Water supply challenge

Droughts, climate change, population growth, economic growth and ageing infrastructure put Melbourne’s water long term water supply under pressure. The Sustainable Water Strategy for the

Central Region predicts a shortage of 205.000 Ml/year by 2055 for the greater Melbourne region.68

Below the different aspects that have effect on Melbourne’s water supply are being explained, as well as the strategy of the Victorian Government to face the water supply challenge.

Climate change:

Climate change is expected to result in the following trends towards 2050:69 • Mean increase in average summer temperatures of 1.4 C

• Reduced rainfall of 4%

• Reduced inflow of annual streamflow into Melbourne’s main water reservoirs of 18% • More extreme weather events

These trends will reduce the long term water supply of Melbourne.

Urban growth:

Population growth and economic growth result in an increased water demand. In an average year the total water consumption for metropolitan Melbourne is around 500 GL/year.70 Figure 3.11 shows the water use of Melbourne per sector in percentages.

The Sustainable Water Strategy for the Central Region of the Victorian Government predicts that the population of the region of Melbourne and surroundings will increase from 4,2 million people in 2004 to 5,7 million people in 2055. This will result in an increased water demand for residential purposes. In 2002, the total water consumption of Melbourne was 311 l/person/day. Residential water use accounts for approximately 60% of this (208 l/person/day). Figure 3.12 shows the residential water use per purpose. The indoor residential water use is approximately 135 l/person/day. In comparison: in 2004 the average indoor residential Dutch water use was approximately 124 l/person/day.71

Economic growth also demands a larger quantity of water. At this moment the greatest industrial water user is the ‘food, beverages and tobacco’ sector, followed by the electricity and gas supply sector.72 It is assumed that industrial growth keeps pace with population growth.

Water use per sector

4% 8% 28% 60% miscellaneous leakage

commercial and industrial residential

Figure 3.11: Melbourne’s water use per sector in 2004 (DSE (2006a))

68 _{Source: Department of Sustainability and Environment (2006b)} 69 _{Source: Howe et al. (2005)}

70 _{Source: Melbourne Water (2007c)} 71 _{Source: NIPO/VEWIN (2005)}

Residential water use 5% 15% 19% 26% 35% kitchen laundry toilet bathroom garden

Figure 3.12: Melbourne’s residential water use in 2004 (DSE (2006a))

Ageing infrastructure:

Figure 3.11 shows that 8% of the supplied water is lost by leakage. According to various water experts in Melbourne the water supply infrastructure is ageing and needs upgrading in order to prevent increased leakage losses.

Strategy to face the water supply challenge:

The Victorian Government has an overarching water policy: the Government White Paper - Securing

Our Water Future Together. The Sustainable Water Strategy for the Central Region is describes the

strategy for the Melbourne Region.

In the beginning of this section it was described that the Sustainable Water Strategy for the Central

Region predicts a shortage of 205.000 Ml/year by 2055 for the greater Melbourne region. This State

strategy includes several measures for facing this water supply challenge:

• Water conservation targets to reduce the total per capita water use by 15% by 2010 (compared to the average in 1990), increasing to 25% by 2015 and 30% by 2020. Measures such as installing water efficient appliances (e.g. water efficient shower heads, laundry machines), encourage planting of native vegetation in gardens should maintain current conservation culture and awareness of water users. Furthermore commercial and industrial customers that use more than 10 ML per year are required to develop plans to reduce water use and water authorities are enforced to improve the water distribution systems to reduce leaks and evaporation.73

• The uptake of alternative water sources is encouraged to complement the drinking water supply. The Victorian government has set a water recycling target of 20% of total treated wastewater for industrial, agricultural, irrigation and residential purposes (see Chapter 4.3: Case study Hunt Club Estate) by 2010. In 2007 14% of the total treated wastewater was recycled.74 Furthermore, the Smart Gardens and homes Rebate Scheme is set up to reimburse purchases that are water efficient, harvest rainwater or grey water to reduce household demand.75 Victoria’s 5 Star Standard requires for all new homes to meet the standard by incorporating the installation of water saving measures and either a rainwater tank or a solar hot water service.76 Finally, a trial is to be conducted with aquifer storage for future recovery and re-use of recycled water.

73 _{Source: Department of Sustainability and Environment (2006b)} 74 _{Source: Victorian Government (2007) www.ourwater.vic.gov.au} 75 _{Source: Victorian Government (2007)}

• Large scale augmentation of water supply by upgrading existing water recycling schemes and the construction of a desalination plant77 complete the water supply strategy. The desalination plant that is planned has a capacity of 150 GL/year. Construction of the plant will commence mid 2009 and the desalination plant will start delivering water by the end of 2001.78

During times of drought water restrictions are being enforced by the Victorian Government to reduce water use. The restrictions restrict for example the water use for irrigation of gardens and public open space and car washing (see also Appendix E). Because residents are affected directly by the water restrictions, water is a hot public issue and therefore high on the political agenda. Water was the most important election issue in the Victorian State elections in the end of 2006.