Managing Water Security (AQA A Level Geography)
Revision Note
Written by: Robin Martin-Jenkins
Reviewed by: Bridgette Barrett
Managing Consumption
Managing the consumption of water is becoming more important as water issues increase and demand rises
Demand is increasing due to population growth and increasing affluence
Leads to an increase in a populations’ water footprint
There are specific strategies targeted at different components of water demand:
Domestic
Industrial
Agricultural
Strategies to Manage Water Consumption
Component of demand | Strategy | Evaluation |
|---|---|---|
Domestic | Dual-flush toilets: the installation of water-saving toilets | These strategies target large populations and tend to be relatively cheap to install and operate. This means they can be suitable for LDEs, as well HDEs Each strategy needs a ‘buy-in’ from the consumer, as alternative, less efficient options might be cheaper These strategies only save small amounts of water, although if used in combination and large numbers, the effect can be significant The proportion of domestic demand for water is similar in countries at all levels of development, so these strategies will have similar impacts throughout the world |
Water metres: allow customers to more easily monitor their use of water | ||
Reduce leaks in water pipes | ||
Shower heads and taps: installation of water-efficient showerheads/taps with aerators and pressure controllers to keep the water flow at desired levels | ||
Washing machines and dishwashers: use of water-efficient appliances | ||
Garden landscaping: introduction of water-efficient techniques (mulching) in private gardens | ||
Industrial | Power industries: replace traditional water-cooling system with an air-cooling system | Industrial strategies tend to be large-scale and so can be effective at saving huge volumes of water These strategies are particularly effective in HICs where 60% of water consumption is through industry They can be expensive to implement and require expertise to install and maintain. This limits their effectiveness in poorer parts of the world |
Wastewater reuse: reuse of treated urban and industrial wastewater as city, public and industrial cooling water | ||
Mining industries and dust suppression: water used to suppress dust on the haulage road, can be reduced through adding a chemical that aids dust suppression. Water sitting in unused underground mines could be pumped out and reused | ||
Pulp and paper industries: can use less water during the process of bark stripping from logs. After treatment, reuse of water evaporated in the pulp formation process; during the pulping process, use concealed units to avoid water loss through spray and evaporation | ||
Agricultural | Genetic crop development: development and adoption of varieties that enable farmers to attain higher yields with less water; includes both conventional breeding and genetic engineering - GMO genetically modified organism | Many of these strategies are relatively cheap to implement and maintain allowing them to be effective in LICs More than 80% of water use in LICs comes from agriculture so large sustainability gains can be achieved with relatively little cost Some measures may still be too expensive to be implemented in the poorest countries Farmers may lack access to training programs, particularly in remote or marginalised regions Agriculture is the biggest user of water (70% globally) so the strategies based around irrigation are likely to have more of an impact than domestic strategies |
Rainwater harvesting: used with fertigation (the injection of fertilisers and other water-soluble nutrients into an irrigation system). This boosts the productivity of rain-fed crops by applying fertilised water during dry spells. It requires the construction of small reservoirs for rainwater collection | ||
Irrigation scheduling: this prevents farmers from over-irrigating; linked to controls and subsidies for groundwater pumping | ||
Mulching: covering soil with protective plastics to prevent water evaporation and keep temperature constant | ||
Micro-spraying irrigation: Sprinkler conversion to micro-sprayers - micro-sprayers consume less water than standard sprinklers | ||
Sprinkler irrigation - This can increase yields and irrigation efficiency (e.g. through reduced evaporation) compared with the use of open irrigation channels | ||
Retaining stubble (i.e. what remains after harvesting) on the land -The retention of stubble (rather than burning it) improves soil water retention and increases moisture levels | ||
Soil techniques/no-till agriculture: Techniques to reduce tillage; laser land levelling to reduce runoff and drain land better, and to conserve water |
Examiner Tips and Tricks
Look out for questions that ask you to compare the effectiveness of strategies that manage water consumption with those that increase supply. Think about different parts of the world and then think about whether increasing supply or reducing demand would be the most appropriate strategy. Remember that a combination of the two approaches is usually the most effective way to tackle water issues
Issues of Water Management
Sustainable use of water involves:
Abstracting it from a source no faster than it is replenished
Avoiding contaminating or compromising the quality of water available to others
Strategies to move towards greater sustainable use of water include:
Accounting for virtual water trade
Water conservation
Water recycling
‘Greywater’ use
Groundwater management and recharging
|
|
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|---|---|---|
Virtual water trade | Many people are unaware that the products they consume use large volumes of virtual water 90% of the water we consume is ‘virtual’ A country that exports a good becomes an exporter of virtual water as well The destination country becomes an importer of virtual water To be more sustainable, Water-scarce regions can import water-intense products from countries with water surpluses, so releasing water for other essential needs | The production of beef is particularly water-intensive: 4650 litres of water are required to produce a 900g steak Potatoes are grown in water-stressed Egypt, using irrigation from the Nile and abstraction from the Nubian sandstone aquifer Germany and the UK jointly imported 44% of Egyptian potato exports to the EU during the period 1994-2012 |
Water Conservation | Minimising the loss of water from pipe leakages Reducing consumption and demand Reducing evaporation from water storage and transfer schemes | 24% of the water supplied by Thames Water is lost through leakage Thames Water use AI to help find and fix more than 1000 leaks a week in their pipe network In the Los Angeles reservoir at Sylmar, 96 million black plastic shade balls were released onto the surface of the lake to prevent evaporation |
Recycling | Impurities can be removed from sewage wastewater so that the water can be reused Re-uses for the water include for irrigation, fire suppression and dust control in industrial settings Recycled water can also be used to ‘recharge’ aquifers More advanced treatment can lead to water being potable or drinkable Climate change is putting pressure on water supply in arid areas so these technologies are increasing in significance and developing fast | Both Singapore and California, USA, use dual-membrane and ultraviolet technologies to recycle wastewater into water that is potentially drinkable It makes up 3% of water use in California but more than 30% in Singapore Concerns exist about health implications for using this water for irrigation and direct drinking |
‘Greywater’ | Capturing internal water from a property for re-use Waste water from bathrooms (but not toilets), kitchens and laundries can be captured and made available for non-drinking purposes, e.g. for flushing toilets Greywater recycling systems can be expensive - each unit costs £2000 in the UK - but can save 30% on household water bills | Australian cities, such as Melbourne and Sydney, have widespread use of greywater recycling systems in residential and commercial buildings The UK have been slow to catch on to this technology but Oxley Gate, a recent housing development in Milton Keynes, has 150 houses with greywater systems installed |
Groundwater Management | Aquifers deplete if abstraction happens faster than replenishment Aquifers can be replenished, or ‘recharged’, naturally or artificially Artificial recharging involves capturing rainwater and re-routing it underground Two methods for artificial recharging:
| In 2016 the Indian government spent US$590 million on well recharge projects across seven of its water-stressed states The volume of water added to the world’s aquifers in recharging schemes is approximately 10 billion cubic metres per year In Australia, 410 million cubic metres of water is recharged into groundwater each year. This is 8% of the country’s annual groundwater extraction |
Examiner Tips and Tricks
You could get asked a 4 mark question on any of these issues associated with water management, so make sure for each you can write at least four sentences on how they make water use more sustainable and try and include an example
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