A whole farm approach to water
A wagon-wheel paddock design turned out to be an all-round success when Tahara farmer Bill Stonnill upgraded his water system. This design simplified the system that Bill needed to both secure his water supply and maximise the property's grazing potential.
Although the 260-hectare property, which is fenced to land type, comprises nearly 40 paddocks, there are just seven watering points all of which are supplied from the permanent river at the bottom of the property.
Backgrounding agisted dairy heifers and/or beef cattle has been the main enterprise. Usually stock come on in the autumn and the last of the cattle are gone by the end of January before declining pasture quality impacts upon
the condition of the cattle.
Using an air compressor located at the house, water is pumped uphill to two header tanks at 30 metres and 60 metres and gravity-fed to the seven concrete troughs.
As long as the river continues to flow, the system is more than capable of watering the property's maximum carrying capacity of 4000-5000 DSE, or about 500 cattle.
The Stonnills' system cost about $10,000 to install. This included the troughs, pump, air compressor and about six kilometres of water pipes and air lines, with the use of another two kilometres of existing water piping.
Bill, who works part-time with the department delivering whole farm planning, Environmental Best Management Practice and E-farmer, described the benefits as enormous.
"As well as securing a reasonably bullet-proof watering system, the system enabled us to fence off the river, giving better stock control and reducing erosion," Mr Stonnill said. "It has provided the flexibility to implement a system of rotational grazing that takes into account variations in land type and seasonal conditions."
"It is also helping us achieve our goal of 100 per cent pasture cover. Our perennial grass health is improving and the biodiversity of our pasture species is also increasing."
Ideally, each paddock receives no more than three days continuous grazing followed by at least 60 days rest.
In dry conditions, the rest period may exceed 120 days. "By managing the grazing so that each paddock gets a long rest, we're seeing much more growth. It's also favouring the deeper-rooted perennials, so we're maximising our rain water and reducing run-off."
Bill said he would not have been able to implement the system if he had been unable to distribute water efficiently and cheaply around the property.
"When we bought the property in 2005 there were two catchment dams at the top of the property and the stock had free range to get into the river.
"There's been so little run-off since then that we'd have been struggling if we'd had to rely on the dams and by eliminating stock from the water course, we have started to reverse the negative effects the cattle were having on the river banks and the water quality. The revegetation of the banks is already showing improvement."
Bill's starting point was to work out the property's maximum carrying capacity (600 head) and design a system to deliver sufficient water to meet peak summer demand of 45 litres per day. He was also keen to ensure a high flow rate of more than two litres per second delivered to the troughs to prevent stock emptying them and becoming stressed.
Another benefit of troughs is that water quality is much higher than if stock have direct access to dams. "They foul the dams up pretty quickly if they're allowed in, especially as our mobs are currently up to 200 head." The system also had to be capable of pumping the required amount of water uphill to a maximum head of 80m.
The only problem was that mains power was only available at the house, which is located at the very top of the property. Bill considered a few different options, including solar, but in the end decided that because of the heights and volumes involved, an Airwell pump operated via an air compressor should be installed at the house.
"We worked out that it was going to be cheaper to operate an air compressor at the mains power source than to try and install some type of power source at the river. Solar could have been an alternative, but I'm happy with our decision."
Water is pumped to the storage tanks located 30 meters and 60 meters up the hill and is gravity-fed to each trough using two inch piping which narrows to 1.5 inch at the floats. The pump is capable of delivering 1125 litres per hour, or around 27,000 litres per day, to the top storage tank. The storage tanks have dual float valves which allow the pump to switch off when the tanks are full and the system is pressurised.
Each trough contains 600 litres and is capable of watering seven or eight cattle at any one time. Bill originally used a mixture of poly and concrete troughs but is switching them all to concrete after experiencing some problems with the floats. The air well pump uses a small solar panel sited at the river. After some initial problems with the positioning of this solar panel to ensure sufficient charge, the system has been operating smoothly since its installation more than four years ago.
"It is a simple watering system which complements the operation perfectly. With the agistment stock we're running, it's a very easy farm to run and takes very little time to run it. "You can't ask for more than that."