Identify and locate two natural river landforms found on the Clutha River’s floodplain.

(i) Briefly explain how one human modification of the floodplain shown in area A (outlined in black) may reduce river flooding.
 

(ii) Suggest two ways in which the settlement of Balclutha may have led to increased river flooding.

Examine how the environmental impacts of agriculture and irrigation on water quality vary from place to place.

Award [1] for naming each feature eg meander, braiding, marshland, slip-off slope, river cliff, oxbow lake, distributary, eyot/ait/island, levee.

Award [1] for either a four-figure grid square reference or a valid locational/situational statement for each.

For example:
There is a meander [1] southeast of Stirling [1].
There is oxbow lake [1] at 4971 [1].

(i)

Award [1] for identifying a modification and [1] for explanation.

For example:
Stopbank/artificial levee/embankment [1] allows higher
discharge/flow/increased capacity [1].
Drainage ditches/canals [1] carry water off the floodplain [1].
River deviation scheme [1] diverts water away from the main channel [1].

(ii)

Award [1] for each valid suggestion and [1] for why it may have led to increased flooding.

• Possibilities include:
• building on the floodplain
• infrastructure eg, roads on floodplain
• growth of town-impermeable surfaces
• bridge(s) over river
• railway embankment
• drains, culverts and sewers
• deforestation
• clearing of land for agriculture.

For example:
Road bridge over the river [1] constricts river flow and allows ponding/overflow of water [1].
Urban growth of Balclutha increases concrete/asphalt [1] which is impermeable so water runs into river [1].

Responses should show an understanding of a variety of impacts (from agriculture and irrigation) on water quality eg, eutrophication, salinization, agro-chemical run-off, groundwater pollution.

It would be expected that the causes and environmental consequences of at least two impacts should be explained.

Variation/scale/place-to-place should be considered.

Good candidates may consider, for example, that eutrophication is widespread wherever there is arable or pastoral farming with unregulated run-off into water courses and it is found worldwide. May affect rivers, lakes, wetlands and coastal margins.

At band D, answers are likely to be mainly descriptive and/or look only at one impact.

At band E, expect either a more detailed explanation of a range of impacts or an examination of how different places are affected in varying ways.

At band F expect both.

Marks should be allocated according to the markbands.

Most were able to identify two river landforms; meanders and ox-bow lake were the most common. There was a surprising inability to give a correct grid reference, or other location factor (although this was improved compared with previous sessions).

(i) No problems; most chose artificial levee/stopbank.

(ii) Few problems; most referred to impermeable surfaces and increased run-off.

Candidates showed understanding of a variety of impacts, such as eutrophication and salinization and their consequences, using located examples.