Warabandi & Know Your Canal Turn to the Minute

Warabandi (literally 'turn-fixing') is a rotational canal-water system where each farmer on an outlet gets a fixed turn (wari) in the rotation cycle (bandi), in proportion to their land. The turn time = (holding area ÷ total command area) × (cycle length − total filling loss). A 2-hectare holding on a 10-hectare outlet running a 7-day (168 h) cycle gets one-fifth of the cycle — about 33–34 hours each week.

Take your area as a share of all the land on the outlet, then multiply that share by the productive cycle hours (the cycle minus the filling-loss deductions). This calculator does it for every holding at once and shows your turn highlighted on the rotation clock, with the start and end clock time and the water depth you receive.

Because the canal outlet delivers a roughly constant discharge, sharing time is the same as sharing water: a holding that runs the channel twice as long gets twice the volume. Allocating by time in proportion to area means every field — head reach or tail-ender — receives the same depth of water per unit area, which is the fairness principle behind warabandi.

When a farmer's turn starts, water first has to fill the empty watercourse (khal) before it reaches their field — that filling time is unproductive. Warabandi rules deduct a fixed allowance (often 5–15 minutes per turn change) so the productive flow time is shared fairly. Lined channels fill faster, so they carry a smaller filling-loss deduction; long earthen khals carry more.

Depth (mm) = outlet discharge × turn time ÷ holding area. For example, 30 L/s flowing for 84 hours onto 2 hectares delivers 9072 m³, which spread over 20,000 m² is about 454 mm. The calculator reports this depth per holding so you can check it against the crop's irrigation requirement for the cycle.

They are closely related rotational systems. Warabandi fixes each cultivator's turn in a published weekly roster; osrabandi (or 'osra') is a similar turn-based rotation used in some regions, sometimes rotating the roster's starting point each week so no one is permanently stuck with an inconvenient (e.g. night) slot. The turn-time arithmetic — pro-rata to area — is the same.

The classic warabandi cycle is weekly (7 days = 168 hours), so the roster repeats every week and each farmer's slot stays on the same days. Some systems use 10-day or fortnightly cycles where water is scarcer or the command area is large. This tool supports 5-day, weekly, 10-day and fortnightly cycles.

Under a strict warabandi the tail-ender gets exactly their area's share of time, the same as everyone else — that is the system's main equity claim. In practice tail-enders lose more to conveyance and seepage along a longer channel, which is why the filling-loss allowance and channel lining matter most for them. The calculator gives the on-paper fair turn; field losses are separate.

Yes — many systems rotate the starting holding each cycle so that the same farmer is not always allotted the least convenient hours (such as the middle of the night). The turn durations stay the same; only the order shifts. This calculator lays out the durations and clock windows for one cycle starting from the first holding listed.

Yes — directly proportional. If your land is 30% of the command area, you get 30% of the productive cycle time. Doubling your area doubles your turn (and the water volume), but the depth per unit area stays the same as everyone else's, because both your time and your area scale together.

It is designed to be: by tying each turn strictly to land area and publishing a fixed roster, warabandi removes day-to-day negotiation and gives every cultivator a predictable, equal depth of water per acre. Its weaknesses are conveyance losses (worse for tail-enders) and rigidity in droughts, which is why supplementary rules and lining are used alongside it.