The following logarithmic graph illustrates the invervals of river discharge and flood recurrence.
Outline why a logarithmic graph was selected to illustrate this dataset.
- The data covers a very large range of values
1 mark - Using a logarithmic scale allows the data to be shown clearly on one graph
1 mark
Explain how changes with time to the volume of water stored as ice in the hydrological cycle could give rise to increased river flows.
Award
For example: The melting of ice could lead to an increase in river flow
Accept other valid examples.
Define the relationship between the river discharge and flood recurrence, with reference to the graph.
There is a positive relationship
As discharge increases, the flood recurrence interval increases
Estimate the flood recurrence interval for a discharge of 10 000 cumecs.
Describe how changes with time in the volume of water stored as ice in the hydrological cycle could impact the size of multiple other stores in the hydrological cycle.
Award
For example: Melting of ice could lead to an increase in the water stored in the oceans
Another change might be runoff from melting ice increasing lake storage
Examine the environmental impacts of agriculture on water quality.
Responses should show an understanding of any of the following: salinization, agro-chemical runoff, groundwater pollution, eutrophication of watercourses. Credit other valid positive impacts.
As agriculture becomes more intensive, there are greater inputs of chemical fertilizer and irrigation and greater outputs of waste, eg manure and chemical fertilizer. These can lead to a variety of types of environmental impacts in different areas.
| Marks | Overall Description |
|---|---|
| 0 | The work does not reach a standard described by the descriptors below. |
| 1-2 | • Response is too brief, lists unconnected information, not focused on question and lacks structure • Very brief or descriptive, listing unconnected comments or irrelevant information • Very general knowledge with large gaps or errors • Examples/case studies absent or only listed • No evidence of analysis • Terminology missing, undefined, irrelevant or incorrect • No evaluation or conclusion expected • Information not grouped logically • Maps/graphs/diagrams absent, irrelevant or unclear |
| 3-4 | • Response is too general, lacks detail, not focused on question and largely unstructured • Very general response • Outlines relevant and irrelevant examples, statistics, facts • Links to question merely listed • Analysis not relevant • Basic terminology used with errors or inconsistently • Irrelevant conclusion • No critical evaluation of evidence • Information not logically grouped • Maps/graphs lack detail or incorrectly interpreted |
| 5-6 | • Response partially addresses question, with narrow argument, unsubstantiated conclusion, and limited evaluation • Describes relevant supporting evidence • Outlines appropriate links to question • Partially addresses question or repeats one point • Relevant terminology used with minor errors • General conclusions, misaligned with evidence • Other perspectives/strengths/weaknesses listed • Some logical grouping but inconsistent • Maps/graphs don't follow conventions |
| 7-8 | • Response addresses whole question, evaluated analysis and relevant but unbalanced conclusion • Describes correct relevant evidence covering all main points • Describes appropriate links • Clear but one-sided analysis • Complex terminology correct but inconsistent • Relevant but unbalanced conclusion • Other perspectives described • Consistent logical grouping • Maps/graphs support analysis |
| 9-10 | • Response is in-depth and question-specific; justified analysis and conclusion through well-developed evaluation • Explains integrated examples, statistics, details • Explains appropriate links • Balanced analysis discussing complexity • Complex terminology used correctly throughout • Balanced conclusion aligned with evidence • Systematic evaluation of perspectives • Discusses strengths/weaknesses • Logically structured • Maps/graphs properly annotated and support argument |
