Drip Zones & Irrigation Zones from Source Flow

By dividing the flow the whole field would need if irrigated at once by the flow the water source can actually supply, then rounding up. Zones = ceil(system flow ÷ source flow). Rounding up ensures the source is never asked for more than it can deliver — the field is split into enough blocks that each one fits within the available flow.

Each zone needs its own run hours to apply the target depth, and the zones run one after another because the source can only feed one at a time. So the total run hours = number of zones × run hours per zone. The tool multiplies the two to show how long the whole field takes to irrigate in a cycle.

A water source — a well, pump, canal turnout or mains connection — can only deliver so much flow. If the whole field's emitters demand more than that, pressure collapses and watering becomes uneven. Splitting the field into zones that each fit the source flow keeps every emitter at its design pressure, so all plants get the right amount of water.

System flow is the total flow the field would draw if every emitter ran at once — the sum of all emitter discharges. Source flow is what the well, pump or supply line can actually provide. When system flow exceeds source flow, you cannot run everything together, so the field is divided into zones sized to the source.

Because a partial zone still has to be watered. If the maths gives 3.2 zones, three zones would leave part of the field demanding more than the source can give, so you round up to 4. Rounding up guarantees every zone's demand stays at or below the source flow, protecting pressure and uniformity across the whole field.

Yes — zones run in sequence, so total run time grows with the number of zones. A field needing four zones at three hours each takes twelve hours to complete a cycle. If that exceeds the daily window, you either need a larger source, lower-flow emitters, or to accept a longer irrigation interval. The tool makes that trade-off visible.

Run hours per zone is the depth you want to apply divided by the zone's application rate (the depth it applies per hour). The application rate comes from the emitter flow, spacing and wetted area. Once you know how long one zone needs to refill the root zone, enter it here and the tool scales it across all the zones.

They can, and in practice they often are — fields are divided along valves, slopes or crop blocks. This tool assumes evenly sized zones sized to the source flow, which is the usual design goal because equal zones share run time and pressure cleanly. If zones differ, size each to stay within the source flow and sum their individual run times for the total.

The zone count and total run hours are exact for the flows and run time you enter. Accuracy depends on knowing the true system and source flows and a sound run time per zone. Treat the result as the scheduling backbone, then verify the source delivers its rated flow and that each zone applies the intended depth in the field.