About water in our towns and cities

On this page:

• The water cycle
• Our many urban water sources
• Urban water challenges
• History of urban water management in South Australia

Almost 90% of South Australians live in cities and towns of more than 1000 people. Smart water management is critical to ensure these are vibrant places to live, work and visit; particularly given our harsh and unpredictable climate, which can be hot and dry, with occasional intense storms with heavy rains.

South Australia’s towns are widely spread across the state. Many are in areas with limited local water sources suitable for safe drinking water supplies; others were developed near rivers where they have experienced flash floods that were not expected when the towns were first settled.

The lifestyle we enjoy in our towns and cities today is the result of a long history of water services development and water management that has provided us with more secure water supplies, reduced flooding and less environmental impacts.

Urban water management has evolved over the years in ways that have enabled development to occur, while meeting a range of challenges including increasing water demands, drought, floods and pollution. In recent decades the need to protect our environment in line with community expectations has led to environmental rehabilitation actions and the use of alternative water sources, such as urban stormwater and wastewater for non-drinking water uses.

The water cycle

Natural water cycle

In natural environments that have not been urbanised, much of the ground surface is permeable to water. Rain soaks in to the soil and recharges groundwater or slowly runs off into creeks, rivers and the coast once the soil has become saturated (fully wet). Water use by plants and animals is limited to what is available from the rainfall and natural flows.

Urban water cycle

The way water flows through our towns and cities is called the urban water cycle. In contrast to natural environments, the built up areas in towns and cities have many hard surfaces that are impermeable to water (water runs off rather than soaking in). This includes roofs, roads and footpaths. These impermeable areas reduce the rate that rain soaks into the soil and recharges groundwater. Larger volumes of water quickly run off these surfaces into the stormwater system (a network of drains) and then flow out to our rivers and coast. In many places what were natural waterways have been re-aligned (straightened) and concreted to help to drain this water away as quickly as possible in order to minimise the risk of flooding properties and roads that were built close to the waterways.

Depending on the soil type, rainfall pattern and amount of impervious area, urban developments will greatly increase the runoff compared to a natural area. These higher and more frequent runoff volumes and flow rates change the flow patterns in waterways and increase erosion of the creek bed and banks. This affects the plants and animals that live in our urban waterways and increases the flows discharging to the coast.

More water is needed to sustain urban populations than can be supplied naturally from local sources in South Australia’s hot and dry climate. Water is needed in our homes, businesses, schools and all activities. The water requirements of many of our gardens, parks and playing fields is much higher than the natural ecosystems would have required. A complex water supply system delivers this additional water to our towns and cities.

Features of the urban water cycle

• Water is supplied from storages to treatment plants and to our taps through a network of pipes thousands of kilometres long.
• Wastewater from homes and businesses travels through a different network of sewerage pipes to treatment plants, where it is treated and then discharged to rivers or the coast – or reused.
• Stormwater pits and drains collect rainwater run-off from roads and roofs and carry it into nearby waterways or in some places, directly to our coastal waters. Some stormwater is captured and treated for reuse.
• Recycled wastewater and stormwater is used in some towns, cities and agricultural areas.
• Discharges to coast and rivers carry any stormwater or wastewater that can’t be used or stored for later use.

Urban water sources

Drinking water

SA Water is the largest water supplier in South Australia. Almost 99% of South Australians are supplied with potable drinking water by SA Water, which also supplies the water for most urban activities across the state.

The water supplied by SA Water comes from the River Murray, reservoirs in the Mount Lofty Ranges, groundwater and seawater that has been desalinated. In towns and cities this water is used for a wide range of indoor and outdoor activities, including drinking and washing; businesses and industries; and watering parks and playing fields.

Non-drinking water

Water that has not been treated to drinking water quality, known as non-potable water, is supplied in some places for uses such as watering gardens and parks and flushing toilets. This water supply comes from treated stormwater, recycled wastewater, groundwater and rainwater that runs off roofs. There are many different non drinking water suppliers in different parts of the state including local councils, SA Water and private suppliers. Some householders also capture and use rainwater from the roofs of their homes.

Urban water challenges

The challenges of the past included droughts, floods, pollution, meeting water demand for a growing population, managing wastewater, and protecting the environment.

We continue to face similar challenges. It is important that we prepare our towns and cities for a hotter, drier future with a growing population and economy, while we continue to maintain our current lifestyle and enjoy greener streets and public spaces. The water challenges facing our towns and cities are expected to increase in the future including:

• Increased water demands as the South Australian climate becomes hotter and drier, our population grows, our economic activity increases and to meet community expectations for green parks and streets.
• Reduced water availability from traditional sources in a hotter, drier climate.
• Greater potential for flooding as urban areas become larger and more densely populated and even with lower average annual and seasonal rainfalls, increasing rainfall intensity with the changing climate.
• Impacts on the natural environment of our towns, cities and surrounds from pollution, the increased water demands and flooding.

Managing the urban water cycle today and into the future.

History of urban water management in South Australia

Water and the First Nations of South Australia

Water availability has always guided human settlement in South Australia. Freshwater systems are fundamental to Aboriginal cultures and identities and First Nations have a deep understanding and connection to water across the South Australian landscape. Find out more about First Nation Partnerships in water resources planning

Water had, and continues to have, great significance to the First Nations people. The area that is now the city and suburbs of Adelaide, from the coast to the foothills of the Mount Lofty Ranges, is the home to the Kaurna people with surrounding lands home to the Ngarrindgeri, Ngadjuri and Peramangk. The rivers crossing the plain have always held special significance to the Kaurna. The River Torrens, known to the Kaurna by names including Karrawirraparri (Red gum forest river) or Tarndaparri (Red kangaroo river) was in summer a series of large waterholes with a trickle of water, which sometimes disappeared under sections of gravel and sandy bed. In winter the river was full of water. When in flood the river was known as Yertalla. The Kaurna moved between the coastal lagoons, the body of the river and the foothills throughout the year as the freshwater availability changed, or in response to large floods that covered much of the Adelaide plain.

1800s - Water in developing towns and cities

With the increased population that followed European settlement, water availability was the most immediate water management issue. Townships were established close to water sources that it was hoped would provide a reliable water supply. Water supply schemes were established very quickly, with the first piped water supply reaching Adelaide homes by 1860.

For towns close to waterways flooding was a regular problem, taking lives and damaging properties, bridges and other public infrastructure. The management of flooding in the flat South Australian landscape has continued to be a major issue for our towns and cities.

Pollution of drinking water supplies from human and other wastes quickly led to disease and environmental impacts that needed to be addressed urgently. In 1881 Adelaide became the first city in the country to have a water flushed sewerage system.

1900s – Major water management developments

During the twentieth century the State’s population continued to grow, requiring significant investment to provide clean drinking water and to keep people safe from flooding and pollution.

Construction of large reservoirs in the Mount Lofty Ranges to supply water for Adelaide and the surrounding regions began early in the century and continued until the 1970s. Local water supplies were also developed for regional population centres as these grew. The second half of the century saw connections from the River Murray to many areas of the state and the introduction of water filtration plants to improve water quality. These developments form the backbone of the state’s water supply system today.

During the twentieth century home rainwater systems were common, but as reliable, high quality water provision arrived in the cities and towns rainwater tanks became less common.

Flooding continued in many towns and the suburbs of Adelaide and urban drainage became a focus. Major drainage works were constructed in the western suburbs of Adelaide including the Breakout Creek outlet at the end of the River Torrens in 1937. The 1960s saw construction of a major drainage scheme, which included the Sturt River flood control dam, channel lining, and new drains which enabled the development of the south western suburbs of Adelaide. In many other areas watercourses were straightened and concrete lined to better drain away high rates of runoff following suburban development. As flooding remained common across towns and cities drainage infrastructure has continued to be improved.

In the latter decades of the twentieth century environmental and sustainability considerations became more important to the community and by the end of the century bodies such as the Environment Protection Authority and the catchment water management boards had been established in response.

The concept of water sensitive urban design was introduced to urban planning at this time. South Australian researchers such as Professor John Argue were pioneers of sustainable water management in urban environments in Australia, and especially in innovative capture and reuse of urban water. Technologies and approaches such as constructed stormwater treatment wetlands, aquifer storage and recovery and watercourse restorations became common. Significant early developments included the New Brompton Estate project (1991) that is widely acknowledged as the first example of water sensitive urban design (other than constructed wetlands) in Australia. Other well-known developments included New Haven, Mawson Lakes and the early stormwater harvesting schemes of the northern suburbs of Adelaide.

Twenty first century – Water for a Growth State

The twenty first century began with the ‘millennium drought’ which led to renewed concerns about water security and the construction of the Adelaide Desalination plant to secure water for Adelaide’s future. Securing water supplies for towns away from Adelaide remains a focus with small scale seawater and groundwater desalination becoming common solutions where suitable. Changes to building and planning regulations has increased the number of new houses which are including a rain water tank, often plumbed into the house to provide an additional water supply, reducing the demands on the traditional supplies.

Occasional flooding still occurs, at times causing significant damage. A program of stormwater management planning has introduced a systematic approach to drainage management planning in the state’s towns and cities and there are clear flood hazard response arrangements.

Environmental regulation and management approaches that were introduced in the late twentieth century are now the standard, providing some protection for our unique environments. Water sensitive urban design principles have been widely adopted and can be seen in towns and cities across South Australia as core parts of urban planning and design. Households, public agencies and private operators all strive for water efficiency gains from wise water use, water recycling and waste reduction. This provides cost savings and improved environmental outcomes as part of South Australia’s move towards a circular economy.

Urban water management remains vital for South Australia’s towns and cities to remain great places to live, work and visit. Urban water management is preparing our towns and cities to be resilient in a warming and drying climate, while supporting our vibrant way of life and economic growth into the future.