WaterIB Environmental Systems and Societies SL: Topic test

1. 1
   In a typical city, roads, roofs and car parks are covered with concrete and tarmac, and rainwater is carried away quickly by drains into rivers. During heavy rain this causes flash floods. China's 'sponge city' programme, started in 2015, aims to make cities absorb and store rainwater using permeable paving, green roofs, wetlands and parks.

   (a)

   Which flow in the hydrological cycle is reduced when soil is covered with tarmac?

   [1 mark]

   • AInfiltration
   • BEvaporation from the sea
   • CCondensation
   • DPrecipitation

   (b)

   Which two factors drive the movement of water in the hydrosphere?

   [1 mark]

   • AWind and tides
   • BPhotosynthesis and respiration
   • CSolar radiation and gravity
   • DPlate tectonics and the Moon

   (c)

   Explain how permeable paving and green roofs can reduce the risk of flooding in a city.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   In April 2014 the city of Flint in Michigan, USA, changed its water supply from the Detroit system to the Flint River, in order to save money. The river water was corrosive and was not treated properly, so lead leached from old pipes into the drinking water of the city. Residents complained about the colour and taste of the water for many months, and their complaints were at first dismissed by officials. Flint has a majority African American population, and a large share of its residents live in poverty. A state of emergency was declared in 2016.

   (a)

   Which statement best defines water security?

   [1 mark]

   • AHaving a water supply that is free of all costs
   • BOwning a private well
   • CLiving close to a large river
   • DHaving access to sufficient amounts of safe drinking water

   (b)

   Which type of factor is shown by the decision to change the water supply in order to save money?

   [1 mark]

   • ACultural
   • BEconomic
   • CClimatic
   • DReligious

   (c)

   Explain how social and political factors affected equitable access to safe water in Flint.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A household of four people in a Gulf city uses an average of 400 litres of water per person per day. The family fits low-flow taps and shower heads, dual-flush toilets and a system that recycles water from showers for flushing, which together save 25% of the household's water use. The city gets most of its drinking water from desalination plants, which use large amounts of energy. (1 cubic metre = 1,000 litres.)

   (a)

   Calculate the annual saving of water, in cubic metres, for the household.

   [3 marks]

   (b)

   Discuss how a society that is developing could increase the supply of water or the efficiency of its use.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Shrimp farming is one of the largest aquaculture industries in the Mekong Delta in Vietnam. Since the 1990s large areas of coastal mangrove have been cleared and turned into ponds, which are stocked with shrimp at high densities and fed with pellets. Wastewater from the ponds, containing uneaten food, shrimp waste and antibiotics, is often released into nearby canals. Ponds often become unproductive after a few years because of disease and the build-up of waste, and farmers then move on and clear more mangrove. Shrimp are a major export, and farming provides income for many families.

   (a)

   Explain the environmental impacts of intensive shrimp farming in the Mekong Delta.

   [6 marks]

   (b)

   Evaluate the role of aquaculture in meeting the growing global demand for seafood.

   [6 marks]

   Total for question 4: 12 marks

5. 5
   Hundreds of millions of people live in the basin of the River Ganges in India. Many towns along the river release much of their sewage without treatment, through pipes into the river. Run-off from fields carries fertiliser and pesticides into the water, and some industries, such as leather tanneries, discharge chemical waste. Monitoring has found concentrations of faecal coliform bacteria in many stretches that are above the safe limit for bathing. The government has built sewage treatment plants as part of clean-up programmes.

   (a)

   Which of the following is a point source of pollution in the River Ganges?

   [1 mark]

   • ARun-off of fertiliser from fields across the basin
   • BA pipe discharging untreated sewage from a town
   • CPesticides carried by rain from many farms
   • DLitter blown from many places along the banks

   (b)

   What does a high biochemical oxygen demand (BOD) in river water indicate?

   [1 mark]

   • AThat the water is rich in dissolved oxygen
   • BThat the water has a low concentration of nutrients
   • CThat the water has been cooled
   • DThat there is a lot of organic matter being decomposed by microorganisms

   (c)

   Explain why the release of untreated sewage reduces the concentration of dissolved oxygen in a river.

   [2 marks]

   Total for question 5: 4 marks

6. 6
   The Ogallala Aquifer lies under the Great Plains of the USA and supplies much of the water used to irrigate crops such as maize and cotton. Rain soaks into the ground and percolates down to the aquifer, but in many dry areas this natural recharge is only a few millimetres to a few centimetres per year. Farmers have pumped water out much faster than it is replaced, and in parts of Kansas and Texas the water table has fallen by more than 30 metres since the 1950s.

   (a)

   Which flow adds water to an aquifer?

   [1 mark]

   • ATranspiration
   • BEvaporation
   • CPercolation
   • DCondensation

   (b)

   Which statement describes the steady state of a water body such as an aquifer?

   [1 mark]

   • AInputs equal outputs, so the amount of water stored is constant
   • BOutputs are greater than inputs, so the store falls
   • CInputs are greater than outputs, so the store rises
   • DThere are no inputs or outputs

   (c)

   Explain how pumping for irrigation has changed the steady state of the aquifer.

   [2 marks]

   Total for question 6: 4 marks

7. 7
   A farm of 150 hectares in the catchment of a shallow lake in eastern England grows wheat. The farmer applies 180 kg of nitrogen fertiliser per hectare each year, and 20% of this is lost in run-off and drainage to streams that flow into the lake. The lake has experienced algal blooms each summer, and fish have died. A local group proposes planting buffer strips of grass beside the streams, which would cut the nitrogen lost in run-off by 60%.

   (a)

   Calculate the reduction, in kilograms per year, in the total nitrogen lost from the farm if buffer strips are used.

   [3 marks]

   (b)

   Discuss how eutrophication of the lake could be addressed at different levels of management.

   [4 marks]

   Total for question 7: 7 marks

8. 8
   Peruvian anchoveta, a small fish that feeds on plankton, supports one of the largest fisheries in the world. Catches rose from a few thousand tonnes in the 1950s to a peak of about 12 million tonnes in 1970. In the years that followed catches fell to less than 2 million tonnes. Most of the catch is made into fishmeal and fish oil for animal and fish farm feed. The anchoveta is the main food of seabirds and sea lions. Today Peru sets annual catch quotas using scientific surveys and closes the fishery in the breeding seasons.

   (a)

   Explain how overexploitation led to the collapse of the anchoveta fishery and how the concept of maximum sustainable yield can be used to prevent this.

   [6 marks]

   (b)

   Evaluate the use of catch quotas, closed seasons and marine protected areas to manage fisheries such as the anchoveta fishery.

   [6 marks]

   Total for question 8: 12 marks

End of questions