Australia, being one of the driest countries on earth, will not be able to
escape the pressures of an increasing population and a finite supply of water.
Already, Sydney is using 106 percent of the annual sustainable yield of its
water supplies. This paper looks at the use of water in Sydney, and the
response by water authorities to managing demand. A brief review of water use
throughout the State is also presented.
The Sydney Catchment Authority and Sydney Water are the two authorities
responsible for the supply of potable water to the Sydney, Illawarra and Blue
Mountain areas. The Catchment Authority provides bulk water to Sydney Water,
which then retails it to approximately 1.3 million accounts and a population of
4.15 million.
In the Sydney Water service area, the residential sector is the biggest user
of water, comprising 61 per cent of total demand. Most of this demand comes
from single dwellings, which use an average 825 litres per day, compared to
units and apartments which use around 495 litres per day. In regard to
residential water use, outdoor water usage is the area of highest consumption
(27.3 per cent), followed closely by showers (24.3 per cent).
The safe yield of Sydney’s drinking water storages is 600,000 ML/year.
The yield is defined as the amount of water that can be withdrawn from a
reservoir on an on-going basis with an acceptably small risk of reducing the
reservoir storage to zero. Demand has fluctuated around 600,000 ML/year since
1980, despite population increasing by around 700,000 during this time.
Sydney’s water consumption has been above the safe yield for the last
three years and for six of the last ten years.
Daily per capita water use has fallen from 506 litres in 1991 to 416 litres
in 2002/03. Demand management targets for water conservation purposes were
first included in Sydney Water’s 1995 Operating Licence. The current
licence has two demand management targets (based on 1990/91 levels). The first
is a 2005 target of a 28% reduction in per capita water consumption – 364
litres per capita per day. The second is a 2011 target of a 35% drop in per
capita water consumption to 329 litres per day. Sydney Water does not expect
the 2005 target to be met.
A review of demand management programs is presented. The most successful
demand management programs (in terms of water saved) have been: water recycling
at sewerage treatment plants; leakage reduction programs; and the residential
retrofit program.
Traditionally, water in urban areas has been supplied through a centralised
water reticulation and waste water system. One of the more topical issues in
regard to water supply and sewerage infrastructure is that of sustainability
and moves towards localised and individual systems. These sustainable
approaches and solutions range from simple items, such as rainwater tanks and
the better integration of current reticulation systems, to fully independent
on-site water systems. Sustainable approaches aim to integrate all elements of
urban water services, reducing water use and reusing water wherever possible.
