4.2 Water access, use and securityIB Environmental Systems and Societies HL: Subtopic test

1. 1
   Cape Town, South Africa, depends mainly on rain-fed surface reservoirs. After three years of very low rainfall (2015 to 2017), reservoir levels fell sharply and the city warned that the taps could be turned off ("Day Zero"). In 2018 each resident was limited to 50 litres of water per day. Households fitted low-flow showerheads and reused washing water on gardens, while the city planned desalination plants and the tapping of groundwater.

   (a)

   Which statement best describes water scarcity?

   [1 mark]

   • AHaving access to sufficient amounts of safe drinking water
   • BThe limited availability of water to human societies
   • CThe total volume of water stored in a country's lakes and rivers
   • DThe proportion of water used by industry rather than by households

   (b)

   Which action described in the scenario is a domestic water conservation technique?

   [1 mark]

   • ABuilding a new reservoir
   • BConstructing a desalination plant
   • CEnhancing natural wetlands
   • DReusing washing water on gardens

   (c)

   Explain one advantage and one disadvantage of using desalination to increase Cape Town's water supply.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Country Y is an arid country of 12 million people. Each year its accessible, clean renewable freshwater supply is 18 billion cubic metres. Much of this water comes from a river that rises in a neighbouring country. The population is growing and irrigated agriculture takes most of the water.

   (a)

   Water stress is defined as a clean, accessible water supply of less than how many cubic metres per person per year?

   [1 mark]

   • A1,700
   • B170
   • C17,000
   • D5,000

   (b)

   Which statement correctly distinguishes water stress from water scarcity?

   [1 mark]

   • AWater stress considers only the amount of rainfall
   • BWater stress applies only to countries with no rivers
   • CWater stress also takes into account water quality, environmental flows and accessibility
   • DWater stress and water scarcity both ignore water quality

   (c)

   Calculate the clean accessible water supply per person per year in Country Y and state, with a reason, whether Country Y is water-stressed.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A water footprint is the total volume of freshwater used to produce a good or service. A school food-technology class compares typical global average water footprints per kilogram of food: beef about 15,000 litres, rice about 2,500 litres and wheat about 1,800 litres.

   (a)

   Calculate how many times greater the water footprint of beef is than that of wheat (to one decimal place) and suggest one reason why beef has such a large footprint.

   [3 marks]

   (b)

   Explain how water footprints can be used to inform decision-making about water security.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Egypt is a mainly desert country of more than 100 million people that receives very little rain. Almost all its freshwater comes from the River Nile, whose flow is regulated by the Aswan High Dam (completed 1970), which created Lake Nasser. Upstream, Ethiopia began building the Grand Ethiopian Renaissance Dam on the Blue Nile, a major tributary, in 2011, mainly to generate electricity. Egypt and Sudan, which lie downstream, have raised concerns about how quickly the new reservoir is filled.

   (a)

   Evaluate the options available to Egypt for increasing its water supply.

   [6 marks]

   (b)

   Discuss how transboundary disputes and governance affect water stress in the Nile basin.

   [6 marks]

   Total for question 4: 12 marks

End of questions