The Narromine Irrigation District is being modernised under an agreement between the landholders, the NSW Government, and the Federal Government. The area serviced by channels has been drastically reduced so the supply from the McQuarrie River can be matched more reliably to the sustainable yield of the catchment. The leakiest of the remaining channels are being rubber lined to further improve water transmission efficiency.
Modernisation usually includes a new pipeline to deliver small quantities of vital stock and domestic water to the whole district. In years when there was no irrigation water, the dry channels were wetted up once or twice a year to feed on-farm dams for stock watering and homestead use. Typically only 5% to 20% of water diverted from the river gets to be used, so a pipeline that feeds small tanks and troughs is a major improvement for water security, quality and efficiency.
Narromine Irrigation Board of Management
obtained their funding of $8,300,000 in June 2012 under PIIOP (Private Irrigation Infrastructure Operators Program) and completed the construction in September 2014. Construction was completed ahead of schedule and under budget.
HydroPlan won the tender for design, documentation and construction services of Narromine’s 186 km pipeline to serve 60 outlets. The previous concepts were changed substantially by HydroPlan to reduce capital costs and add value. Water is lifted from the river to holding tanks then pumped through filters to the network. Three tenders for construction were received within a few percentage points of each other, reportedly because the documentation was clear and risks were well allocated. HydroPlan provided on-site construction services during installation.
Favourable comparisons have been drawn between HydroPlan’s “DTC” delivery method (Design Then Construct) compared to a “D&C” (Design and Construct) delivery method. Through construction efficiency and appropriate allocation of risks, DTC achieved proven savings of 20% over a very similar project delivered by D&C. In addition to lower overall costs, better features like web-based monitoring of outlets were included in HydroPlan’s design. It was evident that the benefit to cost ratio of HydroPlan’s specialised independent consulting services was 5 to 1.
The scheme was officially opened 8 April 2016 when the benefits to the local community brought by funding and change were well recognised and highly appreciated. The champions of the scheme were properly feted and congratulated for their huge contributions, including Col Hamilton for the stock and domestic scheme. Allocations for irrigation had been 6% 2% 7% for the last 3 years so efficient delivery of stock & domestic water from the pipeline water has been a boon. It was described as "the jewel in the crown" by the Chairman Mark Dugan, and he described how much joy and refuge their family has had during these dry years from the large well-watered garden around their homestead.