Sunlands irrigation scheme headworks upgrading, hydraulics of the water distribution system.

Abstract

High salinity levels on the River Murray have caused damage to irrigated crops due to salt toxicity. The toxic effects can be mitigated by irrigating at night only. On Sunlands irrigation scheme (700 hectares) the pumping and distribution system were upgraded to enable all watering to be completed at night. Design of the new pipelines is discussed, including the mathematical modelling of the hydraulics of the distribution system. The upgrading works are described. Pressure testing of the completed pipelines resulted in a number of breakages possibly influenced by pressure transients occurring after an initial break had occurred. Differences in pump discharge pressures at the pump station indicated some unevenness in pressure losses across the new manifold. Measured pipe friction coefficients were similar to published figures for new pipes, but for old pipework much higher coefficients in some cases, but not in others. (A)