Ord Irrigation Area hydrology
The Ord Irrigation Area is a large, highly productive agricultural area near Kununurra, Western Australia. The farms in the area receive water from Lake Argyle via a network of storages and channels.
Major components of the water supply for the Ord Irrigation Area – the Kununurra Diversion Dam and Lake Argyle – were completed between 1963 and 1972. The initial capacity of Lake Argyle was 5,641 GL. This was increased to 10,763 GL in 1996. As well as providing irrigation water, Lake Argyle contributes to local mining, fishing and tourism industries. A hydropower station generates electricity for local towns and industries.
Irrigation supply infrastructure has been progressively constructed since the 1970’s to allow development of irrigation farms. By 2010, most of the Ivanhoe Valley and Packsaddle Plains areas were developed, giving a total of 16,500 ha of irrigated land.
The Ord Irrigation Area Stage II expansion allowed development of a further 7,400 hectares on the Goomig (Weaber Plain) area. Further development is planned for the Knox Plain and Ord (West Bank) areas.
Crops grown include chickpeas, chia, red grapefruit, mangoes, melons, hybrid seeds and sandalwood.
More details of the Lake Argyle and the Ord Irrigation Area are given at the Lake Argyle website.
Government of Western Australia - LandCorp
What we did
Robin worked on hydrology and flood modelling for the civil design and on environmental approval aspects of the project.
The Phase II civil works involved construction of a significant amount of drainage infrastructure for stormwater management, a levee to protect farmland from floodwaters in Border Creek, the modification of Weaber Plains Road, and provision for farm development.
Environmental approvals were also required for the project. A number of studies were undertaken to demonstrate that potential environmental impacts of the development were adequately controlled. Monitoring and management plans were also developed.
Robin developed a series of hydrologic and hydraulic models to help inform the design and the environmental approvals process. This included one and two-dimensional hydraulic modelling to predict flow conditions and flood levels and tracer modelling to predict dispersion and movement of pollutants.
The infrastructure allowed the release of up to 13,400 ha of new irrigated farmland. Stage II expansion has proceeded in two phases with a total project value of $322 million. Some 41 km of new roads, 42 km of irrigation channel, 86 km of drains and 34 km of flood levees have been constructed.
The project delivered sustainable growth and social benefits for the local community.
Key deliverables from the modelling and hydrology aspects of the project included timely provision of information to the project management, design and environmental approvals teams. Model results and interpretation were included in a design reports and incorporated into approvals and design documentation.
The modelling played an important role in the design process, and was used to streamline and optimise various design elements (such as drain size) and to quantify performance under a range of scenarios.