2019 JC2 H2 Geography Prelim P2 ANSWER SCHEME

1 Catholic Junior College 2018/2019 GEOGRAPHY 9751/02 Paper 2 2 September 2019 3 hours Additional Materials: Answer Paper 1 Insert READ THESE INSTRUCTIONS FIRST Write your class and name on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Candidates answer all questions. The Insert contains all the Resources referred to in the questions. You should make reference to appropriate examples studied in the field or the classroom, even where such examples are not specifically requested by the question. Diagram and sketch maps should be drawn whenever they serve to illustrate an answer. The world outline map may be annotated and handed in with relevant answers. You are reminded of the need for good English and clear presentation in your answers. At the end of the examination, you are to hand in each question separately. The number of marks is given in brackets [ ] at the end of each question or part question. Start each question on a fresh sheet of paper. You will hand in each question separately. This document consists of 12 printed pages and 1 blank page. [Turn over Catholic Junior College JC2 Preliminary Examinations Higher 2

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3 Catholic Junior College 2018/2019 Section A ANSWER SCHEME Theme 4: Geographical Investigations Flood Risk Investigation in Hong Kong 1 A group of Geography students carried out geographical investigation along a river in the New Territories, Hong Kong, in February. They wanted to ascertain the flood risk of the region. They divided themselves into 4 teams of 8 members each to measure the cross-sectional area and river velocity of 4 selected sites along the river. The discharge of each of the 4 sections was calculated by multiplying the cross-sectional area of the river by the river velocity. The teams were given the following equipment:  1 x Table Tennis ball  2 x Tape measures  2 x Stop watch  1 x Meter ruler  4 x Range poles To measure river velocity, the time taken for the table tennis ball to cover a pre-determined distance defined by two range poles at the side of the river was recorded for each site. At the field study site C, the team collecting the data noticed that the table tennis ball was stuck in fallen trees or debris in the river. The data collected was then recorded using a data collection sheet. To calculate the cross-sectional area, the width and depth of the river at each site had to be measured. The students laid an unweighted tape measure along the river bed to determine the width of the river. Depth measurements were taken at equal distances across the river using the meter ruler. This data was used to plot the river’s wetted perimeter and then the cross sectional areas of the two rivers were calculated. Resource 1 shows a sketch map of the river showing sites A to D where the students were assigned to. Resource 2 shows a photograph of Site C. Resource 3 shows the data of the river recorded at different sites.

4 Catholic Junior College 2018/2019 (a) With reference to the preamble and Resource 1, state a suitable hypothesis for the fieldwork investigation and explain its suitability. Point marked (accept any possible answer- One of the following) Possible hypothesis: ‘The flood risk at site A and B is higher than the flood risk at Site C and D. ‘The higher the discharge is, the greater the flood risk.’ [3] (b) With reference to Resource 2, suggest what safety precautions the teams should take at Site C. Point marked (full marks to be awarded to responses with at least 2 precautions, 2 marks for well-elaborated answers)  Students should do a visual check if there are dangerous animals in the river or along the river banks e.g. crocodiles, monitor lizards etc before proceeding to carry out the fieldwork  Determine the best section for making wading measurements by noting the potential risk such as slippery rocks, deep segments, pot holes  Students collecting data in the river should always probe the stream bed ahead with a rod when moving from bank to bank. Keep your feet spread apart and alignment of legs parallel to the flow for better stability.  Always follow safety precautions when entering the stream. If the water is too deep or swift, select another site. Never venture out into the stream alone without another person available to assist you in case of emergency.  Determine whether the river stage is rising or falling. Beware of rapid rises in river stage when wading and anticipate and allow for changes in flow conditions at the end of the measurement. It is a good idea to select an object (rock, stump, mark along b ank, etc.) that is just above water surface and keep watching it to determine if the river stage is rising or falling. [3] (c) Explain whether the river velocity data collected in Resource 3 is reliable, and suggest how the data collection could be improved to increase its reliability. [5]

5 Catholic Junior College 2018/2019 Point marked (3 marks for explanation and 2 marks for improvement) Limitations: Data was collected in February during the dry season, might not reveal accurate discharge data. Only one measurement was taken for each of the river sites Measuring tape was unweighted leading to possible inaccuracies in the measurement of river width. In addition, there were some issues concerning the use of the table tennis ball as a floating device for the measurement of river velocity. This led to it being stuck by debris and rocks found along the river bed. Improvements made to planning:  have a contingency plan to come back during the wet season in June/July and if possible during the intermonsoonal months of March and September to do stream measurements so that an average could be obtained across one year (annual Q) apart from noting the peak and low flow periods.  Alternatively, students can also look for secondary data to find out about the level of discharge during the wet season to reduce the risk of having to collect primary data as discharge levels will be higher.  To obtain more than one measurement per day instead of just once in the day. Afternoon measurements may record a different reading owing to greater surface evaporation. Improvements made to the data collection process:  When measuring the overall river width, it will be better to use a rope, securing the ends of the rope to iron pegs lodged securely into the ground of the river banks. This will allow the rope to be pulled tightly and taut so that the measurement is accurate.  As there are irregularities in the river beds, students might want to consider adopting irregular intervals for depth measurements instead of regular intervals. This will allow for a more accurate measurement of the wetted perimeter and eventually the cross - sectional area.  Students might want to consider other floating devices for velocity measurement e.g. food -grade colour dye, dried orange peel. In addition, they should obtain 3 sets of velocity readi ngs in order to obtain the average velocity of river flow. (d) Suggest two limitations of the data representation method shown in Resource 3 and sketch an appropriate diagram to represent velocity at the 4 sites. Point marked  The data representation method in use is not visually friendly as numbers are presented in table format. There are many numbers in columns and rows making it hard to focus on reading the desired information.  In addition, the table format does not allow students to see the trend regarding the change in veloci