O-LevelGeographyThe natural environment2217/13 · Oct/Nov 2017 · Q325 Marks

(a) Study Fig. 4, a map of the Rio Puerco drainage basin in the USA. (b) Study Photograph C (Insert), which shows a river close to its source.

(a)(i)What is meant by the term drainage basin?[1]
(a)(ii)Identify the features labelled X and Y on Fig. 4. X Y[2]
(a)(iii)Using evidence from Fig. 4, suggest why flooding is more likely in the Lower Rio Puerco than in the Torreon Wash.[3]
(a)(iv)Describe four different strategies which can be used to reduce river flooding.[4]
(b)(i)Identify three ways in which the river shown in Photograph C is typical of a river close to its source.[3]
(b)(ii)Explain how the long profile and cross section of the valley of the river shown in Photograph C will change as the river flows towards the sea.[5]
(c)Describe the main natural features of a delta and explain how it is formed. You may use a labelled diagram or diagrams.[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 (Oct/Nov 2017). The mark or mark type is shown in brackets.

[1] Area drained by a river (and its tributaries)/the catchment of a river/area of land where water flows into the river
[2] X = watershed; Y = confluence
[3] Ideas such as: The Rio Puerco drains a much larger area; The Rio Puerco has more tributaries; The Rio Puerco is further downstream; The Rio Puerco is more likely to have a flood plain/flat land by the river etc.; Note: Needs to compare. Accept vice versa answers.
[4] Strategies such as: dams/reservoirs; build/strengthen/raise levees or banks; dredging/deepen the channel/remove debris; overflow channels/flood relief channels; afforestation/reduce deforestation; avoid building on flood plains; widen the river; straighten the river; allow river to flood meadow areas; tidal barrier; line with concrete etc.
[3] Ideas such as: the valley is V shaped/sides are steep/it is steep; the river has a small discharge; the river is shallow; the river is narrow; the river has stones/boulders/rocks in it
[5] Ideas such as: long profile/it will become less steep/gradient becomes gentler; long profile/it will become smoother/less irregular; cross section of valley/it will be wider/wider valley/more open valley; flood plain/flat land alongside river as it gets closer to sea/it gets flatter by the river; and levees; valley cross section/valley sides will become more gently sloping etc.; Note: Do not accept answers relating to the river channel. The focus is on the long profile and valley cross section
[7] Level 1 (1-3 marks): Statements including limited detail which describe the main natural features of a delta and/or explain how it is formed.
[7] Level 2 (4-6 marks): More developed statements which describe the main natural features of a delta and/or explain how it is formed.
[7] Level 3 (7 marks): Comprehensive and accurate statements which, which describe the main natural features of a delta and explain how it is formed.
[7] Content Guide: Answers are likely to: shape; location; distributaries; deposition; flocculation; colonisation by vegetation etc. Note: Credit any descriptive detail or explanation on diagram but do not double credit with text. Need explanation and description for L3 but description can be at L1.