Describe two processes involved in the transport of a river’s load.

Explain two environmental impacts of agriculture on water quality.

“Floodplain management strategies have more costs than benefits.” Discuss this statement.

Award [1 mark] for identifying the process, and [1 mark] for a brief elaboration of each process.

Suspension: particles of finer materials such as clay and silt are held up by turbulence and make up most of the total load.

Solution: the dissolved load, derived from the solution of rocks containing carbonates or salts.

Traction: the movement of the largest particles such as cobbles or boulders along the stream bed.

Saltation: the “jumping”/bouncing of medium-sized particles along the bed.

Flotation: leaves and twigs carried on the surface of the river.

The environmental impacts could include salinization, agro-chemical runoff, pollution of groundwater and eutrophication. For each impact award [1 mark] for use of the correct term and a further [2 marks] for development.

For example, eutrophication [1 mark] is a nutrient enrichment of streams and lakes caused by agricultural runoff from nitrate fertilizers carrying excess nutrients [1 mark]. This can cause algal blooms and reduced levels of oxygen in water [1 mark].

Responses should discuss how strategies may prevent or exacerbate the flood risk, or may do both depending on the hydrological conditions prevalent at the time. Possible strategies could include:

• the construction of artificial levees
• flood barriers/walls to protect settlements
• flood relief channels
• flood basins or zones to absorb floodwater
• the creation/maintenance/restoration of wetland areas
• the removal of settlements from flood prone areas
• afforestation to increase interception
• enlargement of the channel e.g. by dredging
• straightening of river channels
• terracing, soil bunds and contour ploughing to reduce runoff
• dam construction – though this not always related to floodplains.

Answers may refer to several strategies in breadth or fewer strategies in more depth. The inclusion of floodplain examples is not directly asked for but these are expected in responses reaching band D and above.

Answers that simply describe strategies without discussing whether they increase or decrease floods (or both) should not move above band C. Responses that present a balanced argument are likely to be credited at bands
E and F.

Marks should be allocated according to the markbands.

Many (succinct) correct responses. Some did not use correct terms but described the process. Some had erosion and/or transport and deposition terms.

Some very competent answers. Most candidates found it easy to explain one environmental benefit though many failed to find a suitable second benefit. Also, many answers tended to describe the causes of salinization and eutrophication rather than explain their impacts on water quality so an inability to elaborate cost marks. Some weaker candidates stated irrigation was an impact and also lost marks.

Poor answers focused on one aspect of floodplain management, for example, all that can be written about the Aswan Dam. Many listed strategies, like dams, channelization and so on but failed to evaluate them as strategies for preventing/exacerbating floods. Generally, only a limited range of floodplain management strategies were presented and few candidates were therefore able to enter a detailed discussion. Very good responses used good examples to support analysis.