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Hydrosphere Revision. Hydrosphere Questions. Most commonly asked questions, every 2 years on average, are those related to OS maps and those which ask for explanations of the way river features are formed. Every 3 or 4 years question on Hydrological cycle and river flow data . Map work.
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Hydrosphere Questions • Most commonly asked questions, every 2 years on average, are those related to OS maps and those which ask for explanations of the way river features are formed. • Every 3 or 4 years question on Hydrological cycle and river flow data.
Map work • Describe the physical characteristics of a river and its valley, or annotate a map • Compare and contrast 2 rivers and their valleys (physical only)
Using grid references, describe the physical characteristics of the River Booster and its valley from 596020 to573060 Task 1: Fill in the blanks on your worksheet to complete the perfect answer
Sample answer The river meanders towards the NW. An example of the meander is at 587028. The river is roughly the same width throughout this section and could be in its middle course. There are 2 tributaries with confluences at 588036 and 584040.
Sample answer continued There is also an oxbow lake at 585044. There is an embankment at 587038 suggesting that the river is prone to flooding here. The valley has a flood plain which widens from 500m in the S to 2km in the N. The E side of the valley is gently sloping to over 30m whereas the W side is steep, rising to over 70m.
Annotate a base map to show the physical features of a river and its valley. Complete task 2 on your worksheets
Important tips 1 • Always use annotated diagrams in your answer, even when not specifically asked for them. • Practise drawing the diagrams when you are revising. • Use simple line drawings - they are much quicker and easier to draw than artistic block diagrams.
River Features • annotate sketches and diagrams to describe and explain the formation of selected physical features of a river and its valley • e.g. waterfall, meander, levee, river terrace, flood plain, alluvial fan, braiding • explain the effects of flowing water in terms of erosion, transportation and deposition in the upper, middle and lower course of a river • describe methods used to collect river-flow data: e.g. measuring depth, width, speed, gradient
Important tips 2 • Give plenty of detail on the processes - do not be fooled into thinking 'This is easy, I got full marks for this at Standard Grade'. There may be twice as many marks for a question like this at Higher. • When given a choice of features, choose the one you can write most about. • Make sure you can explain the following features: meander, ox-bow lake, waterfall, levee, river terrace, braiding, flood plain. • First four are those most likely to be specifically asked and often there is a choice.
Hydrological Cycle • draw a diagram and describe the global hydrological cycle • explain how balance is maintained within it • explain how water moves within drainage basins.
Hydrographs • describe and explain the patterns shown on a river hydrograph. • construct and analyse river hydrographs to show the relationship between rainfall and river flow
Remember: rainfall totals are always shown as a bar graph. Hydrographs: Know your terms!
Task: Identify descriptive points marking them with the letter D and explanatory points with the letter E.
Sample answer • At first there is no rain so the river remains steady (E) at 4 cumecs (D). • The discharge starts to rise after 9 hours (D) due to the rain which started to fall after 4 hours finally reaching the river (E). • At first the rain would have infiltrated) so would not have raised the river level (E).
Rain continued to fall until 14 hours, getting progressively heavier so that the ground would become saturated (E) and run-off would increase rapidly (E) causing the discharge to rise rapidly as well (D) to a peak of 73 cumecs after 10 hours (D).
This is 3 hours after the peak rainfall due to basin lag (E). • Rain continues, but much less heavily than before, so that discharge drops sharply (E) to 27 cumecs after 25 hours (D).
However, another rainfall peak after 23 hours results in a second peak of discharge (E) 3 hours later at 40 cumecs (D). • After 24 hours the rain has stopped but the discharge only gradually decreases as groundwater and tributaries continue to feed water into the river (E) until, after 48 hours, it is close to its original level at 6 cumecs (D).
Other Questions • On one occasion maps of two different drainage basins and their storm hydrographs were provided and the question was to explain these. • So, make sure you know how factors such as tree cover, gradient, rock permeability, drainage density and urbanisation affect the shape of a storm hydrograph.
Other Questions • You must also know how erosion, transportation and deposition change as the river moves from its upper, through its middle, to its lower course, and twice questions have been asked about this. • You should base your explanation on the fact that the energy of the river decreases as its gradient lessens between the upper and lower courses.
Other Questions • On a couple of occasions questions about rainfall in West Africa have appeared in the Hydrosphere section. • Answer these as you would if they were in the Atmosphere section where they would normally appear, referring to movement of the ITCZ and the mT and cT air masses.
Revision resources BBC Bitesize Revision http://www.bbc.co.uk/scotland/education/bitesize/higher/geography/physical/hydrosphere2_rev.shtml
