Innovative dairy irrigation solution
NSW Northern Rivers dairy farmers Rob and Sue Harnett have come up with an innovative way to secure an alternative water source and reduce their dependence on low flows from their local creek.
“When we were developing an irrigation and drainage management plan for our farm, we identified how vulnerable we were to unreliable access to the creek for irrigation,” Rob said.
“On the north coast, we usually get good late summer and autumn rainfall but suffer a traditionally dry spring and early summer when pasture growth is critical.
“It means more irrigation water is required at exactly the same time that river flows are falling,” he said.
“We needed an alternative water source and the two available were groundwater and town stormwater run-off.”
The Harnetts’ farm is on the outskirts of the Burringbar township and stormwater from the town flows through their property and into the nearby Burringbar Creek.
“We decided to build a storage dam that picks up stormwater drainage flowing from the Burringbar township,” Rob said.
“It gives us improved water security and means urban run-off doesn’t enter the watercourse any more, benefiting the environment.”
The Harnetts, who run 80 milking cows and irrigate 26 hectares, have also constructed a low yield bore with submersible pump to help replenish the storage.
“It’s all about reducing our reliance on Burringbar Creek which also reduces stress on the river – especially at the environmentally- sensitive low flow periods,” he said.
Rob said constructing the dam in what was a messy, swampy area had also resulted in improved water quality.
“Our herd health has improved, especially with less mastitis from cows in the swampy area and we expect less risk from botulism.”
The Harnetts both say developing an irrigation and drainage management plan (IDMP) for their farm was a critical step in improving their water security.
“Initially we were a bit sceptical about its value, but now we feel we couldn’t operate without it,” Sue said.
“It was important in managing the development process and is regularly used for irrigation and business management.”
The irrigation developments at the Harnetts have been supported by the Northern Rivers Catchment Management Authority (CMA), in conjunction with NSW Department of Primary Industries (DPI) because they meet the CAP objective to protect the riverine environment, by reducing stress on the rivers.
Organiser of the project, NSW DPI irrigation officer Gary Creighton said irrigators need to adapt in order to maintain their businesses with lower than normal flows in the rivers and to achieve the environmental objectives of the water plans.
“This CMA-DPI project, called Irrigators – caring for the rivers, is demonstrating to irrigators ways to meet these challenges,” Gary said.
NSW DPI irrigation officer Richard Swinton said the two basic options that are available to irrigators are to increase irrigation efficiency as much as possible and to reduce dependence on low flows by seeking alternate water supplies or by extracting when flows are high.
“Increasing irrigation efficiency means less water is extracted for the same plant demand – which also reduces operating costs for irrigators.
“Seeking alternate water supplies means looking for groundwater, or water from an opportunity supply such as town sewerage or stormwater system.
“It can also be done by extracting when river flows are high and storing the water in a dam for use when river flows are low and crop demand is high.”
Contact Gary Creighton, Grafton, (02) 6640 1600, or Richard Swinton, Wollongbar, (02) 6626 1200.