SAJC Prelim H2 GEO P2 mark scheme

SAJC 2018 H2 Geography Paper 2_Mark Scheme_pg 1 © SAJC 2018 9751/02/18 Prelims Section A Theme 4: Geographical Investigation 1 (a) With reference to Resource 1, describe the main changes made to the river channel, and explain how these are meant to reduce flooding. [5] Changes Reduce flooding because… • Vegetation on the river banks have been removed, and replaced by concrete [ 1 m ] Speeds up the flow, such that flood waters can be removed quickly (i.e. more efficient) downstream: • Reduction of friction between water and the banks (i.e. lowers roughness) • Concrete lining prevents bed or bank erosion, lowers sediment load of the river [ 2 m ] • The river has been widened (note that the natural river banks have been “pushed back” to closer to the buildings) [1m] • Capacity of the river has been increased, allowing more water to be contained within the channel, helping to prevent bankfull discharge from being exceeded [ 1 m ] (b) With the help of Resources 1 and 2, suggest a research question for the group to guide them in their investigation, and briefly explain why it is of a suitable scale. [3] Possible research question: [1m] • To what extent has the channelisation at the confluence of Rivers Klang and Gombak reduced the perception of flood risk among users of the area in its vicinity? Considerations: [not creditable directly, but must be reflected in the research qn] • Fixed variable – channelisation • Variable to be tested – perception of flood risk • Where? – Confluence of the rivers • Who? – Users of the area in the vicinity of the confluence (defined here as within 300m radius) Why it is of a suitable scale: [2m] • Geographical area is small, only 300m radius, which is a little over 0.28km 2 • There is sufficient resources in terms of manpower (20 students) that can be divided into enough teams (5 teams of 4) to be spread out within this area • A total of 4 hours over two evenings is reasonable amount of time to survey 50 members of the public (average one team surveys 5 respondents every evening) (c) With the help of Resource 2, outline the steps necessary for the students to obtain a representative sample they require for the survey. [4] There is no fixed way of sampling, but explanations should be given for the suggested approach. Considerations should include: • Where to conduct the survey (e.g. stratified sampling to select five locations based on characteristics such as distance from the confluence; landuse; etc) • Who to find as respondents (e.g. a blend of quota and convenience sampling to obtain sampling profile that is reflective of actual population by age, gender, etc)

SAJC 2018 H2 Geography Paper 2_Mark Scheme_pg 2 © SAJC 2018 9751/02/18 Prelims Level Marks Descriptors 2 3-4 Response demonstrates good to very good knowledge of sampling method(s). Outlines a clear plan with reference to data collection, methods, and may consider limitations. Response is relevant to context of question but may lack clarity and coherence for lower end of the level. 1 1-2 Response demonstrates limited or no knowledge of sampling methods. Outline of method is limited and may not refer to one or more of the facets of an investigation in their outline plan. Much of the response may not be relevant to context of question. 0 0 No creditworthy response. (d) Explain one strength and one limitation of the data that will be collected using the questionnaire shown in Resource 3. [4] Strengths may include: [Any one strength well-explained, 2m] • Breadth of coverage – perception of risk (Q2 to Q4), cause (Q5), suggestions on mitigation measures (Q6), profile of the respondents (Q1, Q7 and items at end) • Clarity of questions – generally clear, unlikely to cause misunderstanding and hence collect invalid and unreliable information Limitations may include: [Any one limitation well-explained, 2m] • There was no question on comparing between the before and after of the channelisation efforts. This is a major limitation because the investigation was intended to investigate whether flood risks have been reduced because of channelisation. • There is an assumption that respondents are familiar with the mechanisms of flooding in the area (see Q5) and thus be able to identify solutions (see Q6) (e) Evaluate this investigation about flood risk in the area shown in Resources 1 and 2, and explain how it could be improved and extended. [9] Indicative content: Strengths • Flood risk is more commonly understood in terms of whether a river floods frequently and the magnitude of the floods. Investigating through the perceptions of the public is often overlooked, so this investigation will contribute a very useful piece of information from the users’ views. Limitations • However, studying only the perception of the public makes it a very narrow study. Flood risk of an area extends beyond perception of the public. • Difficult to obtain perceptions of respondents who have lived in the area before and after channelisation. Improvements and extension • To more fully meet the investigation’s objective to ascertain flood risk of the area, there are other considerations, including flood recurrence history stretching to in the 1970s, climatic data, landuse change over time, infiltration rates, etc • Flood risk study could consider the various social, economic and environmental costs that could be brought to the area • Channelisation in this area may result in flooding further downstream, so a study can be carried out for lower stream areas.

SAJC 2018 H2 Geography Paper 2_Mark Scheme_pg 3 © SAJC 2018 9751/02/18 Prelims Theme 1: Tropical Environments Cyclone Megi and Mass Movement in the Tropics 2 Resource 4 shows the forecasted rainfall for a region in East Asia, following the predicted path of Cyclone Megi in September 2016. Resource 5 outlines the various factors that affect the development of a tropical cyclone. Resource 6 shows rescue efforts following a mass movement event that was triggered by Cyclone Megi. (a) With reference to Resource 4, describe the passage of the weather system as Cyclone Megi moves inland. [3] Point marked, data referencing is expected. Indicative content: • As the cyclone develops off the shores of the island of Taiwan (South China Sea), it originates as a cyclone of 74 mph, estimated to bring around 1-3 inches of rainfall. • As it hits the shores of Taiwan on 27th September 2016, while wind intensity remains unchanged, the forecasted rainfall increases to 3-6 inches. • Finally, as the tropical cyclone moves towards Fuzhou, China, the tropical cyclone declines in wind speed, slowing down, the forecasted rainfall remains high, with some areas along the coast forecasted to receive 6-9 inches of rainfall. (b) With the help of Resources 4 and 5, suggest and explain the conditions that have allowed Cyclone Megi to form, and develop over time. [5] Response ought to pay attention to both the conditions for the formation as well as the development over space and time of the cyclones. The best answers will be able to address both. Development should also include the decay of cyclones. Indicative content: • Warm sea surface: Sea surface water temperature off the shores of Taiwan must have been above 27°C, which is also highly likely in September even though the overhead sun has shifted towards the equator. The high temp of water to a depth of about 60m (Resource 5) is maintained from heating achieved earlier in June- Aug due to water’s ability to retain heat longer. • Low Pressure cell: Air above the warm sea waters will also be heated, forming an intense LP cell which attracts winds from the surround HP areas, due to the