Background: Human Settlements

A range of human settlement activities impact on the environment. The use of energy (including transport energy) and water, as well as the consumption of goods and services, place pressure on the environment through demands on resources and waste generation.

Population is a key driver of environmental pressure from human settlement activities. As the population increases, so does the demand for energy and resources, the amount of waste generated, and the need for land development for infrastructure, housing, and energy production.

Consequently, everyday decisions made by the community are critical to reducing human settlement pressures on the environment. For example, minimising vehicle use, increasing water and energy efficiency in the home, reducing the consumption of goods, choosing products that are better for the environment, and improving recycling and reuse.

The consumption of fuels and the generation of waste are also major sources of air pollution and greenhouse gas emissions in the ACT. Information on air quality can be found in section Background: Air, and information on and greenhouse gas emissions can be found in section Background: Climate Change.

Environmental pressures are exacerbated by a growing population as it increases the demand for energy, transport, resources such as water, and a range of goods and services. This leads to land use change for food production, housing and other infrastructure, and more waste going back into the environment. Such changes can lead to direct impacts on the environment through the loss of vegetation and biodiversity, increased water extraction and degradation of water quality, increased air pollution and greenhouse gas emissions, and increased land and water impacts from waste.

Although a growing population generally results in increases in environmental pressures, this can be minimised by improving sustainability through energy and resource use efficiencies, and by reducing waste through improved recycling and reuse.

Indicator HS1: ACT’s ecological footprint

An ecological footprint assesses the pressures on natural resources, expressed as land area, required to sustain a population. This comprises the land for agriculture, forestry, built environments and water required to provide a range of resources, and all goods and services. A footprint also includes a general estimate for the land deemed to be disturbed by the greenhouse gas emissions arising from the population’s resource use and consumption of goods and services.

Changes in the ecological footprint are an overall measure of the effect our daily activities and resource consumption have on the environment. While the size of the total footprint is influenced by increasing population and changes to industry, individual behaviours can also affect sustainability. Actions to minimise resource use and waste can help to reduce the ACT’s ecological footprint.

The ecological footprint currently used for the ACT State of the Environment reporting uses a land disturbance approach. It is based on areas of land use which are weighted by disturbance factors to account for how transformed each land type is from a pristine state. In addition, the calculation of an emissions land component is included. The emissions land component converts the total greenhouse gas emissions to a disturbed land area and is calculated from a full carbon footprint.

Indicator HS2: Energy consumption and generation

Energy is central to everyday life for both social and economic activity. The level of energy use is determined by a range of factors including population and economic activity. Another significant driver of energy use is climate through increased demand for heating and cooling. Consequently, climate change will increase energy demand in the future with more frequent hot days and heatwave periods although this may be partially offset by a reduction in colder temperatures (see Climate Change).

The environmental impacts of energy use are determined by the type of generation. Non-renewable energy based on fossil fuels (including transport fuels) make significant contributions to greenhouse gas emissions and air pollution. They also impact on the environment through land use changes (both resource extraction and infrastructure requirements) that cause habitat loss and degradation of land and water, and can require high levels of water consumption. Renewable energy such as solar, wind and hydro-electricity have substantially lower environmental impacts, particularly for greenhouse gas emissions and air pollution, but can still impact on the environment through land use change and the use of hazardous material for construction and maintenance. Hydro-electricity also affects aquatic health due to the alteration of river flows (see Water).

Regardless of generation type, it is vital to reduce energy demand to minimise environmental impacts. With the population increasing in the ACT, reducing energy usage and improving energy efficiency will negate the need for new energy generation infrastructure.

With the ACT moving to 100% renewable energy for electricity generation, transport will become the main focus for further reductions in non-renewable energy consumption. Reductions will necessitate an increase in the number of electric vehicles, which combined with renewable energy for charging, will further reduce ACT’s energy consumption impacts. In addition, the phasing out of natural gas will also be important. 

How does the ACT’s renewable electricity program work?

Although the ACT reached 100% renewable electricity in 2020, it remains connected to the national electricity grid. This means that the ACT still receives electricity generated from non-renewable sources which may be consumed at any time. However, the ACT has purchased enough renewable energy to meet its electricity needs. This renewable electricity is available to the national grid and is used in other parts of Australia, offsetting the non-renewable energy consumed in the ACT. This is a system used by most of the European jurisdictions that have moved to 100% renewables.[1] The system also allows the ACT to keep using the national grid which is important during periods of high demand.

The ACT’s renewable energy was purchased using what is known as a reverse auction, where companies were invited to bid to supply renewable energy at the lowest price for the ACT. This has resulted in the development of new renewable energy generation.

Ideally, all electricity should come directly from renewable sources where possible. However, this would be difficult for the ACT and other jurisdictions to achieve where sufficient generation opportunities are not available. Consequently, supplying renewable electricity into the national grid is an effective means to achieving 100% renewable electricity, and to reduce the impacts of energy use on the environment.

Indicator HS3: Solid waste generation and management

The generation of waste places pressure on the environment, requiring land for its disposal, and ongoing management to prevent contamination and pollution. Waste can also have adverse impacts on human health and the liveability of our environment. Depending upon the way it is managed, waste can have a number of different environmental impacts including:

The amount of waste generated is not only determined by population, but also the level of consumption of material resources and manufactured goods. Increased consumption has significant consequences for the environment and for resource demand and depletion, particularly outside the ACT where goods and materials are sourced and manufactured. Waste is also highly influenced by the level of activity in the commercial, industrial, construction and demolition sectors. Waste is produced at all stages in the manufacture of products and services, as well as at the end of a product’s lifecycle.

When waste is not reused, recycled or used efficiently there is an opportunity lost, as the material can no longer be used to contribute to the economy. Recycling waste also reduces the demand for resource extraction, and conserves energy and water compared to manufacturing products from raw materials.

Total waste generation, waste to landfill and resources recovered are highly variable in the ACT with changes mostly occurring in response to specific activity from the construction and demolition sector and increases in garden waste. These waste types are also responsible for most of the resource recovery in the ACT; for example in 2018–19, waste from these sources represented 85% of the total tonnes recovered.

A large proportion of waste in the ACT comes from construction and demolition activities. Poor planning in design and assembly can lead to inefficient use of resources in manufacturing or construction, leading to unnecessary material waste. The management of such waste can be an economic burden which is passed on down the supply chain of products, increasing the price to the consumer. In the case of construction, poor design can not only create unnecessary material waste, but also a legacy of inefficiency throughout a building’s life.

For more, see Cross-Border Dumping, Turning Timber from Trash to Treasure and Waste Not, Want Not.

Indicator HS4: Transport

Bike lane on Binara St. Source: Richie Southerton

Transport is an essential part of modern living, enabling the movement of people and goods for work, education, industry, social connection and recreation. However, road-based transport in the ACT and globally is dominated by vehicles, mainly private cars. This requires continual investment in extensive infrastructure such as roads and parking areas to cope with growing transport needs, as well as increased demand for fossil fuels. This has many environmental impacts including:

Most of the ACT’s transport emissions come from passenger vehicles. Private modes of transport such as cars are less efficient at moving large numbers of people and so have greater impacts on the environment than public transport. In addition to environmental impacts, the increased use of private vehicles leads to greater congestion and travel times, and demand for new road infrastructure. Consequently, improving the uptake of public and alternative forms of transport, as well as increasing the number of electric vehicles, is important for the ACT.

Urban expansion and population growth are the main drivers for escalation in private car usage. Urban spread has also increased requirements for transport infrastructure in the ACT, including the expansion of freeways.

For more, see Zero Emissions, Go Electric.

Indicator HS5: Water resources

Water resources and consumption

Water underpins almost every aspect of life and is a vital component for human health and wellbeing as well as the health of the ACT’s landscapes and urban environments. The availability of water is key for residential supply, commercial and industrial activities, and agriculture. Water availability is also essential for supporting the ACT region’s population growth.

The availability of water resources is largely determined by the spatial and temporal variability of rainfall, temperature and evaporation, as well as impacts of land use on catchment hydrology. Stream flows in the ACT are highly variable, with drier conditions punctuated by wet years that replenish water storages and river systems. Extended dry periods, such as the Millennium Drought, can lead to severely reduced surface water flows and storage levels in the ACT. While such conditions may necessitate restrictions on water use, it is important that water is used sustainably at all times to ensure secure levels of water resources prior to dry periods.

In response to the Millennium Drought, the ACT Government enlarged the Cotter Dam to increase water storage capacity for long-term droughts. Climate change is predicted to increase the frequency and severity of droughts and will have consequences for the ACT’s water resources in the future (see Climate Change).

Water consumption is determined by a range of factors including population, urban densification, changes in household usage, restrictions on use due to water availability, changes in demand due to rainfall, and water use by commercial, industrial and agricultural sectors (within consumptive entitlements).

Water reuse and recycling, both by households and larger users reduces the need to harvest water from the natural environment. In addition, the volume of wastewater that the community produces is relatively stable, so recycling provides a reliable source of water.

ACT’s urban water supply

The ACT draws water from three separate catchments (Figure 1):

Figure 1: The ACT’s water supply network.

Source: Icon Water.

Water storages in the ACT have a combined capacity of 278 gigalitres. This includes the Corin (70.8 gigalitres), Bendora (11.4 gigalitres) and Cotter (76.2 gigalitres) storage reservoirs on the Cotter River and the Googong (119.4 gigalitres) storage reservoir on the Queanbeyan River. The Googong reservoir is the largest water supply reservoir and represents 43% of the ACT’s storage capacity.

The ACT sources water from each catchment depending on water availability, water quality, ability to meet demand, operational cost and infrastructure performance. Corin and Bendora reservoirs are the cheapest sources of water in the ACT due to their gravity-fed supply to the Stromlo water treatment plant and cleaner water requiring less treatment.

Water can also be sourced come from:

ACT’s per capita water use

The ACT’s total annual water use is influenced by the decrease in per capita water use since the early 2000s. This decrease was in response to the Millennium Drought and has been maintained since. Reasons for the decrease in per capita consumption include: