INSTALLING a storage dam was one of the best moves Maffra dairy farmer Alex McArthur ever made.
The sheep farmer-turned-dairy producer put in a 70-megalitre dam almost three years ago to build security for his 163ha property, which has a low allocation of high-reliability water.
Alex with parents Andrew and Lou bought their current Maffra property five years ago and quickly switched from sheep to dairy. The McArthurs wanted to improve the irrigation on the new block, mainly wild flood irrigation, and install central pivots and lateral move systems.
"The proposal was if we were to put in pivots we needed somewhere to store the water and have a bit of flexibility," Alex said.
Their allocation of high-reliability water a season is about 350ML, and Alex estimated they were about 70ML, or about two irrigations, short each year.
He said the dam's main benefit was the flexibility to capture spill water from the Glenmaggie Weir, which represents a major saving, as the difference between allocated and spill water is about $60/ML.
The spill water can be stored and it doesn't come out of his his annual water entitlement. Plus with plenty of reserves he does not have to worry about the time it takes to get water from his local supplier.
"Not only is it cheap, but it's not coming off my water right, I can effectively capture or harvest water when no one else wants it," Alex said.
"If I start irrigating now and I need more water I can ring Southern Rural Water and it doesn't matter if it takes 15 days."
The dam, which cost $70,000, takes up 1ha and was built in an unproductive gully on the farm.
The soil was tested for suitability before construction, meaning 90 per cent of the 4.8m wall came from back-fill.
At its deepest point the dam is 6m when full.
Department of Primary Industries southern irrigation manager Gavin Lamb said not all soil would be suitable to build a dam and that saline water tables could be a problem in many areas. "Doing an analysis of the soil is very important and you need to (go) 1m deeper than you think you need," he said.
Gavin said producers should consider their annual water use limits and do an economic analysis before opting for a storage dam.