Water research

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Consider this:

  • Ministry of Health guidelines indicate that only about five litres per person/day (L/p/d) needs to be biologically and chemically safe.
  • Average domestic water use is probably about 300-350l/pp/pd – all of which is currently cleaned to a potable standard. The actual usage is unknown as only about 40% of reticulated water supply is metered.
  • Clothes and cars are washed, toilets flushed and gardens watered with high quality drinking water.  
  • 80% of New Zealanders get their water through a reticulated network.
  • Competition for water in growing with increasing population and agricultural and industrial use.

The increasing cost and decreasing availability of water supply will require a more efficient and conservation-oriented supply and management approach if New Zealand is to achieve widespread household sustainability.

Beacon’s research was focused on savings through water demand management.  It includes:

  • A framework (Slowing the Flow) to help councils evaluate and prioritise a demand management approach.
  • An approach to economically valuing demand management strategies and its application to a case study of Tauranga City Council
  • A review of energy use in reticulated water supply and treatment.
  • Consideration of various water saving technologies.

 

What is water demand management?

In the face of growing demand, councils and other water supply authorities are faced with alternatives. They can continue to build water infrastructure, or they can manage demand through a programme of water efficiency policy.   

Under the ‘build to supply demand’ approach, consumers will continue to be exposed to funding heavy capital programmes.  According to the Rates Inquiry Report, the management of the three water services (water supply, wastewater and stormwater) is 29% of total council expenditure.
 
Demand management, however, is the first and easiest step for councils to take towards sustainable urban water management and can have a significant impact on the bottom line.

Water demand management is about using centralised reticulated water efficiently by reducing demand.  Demand management measures aim to minimise either the overall or peak demand for water (or energy or other resource).  Councils taking a demand management approach can consider a range of possible interventions:

  • Maintenance of the water system to prevent leakage
  • Using pricing, tariffs, and incentives/rebates to encourage reduced use
  • Promoting water efficient technology—rainwater tanks, wastewater reuse, appliances and plumbing fixtures
  • Using promotional materials and education programmes to educate householders
  • Regulating to require lower water use