Multi-zone gravity feed measured irrigation with a flow-splitter is completely automatic and is suitable for much larger applications with many separate zones. The flow-splitter delivers water to all the zones simultaneously. If the land is sloping, a separate zone is required at each level and the zone should follow a contour line.

 

The flow-splitter divides a single inflow of water into multiple outflows with one outflow for each irrigation zone. A control dripper is connected to one of the outlets on the flow-splitter.

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The volume of water required to raise the water level from the low probe level to the high probe level is called the control volume. It is also the volume of water that must evaporate between irrigation events. A tube is connected to the control dripper to deliver water to the evaporator. The irrigation event will stop when the control volume of water has been delivered to the evaporator. The other tubes are delivering water to the various irrigation zones. The volume of water delivered to an irrigation zone during an irrigation event depends on the control volume and the ratio of the flow rate of the adjustable valve for the zone to the flow rate of the control dripper. For example, if the control volume is 2 litres and adjustable valve has 50 times the flow rate of the control dripper, then 100 litres of water is delivered to the zone. More details are available in the Measured Irrigation from Scratch Manual.

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The water level in the flow-splitter will stabilize so that outflow rate matches the inflow rate. Suppose that the inflow is increased by adjusting the inlet valve. The water level in the flow-splitter will rise until the outflow rate matches the increased inflow rate. However, the volume of water delivered to the evaporator (namely, the control volume) does not change, and so the volume of water delivered to any zone does not change. Note that a flow-splitter can be any shape or size provided that all the outlets on the flow-splitter are at the same level.

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Depending on the application, one can water the plants in a zone using Miniscape dripper line or any other non-pressure compensating (unregulated) drippers or dripper line.

 

Multi-sector gravity feed measured irrigation with a flow-splitter has been installed at the following community gardens in Australia: Sophie's Patch (Mount Barker), Fern Avenue Community Garden (Adelaide), Prospect Community Garden (Adelaide), Henley Community Garden (Adelaide), Yarrawonga Community Garden (Victoria), University of the Sunshine Coast Community Garden (Queensland), Glenelg Community Garden (Adelaide), Windsor Gardens Vocational College (Adelaide) and Trott Park Community Garden (Adelaide).