Irrigation and drainage improvements

From settlement of South Australia until WW1, most stone fruit production was located in the Barossa and Clare Valleys, Adelaide Hills and Adelaide Plains. Orchardists in these districts were highly reliant on natural rainfall. Improvements in irrigation technology post WW1 allowed gradual development of irrigation for orchards. The use of irrigation accelerated further post WW2 with the move away from flood irrigation to sprinkler systems, and subsequently drippers and under tree sprinklers.

The most significant development of irrigation technology occurred in Riverland districts.

The original Riverland Government Irrigation Districts used a General/Special irrigation allocation system applied mainly as flood irrigation. This generally involved five or six irrigations each irrigation season which the grower had to pay for in his rates whether they took them or not. These were heavy irrigations that applied up to six inches (150 mm) of water to a block. Spaced between the “general” irrigations were “special” irrigations which the grower had to elect to take and for which he paid separately. The dates for the “general” irrigations were set each season by a local irrigation board made up of local growers and the District Officer from the Irrigation Section of the Lands Department.

Even application of water across a field was difficult, especially on sandy soils in the ‘highland’ areas along the River Murray. Uneven and excess water application frequently occurred, resulting in rising water tables and surface salinisation. Serious salinity problems killed trees, and required abandonment of lower lying land or installation of subsurface drains.

Sprinkler irrigation was used increasingly from the 1950s and gave more uniform water application on the sandier, lighter textured soils. Loxton Irrigation Area, constructed in the late 1940s, was the first Riverland district to be partially pipelined and use fixed overhead sprinklers on sandier soils. In the 1960s, Department of Agriculture staff Bill Harris and Max Till, lead work on pressure testing and other techniques to improve efficiency of sprinkler irrigation systems.

From around 1970 drip and micro-irrigation systems were developed, led by the plastics industries with factories based in Adelaide. These systems offered potential for greater precision in water application. The plastics industry also introduced PVC pipe systems that could be easily installed more cheaply.

Collaboration between equipment manufacturers and the irrigation team at Loxton Research Centre (under the leadership of Irrigation Extension Officer, Keith Watson) developed a comprehensive array of initiatives that improved irrigation efficiency and water management. This collaboration also led to establishment of the Irrigated Crop Management Service.

For more information on development of improved Riverland irrigation systems.