The Dumbéa golf course covers an area of nearly 65 hectares and is one of the three golf courses in New Caledonia. 5 of its greens are currently irrigated thanks to a prototype of Aqualone buried underground. This facility uses a prototype that we are perfecting and will be producing during the year 2018 for golf courses and green spaces. This document presents the installation of Aqualone and an appendix presents the work done for the automation of the pumping station.
SETTING UP AQUALONE
The Aqualone must be installed under the golf course sprinklers to be placed in the same conditions as the lawn of the green. This Aqualone will control the opening of the valve that controls the irrigation of the green thanks to a hydraulic control. You don’t need electricity. The old solenoid valves are thus replaced by our solenoid valves. Hydrovalves.
A slot is created between the box that hides the valve and the entrance to the green. This is where the valve pilot pipe (6mm pipe) and a second pipe will pass through to manage the leakage rate required for valve operation.
A small hole is carefully dug into the green to introduce the Aqualone container, its magnetic float and porous ceramic.
The pilot tube and the return tube are connected to the small integrated valve of Aqualone. It is important to us that in order to operate, the pressure reaching the Aqualone valve must be less than 4 bar. We therefore recommend to install a small pressure reducer on the pilot pipe thanks to simple quick couplings (pictured below).
In the following picture you can see a small pipe overlooking the porous ceramic. It corresponds to the pipe of the integrated Aqualone dripper. We have installed this option to allow you to change the default setting obtained by putting Aqualone under the green sprinkler.
The previously removed green piece is inserted back into the porous ceramic to simulate the behaviour of the green.
The installation is functional! If the green is too dry, Aqualone triggers the opening of the hydraulically operated valve, the pumps start up and start irrigation. But of course you shouldn’t water golfers playing golf. A clock was installed at the pumping system to irrigate only after golf course opening hours. The next chapter deals with the modification of the pumping system.
The water is pumped into a concrete pool which is naturally charged with water from the river Dumbéa. 2 main pumps of 55m3/h and an additional pump of 35m3/h are immersed in the concrete pool. Pumps are horizontal borehole pumps (multi-cell pumps).
The pumps were previously manually activated by the gardeners, making sure to open the valves of 5 greens so that the pressure does not rise in the network. The first action was to repair the relief valve so that a pressure higher than 6 bar would return the water to the pumping area. This avoids damaging the pipes in the underground network.
The network was also automated by setting up a mano-contact. As soon as the pressure approaches 3 bars, the pressure switch marks it and starts the pumps. When the pressure rises to 6 bar the pumps shut down automatically. This system makes it easy to automate the pumping system as soon as a valve opens.
4 storage tanks have been installed to allow progressive pressure build-up and avoid water hammer without having to install a variable speed drive on the pumps.
The underground irrigation system is old and leaked many times. In order to limit losses, a master valve has been installed to close this network outside the irrigation slots. This valve is controlled by an electronic control unit. A clock closes the master valve during the day to avoid leaks and watering golfers.
A control allows the master valve to be opened outside the defined window to carry out fertilisation operations, for example.