There is a general lack of knowledge about land health in the ACT, both for long-term changes and current conditions. This lack of information does not enable an assessment of land and soil health and remains a critical gap in our understanding of environmental condition.
- ? Poor
- ? Unknown
- ? Good
Indicator assessment legend
Environmental condition is healthy across the ACT, OR pressure likely to have negligible impact on environmental condition/human health.
Environmental condition is neither positive or negative and may be variable across the ACT, OR pressure likely to have limited impact on environmental condition/human health.
Environmental condition is under significant stress, OR pressure likely to have significant impact on environmental condition/ human health.
Data is insufficient to make an assessment of status and trends.
Adequate high-quality evidence and high level of consensus
Limited evidence or limited consensus
Evidence and consensus too low to make an assessment
Assessments of status, trends and data quality are not appropriate for the indicator
- Land health
- Land contamination
- Compliance with site contamination National Environment Protection Measure (NEPM)
Healthy land supports agriculture, native ecosystems and ecosystem services such as clean water. Soil condition is the main driver of land health and a fundamental part of ecosystems and natural processes including biological activity, the cycling and storage of nutrients and carbon, and the decomposition of organic wastes.
Soil health is mostly determined by land use intensity and the degree of modification, or loss of, vegetation cover. The clearing of vegetation can result in accelerated erosion, acidification, salinity, and a reduction in soil nutrients and organic content. Pressures that leave soils bare of vegetation and promote soil degradation include land clearing, fire, high-intensity storms, and agriculture (cropping and grazing). In addition, soil erosion can increase due to the compaction of soil from urban and industrial activities, vehicle use, stock grazing, and invasive species such as horses, deer and feral pigs which can also degrade soil structure.
ACT soils are highly variable, but most are considered to be infertile, fragile, and prone to becoming impermeable and eroded. Consequently, soil management is vital to maintain and improve soil health.
Degraded soil and land health has a range of consequences, including:
- degradation of water quality from increased sediment and other pollutants deposited into rivers and streams (see Indicator W3: Water quality)
- air quality and human health impacts from dust storms (see Indicator A1: Compliance with air quality standards)
- loss of topsoil limiting the establishment of new vegetation, removing native seedbanks, and promoting the spread of weeds
- reduction in agricultural land productivity through reduced yields and pasture growth
- increased agricultural costs from greater fertiliser use and land restoration activities, and
- erosion damage to infrastructure such as fencing, roads and buildings.
Climate change impacts, such as more frequent drought, increased storms and fires, will add to current pressures on land health, particularly through the reduction of vegetation cover and erosion of exposed soils.
Condition and trends
Land health assessments are most commonly made through soil measures such as salinity, acidity, erosion and carbon. Baseline data and ongoing monitoring are required to determine changes in soil condition.
There has been no recent systematic assessment of soil condition in the ACT. Consequently, it is not possible to assess the condition of soils and land health in the ACT due to the lack of data.
It should be noted that research has been undertaken on the types and characteristics of soil landscapes in the ACT, the nature and consequences of potential soil degradation and the management required to reduce risks, and the salinity risks and priority areas for management. Cook, W. et al., 2016, Soil Landscapes of the Australian Capital Territory, Office of Environment and Heritage, Queanbeyan, NSWMuller, R., Jenkins, B. and Nicholson, A., 2017, Soil and Land Degradation Management for the Australian Capital Territory, Office of Environment and Heritage, Wagga Wagga, NSWMuller, R. et al., 2017, Hydrogeological Landscapes of the Australian Capital Territory, Second edition, Office of Environment and Heritage, Wagga Wagga, NSW
This information will be valuable to assist planning for the most appropriate land use, and improve management to prevent soil degradation. It can also be used to determine where soil monitoring will be most beneficial. However, these studies do not measure the actual extent of soil degradation in the ACT, nor the impacts of such degradation.
For private land, assessments of soil health and remediation may be undertaken by community natural resource management groups such as Landcare and Greening Australia with participating landholders. This is discussed in Community leadership in sustainability and science.
Contaminated sites include former petrol stations, landfills, and sites with previous chemical uses (such as sheep dips). These sites can impact on human health and the environment through the leaching of chemicals into groundwater and waterways, the release of air toxics, or through direct contact with contaminated soils and other substances.
As the rate of urban infill and greenfield development increases, it is reasonable to expect an increasing number of contaminated sites. The identification of contaminated sites allows their remediation, if required, and allows appropriate land use to be considered for the sites. In this way, development can be a driver for both the increased reporting and remediation of contaminated sites.
The Environment Protection Authority has the regulatory responsibility for the oversight of the remediation of contaminated sites. Contaminated sites such as old petrol stations, or those that were used for fuel storage, often require ongoing monitoring to determine any continuing impacts; other sites may be remediated with no further monitoring required.
Remediated sites are not currently removed from the contaminated sites register to ensure that any future use of these sites is compatible with site remediation. For example, a site may be remediated to a level that can accommodate industrial development, but may not be appropriate for residential development.
As at 2019, there were 1,088 contaminated sites in the ACT. These are mostly sites of former petrol stations or other fuel storage activities which accounted for 587 of the total. Other contaminated sites included 153 former sheep dips and 121 landfills.
Compliance with site contamination National Environment Protection Measure (NEPM)
Compliance with the National Environment Protection (Assessment of Site Contamination) Measure ensures that the ACT is achieving the national environment protection standard for the assessment of contaminated sites. This NEPM does not include site remediation.
The ACT must report annually on compliance with the site contamination NEPM to the National Environment Protection Council. Up to and including 2017–18, the ACT’s contaminated sites monitoring and reporting activities were found to comply with the NEPM. National Environment Protection Council (NEPC), 2019, Annual Report 2017–2018, Canberra, accessed 13 October 2019.