Managing Water Security (AQA A Level Geography)

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

Issue

Explanation

Examples

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:

1. Direct surface infiltration: depressions are excavated in the ground which are filled with recycled and treated wastewater. This water then percolates through permeable soil and rock into the aquifer
   
   
2. Recharge wells: treated wastewater is pumped directly into aquifers through ‘injection’ wells or boreholes

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