Event highlights importance of fencing-off farm dams

THE huge turn-out at South Gippsland Landcare Network’s field day on May 18 revealed the high level of interest in the economic and environmental impacts of fencing-off farm dams.

Fifty people attended the event that was funded by the Victoria Drought Resilience and Adoption Hub and held on Jillian Staton and Bruce Whittaker’s beef farm at Cape Liptrap. 

Expert speakers included agricultural economist Professor Bill Malcolm, aquatic ecologist Dr Ty Matthews and large animal vet Dr Phil Poulton. 

Jillian described how she and husband Bruce fenced-off a centrally located spring-fed dam six years ago to pipe water to troughs across their home farm. 

In her opinion, the investment (which included replacing a faulty pump) has already paid for itself by giving them flexibility and the ability to graze the entire property more effectively. The improvement in pasture quality was evident in both the before and after aerial photos included in her presentation and while walking on the property after lunch.

Professor Bill Malcolm urged participants to distinguish between economic and financial factors when making decisions as many outcomes cannot be ascribed a monetary value. Given the current lack of hard data proving a link between clean water and increased meat and milk production, he said that an economic decision to fence off a farm dam should be made in the context of the farm business as a whole. It should consider the dam as an asset with a finite life (he suggested 40 years for a new dam) and compare the likely returns if the money was invested elsewhere.

Dr Phil Poulton considered the economic impacts of fencing off farm dams from a risk management perspective. He said that providing stock with clean water from fenced off dams virtually eliminates the risk of stock and production losses caused by diseases like Salmonella and Leptospirosis and toxic blue-green algae. It also prevents animals dying or getting injured from drowning or being stuck in mud. 

On the flip-side, he reminded participants of the need to monitor troughs regularly, especially in hot weather, as lack of drinking water can be catastrophic.

Dr Ty Matthews said that despite there being around 450,000 farm dams in Victoria, little research has been done into their ecological values. A recent project he has been involved in, however, indicates that fenced-off farm dams are providing refuge for aquatic fauna that are struggling to survive due to habitat loss caused by climate change and human activity. He believes that farm dams could play an important conservation role in the future, particularly in respect of threatened native frog and fish species.

Later, on the farm walk, Ty took water samples from the fenced-off dam, a dam with a newly-constructed restricted access point, and a fully open dam. The first sample demonstrated the high biodiversity benefits of excluding stock from dams. As well as being exceptionally clear, it contained highly sensitive macro-invertebrates (including mayflies) and a huge tadpole which was possibly a banjo frog. In contrast, the other samples had high turbidity and contained macro-invertebrates that have a high tolerance for poor water quality.

Another field day will be held in a year’s time by which stage the restricted access dam will have refilled and been in use for some time. Its value in preventing erosion, providing cleaner water for stock and habitat for wildlife will be discussed along with any lessons learned from a farming perspective.

SGLN will be preparing resources on fencing-off farm dams that will be available on its website (www.sgln.net.au). Contact cassie@sgln.net.au for more details.