Saturday, 29 January 2011

Ochre Arch Farm Water Scheme - The Basics

In July 2010 our own on-farm stock and domestic water scheme was installed on a contract basis by Aquawest from Dubbo. The basic design elements are:
  • 104,000 Rhino tank near the back of the house. It has a water depth gauge that is easily visible from the kitchen window making for easy monitoring. The tank has two sources of water: bore water from the Ooma Water Scheme (See post 11 March 2010) and back-up gravity fed water from the main dam in the place. The Ooma scheme is not yet finished so we are currently filling the tank via the second option.
  • Grundfos electric water pump located in the same shed where the stand alone power supply scheme is installed. The pump was selected to pump 10,000 litres of water to the tanks at the top of the farm in 2 hours … a flow rate of about 1.5 litres per second. This is the same amount of water as we will be receiving on a daily basis from the Ooma Water scheme and is sufficient to water 2,000 sheep or 200 cattle in mid summer. The pump is located about 1 metre lower than the bottom of the Rhino tank creating what’s called a ‘flooded suction’ line. These are much better than the alternate (where the pump has to suck water up from, say, a dam) as it then means that the only time the pump is likely to run dry is if the tank runs dry.
  • A 22,730 litre balance tank located about 4 fifths of the way up the farm and two 22,730 litre tanks at the top of the farm. One of the top tanks acts as a reserve as does the balance tank depending on stock location. The top tanks are just over 100 metres in elevation above the house creating water pressure at the pump of 1040 kilopascals. Each tank has float valves installed, cutting off the water flow when they are full.
  • Controls on the pump such that it auto starts at 8.30 am and runs until the balance and top tanks are full. There is a water pressure monitoring mechanism in place and when the pressure reaches 1200 kilopascals (which can only be reached once the tanks and full and the float valves stop the flow) the pump stops.
  • Just less than 5 km of 63 mm polythene pipe and 16 water hydrants each fitted with 1.5 inch gate valves and male cam lock fittings. The hydrants have been positioned to allow for further subdivision of paddocks should this prove appropriate. A water flow rate to most of the hydrants is in excess of 2 litres per second. There is one main line of pipe and several spur lines. In essence water is pumped to the 3 tanks up the farm and flows to the appropriate hydrant via gravity.
  • 3 portable aluminium water troughs and connecting ‘safety’ hoses

We now have water accessible in every one of our 21 paddocks and remain extremely grateful to Phil Wells from Cootamundra for his awesome knowledge and skill in assisting us with the design.

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