Just three per cent of all of the water found on Earth is fresh. Of this, less than one-third of one per cent is available to humans as the remainder is locked up in snow and icecaps. Australians are among the greatest users of water on a per capita basis, yet Australia is a nation that must live with drought. Previous Heinemann Atlas Updates, such as ‘Securing Perth’s Water Supply’ (Australian Themes, Natural Resource Management), have considered the impacts of drought on the Australian landscape. This Update focuses on the Melbourne region and investigates the approach being used to manage the effect of drought on the city’s water supply system.

Stage 1 restrictions begin

On 1 November 2002, Stage 1 water restrictions were introduced in the city of Melbourne. The state capital joined up to 150 other towns and cities around Victoria that had already applied water restrictions after the 6^th consecutive year of below average rainfall.

Melbourne’s history of water shortages

It had been almost 20 years since water restrictions were last applied in Melbourne. Nevertheless, restrictions have not been unusual in the city’s history. They have in fact been enforced in Melbourne no less than 15 times, for a total of 70 months, since 1939. This is a reflection of the fact that Melbourne is located in a region a city that often experiences drought. Table 1 below shows the major periods of drought that have occurred in Melbourne since meteorological data was first recorded.

Table 1: Years of Drought in Melbourne

Triggers and levels

The water restrictions in the state capital were enforced once water storage in the city’s reservoir system fell to the trigger level of 54 per cent of full capacity in late 2002. Rainfall over the next 6 to 9 months was the key to determining whether the water restrictions remained at Stage 1 or whether they were ‘toughened’. In the Internet Investigation included with this Atlas Update you can find out more about the nature of the rules and regulations relating to water use that are included in each of the Stages, 1 to 4, of Melbourne’s water restrictions.

Melbourne region catchment areas

The freshwater supply to the city of Melbourne and its metropolitan area is based upon a catchment area of more than 140 000 hectares located mainly in the Yarra Ranges to the east of the city. Most of this catchment area (approximately 80 per cent) is covered by forests of the mountain ash type that effectively catch, store and filter rainfall. From here, the city’s freshwater supplies are channelled into the 9 main storage reservoirs, which have varying capacities, as shown in Table 2 below. (Three of these – Yan Yean, Cardinia and Sugar Loaf – can be located on page 90 of the Heinemann Atlas 3^rd edn.)

Table 2: Melbourne’s freshwater storage reservoirs

Responsible body: Melbourne Water

The Victorian State Government is well aware that Melbourne’s pattern of drought over time can largely be explained in terms of El Niño. The mechanism behind this drought-causing meteorological phenomenon is explained in detail on page 23 of the Heinemann Atlas 3^rd edn. Overseeing the supply of fresh water to homes in the city is the responsibility of the state government agency, Melbourne Water. According to this agency, drought is a ‘normal feature of Melbourne’s climatic variability’. It is evident, therefore, that Melbourne Water sees drought as a feature to be managed in the city’s water supply system, as it quite simply cannot be evaded.

At present, Melbourne Water is responsible for ensuring that the 3 million residents of the Melbourne metropolitan area are adequately supplied with their water needs. It does so via 3 privately owned water retailers, namely City West Water, South East Water and Yarra Valley Water.

Increasing demand

Inevitably, demand for water is set to rise in the face of a growing population. Combined with Melbourne’s frequent periods of drought, careful planning is required in order to meet the city’s future water needs.

Demand in Melbourne currently stands at 500 000 million litres of fresh water each year. The State Government has begun planning to counter the dual impacts of drought and increasing demand on fresh water supplies.

Recent report on strategy for management

A recently released report entitled ‘21^st Century Melbourne: A WaterSmart City’ established a number of ‘cornerstones’ on which the city’s future water supply is to be built. This strategy revolves around:

• community consultation and discussion
• undertaking key research
• understanding the water cycle
• promoting sustainability
• factoring in a growing population
• assessing the future demand for water.

Forward estimates in this report indicate that Melbourne’s population will increase 32 per cent by the year 2050, to reach a figure of 4.6 million. Understanding Melbourne’s climatic variability and managing the supply through periods of drought is evidently a key part of the water use strategy being developed by the Victorian State Government.

Government plans

Among many ideas outlined in what the report terms the ‘Preferred Way Forward’, the government plans to meet the growing demand for water by setting future targets for the rate of per capita water consumption back to 1950 levels. This will obviously require significant changes to the nature of water use within the city, and associated lifestyle changes within the population.

Raising awareness of necessary lifestyle changes

As has been the experience in other Australian cities, such changes are not always easily made. Raising awareness about the need to be water wise will play a key role in this process. Education campaigns, in schools and at all levels in the wider community, will take on great importance.

This Atlas Update, and others like it, can be considered to be part of this campaign. Later, in the Internet Investigation included with this Update, you will be presented with the opportunity to play your part in the helping to make Australia more ‘water smart’ in the 21^st century.