Ord Land and Water (OLW) received funding under the National Action Plan for Salinity and Water Quality to implement a project to develop best management practices for soluble pesticide use in the Ord River Irrigation Area (ORIA).
This project builds on previous work to assist development and adoption of Best Management Practices to reduce the movement off site of agricultural pesticides in the ORIA. Past work developed guidelines across a broad range of chemicals; this work assisted in reducing significantly traces of insoluble chemicals found off farm. However, there has not been the same success with soluble chemicals currently in use.
By design, soluble chemicals move easily with water and therefore are prone to movement off farm with irrigation and rain events. Reasons for this include:
The soluble nature of the chemicals,
Their efficacy being reliant on timely water incorporation
Management difficulties encountered by growers in the broader scale adoption of guidelines for use with soluble pesticides
In order to gain a better understanding of the characteristics of soluble chemicals in irrigation water, Ord Land and Water (OLW) devised a trial watering strategy. It was proposed to test differences in Atrazine concentrations, as an indicator soluble pesticide, over several watering time lags. Atrazine is a triazine herbicide which is reactive in the water column.
The project will:
- Test the efficacy of a soluble pesticide (atrazine) over a number of different application to irrigation time lags to determine an irrigation window that provides efficient control whilst minimising the risk of off site movement of the pesticide.
- Measure and compare pesticide concentration levels moving off treatment areas over different application to irrigation time lags in the initial and a further two subsequent irrigations.
Soluble Pesticide Report [850kb pdf] [download]
To support the long-term sustainability of irrigated agriculture in the Ord through the development of guidelines with the agricultural industry for Minimising the off-site impacts of pesticides in the Ord River Irrigation Area.
The major aims of the project were to:
- Carry out a risk assessment and identify pesticides of most concern in terms of threat to the riverine ecosystem health in the Ord River.
- Conduct monitoring of pesticide residues in tail waters.
- Enhance the natural attenuation of pesticides prior to the release of drainage water.
- Develop with industry guidelines for better on-farm management of pesticides to minimise off-site impact on surface and groundwater.
Funding and support for the project has come from the following organisations -
- ORIA Farmers
- Department of Transport and Regional Services
- Horticulture Australia Limited
Risk assessment and monitoring
The risk assessment for surface water and ground water of the ORIA involved gathering of pesticide use data for selected farm production systems including information on soil and climatic conditions, hydrological conditions and an integration of pesticide loading, toxicity and transport parameters.
Key factors included agronomic practices and how they related to pesticide migration, with particular reference to water management practices. The Risk Assessment provides a list of compounds that represent the greatest risk to the environment and therefore were the targets of focused monitoring and management.
The risk assessment was followed by limited targeted monitoring for the ‘high-risk’ pesticides that have been identified. The timing of this monitoring coincided with pesticide application. This helped to validate the assessment by confirming which pesticides and in what quantities were likely to leave the farms and their pathways of migration.
Risk Assesment[850kb pdf] [download]Stage 2
Monitoring and experimentation
The initial phase of this stage of the project was aimed at developing a better understanding of pesticide migration from farms. To achieve this, samples of tail-water were obtained during the first irrigation after pesticide application to understand when and in what quantities pesticides were leaving the paddock.
This was followed by experiments to test several on-farm management options that would become the basis form further work.
A three-pronged approach was developed and implemented in consultation with the growers. The experiments for developing on-farm management options were selected on their practicality and as likely to be adopted by the irrigation community.
The approach and experiments planned included:
(i) Minimise residue moving off farm: Options selected included using polyacrylamide (PAM) as a flocculant, incorporating pesticides mechanically into the soil and targeting pesticide contact away from water furrows.
(ii) Enhanced natural degradation: This entailed enhancing natural degradation of the pesticide through grassed tail water ditches, however it was realised that water flows off farm were substantial and backing up water would cause problems with crop waterlogging. Therefore this line of investigation was halted after grower consultation.
(iii) Removal of residues from drainage water: Novel cost-effective sorbents for removal of pesticides from water are being developed by CSIRO and other agencies. Laboratory tests appeared promising. Some preliminary trials were done using these materials, however they were found to be impractical under the conditions.
In addition, experiments were carried out to test the commercially available rapid screening kits for pesticide residues under ORIA conditions, for selected pesticides such as atrazine.Stage 3
Data analysis and development of Guidelines for on-farm management
In this stage of the project results from the first two stages were analysed in order to develop guidelines to minimise off-site migration of pesticides in ORIA.
Additionally training in the use of kits tested in Stage 2 was provided to stakeholders providing them with simple techniques to detect residues moving off-farm providing early warning and facilitating better management.Outputs
- A better understanding and awareness of the impact of pesticide residues on ecosystem health in the ORIA and associated riverine ecosystems.
- A list of pesticides considered ‘high risk’ using present management practices.
- Identification of on-farm management approaches for minimising the off-site migration of pesticides and enhancing their natural breakdown on farm and in drainage water.
- Practical guidelines for better management of pesticides in the ORIA.
Validation of simple residue analysis kits and training of industry users.
This is a cooperative project with a number of partners working locally to meet the needs of the present irrigated agricultural industry in the ORIA.
Funding and Project Partners
- ORIA Farmers
- Department of Transport and Regional Services
- Horticulture Australia Ltd
- National Action Plan for Salinity and Water Quality
- National Heritage Trust
- Department of Environment
- Department of Agriculture Western Australia
- Ord Bonaparte Program
This work was undertaken jointly by ORIA farmers, the Department of Agriculture and Ord Land and Water in 2004 in an attempt to develop water efficiency guidelines. This work was continued and expanded into the projct 'Demonstrating Sustainable Farming Systems' by the Depatment of Agriculture in 2005.
This project builds on earlier work that has identified suitable existing artificial wetlands for assessment of their capacity to act as a ‘filtering system’ to remove contaminants in irrigation drainage water, and preliminary monitoring for chemical and nutrient attenuation within the system. This project will monitor a production season and the following wet season for movement of contaminants into and out of the artificial wetland system. Information from this project will be used to develop recommendations of the feasibility of using artificial wetlands as a management tool to reduce the impact of contaminants in irrigation drainage water on the Lower Ord River.
Artificial Wetlands Report [2.9mb pdf] [download]
The Ord River Irrigation Area (ORIA) was built in the early 1960’s utilising practices that did not consider many of the environmental issues that are relevant to present day thinking and values. Since that time much has been done in an attempt to improve on the design and management of irrigation systems to address water quality, water efficiency and ground water.
In conjunction with the improvement of irrigation systems has come the need to allocate water for environmental, social and other economic uses. ‘Water Allocation’ came as a result of the establishment by the Council of Australian Governments (COAG) in 1994 of a national Water Reform Framework to address the need for the sustainable management of Australia's water resources. The framework was formulated in response to considerable concern about the state of many of Australia's river systems and a recognition that an important part of the solution lay in significant policy and institutional change.
The design of the ORIA as a ‘flow-through’ flood irrigation system makes the management of water efficiently difficult. In addition the current system design is prone to facilitating the transportation of silt, nutrients and pesticides off farm into the drainage system and the Ord and Dunham Rivers.
Within the ORIA there is a need to increase irrigation efficiency levels and reduce off farm movement of silt, nutrients and pesticides. This has come from a regulatory perspective where water quality and efficiency targets will be a part of the licensing agreement of the Ord Irrigation Cooperative (OIC). In addition present community expectations expect that farm management practices are developed to reduce the impacts of agriculture on riverine systems.
With the release of the Ord Land and Water Management Plan 2000 came a commitment from industry and the community to reduce waste moving off farm and increase on-farm and system water efficiency. Goals that specifically address these issues are-
- To improve irrigation management to achieve 65% average annual water use efficiency on all irrigation farms within five years.
- To improve irrigation infrastructure and management to achieve a water delivery efficiency of 75% within five years.
- To reduce the load of chemical contamination in tailwater by 40% within five years.
- To reduce the load of nutrient contamination in tailwater by 40% within five years.
- To reduce sediment loads in tailwater by 40% within five years.
The role of Ord Land and Water (OLW) is to encourage and assist where able in the implementation of the plan and the achievement of the goals within.
Scope and Purpose
Currently there are several projects and initiatives within the ORIA that are addressing surface water quality and water efficiency managed by organisations such as Department of Agriculture, Ord Irrigation Cooperative, Ord Land and Water and the Water and Rivers Commission. These are dealing with pesticide runoff, monitoring and on-farm water efficiencies.
In addition to this, two concepts that industry and the community have flagged to be further explored are –
- Increasing water efficiency within the ORIA by pumping wastewater from the drains back into supply channels for irrigation.
- Developing wetlands at the end of drainage systems to remove silt and pollutants from drainage water prior to it entering the riverine environment.
In order to test the validity of these two concepts OLW secured Envirofund funding to gather for further use specific information on the present channel and drainage systems.
The purpose of this report is to –
Identify where tailwater can be re-used from within the drainage systems for further on-farm use at a system level.
- Perform some limited monitoring of the effectiveness of a wetlands system for containing contaminants.
- Examine what and how wildlife utilises the current drainage system.
- Explore some concepts relating to infrastructure required for waterr e-use.
It is understood that currently the Ord irrigation Cooperative (OIC) is unable to return used water to the system’s supply channels. This is due to potential quality issues that are associated locally with used water. They include the potential for unwanted nutrients and pesticides to be transported off farm and affect crops down stream.
The OIC is currently investigating ways that this issue can be overcome including actively seeking with OLW reductions in nutrients and pesticides leaving the farms. If this can be achieved re-use will become a viable option to ensure water efficiency commitments are met.
Summary and Recommendations
This study concludes that there is significant potential for the re-use of tailwater at a system level within the ORIA. This report identifies a total of six points within the drainage system that could potentially become pump out points for water to be re-used both within the existing irrigation system and on areas yet to be developed.
Of the sites selected two have the capacity to contribute to the irrigation requirements of large areas of existing farmland (2967ha). Prior to this happening however the issue of the quality of re-use water in terms of potential pesticide and nutrient levels would need to be dealt with by the Ord Irrigation Cooperative and the local agricultural industry.
The other four remaining sites would have the potential to supply some water in the event that new irrigated farmland was developed close to these sites.
Waste Water Re-use Study (1047kb pdf] [download]