Salinity - Monitoring
Australia
Why monitor dryland salinity?
Assessment and monitoring-current capability
This assessment is the first rigorous scientific attempt to present a national perspective of salinity. It has built on recent assessments in Western Australia and the Murray-Darling Basin, and provided an opportunity to assess the adequacy of data and information and to identify the elements of better collection, analysis and reporting systems.
The groundwater rise projections and scenario modelling summarised in this report have been based on available data in each State and Territory. It is clear from the studies undertaken as part of this Audit that monitoring and assessment systems for dryland salinity are incomplete for determining the current and future extent of salinity across the continent, or for assessing the effects of any remedial or preventative management responses. We have limited capability to predict salinity trends with confidence even in catchments that are supposedly well instrumented, such as those chosen for the Audit?s case studies.
Assessment and monitoring capabilities
- Lack of comparability: There is no consistent national approach to monitoring the extent of and trends in dryland salinity.
- Monitoring design: Surface water monitoring systems in most States have not been specifically designed to enable monitoring of salt loads. This limits the ability to assess the effectiveness of land and water management options in managing salt export out of catchments.
- Monitoring sites are often not strategically placed in the landscape, nor is there adequate knowledge about the groundwater flow systems being monitored, and hence we have a limited ability to evaluate impacts of land use on dryland salinity.
- Where data on surface water or groundwater have been collected, there are major gaps in the length and frequencies of measurements, and inconsistencies in chemical analyses carried out. This limits the interpretations that can be made of salt load and salt concentration trends through time.
- No formal monitoring system exists for changes in land use / land management and therefore tracking changes to water balance.
- Monitoring network: Although groundwater level and trend data are recognised as a fundamental requirement in evaluating the size of the problem and the rates at which it is changing, there are major deficiencies in the design and coverage of groundwater monitoring networks. Even in Victoria, South Australia and Western Australia, where monitoring sites have been established, there are significant gaps in coverage or design, that limit the ability to evaluate effects of land use systems. Queensland and Tasmania have very limited formal groundwater monitoring systems suitable for assessing dryland salinity.
- Many groundwater monitoring sites are neither georeferenced nor related to an elevation datum.
- Validation: Data on groundwater trends have been used in Victoria and Western Australia to supplement field survey or remote sensing. Groundwater monitoring in these States has been developed by State and community groups largely on a project-by-project basis.
- Other assessment tools: In Western Australia, ?Land Monitor? based on the use of multi-temporal Landsat imagery is the main form of monitoring the extent of area affected by dryland salinity. This approach has yet to be fully developed and accepted in the eastern States. Recent work in the Great Southern region of Western Australia, as part of the Audit salinity theme, has identified a number of constraints to integrating the groundwater information with the Land Monitor data to improve the confidence in assessing the extent and risks of dryland salinity (Campbell et al. 2000).
- Economic analysis: Lack of formal design in biophysical monitoring systems then limits our ability to develop an economic evaluation of impacts.
Most States have highlighted the need for improved monitoring systems for evaluating salinity management responses in the future. Improvements include better design and performance indicators appropriate to the questions being asked and the scale being considered. Because timeframes for measuring responses for some indicators such as salt trends in streams are long, surrogate measures (such as changes in the levels of perennial vegetation) will be required to assess impacts of land use changes/management responses in the short term.
Future knowledge requirements
Land use solutions to control recharge
There is an urgent need for land use solutions to control recharge and to achieve reductions to levels equivalent to the discharge capacity of the catchments. Stirzaker et al. (2000) set out some prospects but research, development and innovation to build these new industries is essential.
We also need to know more about how changing land use affects the landscape, so we can predict downstream impacts more confidently. We need to invest in development of specific tools, such as techniques that link surface water balance models and groundwater models to improve estimates of salt flows through the landscape.
Land use solution for salinised land and water
It is clear that despite best efforts, increasing areas of salinised land and salinised rivers and wetlands will need to be used for production. Salt-tolerant crops and pastures will be required where (from an economic point of view) ?living with salt? is the only feasible alternative.
Improved knowledge of Australian groundwater flow systems
We lack detailed knowledge about the groundwater processes that lead to dryland salinity for many parts of Australia. This is due to a lack of data and inability to transfer knowledge from well-studied areas to less familiar parts of the country.
Further development of the groundwater flow systems framework at the catchment scale is warranted to improve our understanding of individual flow systems and their responses to changes. If the full benefits of the application of the groundwater flow systems in tactical planning at the catchment scale are to be achieved, investment in catchment-scale data to support the assessments is required.
How might we monitor progress across Australia?
Designing a monitoring system for Australia
If we are to make informed decisions about how to prioritise our investment in salinity, and how to assess the effectiveness of investments, we need to be equipped with sufficient, good quality data that enable us to answer some fundamental questions at the catchment scale.
- How effective have management activities been?
- What is the likely future extent/severity/impact of salinity?
- What is the contribution to improving groundwater level of any salinity management investment?
- What investments are likely to deliver the most effective changes to water balance and over what time frame?
- How are systems-such as in-stream water quality, wetlands and soils-responding to improvements in groundwater level?
- What are the minimum components for an effective Australia-wide dryland salinity assessment and monitoring program?
We need:
- an analytical framework based on our understanding of hydrogeological processes controlling salinity, including timescales and spatial extents;
- evaluation methods and appropriate data (including indirect and surrogate indicators) that allow continuing evaluation of land management responses; the methods must enable the linking of biophysical, social and economic dimensions;
- consistent design and standards for data collection; and
- a capability to collect and manage data, and to produce information and assessments from this data.
The conceptual framework of groundwater flow systems provides the biophysical understanding to ensure that monitoring systems at the catchment scale:
- are consistent with the physical characteristics of areas at risk of salinity;
- are cognisant of the differing time periods of salinity development and specify the frequency and minimum duration of activities;
- allow comparison of like areas irrespective of State/Territory boundaries;
- concentrate on measuring change at a minimum number of locations, representative of that region and for the groundwater system type;
- can be aligned with other key aspects of monitoring (e.g. stream flow salinities) where these are compatible with strategic salinity monitoring; and
- are based on key agents of change for groundwater in a particular groundwater system (e.g. land use changes that impact on water balance).
Core data requirements of any monitoring program
- Extent of land salinisation.
- Trends in groundwater levels, stream salinities and salt loads.
- Land use/land cover (including native vegetation).
- Aquifer characteristics of major flow system types.
- Soil-water characteristics and parameters for crop-pasture-tree-water balance models.
- Crop and pasture production data (costs and returns).
An essential requirement for any monitoring system is long-term funding security and clearly defined roles for those with responsibilities in evaluating dryland salinity management activities.
Coordinating activities across Australia in designing systems, developing methods and reporting regular assessments would promote information sharing and improve both systems capability and return on dryland salinity management investments. This will require a national sponsor to ensure that the benefits of coordination are realised.
What type of monitoring is required across Australia?
Management objectives and options
In the past, dryland salinity management has been applied with the implicit objective of ameliorating the causes and symptoms of dryland salinity through a range of approaches either to reduce or manage discharge. We now know that salinity management objectives must be more explicit. To achieve this, we must take into account the characteristics of the different groundwater flow systems and their interaction with surface water hydrology. These objectives should reflect a realistic understanding of the feasibility of reversing, halting or slowing the manifestation of dryland salinity.
Dryland salinity management objectives and options broadly consist of:
- Prevention and protection (for example, native vegetation retention);
- Treatment of cause (for example, recharge management or interception of groundwater);
- Amelioration of symptoms (for example, interception and storage of salt; managing saline discharge; developing alternative production systems);
- Living with salt (for example, alternative use of saline land and water resources; optimisation of the use of non-saline resources).
The mix of management options that is appropriate to achieving these objectives in any particular region is further discussed in Australian Dryland Salinity Assessment 2000 (NLWRA, 2001). The evaluation approaches taken to achieve the management objectives must vary according to the management activities and performance targets specified in plans, and the scale at which these objectives are to be addressed.
Evaluation objectives and approaches
The evaluation approach should also be developed within a framework of explicit management objectives:
- To define baselines of the extent/severity/impacts of dryland salinity;
- To predict the likely future extent/severity/impact of dryland salinity;
- To refine understanding of the processes causing dryland salinity;
- To measure the effectiveness of previous management activities;
- To provide data to decide upon the most appropriate management options for delivering the changes to catchment water balances, and the likely time frames over which these might be achieved;
- To measure how well proposed management activities been implemented;
- To measure changes in extent/severity/impacts of dryland salinity.
The attributes chosen to map, model and monitor dryland salinity need to be:
- readily understood;
- able to be measured regularly and unambiguously;
- readily interpreted;
- informative and readily communicated;
- scientifically credible;
- in accord with existing national standards, programs and policies.
Furthermore, the data being collected need to be relevant at a catchment scale, and able to be aggregated for assessments at regional and national scales.
Recommended attributes for evaluating dryland salinity
Mapping, monitoring and modeling of the following attributes is necessary:
- As a baseline to define current rates of change, to inform conceptual models of dryland salinity processes, and to underpin decisions about targets for evaluating dryland salinity management;
- To generate knowledge about processes controlling dryland salinity, either through the development of conceptual models or through investigations using numerical models;
- To assess the potential effectiveness of management activities using predictive scenario modeling;
- To evaluate the effectiveness of dryland salinity management activities.
Groundwater levels and groundwater salinity
Monitoring of groundwater level trends provides information about change in groundwater pressures and likely discharge volumes, in response to changes in recharge. Groundwater salinity concentrations may also provide a baseline against which changes can be detected. However, the practical complexities in measuring them, and their usually limited value in indicating catchment salinity processes, mean that they are not recommended as primary attributes for ongoing monitoring. Nevertheless occasional measurements can provide useful information to inform understanding of processes and to parameterise models.
Surface water salinity concentrations and salt loads
Monitoring of surface water salinity concentrations and salt loads provides a baseline against which changes can be detected. Trends in surface water salinity concentrations and salt loads provide information about changes in the volumes of discharging groundwater to surface water bodies, and the amount of salt being exported from the catchment.
Extent of land salinisation
Mapping of the extent of land salinisation provides information about the current extent and impacts of dryland salinity to define the problem and serve as a baseline against which changes can be measured.
Land cover and land use
Mapping of changes in land cover and land use provides a context for interpreting trends in groundwater, surface water and soil salinity data. Mapping can also be a direct measure of the implementation of some management activities.
Contextual data
Databases of the hydrogeological and soil characteristics of groundwater flow systems, climatic characteristics, and digital elevation models provide a context for interpreting trends and assessing the effectiveness of management strategies. These data are also essential for parameterising predictive scenario modeling of dryland salinity processes.
Alternative attributes for evaluating implementation
Sometimes the recommended attributes will not be suitable for evaluating the implementation of management activities: for example, if the timeframes for assessment are too short to detect a direct landscape response to management, or data are not available. In these cases, alternative attributes can be included in evaluation programs.
Alternative monitoring attributes can include:
- agricultural systems productivity
- changes in land management practices
- vegetation health
- adoption of best-practice catchment planning approaches
- socio-economic status of primary production
- social viability of rural communities
- degree of implementation of catchment strategic plans
- volume of water and salt diverted from key assets
- adoption of new saline industries
- level of funding applied to salinity management.
These data are ambiguous, however, as they reflect a number of influences that may or may not impact on dryland salinity. These attributes should only be used for evaluating implementation of management options, or where the recommended attributes are not available for a sufficient period, or are not sufficiently comprehensive or representative. Table 2 shows the relationship between the range of management objectives and desired outcomes, and the mix of recommended and alternative attributes to each case. Note that the list of alternative attributes is not exhaustive.
Table 2. Evaluation attributes for different dryland salinity management options
| Management objective | Strategy | Outcome sought | Recommended evaluation attributes | Alternative attributes |
|---|---|---|---|---|
| Prevention | Manage vegetation in such a manner that deep drainage does not increase in high risk areas | Land and surface waters will remain free from degradation from salinity | Percent retention of native deep-rooted vegetation in high risk areas Long term groundwater level trends Long term stream salinity and salt load trends Extent of land salinised Land cover change Hydrogeological and soil characteristics Climatic characteristics Digital elevation models |
Land use management practices Vegetation condition Catchment planning based on resource assessment and daily water balance modeling |
| Reduce recharge to the groundwater system by increasing vegetation water use through land management practices | Land and surface water salinisation will diminish | Long term groundwater level trends Long term stream salinity and salt load trends Extent of land salinisation Land cover change Hydrogeological and soil characteristics Climatic characteristics Digital elevation models |
Proportion of landscape where water-efficient land use is adopted Land use management practices |
|
| Treatment of cause | Interception of water either prior to infiltration or from groundwater upgradient of discharge zone | Land and surface water salinisation will diminish | Long term groundwater level trends Long term stream salinity and salt load trends Extent of land salinisation Hydrogeological and soil characteristics Climatic characteristics Digital elevation models |
Volume of water and salt diverted or pumped from groundwater Land use management practices |
| Interception and disposal of salt, and reduction of groundwater levels in transmission zones | Land and surface water salinisation will diminish | Long term stream salinity and salt load trends Extent of land salinisation Hydrogeological and soil characteristics Climatic characteristics Digital elevation models |
Volume of water intercepted and disposed Mass of salt intercepted and disposed Land use management practices |
|
| Managing saline discharge | Land and surface water salinisation will diminish | Long term stream salinity and salt load trends Hydrogeological and soil characteristics Climatic characteristics Digital elevation models |
Volume of water and salt diverted Land use management practices |
|
| Amelioration of symptoms | Application of soil treatments (ameliorants) | Agricultural production from saline land is increased | Extent of land salinisation Soil water characteristics Climatic characteristics Digital elevation models |
Proportion of potential discharge area applying treatments Increase in gross margin ($/ha) from salinised areas determined from farm financial information Land use management practices |
| Establishment of salt tolerant land cover | Productivity from salt affected land will increase | Extent of land salinisation Land cover change Increase in production of biomass |
Increase in long-term productivity from saline resource Proportion of potential discharge zone applying alternative, salt- tolerant land uses |
|
| Productive uses of saline resources | Alternative use of saline land and water resources | Productivity from salt affected land and water will increase | Extent of land salinisation Land cover change |
Rate of adoption of new saline industries |
| Optimisation of the use of non-saline resources | Productivity from non-salt affected land will increase | Land cover change | Increase in long-term productivity from non-saline resource Rate of adoption of new practices that optimise non-saline resources |
Specifications for recommended evaluation attributes
The following tables provide guidelines for the monitoring of each of the recommended attributes. The tables describe evaluation and reporting techniques for each of these attributes. They also provide guidelines for which techniques are suitable for each type of groundwater flow system.
More detailed discussion of the biophysical considerations in designing evaluation systems and interpreting monitored data is provided in Appendix A of the Dryland Salinity Evaluation Framework report. Descriptions of the critical groundwater flow system characteristics influencing the design of evaluation systems are provided in Appendix B of the Dryland Salinity Evaluation Framework report.
Specifications for recommended evaluation attributes:
- Groundwater evaluation
- Stream monitoring
- Land salinisation
- Land cover and land cover change
- Hydrogeology
- Soils
- Climate
- Land relief
- Specifications for monitoring alternative attributes
What is being monitored now?
This review assesses the adequacy of current arrangements for monitoring the severity, impacts and likely future costs of dryland salinity. The assessment identifies the aspects of monitoring undertaken in each State and Territory that could be incorporated into a national framework.
The review is based primarily on a questionnaire sent to key state and territory contacts. Additional information was provided by an examination of major Murray-Darling Basin Commission (MDBC) and National Land and Water Resources Audit (Audit) documents, review of significant publications on dryland salinity, and a search of federal and state agency websites.
Federal Government
While no federal agency has specific responsibility for salinity management, several agencies are involved in research and the collection of data relevant to dryland salinity.
Agriculture Fisheries and Forestry - Australia (AFFA)
In November 2000, the Federal Government announced its $1.4 billion Salinity and Water Quality Action Plan, with funding to be split between the Commonwealth and the states. An important component of the plan was a commitment to fund mapping of salinity using airborne geophysics in twenty priority catchments across the country. AFFA has also committed about $1 million to a national land use mapping program.
Bureau of Rural Sciences (BRS)
BRS is taking a major role in the national salinity mapping program. Airborne electromagnetic, gamma radiometric and high resolution magnetic surveys will be flown in twenty catchments across the country which have been identified as priorities for salinity management in the Salinity and Water Quality Action Plan. Based on the geophysical data, and field survey, BRS will also produce models of the hydrogeological processes controlling dryland salinity in each catchment.
As part of a Audit project, BRS produced a national land use map at 1:1 000 000 scale based on Landsat and Agricultural Census data. BRS is also leading a national land use mapping program which aims to map most of the country at scales ranging from 1:25 000 to 1:250 000 by 2003. The Australian Land Cover Change (ALCC) project of BRS quantified land cover change from 1990 to 1995 for the entire intensive land use zone based on Landsat data.
Along with CSIRO Land and Water, BRS is also developing the Australian Soil Resources Information System (ASRIS), a nationwide database of soil attributes funded by the Audit.
Australian Geological Survey Organisation (AGSO)
AGSO is a partner in the airborne salinity survey described above. AGSO has also produced extensive geology and hydrogeology maps for the country at a range of scales. For example, mapping of the Murray Basin is available at 1:250 000 while mapping of the Darling Basin is available at 1:1 000 000.
Environment Australia (EA)
EA maintains several databases relating to aspects of biodiversity which could be at risk from salinity. This includes threatened species, internationally significant wetlands and World Heritage Sites.
Commonwealth Scientific and Industrial Research Organisation (CSIRO)
CSIRO, especially its Land and Water Division, conducts the most extensive research on salinity of any federally funded organisation. The Sustainable Agriculture and Sustainable Catchment and Groundwater Management programs of CSIRO Land and Water are two particularly important programs for salinity research.
National Land and Water Resources Audit (Audit)
The $29.4 million National Land and Water Resources Audit commenced in 1997 with a four year mission to provide a comprehensive national appraisal of Australia's natural resource base. The Audit consists of seven themes of which Theme 2 is Dryland Salinity. Projects under Theme 2 include an assessment of the current extent and future risk of salinity in all states and territories, a catchment classification framework for salinity management, several case studies on catchment management and salinity impacts, and recommendations on a national program for salinity monitoring.
Products from other themes of the Audit are also relevant to salinity. These include the National Vegetation Information System (NVIS), the Australian Soil Resources Information System (ASRIS) and the National Land Use Map produced by BRS.
Murray-Darling Basin Commission (MDBC)
The Murray-Darling Basin Commission is a partnership among Federal Government and all of the states represented in the Murray-Darling Basin. The MDBC commissions a wide range of research on salinity in the Murray-Darling Basin. Examples of current projects relevant to salinity include "Salinity control with sustainable farm salt balance through integrated management" and "Catchment characterisation and hydrogeological modeling to assess salinisation risk and effectiveness of management options".
Research and Development Corporations
Land & Water Australia (Land and Water Research and Development Corporation) commissions a wide range of research on salinity across the country. Land and Water Australia also leads the National Dryland Salinity Program (NDSP). The Rural Industries Research and Development Corporation (RIRDC) and the Grains Research and Development Corporation (GRDC) also commission research relevant to salinity.
Bureau of Meteorology (BOM)
BOM collects, archives and provides access to climate data such as rainfall and temperature from its network of climate stations across the country. BOM also maintains the SILO system (developed by Queensland Department of Natural Resources) which provides interpolated climate data for any point across the country.
Australian Bureau of Statistics (ABS)
Through the Agricultural Census and the Agricultural Commodity Survey, ABS collects yearly data by census area on crop production, livestock numbers, land use practices and the financial performance of agricultural industries.
Australian and New Zealand Environment and Conservation Council (ANZECC)
Core attributes have been developed by the State of Environment Reporting Task Force of ANZECC through extensive consultations involving both government agencies and the general public (ANZECC, 2000). Examples of attributes important to dryland salinity assessment, risk or impacts include:
- L4 - area of rising watertables
- L5 - area affected by salinity
- BD9 - populations of selected species
- BD11 - marine and estuarine protected areas
- IW7 - surface water salinity
- IW13 - river health.
ANZECC's role does not include collecting any data for these attributes.
State Governments
Information on state salinity monitoring activities is presented under the following headings:
- responsibility for salinity monitoring;
- current extent of dryland salinity;
- ground water levels and trends;
- surface water flow and salinity;
- land use/cover;
- salinity impacts (social, economic, biological);
- predictions of future extent of dryland salinity.
The adequacy of the activities for monitoring both current and future extent and impacts of dryland salinity is then assessed. A brief summary of monitoring by the States and Territory relevant to dryland salinity management has been compiled:
Further information
- Australian Dryland Salinity Assessment 2000 report
- National Technical Overview Report of the State-based dryland salinity assessments
- Dryland Salinity Evaluation and Monitoring Report
- Australian Groundwater Flow Systems Technical Report
- National Dryland Salinity Program
- National Action Plan for Salinity and Water Quality
Australian Dryland Salinity Report
Link to the Map Maker to make a map using this information.