O-LevelGeographyThe natural environment2217/11 · Oct/Nov 2011 · Q325 Marks

(a) Study Fig. 5, which shows part of a river. [Figure 5]

(a)(i)What river feature is shown by Fig. 5?[1]
(a)(ii)In which areas shown on Fig. 5 are each of the processes of erosion and deposition taking place?[2]
(a)(iii)Describe how the velocity varies across the river cross section labelled X-Y.[3]
(a)(iv)Explain why a flood plain and levees may develop in the lower course of a river.[4]
(b)(i)Explain why removal of forest to build the airport road is likely to increase the risk of flooding in the area.[3]
(b)(ii)Explain why, in many LEDCs, large numbers of people live close to rivers which may flood.[5]
(c)For a named river which you have studied, explain what has been done to reduce 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 (Oct/Nov 2011). The mark or mark type is shown in brackets.

[1] Meander
[1] Erosion on outer area/outer bank/concave bends/X
[1] Deposition on inner area/inner bend/convex bends/Y
[1] High velocity near X near outer bend
[1] Low velocity near Y inner bend
[1] Higher velocity in deeper water
[1] Higher velocity just below surface (than on surface)
[1] Lower velocity near bed (than away from it)
[1] flooding/river overflows in time of flood/after heavy rain
[1] water is still/slowed down (after the flooding/by river/on flat land)
[1] water retreats/evaporates/is absorbed
[1] coarse material deposited first forming levees
[1] light materials deposited further away build flood plain
[1] process repeats and levees/flood plain builds up
[1] Forest will no longer intercept rainfall
[1] take up water
[1] transpire it
[1] trees hold soil together
[1] Soil will be compacted/easily saturated
[1] Or replace it with tarmac
[1] More overland flow will take place
[1] Drains will take water to river more rapidly
[1] Lag timer reduced
[1] Mangroves protect area from tsunami/cyclone
[1] flat building land
[1] ease of communications using river
[1] or roads/tracks can easily be made on flat land
[1] flat land for growing crops
[1] water for irrigation
[1] eg for rice growing (dev)
[1] water supplies for domestic use/river for washing
[1] disposal of waste
[1] population pressure leaves them with no choice
[1] fishing in river/food supplies
[1-3] Level 1: Statements including limited detail describing what has been done to reduce flooding. Names the method of protection (e.g. build higher banks, plant trees in drainage basin, build dams/reservoirs along course of river, straighten river etc.).
[4-6] Level 2: Uses named example. More developed statements describing the method of protection/what has been done to reduce flooding (e.g. build higher banks so the river will have a greater capacity, raise banks especially in areas where river flows at a higher level than flood plain, plant trees so flow will not be so flashy/so less water will get to river as more evapo-transpiration occurs; build dams to regulate flow of water, straighten river so water is removed from drainage basin more quickly etc.). NB MAX 5 marks if no named example.
[7] Level 3: Uses named example (e.g. River Mississippi). Comprehensive and accurate statements including some place specific reference (e.g. built high levees so the river will have a greater capacity, raised banks protecting cities like Memphis where river flows at a higher level than flood plain, planting trees in Tennessee Valley so flow will not be so flashy/so less water will get to river as more evapotranspiration occurs; much straightening of river/meanders cut off between New Orleans and Memphis etc.).