(i) Define the term wetland area.

(ii) Describe the pattern of wetland areas shown on the map.

(i) State one component of agricultural run-off that contributes to the eutrophication of lakes and wetlands.

(ii) Suggest two impacts of eutrophication that can have adverse effects for people.

“The drainage basin is an open system with inputs, outputs, transfers and stores.” Discuss how this knowledge helps people to prevent flooding.

(i) An area regularly/seasonally/permanently/always saturated [1] by surface water and/or groundwater [1].

[2 marks]

(ii) Possibilities include:

• mainly in the Tropics (Mexico/Central America/Caribbean) [1]
• fewer in higher latitudes [1]
• fewer in the Amazon/Brazil [1]
• concentrated along the coast [1]
• islands [1].

[3 marks]

(i) nitrates/fertilizers/phosphates/manure [1].

[1 mark]

(ii) In each case, award [1] for a valid impact and [1] for further development.

For example: Reduction of water quality for humans [1] resulting in health risks due to high nitrate concentrations [1].

Other possibilities include:

• loss of wildlife/fish reduces tourism potential
• high cost of cleaning water
• other valid impacts.

[4 marks]

The drainage basin is the area of land drained by a river and its tributaries, separated from adjacent basins by a watershed. The drainage basin is an open system as it has an input in the form of precipitation and a series of outputs such as evapotranspiration and water returning to the sea. There are stores and transfers facilitating the movement of water.

Flood prevention could be achieved by modifying different stores or parts of the system, eg forestry (interception) or reservoirs (less transfer). Knowledge of saturated soil stores can help with flood prediction though not prevention.

Some candidates may work systematically through each aspect of the drainage basin system, commenting on flood management in each case.

Good answers may discuss reasons why knowledge of the drainage basin system does not necessarily help prevent floods, for instance there are long-term unpredictable changes, eg climate change. Good answers might discuss the difference between flood prediction and flood prevention (knowledge of systems helps predict but not prevent).

At band D, expect some description of parts of the drainage basin system, with some relation to flooding.

At band E, expect either a more detailed explanation of the drainage basin system and possible flood prediction/prevention (may query whether a knowledge of drainage basins actually helps to prevent flooding) or explicitly discusses the relative importance of inputs, outputs, transfers and stores.

At band F, expect both.

Marks should be allocated according to the markbands.

[10 marks]