Irrigation Zone Runtime and Cycle-and-Soak
The controller runtime to apply a target depth.
Example
You enter
- Target depth this run (in) 0.75
- Precipitation rate (in/hr) 1.2
- Distribution uniformity (0-1) 0.75
- Max cycle before runoff (min) 10
You get
- Net runtime 37.5 min
- Gross runtime (DU adjusted) 50.0 min
- Cycles 5
- Per cycle (min) 10
Details, formula, and sources
Net (depth / rate x 60), gross (net / distribution uniformity, so the dry quarter gets the target), and a cycle-and-soak split into runs short enough to beat runoff on the soil and slope. The DU comes from a catch-can audit and the soil caps the cycle length; a program aid, not a guaranteed schedule.
net_min = target_in / precip_in_hr x 60; gross_min = net_min / du; cycles = ceil(gross_min / max_cycle_min); per_cycle_min = gross_min / cycles.
First-principles runtime and cycle-and-soak relations with the Irrigation Association scheduling references (by name); no edition cycle.
The runtime and cycle-and-soak relations are public irrigation-scheduling practice. The DU comes from a catch-can audit and the soil intake rate governs the cycle length.
Estimate. AHJ and licensed professional govern.
Field names used by the API: target_in, precip_in_hr, du, max_cycle_min, net_min, gross_min, cycles, per_cycle_min
- Net runtime net = target depth / precipitation rate x 60 (depth over rate)Irrigation Association scheduling references
- DU adjustment gross = net / lower-quarter distribution uniformity so the dry quarter receives the targetIrrigation Association scheduling references
- Cycle-and-soak the gross time splits into cycles no longer than the soil/slope runoff limit, with soak gaps between themIrrigation Association scheduling references