Homework review: Work handed in 13th December

You had two pieces of homework last week - a question and answer sheet (which had a resource sheet to go with it) and a past exam question. You didn't need to do (e) from the past exam question.

Question and answer sheet
For some reason lots of you didn't attempt the first question. It gave you a series of statements and asked to you explain why it might lead to flooding. To do it right, you just had to use 'so ... what?'. For example "at the equator it rains all year round so ... there was plenty of water available for flooding".

Past exam question
There were the usual classic mistakes here - missing the command words, not using facts and figures, and not using the information from the resources. Don't forget that the command words are available on lots of websites - just type in 'command words' into Google for help!
This is a model answer of how to do this question:
a)
i) Study the diagram. Name two stores and flows. [2]
Stores = soil, rocks, river channel, cloud
Flows = transpiration, condensation, evaporation, precipitation, groundwater flow, throughflow

ii) Explain how the cutting down of the trees may affect the water cycle. [3]
No trees means no interception so increased infiltration of water into the soil. Also no trees means no transpiration so evaporation will become more important.


b)
i) Describe the locations of the areas that were flooded. [2]
(NB You can see the map in an earlier post on this website.)
East of Harbin City for 200km along the Sungari River
100km north of Khabarousk.

ii) Suggest two reasons for the flooding. Use evidence from the map to help. [4]
Deforested areas to the north of Harbin City reduces the amount of water held back from the river as there is no interception to slow down the water.
Marshland to the southwest of Khabarousk would be saturated leaving only a small amount of water needed to flood the area.

c)
i) Describe the pattern of river discharge shown by the graph. [3]
The discharge rises steeply from about 17.5 cumecs at the start of the 11th July 1997 to a peak of 36 cumecs on the 15th, before dropping to a steady 17-20 cumecs between the 17th and 22nd before sharply rising again to a peak of 37 cumecs on the 25th.

ii) Suggest reasons for the time lag betwen the peaks of rainflal and river discharge. [4]
The time lag may have been short due to the ground already being saturated from a previous storm, leading to increased overland flow and more water in the river.
The time lag may also have been short due to the water landing in the mountain area meaning it landed on steep slopes and moved more quickly into the river under the force of gravity.

d) Suggest two measures that people or organisations might take to protect property when given a flood warning. Explain your choices. [4]
Property may be removed to areas of higher land to reduce the likelihood of flood waters reaching them and causing damage.
Sand bags may be used to prevent water entering buildings and causing damage to the contents.

You didn't need to do question (e).