Changing Irrigation Systems and Management in the Harvey Irrigation Area
Project DAW45 was conducted over the Harvey irrigation seasons 2003-04 and 2004-05. Seasons in Harvey are relatively consistent extending usually from October to May.
The project was conducted in two stages to ensure adequate consideration of the issues and planning for the case study, along with integration with other related research work, prior to the commencement of the case study.
As a result, Stage 1 involved:
- working with the project partners, including NPSI to develop the project plan;
- locating the centre pivot on a case study site on the Hanks’ property and bringing it up to farm operational standards;
- selecting a surface irrigation site for the case study (the monitor bay for the site was changed after independent assessment in 2004-05);
- establishing working relationships between the partners;
- establishing links with the Australia Dairy project ‘DairyCatch’;
- examining research and experiences elsewhere in Australia on changing irrigation systems and the relative merits of surface versus centre pivot irrigation;
- surveying irrigators as to their level of knowledge and interest in changing irrigation systems; and
- considering the aspects of farm planning and decision support necessary for farmers to make informed decisions.
The output was the Stage 1 Report of February 2004.
Stage 2 of the project involved the actual case study conducted over the two irrigation seasons, with the first season’s results and plans for the second season being presented as a Progress Report in December 2004.
An economic analysis was carried out on this project, looking at the following benefits: productivity and profitability; environmental; and social.
- Bring innovation to irrigation systems and agronomy on-farm in the South West Irrigation Area that will increase water use efficiency and farm productivity, and reduce ecological impacts through factors such as water and nutrient seepage to the water table, downstream nutrient run-off and soil structural problems.
- Demonstrate and document a model of integrated R&D and knowledge management through a strategic alliance that is capable of achieving sustainable irrigation on-farm and extended across the broader farming community and irrigation area with lessons.
- Develop a learning and information exchange strategy to provide opportunities for SWIA irrigators to learn from other Australian irrigation areas and industries.
- Demonstrate the energy efficiencies and overall energy balance of a pressurised gravity-fed piped system of irrigation water delivery.
The Project has demonstrated, in a two-year on-farm case study during 2003-04 and 2004-05, that water savings can be achieved along with increased pasture production and better quality pasture through centre pivot irrigation. Associated with the economic benefits were minimal water and nutrient run-off thereby contributing to the sustainability of irrigation in the Harvey Water Irrigation Area.
The essence of Project DAW45 evolved from the initial idea of an on-farm trial comparing centre pivot and surface irrigation; to a demonstration case study of the comparative performance of pivot and surface irrigation; to recognition that the greatest benefits will accrue to farmers and the HWIA by improving the performance of both centre pivot and existing surface irrigation.