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We begin by drawing a water cycle on the board. What can you remember?
Next we will use the syllabus to improve the diagram.
4.1.1. Movements of water in the hydrosphere are driven by solar radiation and gravity.
Heat is required for evaporation of water and is released when water condenses.
Gravity causes water to drain through soil and in rivers to the sea.
4.1.2 The global hydrological cycle operates as a system with stores and flows.
In water cycle diagrams, stores should be shown as boxes and flows as arrows.
4.1.3 The main stores in the hydrological cycle are the oceans (96.5%), glaciers and ice caps (1.7%), groundwater (1.7%), surface freshwater (0.02%), atmosphere (0.001%), organisms (0.0001%).
Percentage values are approximate so there is no need to memorize them, but students should have some idea of the relative proportions.
Make a suitable graph of this data.
4.1.4 Flows in the hydrological cycle include transpiration, sublimation, evaporation, condensation, advection, precipitation, melting, freezing, surface run-off, infiltration, percolation, streamflow and groundwater flow.
Sublimation is the transformation of ice directly to water vapour.
Advection is the wind-blown movement of water vapour or condensed/frozen water droplets (clouds).
Infiltration is water entering the soil.
Percolation is water movement in the soil.
4.1.5 Human activities, such as agriculture, deforestation and urbanization, can alter these flows and stores.
Change in land use, deforestation and urbanization often lead to reduced evapotranspiration and increased run-off, resulting in flash floods.
Change in land use, deforestation and urbanization often lead to reduced evapotranspiration and increased run-off, resulting in flash floods.
4.1.6 The steady state of any water body can be demonstrated through flow diagrams of inputs and outputs.
These can be used to calculate sustainable rates of harvesting from, for example, lakes and aquifers.
Water Balance in Russian Lakes
Source: https://www.researchgate.net/figure/Average-annual-values-of-the-lakes-input-output-water-balance-components-12-13-14_tbl1_331325627
Construct a flow diagram for lake Baikal in 1981-2005
North London Artificial Recharge Scheme (Aquifer)
Source: https://assets.publishing.service.gov.uk/media/5b7d2ddeed915d14e1fe3505/2018_Final.pdf
Working in a Google doc, answer the following questions
Which year had the greatest abstraction from the North London Artificial Recharge Scheme?
Which year had the greatest recharge into the North London Artificial Recharge Scheme?
What percentage of the abstraction in 2005 was replaced by recharge?
In order to be sustainable, what must be true of abstractions and recharge in the NLARS?
HL ONLY
HL ONLY
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