Ord River Irrigation Scheme - Stage 2

The M2 Channel Supply Area comprises the Weaber, Keep River and Knox Creek Plains which are black soil plains. These plains are suitable for broad acre cropping such as sugar cane, cotton or leuceana. The area covered straddles the NT/WA border. Construction of the M2 channel is necessary for the establishment of irrigation in this area.

The development of the M2 Channel Supply Area involves the provision of the necessary infrastructure to allow for irrigation of approximately 50,000 ha of black soil plains.

The area will be serviced via a proposed supply channel known as the M2. The necessary infrastructure includes:

• the main M2 supply channel
• additional supply channels
• on route storage
• hillside drainage
• farm drainage
• tail water storage
• pumping stations
• main drains
• flood levees
• access roads
• associated infrastructure

The development also involves the preparation of the land for irrigation which includes:

• clearing
• levelling
• survey
• soil preparation on farm channels and banks
• fencing
• buildings, roads etc.

The design of the main channels has been based on providing the water requirements of 3.89 megalitres/hectare/month after allowing for an efficiency factor of 80% in the main channels and in the field. Stormwater drains have been designed on a 5-year, 48-hour storm to ensure that on -farm ponding is limited to forty-eight hours and 0.5m depth. Tailwater drain capacities have been based on 33% of applied irrigation water. The capacity will be adequate to ensure that irrigation tailwater is able to be maintained on the farming area and returned to the supply system. In addition this could allow the initial portion of runoff from storms to be harvested. Hillside drains are provided to prevent waters from hillsides entering the irrigated areas and causing localised flooding. Levee banks are proposed to protect farming areas from river flood waters.