O-LevelGeographyThe natural environment2217/13 · May/June 2016 · Q425 Marks

Study Fig. 5, which shows information about the flows which take place in a drainage basin. What is meant by drainage basin?

(a)(i)Study Fig. 5, which shows information about the flows which take place in a drainage basin. What is meant by drainage basin?[1]
(a)(ii)Identify from Fig. 5 a flow which takes place: – in the soil; – in the rock.[2]
(a)(iii)Explain why the amount of interception may vary within the drainage basin shown in Fig. 5.[3]
(a)(iv)Describe how the characteristics of the river are likely to change between points A and B on Fig. 5.[4]
(b)(i)Study Fig. 6, which shows a map of the delta of the River Nile. Using Fig. 6 only, describe three characteristics of the delta of the River Nile. 1 2 3[3]
(b)(ii)Explain how a delta is formed.[5]
(c)For a named river you have studied, explain the causes of flooding. Name of river[7]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Mark scheme

Marking points from the official mark scheme (May/June 2016). The mark or mark type is shown in brackets.

[1] (a) (i) Area of land drained by a river and its tributaries
[2] (ii) In the soil = infiltration/throughflow; In the rock = percolation/groundwater flow. 2 @ 1 mark
[3] (iii) Ideas such as: variation of precipitation within drainage basin; variation in vegetation cover/in some areas there is more/less vegetation/presence/absence of trees; type of trees, e.g. coniferous compared with deciduous/broad leaf; size of trees; as precipitation can reach the surface directly; trees are likely to intercept more precipitation than grass; as their leaves have more surface area, etc. NB: Ideas must link to interception. 3 @ 1 mark
[4] (iv) The river is likely to become: wider; deeper; with more discharge; faster flowing; more meandering/winding; more load; smaller size of particles in load; more deposition less erosion or examples; presence of ox-bow lakes; levees; gradient is less steep/flatter; channel bed gets smoother; vertical erosion at A and lateral erosion at B, etc. 4 @ 1 mark
[3] (b) (i) Ideas such as: arc like/arcuate/triangular shaped/fan shaped; north facing/flows to north; many distributaries/splits into smaller rivers/streams; 200-300km maximum west to east; 150-200km maximum from north to south, etc. 3 @ 1 mark
[5] (ii) Ideas such as: large amounts of sediment brought downstream; deposition in lower course; as speed of flow is reduced; and flocculation occurs due to salt in water; deposited silt blocks course of river; which splits into distributaries to reach sea; deposited materials are not washed away/grows towards sea; due to lack of current; colonisation by vegetation, etc. 5 @ 1 mark or development
[7] (c) Levels marking; Level 1 (1–3 marks) Statements including limited detail which explain the causes of flooding. Level 2 (4–6 marks) Uses named example. More developed statements which explain the causes of flooding. NB: Max 5 if no named or inappropriate example. Level 3 (7 marks) Uses named example. Comprehensive and accurate statements, including some specific reference. Content Guide: Answers are likely to refer to: heavy/continuous rainfall; saturation of rocks/soil; snow melt; deforestation; building on flood plains/urbanisation; lack of protective measures; dam collapsed, etc. Place specific reference is likely to consist of: locational details, statistical information, etc.