9. Water use and Conservation

Question 1

3 Ways of Increasing Supply

Answer 1

1. Increasing Abstraction
2. Drawing from Groundwater
3. Desalination

Question 2

Increasing Abstraction

Answer 2

• Abstraction refers to the volume of water taken from natural or modified (e.g. reservoirs) resources over a given period, typically a year
• Water is a seasonal resource – reservoirs are a means of ensuring a constant supply despite fluctuation in rainfall or other water flows
• However creating new reservoirs can have negative environmental impacts
• The aquifer can also be used a reservoir through artificial water recharge – pumping water into the ground during wet periods
• Water transfer refers to moving water between river basins. This can also have negative environmental effects

Question 3

Drawing from Groundwater

Answer 3

• Groundwater is underground water contained in porous or fractured rock, referred to as the aquifer
• It is an important source of freshwater for human use
• Shallow groundwater is in dynamic exchange with surface water - so it can be exploited sustainably if not too much is drawn off
• Over-exploitation causes environmental problems – e.g. land sinkage, infiltration of saltwater, contamination
• Groundwater is less visible than surface water, so effects of human activity on it can often be missed until environmental problems become obvious

Question 4

Reducing Consumption

Answer 4

• Social and behavioural: awareness campaigns, water pricing and water metering
• Distribution system: reducing losses through leaks and evaporation
• Water saving devices: e.g. low flush toilets, aerated showers, sensor taps, water efficient white goods
• Reuse of greywater: Greywater is all household water apart from that from toilets. It can be used for non‐potable uses such as flushing toilets and watering gardens. Care must be taken with microbial loads and health risks.
• Rainwater harvesting
• Industry: water efficient processes, onsite reuse or recycling of wastewater, alternatives to water for cooling
• Agriculture: efficient irrigation (drip irrigation, closed pipes rather than open channels), recycling (use of treated wastewater), crop choice, crop management, soil management

Question 5

Measure of Wastewater strength

Answer 5

1. Density of Suspended Solids

2. Biological Oxygen Demand

Question 6

Water reduction management

Answer 6

1. Obtain commitment
2. Measure water use
3. Analyse results for potential measures
4. Set targets
5. Plan
6. Involve staff
7. Implement improvements
8. Monitor, report & review
9. Repeat

Question 7

Waste hierarchy for water

Answer 7

1. Avoid
2. Reduce
3. Reuse
4. Recycle