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S5 Geography Practice Paper: River Processes, Coastal Landforms, Weather, Plate Tectonics and Map Skills

S5 Geography Practice Paper: River Processes, Coastal Landforms, Weather, Plate Tectonics and Map Skills

  • 2026-11-12

S5 Geography

S5 geography practice paper: river discharge, coastal erosion, lapse rate and humidity, plate motion and earthquake energy, catchment runoff and map scale.

Paper details S5 geography practice paper with worked answers on river discharge, coastal erosion, lapse rate, earthquake energy, runoff and map scale.

Part 1: River discharge and channel characteristics (20 marks)

A river reach is 24 m wide with a mean depth of 2.5 m and a mean velocity of 1.2 m per second. Over the 8 km upstream of the reach the bed falls 12 m. The channel itself measures 11.2 km long, while the valley it occupies is 8.0 km long.

# Question Answer and marking notes
1 Calculate the cross-sectional area and the discharge of the reach. Answer: Area = 24 x 2.5 = 60.0 square metres; discharge = 60.0 x 1.2 = 72.0 cubic metres per second.
2 Estimate the hydraulic radius, taking wetted perimeter as width plus twice the mean depth. Answer: Wetted perimeter = 24 + 2 x 2.5 = 29.0 m; hydraulic radius = 60.0 / 29.0 = 2.07 m. A larger hydraulic radius means less frictional resistance.
3 Calculate the channel gradient and express it in the form 1 : N. Answer: Gradient = 12 / 8,000 = 0.0015, that is 1 : 667.
4 Calculate the sinuosity and describe the channel form. Answer: Sinuosity = 11.2 / 8.0 = 1.4. Above 1.3 the channel is meandering, with slower flow, deposition on the inner bank and erosion on the outer bank.

Part 2: Coastal erosion and longshore drift (20 marks)

A sea cliff is 35 m high and loses 42 cubic metres of rock per metre of coast each year. Mean wave height there rises from 1.5 m to 3.0 m. Longshore drift moves 45,000 cubic metres of sand past a section each year, and the beach is 5 km long and 30 m wide. Sediment input to the coast is 62,000 cubic metres a year against an output of 78,500 cubic metres.

# Question Answer and marking notes
5 Calculate the annual retreat of the cliff. Answer: Retreat = 42 / 35 = 1.2 m per year. For the same volume lost, a lower cliff retreats faster.
6 Wave energy is proportional to the square of wave height. If height rises from 1.5 m to 3.0 m, by what factor does energy increase? Answer: Height ratio = 3.0 / 1.5 = 2; energy ratio = 2 squared = 4.0 times. Winter swell can therefore multiply erosive power.
7 Assuming all drifted sand stays on the beach, calculate the average annual thickening of the sand layer. Answer: Beach area = 5,000 x 30 = 150,000 square metres; thickening = 45,000 / 150,000 = 0.3 m per year.
8 Calculate the annual sediment budget and state the coastal trend. Answer: Net change = 62,000 – 78,500 = -16,500 cubic metres. Output exceeds input, so the beach is narrowing and erosion dominates.

Part 3: Lapse rate and atmospheric humidity (20 marks)

Sea-level temperature is 28.4 degrees C and the lapse rate is 6.5 degrees C per km. At a station at 20 degrees C the actual vapour pressure is 16.8 hPa and the saturation vapour pressure at that temperature is 23.4 hPa. Saturation values are 16.0 hPa at 14 degrees C and 17.1 hPa at 15 degrees C. Annual rainfall at the foot of the windward slope is 1,180 mm; the air then rises a further 500 m, giving 22 mm per 100 m. Leeward rainfall is 72 per cent of the windward total.

# Question Answer and marking notes
9 Calculate the temperature at the top of a 1,600 m peak. Answer: Lapse = 6.5 x 1.6 = 10.4 degrees C; summit temperature = 28.4 – 10.4 = 18.0 degrees C.
10 Calculate the relative humidity at the station. Answer: Relative humidity = 16.8 / 23.4 = 71.8 per cent. The air is unsaturated and can still take up more water vapour.
11 Use the saturation values given to estimate the dew point. Answer: The actual vapour pressure of 16.8 hPa lies between 16.0 at 14 degrees C and 17.1 at 15 degrees C, so the dew point is about 14.7 degrees C, close to saturation.
12 Calculate the annual rainfall on the leeward slope. Answer: Windward total = 1,180 + 5 x 22 = 1,290 mm; leeward = 1,290 x 72 per cent = 928.8 mm, giving a rain shadow.

Part 4: Plate motion and earthquake energy (16 marks)

A plate moves 6.5 cm a year for 2.4 million years. One earthquake measured 5.2 and another 7.2; each unit of magnitude multiplies energy by about 31.6. P waves travel at 6.0 km per second and S waves at 3.5 km per second, and the epicentral distance is 84 km. Earthquake energy can be estimated from log E = 4.8 + 1.5 M, with E in joules.

# Question Answer and marking notes
13 Calculate how far the plate moves in 2.4 million years, in km. Answer: 6.5 x 2,400,000 = 15,600,000 cm = 156,000 m = 156 km.
14 Calculate how many times more energy a magnitude 7.2 event releases than a 5.2 event. Answer: Magnitude difference = 2.0; energy ratio = 31.6 squared which is about 1,000 times, that is roughly one thousand.
15 Calculate the difference in arrival time between the P and S waves. Answer: P wave = 84 / 6.0 = 14.0 s; S wave = 84 / 3.5 = 24.0 s; difference = 10.0 s. A larger gap means a more distant epicentre.
16 Use the formula to estimate the energy released by a magnitude 6.0 earthquake. Answer: log E = 4.8 + 1.5 x 6.0 = 13.8; E is about 6.3 x 10^13 joules, comparable to roughly 15,000 tonnes of TNT.

Part 5: Catchment runoff and water resources (12 marks)

A catchment covers 48 square km. A storm delivers 165 mm of rain and the runoff coefficient is 0.35. The reservoir can capture 60 per cent of the runoff, and daily supply is 180,000 cubic metres.

# Question Answer and marking notes
17 Calculate the total volume of rain falling on the catchment. Answer: 48 x 165 x 1,000 = 7,920,000 cubic metres. One square km receiving 1 mm of rain gains 1,000 cubic metres.
18 Calculate the runoff generated by the storm. Answer: 7,920,000 x 0.35 = 2,772,000 cubic metres.
19 Calculate the combined volume lost to evaporation, infiltration and groundwater recharge. Answer: 7,920,000 x 0.65 = 5,148,000 cubic metres.
20 Calculate the volume the reservoir can capture and how many days of supply it supports. Answer: Captured = 2,772,000 x 0.60 = 1,663,200 cubic metres; days = 1,663,200 / 180,000 which is about 9.2 days, under a fortnight.

Part 6: Map scale, gradient and area (12 marks)

A map has a scale of 1 : 20,000. Two points lie 6.4 cm apart on the map. The horizontal distance between the 120 m and 240 m contours on the map is 1.2 km. A rectangular area measures 5 cm by 4 cm on the map. A walking route is 4.8 km long and walking speed is 4 km per hour.

# Question Answer and marking notes
21 Calculate the real distance between the two points. Answer: 6.4 x 20,000 = 128,000 cm = 1,280 m = 1.28 km.
22 Calculate the slope percentage of that hillside. Answer: Height difference = 240 – 120 = 120.0 m; horizontal distance = 1,200 m; slope = 120.0 / 1,200 = 10.0 per cent.
23 Calculate the real area of the rectangular region. Answer: 1 cm represents 200 m, so 1 square cm represents 40,000 square metres; 20 x 40,000 = 800,000 square metres, that is 0.8 square km.
24 Calculate the time needed to walk the whole route. Answer: 4.8 / 4 = 1.2 hours, that is 72 minutes. Add rest time for uphill sections.

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