Date | May 2015 | Marks available | 2 | Reference code | 15M.2.hl.1 |
Level | HL only | Paper | 2 | Time zone | |
Command term | State | Question number | 1 | Adapted from | N/A |
Question
The diagram shows competing water demands and water conflict in a river basin.
State two possible uses of water for industry.
Outline two possible reasons for the conflict shown.
Explain how a drainage basin functions as an open system.
Compare the importance of river erosion and deposition in the development of floodplain landforms.
Markscheme
Award [1] each for any of the following up to a maximum of [2]:
- electricity/HEP
- transport
- raw material
- cooling
- waste disposal
- recycling, eg paper
- manufacturing of goods
- cleaning (must be related to industry) – eg in fish factory
- other creditable suggestions.
The conflicts can relate to water quality or water quantity. In each case, award [1] for identifying a specified reason of conflict and [1] for some outlined development, either of why the conflict occurs, or what its impact is on ecosystems.
For example: Irrigation can lead to agricultural runoff [1] which pollutes rivers with nitrates leading to eutrophication [1]. Dam building to increase water supply for agriculture [1] means fish cannot migrate and breed [1].
Possible reasons could include, but are not limited to:
- groundwater depletion
- salinization
- drainage diversion
- dam building
- pollution/eutrophication.
Award no more than [1] in total for responses that simply assert that there is not enough water to go around, unless some additional details are given.
Award [1] for identifying that the system has inputs (precipitation/rainfall) and outputs.
Award [1] for each of the following, up to a maximum of [2]:
- discharge, evaporation and/or transpiration are the outputs (must identify two)
- transfers take place, such as overland flow (must specify at least one transfer)
- stores such as soil moisture, interception storage (must specify at least one store)
- operation of feedback loops.
Reserve the final [1] for explicit recognition of the meaning of “open” (allows transfers across system boundary).
Up to [4] may be awarded for a diagram that includes specific inputs, outputs, stores, transfers and feedback related to a drainage basin. If the system diagram is not related to a drainage basin, award up to a maximum of [2].
Key processes include erosion (abrasion, hydraulic action, corrosion) and deposition (sorted by sediment size and shape).
Landforms include floodplain, meanders, oxbow lakes, levees, braided channel, delta, river terrace, slip-off slopes, etc.
Do not expect wide coverage of landforms if the quality of the argument (compare) and detail of the process is strong. Any argument should focus on the comparative importance of erosion and deposition for individual landforms or the floodplain as a whole.
Good answers may compare the importance of different processes for different landforms on a case by case basis (eg compare the role that both erosion and deposition play in floodplain or meander formation). Another approach might be to offer an overview of the development of the floodplain as a whole, during times when either erosion or deposition dominates (linked to flood events perhaps).
For band D, expect some description of some landforms, with some basic link(s) with river processes (erosion and/or deposition).
At band E, expect either a more detailed explanation of landforms (eg different types of erosion) or a structured comparison (eg can group landforms into erosional and depositional types).
At band F expect both of these elements.
There may be other approaches and these should be credited accordingly.
Marks should be allocated according to the markbands.
Examiners report
No problems.
There was some confusion over the diagram and the arrow, which showed conflict between water for agriculture and ecosystems. Reasons for conflict were stated, but often not developed sufficiently for the second mark.
This was generally poorly answered, with many candidates not understanding how a drainage basin functions as an open system, with inputs, outputs, stores and transfers. Many were unable to define the word “open system” beyond the fact that it has inputs and outputs.
There was a general lack of knowledge and understanding regarding floodplain landforms, and the contribution of erosion and deposition in their formation. Meanders, oxbow lakes and levees were popular. It was worrying that some candidates thought that waterfalls are a feature of floodplains. The command word “compare” was largely ignored, and there was little evaluation of the relative roles of erosion and deposition in the formation of landforms.