Ways forward: implications of Audit findings for salinity management
Australian Dryland Salinity Assessment 2000 has focused on developing an understanding of how the major groundwater systems across Australia function and, from this basis, an analysis of management options to control dryland salinity.
The improved understanding of groundwater processes and types provides information on:
- the extent of land use change and recharge reduction required to halt, and maybe reverse, the spread of rising watertables and salinised lands.
- the lag times between adopting recharge reduction or interception of saline groundwater and consequent responses in groundwater levels, area of land salinised and/or salt delivery to streams.
Local groundwater flow systems
Australia has close to 25 million hectares of local groundwater flow systems. Approximately 3% of these are considered to be at risk of developing some dryland salinity. These systems are commonly deeply weathered, low permeability systems that are already almost full and occur in cleared areas of temperate Australia.
These areas are likely to exhibit a lag of three to ten years or more between changes in the water balance and the initial occurrence of salinity. For these systems there is a probable lag of several decades before hydrogeological balance is reached. Consistent with these relatively small systems, changes in land use to effect significant reduction in recharge are needed on a local scale for each system.
Based on a conservative assumption that changes are required over half of each catchment area, approximately 12 million hectares in temperate Australia could require treatment to reduce recharge and restore hydrogeological balance. If these treatments are undertaken the area of salinised land will reduce fairly rapidly, probably within 10 to 15 years and in some cases much less time. However, low discharge capacity of many of these systems means that it is likely to be decades before salt delivery to water resources is significantly reduced. Biophysical options are appropriate for these systems. Recognising that lag times to improve land will be much less than those to improve water resources, application of recharge management will depend on whether the main objective is land or water rehabilitation.
Intermediate groundwater flow systems
Australia has around 40 million hectares of intermediate groundwater flow systems. Approximately 5% of these systems are considered to have a high risk of developing dryland salinity. They are mostly (75%) deeply weathered, low permeability systems. They are already close to full and occur in cleared areas of temperate Australia. These systems also include some high permeability, buried river channel systems.
These areas are likely to exhibit a lag of several decades or more between changes in water balance and the initial occurrence of salinity, and 50 years or more before hydrogeological balance is reached. To rehabilitate land and waters, changes in land use / water balance are needed over a significant proportion of each catchment. Based on a conservative assumption that land use changes to reduce recharge are required over half of each catchment this would amount to an area of approximately 20 million hectares. In most intermediate flow systems, the low discharge capacity means that it is likely to be decades before the effects of such changes become evident on land. In the higher permeability flow systems the effects of changes in land use are likely to become evident within a shorter period, possibly with similar response times to the local systems.
Regional groundwater flow systems
Australia has around 45 million hectares of regional groundwater flow systems. Approximately 6% of this land is considered to be at high risk of salinity in the next 100 years. These systems are characterised by broad plains and deep sedimentary sequences. They are likely to exhibit a lag of over 100 years between changes in water balance and the initial occurrence of salinity, and probably over 1000 years before hydrogeological balance is reached. Consistent with these extensive systems and very slow response times, it is likely to be many decades before the effects of recharge management become evident in groundwater levels. Improvements in salt loads to streams as a result of recharge management may not be detected within our natural resources management planning horizon of 50 years.
Table 26. Changes in recharge (mm/year) following conversion to crops or pastures (Williamson 1998).
|
Land use change |
State |
Average rainfall (mm/yr) |
Recharge increase (mm/yr) |
Recharge increase to rainfall ratio |
|
Mallee to agriculture |
SA |
340 |
17 |
0.05 |
|
Mallee to agriculture |
SA |
370 |
27 |
0.07 |
|
Woodland to cropping |
WA |
500 |
36 |
0.07 |
|
Shrubland to cropping |
WA |
500 |
26 |
0.05 |
|
Forest to crop/pasture |
Vic |
620 |
20 |
0.03 |
|
Forest to crop/pasture |
Vic |
650 |
17 |
0.03 |
|
Forest to crop/pasture |
WA |
720 |
30 |
0.04 |
|
Sclerophyll forest to cropping |
WA |
730 |
24 |
0.03 |
|
Pine to pasture |
SA |
750 |
64 |
0.09 |
|
Forest to cropping |
WA |
910 |
65 |
0.07 |
|
Forest to pasture |
Vic |
990 |
80 |
0.08 |
|
Forest to pasture |
WA |
1010 |
60 |
0.06 |
|
Forest to pasture |
WA |
1150 |
52 |
0.05 |
Further information on the advantages and limitations of a range of salinity management measures is provided in the fact sheets at the end of this document.
Ways forward: management options for dryland salinity
Once salt has been mobilised, it will continue to move to the discharge areas in the lower regions of the landscape including streams, rivers and wetlands. Slowing or halting salt transport will require recharge control. Salt will continue to have an effect until its store is exhausted. Recognition of the central role of recharge control for managing salinity must be central to our strategic planning. It is sobering to extrapolate the results of the Audit case studies across Australia. Both the extent of land use change required and the likely lag times to treat the cause of salinity are far greater than generally recognised at either the policy level or in regional communities striving to control salinity.
If and where recharge control is not possible or feasible then we are dependent on engineering solutions that can effectively intercept the salt and store it safely in the landscape.
In other cases, particularly if land rather than water is the main asset at risk, adapting to salinity may well be the best option - there are many beneficial uses of salinised land and water resources.
Landowners, individually or as part of a catchment, must be confident that there will be a positive result before undertaking any salinity work based on recharge management. To meet this need, scientists must continue to develop, test and revise recharge management techniques in the context of the time taken and efficiency of the technique to improve groundwater levels.
The ways forward in salinity management are many and varied depending on objectives and the local biophysical environment. A combination of approaches that considers both individual farm and whole catchment factors is likely to be the best option.
Options for recharge management
Recharge reduction options include changing land use and farming practices, intercepting fresh water using engineering methods; retaining, re-establishing and managing remnant native vegetation, or a combination of these.
Substantial land use change will be required to significantly reduce recharge, by introducing high water-use farming systems in cropping areas, high water-use pasture systems and by revegetating with trees or agro-forestry systems.
Engineering methods that intercept surface water through banks or shallow drains are used for recharge control. Good quality water harvested by pumping or water diversion can be reused elsewhere on a property for irrigation or stock watering, by making productive use of water that may otherwise be a problem once it intercepts salt in the landscape.
Native vegetation over a substantial part of a catchment provides optimum recharge control as most salinisation is the consequence of water balance change that followed tree clearing. Management and protection of remnant native vegetation is the first step in working towards a higher water-using landscape. The scale of change in recharge following conversion of native vegetation to crops and pastures varies between 3% and 9% (Table 26) of the average rainfall (Williamson 1998). As recharge processes are generally faster than discharge processes, measures required to re-establish the water balance are substantial.
Stirzaker et al. (2000) and others suggest a revolution in land use and farming systems including:
- opportunity cropping (rotations of winter and summer crops that are sensitive to soil water);
- phase farming (alternating phases of crops and lucerne);
- companion farming (over-sowing annual cereals into perennial forages/pastures);
- new agricultural plants;
- perennial pasture;
- high rainfall tree products;
- low rainfall tree products and revegetation with native woodlands and forests; and
- agroforestry.
Some of these options are more beneficial than others in controlling `leakage'; some are available now, while others require additional research. Further research is also needed to determine which tree-crop-pasture mixes can reduce `leakage' to acceptable levels and continue to generate attractive farm and community wealth. The appropriate siting of two or more of the above options within a catchment (taking account of soil type and landscape position) may have a beneficial multiplier effect for salinity management.
Significant changes in land use over a smaller proportion of catchment areas may not ultimately reduce the extent or severity of salinity, but may reduce the rate of salinisation in systems that are not yet full (particularly regional systems). Modelling the benefits of adopting land uses that partially reduce recharge levels indicates that it may be possible to delay the onset of salinisation for several decades. Partial changes in land use may be the realistic option, while more long-term options are researched, developed or evaluated (Stirzaker et al. 2000).
By overlaying our understanding of the geophysical characteristics of a catchment with the knowledge acquired from modelling of groundwater and farming systems, we can develop principles about the effectiveness of land use options. These principles will allow regional groups to make informed judgements about the likely performance of catchments under a range of land use options.
The flow systems where farming systems might be expected to deliver whole-of-catchment/end-of-catchment salinity benefits within an acceptable timeframe are those made up of responsive permeable aquifers in either local, or perhaps some intermediate flow systems. These are not extensive in the Australian landscape and are found mainly in some fractured rock aquifers in eastern Australia. Farm planning that integrates production and recharge management options is likely to be a necessity if catchment groups/authorities are to meet the types of water management targets being considered in catchment management plans in southern Australia.
As it is difficult to make generalisations about what will be effective for a particular catchment it is important to consider each option within the context of local catchment and farm conditions.
The sobering reality for most groundwater flow systems is that while recharge reduction may restrict the expansion of saline land, and may even reduce its area in some cases, it is unlikely to be successful in reducing the delivery of salt to the streams, rivers and wetlands. The salinisation of the water resources in these systems will continue unless engineering interventions to intercept the salt are put in place.
Engineering options for recharge and discharge management
Engineering options fall into two broad groups: the fairly simple, largely on paddock surface water management measures (e.g. banks, drains) and the more expensive, often larger area measures (e.g. deep drains, sub surface drains, pumps, interception and diversion systems).
Surface water management to control flows for erosion, waterlogging and harvesting water on farms has been a common feature of many regions, and offers opportunities for removing surface water before it can infiltrate and contribute to recharge. These measures along with more innovative measures such as raised bed farming will be a feature of farming systems particularly in Western Australia.
The more classical engineering options using groundwater pumps, deep drains and interception and storage/disposal structures have been limited mainly to irrigation areas or areas where water resources are being threatened. The high cost of establishing and operating these technologies mean that they are applicable either to protecting high value assets, or where it is necessary and economically viable, to extracting groundwater for industry development. Where groundwater is `fresh', it might be used to support industries such as intensive horticulture; where saline, it might be used as the resource base for new and emerging saline industries.
In general, the application of these engineering options is limited by the permeability of the groundwater flow system being pumped or drained, although where high-value assets need protecting, it will usually be technically feasible, although sometimes costly, to implement these options. The pilot investigation at Merredin (see p. 12) in Western Australia is an example.
Productive uses of saline land and water
The productive uses of saline land and water include: halophytic vegetation and salt-tolerant grasses for stock fodder; salt-tolerant trees and horticulture; saline aquaculture; and nature conservation areas for biodiversity protection, greenhouse credits and recreational values. Chemical extraction and desalinisation of water are further options, more likely to be used to defray some of the costs of protecting high value assets.
These measures are limited to discharge areas, and their suitability is determined by the quantity and quality of groundwater, and varies between groundwater flow systems. The demand for saltland production systems will become more widespread as the extent of salinity increases.
Applicability of options
No one option is likely to work in isolation and most situations will require a suite of `tools' for effective salinity management.
Current farming systems options for combating dryland salinity are limited by their ability to achieve sufficient recharge reductions in many situations; the scale at which they would need to be applied; and the lag times in influencing intermediate, regional and many local groundwater flow systems. Farming systems will also have to demonstrate economic benefits in their own right if they are to be adopted at the scale required.
In most systems it will be technically feasible to apply engineering options to protect major assets. It will also be possible to extract groundwater where salinity mitigation might be used in conjunction with industry or regional development. Costs and benefits relating to asset protection and industry development will determine the level of application of engineering technologies.
In most instances we can also apply a range of productive uses to the management of saline land and saline water resources.
An important determinant of options selected will be the benefit-cost analysis irrespective of the scale. Not only will new farming and land use systems that suit Australian environments be required, but innovative and inclusive approaches that permit fair comparison of market and non-market values will need to be developed.
Overall conclusions
- Different groundwater flow systems require substantially different combinations of management options.
- Holistic approaches to salinity that take account of the groundwater flow systems and the objectives of management are essential.
- In most instances there will be no single solution to the problem, and the combination of approaches will differ across temperate Australia.
- Adaptive management and innovation have a significant role to play in maintaining productivity and profitability. Strategic investment in management measures and mitigation may provide options to live with the current and rising levels of salinity.
- Intervention needs to be driven by asset protection plans for infrastructure, biodiversity, productive soils, water resources and combinations of these assets, with realistic targets set in terms of the level of salinity management that is feasible.
Northern Australia: a special case
Prevention and protection: opportunities in northern Australia
Treating the cause of salinity through recharge reduction may be effective in reversing salinisation in only a few responsive groundwater systems. Once the salinisation process is under way it is extremely difficult to slow, halt or reverse in order to protect water and land resources. Prevention is a far better investment than any attempt at control or management.
Northern Australia presents opportunities to avoid the dryland salinity problems of temperate Australia. Broad-scale clearing without recognition of salt stores and the resulting change in water balance is a recipe for problems, whether it is in 20 or 100 years. Wise management now to protect the landscape and prevent dryland salinity will prove far more cost-effective than any attempts to solve the problem once it occurs.
While salinity analysis has focused on southern Australia, sound scientific evidence (Bui et al. 1996, Williams et al. 1997, Bui 2000, Gordon et al. 2000, Gunn1967, Shaw et al. 1994) shows that all the factors that contribute to salinity hazard also exist over large areas of the semi-arid zones of northern Australia. Two factors that must be present for a salinity hazard to exist after clearing or change in vegetation cover are :
- presence of stored salt in the soil, regolith or groundwater systems, and
- an increase in the water draining beneath the root zone following tree clearing or vegetation change.
Hazard assessments have been carried out in Queensland as part of the Audit program and previously for the Northern Territory (Tickell 1994a, 1994b).
An assessment is yet to take place for northern regions of Western Australia.
Northern Australia has seasonal patterns of high evaporation and summer rainfall. A common misconception is that these patterns mean that land clearing and other vegetation management cannot increase the amount of water draining below the root zone to intercept the salt and move it to lower positions in the landscape and to rivers, streams and wetlands.
Hydrogeological evidence does not support this perception. The summer wet season rainfall pattern in northern Australia is concentrated between December and April. These rainfall patterns respond to vegetation change (particularly the removal of deep-rooted perennial species) in a similar way and extent to the winter-dominant rainfall patterns of southern Australia where salinity is widespread (Williams et al. 1997, Gordon et al. 2000, Stirzaker et al. 2000). A change in vegetation can significantly increase the water that drains (deep drainage) beneath the root zone in northern and central Queensland. It is important to conduct water balance analysis over periods of a day or so, to see evidence of increased deep drainage following clearing. Coarse, monthly analysis of water balance can be misleading and is the basis for current misconceptions.
Key messages
- Hazard assessment has confirmed that large areas of the tropics and subtropics have a potential salinity problem if clearing occurs.
- Broad-scale land clearing with little or no regard for the salinity hazard is a recipe to repeat the problems of temperate Australia.
- Assessment of areas identified as having a hazard, particularly areas of extensive clearing in central and southern Queensland, is essential and would underpin the development and implementation of vegetation management policies and guidelines.
- Opportunity exists for a major national, well-focused investment in preventive action in northern Australia.
Ways forward: regional approaches essential
Dryland salinity is a reality for thousands of rural landholders and urban householders dealing with salinised land and facing crumbling foundations and diminishing water quality. Salinity will continue to worsen because the processes that control it operate over large areas and responses in groundwater levels to changes in the water balance are slow. Realistic options for its management are limited, and substantial changes in our land use patterns may be required in many areas before groundwater levels begin to fall.
Our requirement to manage recharge is a consequence of changes in the hydrogeological balance imposed over the past one hundred and fifty years; continuing or increasing salinity problems are a measure of the limited responsiveness of groundwater systems to management efforts. Given that many groundwater systems are slow to change - and that it is unlikely that they will respond within timeframes acceptable to contemporary stakeholders - we need to be more selective in the use of biologically-based salinity management programs.
Biological approaches (e.g. adoption of perennial vegetation, such as perennial pastures, woody vegetation and reforestation) do give us the opportunity to slow salinisation sufficiently to `buy time' and to limit the ultimate size of the problem. In some cases they may also lessen the amount of groundwater that needs to be managed (e.g. where engineering options are applied to protect important assets or where they afford positive benefits in concert with options for managing saltland productively). In other circumstances, potential increases in farm productivity resulting from the more efficient use of water will be an essential part of the overall suite of required responses. They are likely to work best when combined with surface water management or other engineering options.
Given that we face a three-fold increase in salinity over the coming decades:
- We need to recognise that there is no quick fix. Salinity can be managed by prevention, treating the cause, ameliorating the symptoms, living with it or a combination of these.
- Salinity management requires knowledge about soil, salt, water and vegetation; integrated with knowledge about groundwater flow systems.
- We need to implement a landscape function approach to the management of on-site and off-site impacts of dryland salinity. In some areas this may require a mix of biological, engineering and industrial responses in accordance with biophysical and hydrogeological systems.
- We need to enhance monitoring systems to allow evaluation of the effectiveness of management responses and to build on our understanding of landscape processes.
Options for managing dryland salinity will vary across Australia in response to environmental conditions and social and economic aspirations for the catchment. These communities will need to identify the level of salinity management they wish to achieve in conjunction with their other objectives.
The National Action Plan for Salinity and Water Quality agreed by the Commonwealth and States on 3 November 2000 has, as its centrepiece, community-driven action directed at salinity and water quality problems in key catchments and regions. The plan recognises the importance of knowledge and data to underpin management responses and seeks to address this through a range of capacity building activities including research, extension and training. These activities will include mapping of salinity risk using airborne electromagnetic methods and ground truthing.
The Commonwealth has been extensively involved in the development of the mapping technology. Mapping in a number of regions is to commence during the first half of 2001.
The salinity-risk mapping and support of community actions are intended to assist communities to ensure that their actions are cost-effective and well targeted. The findings of the National Land and Water Resources Audit are a key input to inform this process and assist with monitoring outcomes.
Ways forward: building better knowledge and information
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
- There is no consistent national approach to monitoring the extent of and trends in dryland salinity.
- 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.
- 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.
- 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.
- 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).
- Many groundwater monitoring sites are neither georeferenced nor related to an elevation datum.
- 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.
- Lack of formal design in biophysical monitoring systems then limits our ability to develop an economic evaluation of impacts.
- No formal monitoring system exists for changes in land use / land management and therefore tracking changes to water balance.
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.
Details of the framework and guidelines proposed by the Audit for monitoring dryland salinity have been prepared and are available on the Audit's Australian Natural Resources Atlas.
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.
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.
Ways forward: key implications for policy makers
Implications of long response times in groundwater flow systems to remedial measures
- A central feature of policy making on dryland salinity is that decisions are going to be made in the context of considerable uncertainty about outcomes, and trade-offs in targeting investments will be inevitable. Regional bodies that are to develop integrated regional/catchment strategies for salinity and water quality under the National Action Plan will need to be conscious - while setting targets and regional outcomes and assessing the trade-offs - of the level of temporal and spatial uncertainty, and lags in management actions.
- Evaluation of the effectiveness of management responses will be difficult or imprecise, and surrogate performance indicators will be required. These will need to be well understood by those involved in monitoring the effectiveness of investments.
Implications of the limited responsiveness of some groundwater flow systems to biological management options
- Surface water and groundwater resources will continue to salinise, with major impacts on rural communities and aquatic ecosystems.
- Although the rate of salinisation may be able to be slowed or reversed in some areas, in others land resources will continue to salinise, with major impacts on rural communities and terrestrial biodiversity.
Where salinisation can be halted or reversed, innovative land use systems will be required to produce the required reduction in recharge.
- Alternative industries using saline resources may be required in large areas of Australia.
- Existing pasture and crop species will require specific genetic improvement to tolerate saline conditions if existing production systems are to be maintained in areas of major salinisation.
- The development of new industries and land uses based on deep-rooted perennial plants, that are commercially viable and control the leakage beneath the root zone at levels similar to native vegetation, will require a long-term, well-focused and funded strategy of research, development, adoption and enterprise innovation.
Implications of the inadequate land and water monitoring and assessment systems
- There is a lack of comparability of assessment data across States and Territories. Some have capacity to report risks while others are limited to hazard. Methods and data constraints can lead to over estimates or underestimates.
- Lack of design and purpose in the groundwater monitoring networks limits our capability to assess change, evaluate the effectiveness of management programs and prioritise activities.
- Design of salinity management responses for nature conservation assets is severely compromised by inadequate knowledge on our biodiversity and the impacts of salinity.
Policy Direction
The Prime Minister, Premiers and Chief Ministers agreed on 3 November 2000 to a new National Action Plan for Salinity and Water Quality that sets policy direction for addressing dryland salinity and the deterioration of water quality. Core elements of the plan are:
- Setting targets and standards for natural resource management, particularly for water quality and salinity. Targets and standards will cover salinity, water quality and associated water flows, and stream and terrestrial biodiversity based on good science and economics.
- Integrated catchment and regional management plans developed by communities, in all highly affected catchments and regions where immediate action will result in substantial progress towards meeting State, Territory and basin-wide targets to reverse the spread of dryland salinity and improve water quality. The Commonwealth, States and Territories will need to agree on targets and outcomes for each integrated catchment or region management plan, in partnership with communities. Each plan will need to be accredited for its strategic content, proposed targets and outcomes, accountability, performance monitoring and reporting.
- Capacity building for communities and landholders to assist them develop and implement integrated catchment and region plans, together with the provision of technical and scientific support, and engineering innovations. It will include: research and development of new production systems attuned to Australian conditions, extension of information/data from the Audit to communities, provision of technical support through `salinity response teams', and salinity mapping and training support. l An improved governance framework to
secure the Commonwealth_State/Territory investments and community action in the long term. This would include property rights, pricing and regulatory reforms for water and land use; placing caps for all surface and groundwater systems identified as over-allocated or approaching full allocation; prohibition of land clearing in areas where it would lead to unacceptable land or water degradation; and development of market-based incentives for adoption of best land and water management practices. - Clearly articulated roles for the Commonwealth, State and Territory, local government, and community to replace the current disjointed Commonwealth_State/Territory frameworks for natural resource management. This would provide an effective, integrated and coherent framework to deliver and monitor implementation of the action plan.
- A public communication program to support widespread understanding of all aspects of the action plan to promote behavioural change and community support.
The action plan recognises the importance of knowledge to underpin management change. The work of the Audit on dryland salinity will provide valuable support in this and in implementation of the action plan, by informing regional communities and landholders of the regional and local natural resource condition: so that they are better able to plan regional and catchment salinity and water management strategies, and to monitor the performance of their actions.
The action plan also recognises the importance of on-going evaluation and monitoring of the natural resource base.
Table of Contents for the Australian Dryland Salinity Assessment 2000
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