Improving the performance of basin (contour) irrigation layouts
Contoured land can present challenges to water use efficiency
Summary
This project aims to improve the water productivity and cropping flexibility of contour irrigation systems so that they can be used to achieve higher yields for a wider range of crops (other than rice) with reduced operating and environmental costs.
Field data will be used to validate a hydraulic model. In consultation with irrigation practitioners and designers, this model will be used to develop an optimum design for contour irrigation systems.
Objectives
Specific objectives:
- Determine the current state of knowledge, practice and tools for basin irrigation system design and performance evaluation.
- Develop clear recommendations for “best practice” basin irrigation system design(s) based on hydraulic and economic performance.
- Develop tools and techniques that can be used to evaluate basin irrigation system performance.
- Train irrigation surveyors and designers in the use of recommended design software and irrigation system evaluation tools.
A staged project is proposed by the two project partners (i.e. NSW Department of Primary Industries (NSW DPI) and National Centre for Engineering in Agriculture (NCEA).
Stage 1: A scoping study will be conducted first by both project partners to determine the current state of knowledge and practices and to identify 'gaps'. A 'best bet' hydraulic model will be identified at this Stage, along with the tools and techniques to be used for evaluating basin irrigation performance.
Stage 2: NSW DPI will use the tools and techniques identified in Stage 1 in replicated field trials to measure the contribution of individual design elements (e.g. toe furrow size and shape, slope, roughness, in-field drainage) to improving watering times and application uniformity. The hydraulic performance of a range of existing “new” basin irrigation designs will also be measured and data (agronomic, machinery performance and labour) will be collected so that economic performance can be assessed. At the same time, the tools and techniques being used to evaluate basin irrigation performance will be assessed with a view to making recommendations for future commercial applications.
Stage 3: NCEA staff will develop the “best bet” hydraulic model identified in the Scoping Study. The data produced by NSW DPI in Stage 2 will be used to validate the hydraulic model and a Desktop Study will be conducted by NCEA to evaluate the hydraulic and economic performance of a range of basin irrigation systems.
The main benefits from this research are anticipated to be:
- reduced groundwater accessions; and
- improved water productivity.
If contour irrigation systems can be designed with both improved hydraulic performance and improved operational efficiency, then additional flow-on benefits are expected if farmers adopt controlled traffic (tram-lining) and precision farming technologies. These benefits include:
- a reduction in machinery induced soil compaction leading to improved infiltration, soil water storage and aeration resulting in higher yields and greater water productivity;
- the creation of 'tram-lines' has the potential to reduce tractor horsepower requirements and increase the timeliness of operations as a result of earlier trafficability after rainfall events;
- increased machinery efficiency will reduce fuel consumption and labour costs as well as greenhouse gas emissions;
- eliminating unsown areas in check banks and headlands will reduce weed seed burden, leading to production and environmental benefits through lower labour and herbicide use; and
- reduced risk of waterlogging leading to increased crop options (including oilseeds and pulses) and attendant economic, soil improvement and crop rotation benefits.
Collaborating agencies
Cooperative Research Centre for Irrigation Futures
Funding agencies
NSW DPI
Murray Irrigation Limited
Leader
Sam North
Deniliquin