Salinity - Monitoring - South Australia
South Australia
Monitoring now and in the future
The monitoring of groundwater and surface water resources is fundamental to the understanding of the processes, impacts and risk assessment of dryland salinity, and also the effectiveness of various treatment options. A State Water Monitoring Review is underway to develop an integrated statewide monitoring program and to specify data sharing mechanisms.
Groundwater levels
All groundwater monitoring data in SA is stored on OBSWELL administered by DWR. The system has been incorporated with the corporate drillhole database SA_GEODATA using Oracle. A web interface is being developed to allow convenient access to the data.
The regional groundwater systems of the Murray Basin are generally well monitored through various agencies, with the only improvements required being in the western area between Morgan and Karoonda where a more comprehensive network is necessary to monitor the watertable rise which will increase saline groundwater inflows to the River Murray.
In other regions where local or intermediate flow systems predominate, the representative catchment observation wells are the only monitoring sites. Although restricted in areal extent, it is thought that these networks are sufficiently indicative of regional trends that extra monitoring is not necessary (any additional observation wells would require drilling because of the lack of private wells due to poor groundwater quality). A stronger agency commitment is required to ensure regular monitoring of these existing networks.
A number of Landcare Groups have also been involved with installing piezometers, however these were usually installed in discharge areas, therefore not providing any significant additional information. Monitoring of these piezometers has been discontinued in most areas due to lack of funding and insufficient agency resources to provide support.
Recommendations for improved groundwater monitoring include ;
Improved coverage in the northern Mallee and more consistent monitoring in the Riverland to help more accurate predictions of salinity impacts on the River Murray.
Stream Salinity
Monitoring and data collection of surface water quantity and quality has been undertaken by government agencies in SA for many decades. In the early 1970s, a network of surface water monitoring was established to meet the needs of water supply obligations. Surface water salinity monitoring in SA occurs in the form of grab samples, continuous monitoring and composite samples which have all been collected using different methods.
Jolly et al. (2000) analysed EC trends from 39 grab sample and continuous monitoring stations throughout the State (Appendix 2), and found the statistical analysis of stream salinities constrained by lack of data, with either short-term, irregular or sparsely sampled records in some areas. Recommendations to overcome these shortcomings include ;
Chart salinity data for stations in the Mount Lofty Ranges that has not been analysed should be digitised, entered in the appropriate database and included in future analyses of stream salinity trends.
Detailed studies are carried out to identify the causes of the observed stream salinity trends for all stations in the Mount Lofty Ranges. This should include updated salt balance studies for the previously studied catchments.
A gauging station should be installed upstream of the Middle River Reservoir, and any decision on the long-term future use of the reservoir should also consider the viability of catchment rehabilitation and alternative uses of the resource.
Detailed studies are carried out to identify the causes of the large variations in stream salinity trends with time that are observed for stations in the Wakefield and Broughton catchments.
The current PIRSA investigations which are seeking to determine the viability of rehabilitating the Tod River catchment to reduce the effects of dryland salinity should continue. Meanwhile, all existing groundwater basins should be maintained until such time that the Tod River catchment is rehabilitated, if this is possible.
Further salt balance studies in Mount Lofty Ranges catchments will require monitoring of rainfall salinity.
Land Management
Dryland salinity is fundamentally a water balance issue where recharge to a groundwater system exceeds the natural capacity for discharge. The management challenge must therefore include the following actions:
- reducing the recharge (usually with the aid of deep-rooted perennial vegetation); and/or
- utilising the discharge (usually with salt-tolerant plants or in other industries that can use saline water); and/or
- disposing of surplus water (usually by drainage).
What is being monitored
South Australia
Responsibility
Primary Industries and Resources South Australia (PIRSA) and the Department of Water Resources (DWR) share responsibility for salinity monitoring and management in South Australia.
Mapping of land salinisation
Mapping of dryland salinity in South Australia has been completed using 1:40,000 aerial photographs. This involved mapping of individual seeps, scalds and other indicators of salt-affected land. Data have been compiled on 1:50,000 topographic maps. Data reliability is limited by lack of ground truthing. The airphoto analysis was used for South Australia's report for the NLWRA Salinity Extent and Impacts project (Barnett, 2000).
Groundwater monitoring
South Australia maintains a groundwater database, OBSWELL, administered by DWR. The system has been integrated with the corporate drillhole database SA_GEODATA. Most bores were drilled for purposes other than salinity monitoring.
A five-year project entitled 'Dryland Salinity Catchment Investigation' commenced in 1989, to establish demonstration catchments in areas of the state affected by dryland salinity. This project implemented a groundwater monitoring network in each of five key catchments / subcatchments:
- Naroonda, Kangaroo Island (16 piezometers)
- Wanilla, Lower Eyre Peninsula (30 piezometers)
- Jamestown, Mid North (17 piezometers)
- Darke Peak, Upper Eyre Peninsula (13 piezometers)
- Miniaton, York Peninsula (15 piezometers).
Barnett (2000) summarised the distribution of bores suitable for salinity monitoring in South Australia, as reproduced in Table C-5.
Table C-5: Distribution of Bores Suitable for Salinity Monitoring in South Australia.
| Region / Catchment | Number of Bores | Monitored by |
|---|---|---|
| MURRAY BASIN | ||
| Coastal Plain | 38 | DWR (Contractor) 6 mthly (Mar,Sep) |
| Upper South East | 300 | DWR (Naracoorte) 6 mthly (Mar,Sep) |
| Mallee | 30 | DWR (Naracoorte) 6 mthly (Mar,Sep) |
|
EYRE PENINSULA Wanilla Cummins Basin Darke Peak |
30 17 13 |
DWR (Crystal Brook) 6 mthly (Apr,Oct) DWR (Crystal Brook) 6 mthly (Apr,Oct) DWR (Crystal Brook) 6 mthly (Apr,Oct) |
| YORKE PENINSULA | ||
| Minlaton | 15 | DWR (Crystal Brook) 6 mthly (Apr,Oct) |
|
KANGAROO ISLAND Narroonda |
16 | Discontinued |
|
MID NORTH Jamestown |
17 | DWR (Crystal Brook) 6 mthly (May,Nov) |
| MT LOFTY RANGES | ||
| Harrogate | CSIRO | |
| Keyneton | 21 | PIRSA 2 mthly |
The regional groundwater systems of the Murray Basin are generally well monitored, with the only improvements required being in the western area between Morgan and Karoonda where a more comprehensive network is necessary to monitor the watertable rise that will increase saline groundwater inflows to the River Murray. In other regions where local or intermediate flow systems predominate, the demonstration catchment observation bores are the only monitoring sites. Although restricted in areal extent, it is thought that these networks are sufficiently indicative of regional trends that extra monitoring is not necessary (Barnett, 2000).
The spatial distribution of monitoring bores in South Australia is summarised in Table C.6. Figure C.5 shows the spread of bores with respect to local (light grey), intermediate (mid grey) and regional (dark grey) groundwater flow systems.
Table C-6: Distribution of Groundwater Monitoring Bores in Groundwater Flow Systems in South Australia
| Basin Number | Basin Name | Region Name | kmē per monitoring Bore - Local GFS | kmē per monitoring Bore - Intermediate GFS | kmē per monitoring Bore - Regional GFS | kmē per monitoring Bore - Entire Basin |
|---|---|---|---|---|---|---|
| 426 | LOWER MURRAY RIVER | LOWER MURRAY | 15 | 6 | 223 | 106 |
| 507 | BROUGHTON RIVER | NORTH ST VINCENT-SPENCER GULF | 3 | 3 | - | 31 |
| 505 | GAWLER RIVER | ADELAIDE HILLS | 0 | 150 | - | 50 |
| 414 | MALLEE | WIMMERA-MALLEE | 146 | 152 | 43 | 55 |
| 512 | EYRE PENINSULA | NORTH ST VINCENT-SPENCER GULF | 4 | 41 | 0 | 7 |
| 504 | TORRENS RIVER | ADELAIDE HILLS | - | - | 0 | 55 |
| 239 | MILLICENT COAST | MILLICENT COAST | - | - | 3 | 49 |
| 513 | KANGAROO ISLAND | NORTH ST VINCENT-SPENCER GULF | - | 6 | - | 13 |
| 1201 | GAIRDNER | GAIRDNER | 10 | 262 | - | 852 |
Figure C-5: South Australian Monitoring Bore Network
Surface water monitoring
In the early 1970s, a network of surface water monitoring was established by DWR to meet the needs of water users. Surface water monitoring involves both water quality and flow monitoring. Barnett's (2000) summary of stream data available in the state is reproduced in Table C-7.
Table C-7: Summary of Stream Data Available in South Australia.
| Region / Catchment | Monitoring Data available |
|---|---|
|
KANGAROO ISLAND Middle River |
No data |
|
MID NORTH Baroota, Bundaleer, Beetaloo |
No data |
|
Wakefield Broughton |
1 grab sample station 3 grab sample stations |
|
EYRE PENINSULA Tod River |
<6 years of continuously monitored data, 2 gauging stations only |
| MT LOFTY RANGES | |
| Angas Bremer |
4 grab sample stations, 2 continuously monitored stations |
| Finniss | 1 grab sample station |
| Marne | 1 grab sample station |
| Myponga | 1 grab sample station |
| Onkaparinga |
5 grab sample stations, 3 continuously monitored stations |
| Torrens |
4 grab sample stations, 1 continuously monitored station |
| North Para |
5 grab sample stations, 6 continuously monitored stations |
| Wakefield | 1 grab sample station |
| Broughton | 3 grab sample stations |
Jolly et al. (2000) found that statistical analysis of South Australian stream data was constrained by short-term, irregular or sparsely sampled records in some areas.
Mapping of land cover/land use
Throughout most of the state, vegetation change and clearing are not monitored routinely. The exception is the Upper South East region, where approval is required for vegetation clearance.
Land use was mapped by PIRSA in the Mount Lofty Ranges in the early 1990s. Since then, portions of the Murray-Darling Basin in South Australia have been mapped at 1:25 000 - 1:100 000 scale as part of the MDBC Landmark project. South Australia plans to map the rest of the Murray-Darling Basin component of the state using MDBC funding, and the remaining part of the state in the intensive land use zone using funding from the Bureau of Rural Sciences' land use mapping program.
Modeling of current impacts
A NLWRA study by Grear and Moyle (in prep) examined the threats to biodiversity in the agricultural regions of South Australia by intersecting biological data (vegetation associations, landcover type, threatened species, conservation tenures and wetlands) with information on depth to watertable and shallow aquifer salinity.
As part of South Australia's NLWRA report on salinity extent and impacts, Barnett (2000) intersected salinity extent and projections with agriculture and infrastructure. This information was used with economic analysis to assess the potential costs of salinity impacts on agriculture, roads and building maintenance.
Future Extent
The future extent of salinity in the Upper Southeast Region has been modeled using a digital elevation model in conjunction with groundwater trends. A 1993 Dryland Salinity Project estimated extent of dryland salinity for 2010 based on guesstimates of the percentage increase in salinity in each region. Anecdotal information from individual landholders has also been used for local indications of increases in dryland salinity, but this information has not been used on a regional scale.
Barnett (2000) extended observed groundwater trends in regional flow systems such as the Murray Basin, to estimate salinity extent in 2020 and 2050. For most other areas of South Australia, which do not have sufficiently accurate bore and topographic information for this approach, a combination of anecdotal evidence and professional judgement was used to determine percentage increase in salt affected land for 2020 and 2050.
What type of monitoring is needed 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.
Link to national overview of: What type of monitoring is needed for Australia?
Further information
- Dryland Salinity Evaluation and Monitoring Report
- South Australia Dryland Salinity Assessment 2000 report
- Australian Dryland Salinity Assessment 2000 report
- National Technical Overview Report of the State-based dryland salinity assessments
- Australian Groundwater Flow Systems Report
- Primary Industries and Resources South Australia
- National Dryland Salinity Program
- National Action Plan for Salinity and Water Quality
South Australian Dryland Salinity Assessment 2000
Link to the Map Maker to make a map using this information.
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