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

1. 1
   Between 2015 and 2018 Cape Town, South Africa, suffered a severe multi-year drought. Dam levels fell so low that the city warned of "Day Zero", the day on which most taps would be turned off. The city imposed strict limits on water use, reaching 50 litres per person per day in 2018, and campaigns urged households to save water.

   (a)

   Which statement best defines water security?

   [1 mark]

   • AHaving enough water in a country's rivers and lakes to meet the needs of ecosystems
   • BHaving access to sufficient amounts of safe drinking water
   • CHaving a dam within 10 km of every settlement
   • DHaving the lowest water price in the region

   (b)

   Which of the following is the best description of water scarcity?

   [1 mark]

   • AA rise in the quality of drinking water supplies
   • BAn excess of water leading to flooding
   • CThe permanent loss of all surface water in a region
   • DThe limited availability of water to human societies

   (c)

   Outline two techniques that households can use to conserve water.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A dry coastal country has a growing population and a rapidly developing economy. Its government is considering three ways of increasing the water supply: building a dam and reservoir across a seasonal river, building a large reverse-osmosis desalination plant on the coast, and subsidising rainwater catchment tanks on rooftops.

   (a)

   Which is the most likely environmental impact of a large desalination plant on the coast?

   [1 mark]

   • ADischarge of very salty brine that can harm marine organisms near the outlet
   • BA fall in the salinity of the sea along the whole coastline
   • CIncreased flooding of upstream habitats
   • DReduced groundwater recharge inland

   (b)

   Which is a disadvantage of constructing a dam and reservoir?

   [1 mark]

   • AIt cannot store water for use in dry seasons
   • BIt always increases the flow of the river downstream
   • CIt floods land upstream, destroying habitats and displacing people
   • DIt reduces the water available for hydroelectric power

   (c)

   Explain why desalination may not be a suitable way of increasing water supply for a low-income country.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A survey compares water access in two districts of the same country. In the urban district, 95% of households have piped water supplied all day and average use is 150 litres per person per day. In the rural district, 40% of households have piped water, average use is 25 litres per person per day, and women and girls often spend several hours a day collecting water from a distant river. Most national investment in water infrastructure has been spent in the urban district, where incomes are higher.

   (a)

   Using the data, compare water access in the two districts.

   [3 marks]

   (b)

   Explain how two different factors could account for the difference in access to water between the districts.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Almería in south-east Spain is one of the driest regions of Europe, yet thousands of hectares of greenhouses there grow tomatoes, peppers and cucumbers for export across Europe. Water for the greenhouses comes from groundwater and, increasingly, from desalinated and recycled water. Over-use of groundwater has lowered the water table in the region.

   (a)

   Explain how water conservation strategies can be applied in food production systems such as these greenhouses.

   [6 marks]

   (b)

   Evaluate strategies that can be used to mitigate water scarcity.

   [6 marks]

   Total for question 4: 12 marks

End of questions