 6 Poor diagram, less detailed explanation and fewer references to examples. More concentration on either rivers or coasts. 1 - 3 No diagram, very little evidence of understanding of the links between processes. No examples used (or vague).
(Total = 16 marks)
a) Draw a fully labelled diagram to show the process of long shore drift.
b) Explain why many spits develop a curved end.
c) For any named stretch of coastline evaluate the success of the coastal management strategies adopted.
(Marks available: 20)
Answer outline and marking scheme for question: 3
a) Make sure that your diagram is annotated as fully as possible in order to gain full marks. In addition you should illustrate:
- That you know what long shore drift is
- That it can operate in more than one direction
- It tends to correspond with direction of maximum fetch and prevailing wind direction
- It can be limited by the use of groynes
b) Although a brief answer it is important that you relate to a named spit in this answer. For example, Spurn Head. = 3 marks maximum without it.
Other marks will come from mentioning:
- Usual direction of dominant fetch / prevailing wind
- 2nd most dominant fetch / prevailing wind
- Frequency of 2nd most dominant fetch and wind
- Importance of presence of a river or any other area of shelter
- A quick sketch of the processes acting on the feature
c) It is vital that you name a stretch of coastline to gain maximum marks. You will need to examine the success and failure of the strategy you have chosen to look at.
Marks will be awarded in your answer for the following points:
- Description of area you are looking at, for example, location, pressures on the area past history, rates of erosion, etc.
- Why there was a need for coastal management - aims
- A sketch map
(2 marks if well annotated)
- Outline of the measures adopted and how they work
- Evidence of success
- Evidence of failure (perhaps at other coastal locations)
This means not all the points are needed but instead a good explanation of the points you are making.
Remember to include facts and figures to support point you make. An example of a good part of this answer is illustrated below:
"The need for coastal management at Chesil Beach stems from its importance for coastal protection, and the wide variety of flora and fauna that is found on its stony habitat. The plan was devised in 1989 with its main aims being, to manage conflicts between recreational users and limit their impact on ecosystems, educate visitors about the area, reduce soil erosion and produce a sustainable development plan for all interested parties."
(Total = 20 marks)
a) What is a coastal sediment budget?
b) Explain the difference between isostatic and eustatic sea level change.
c) For a named feature of coastal submergence, explain its formation and usefulness to man.
(Marks available: 24)
Answer outline and marking scheme for question: 4
a) No need for detail here just a straight definition will gain 2 marks.
Movement of sediment in one cell does not impact on beaches in another. It is the division of the UK coastline into separate cells, where sediment from one cell does not venture into another. It is very important for coastal management strategies.
b) 2 marks per definition one on isostatic change the other on eustatic.
- Isostatic Change:
Local changes in sea level, due to ice weight depressing Earth's crust lying beneath it.
- Eustatic Change:
Large scale / worldwide changes. In times of maximum glaciations three to four times more water was stored on land than it is today. Global change in the hydrological cycle resulted and a worldwide eustatic fall in sea level of up to 150m.
c) Several choices of features are available although the best / easiest example is that of a Ria. Marks will be awarded for the following:
- Definition of a Ria: drowned river valleys. In the ice age when rivers still flowed they cut down to the new lower sea level. With the rise in temperatures and release of water from land they became flooded
- Example of a Ria (Milford Haven in South Wales)
- Brief diagram of formation
- Sequence of events in ice age leading to its formation (- Ice sheets and glaciers form, eustatic fall in sea level, and negative change in base level
- Ice sheets continue to grow. Land is depressed by weight, isostatic change, and positive change in base level
Ice sheets begin to melt, eustatic sea level rise, positive change in base level.
- Continued decline of glaciers, isostatic uplift of land, positive change in base level.)
- What it is used for today (deep water port for the docking of oil tankers)
- Why it is so suitable for this.
- Examples of economic and recreational activities that take place in the named ria.
Each statement will receive at least one mark. Up to 2 with more detailed explanation.
(Total = 24 marks)