Weekly water budget

LocalSky tracks how much water each zone has received over the trailing week, from every counted source, against what the engine thinks the week should deliver. Rain counts per day, and each day is capped at what the zone’s root zone can hold: rain beyond that in a single day drains past the roots and never reaches the plant, so it does not count against the week.

There is no budget screen yet. What you see of it in the app is the hold line on a zone card and on zone detail, which names the gate that zeroed the zone for the day. The full per-zone rows (target, applied, observed rain, forecast credit, remainder, remaining sessions) are on the API at /api/v1/irrigation/snapshot under water_budgets.

Counted in:

• Irrigation runs (recorded per zone, per second of runtime, converted through the zone’s precipitation rate). Applied water counts in full; the per-day cap below is a rain rule only.
• Measured rainfall (from your station or gateway), credited per day: each day counts up to the zone’s per-day cap, which is the root zone’s own capacity (field capacity minus wilting point, times root depth) unless you set Rain the soil can bank per day in the zone editor. The forecast credit takes the same per-day cap.

The target is a flat weekly depth per zone, in inches including rain. It comes from the zone’s weekly_budget_in setting, or, when you have not set one, from a default set by the species you declared on the zone: its peak crop coefficient against a reference peak of 1.00, so warm-season turf starts at 0.85 in over 2 sessions and established shrubs at 0.55 in over 1. A zone with no zone config declares no species, so its default comes from the zone’s name instead: 0.50 in over 1 session when the slug carries shrub, garden or bed, and 1.00 in over 2 otherwise. The target does not move with the season, and nothing recomputes it from ET0 or the species coefficient. ET0, Kc and ETc are computed and displayed, and the tuning report will suggest a different weekly_budget_in when the zone cannot deliver the one it has, but the target itself changes only when you change it.

Sandy soil

The per-day cap is why a sandy yard no longer skips a whole week after one storm. Sand at default turf roots (150 mm) holds about 0.35 inches; a 1.2 inch storm day credits 0.35 inches and the rest drains past the roots, so the balance resumes watering mid-week instead of counting water the lawn never kept. A loam yard holds 0.89 inches a day and only notices the cap in storms bigger than that.

Derived caps at default turf roots (150 mm), per soil texture:

A deeper root depth (a species default or the zone’s own override) raises the cap proportionally. Set Rain the soil can bank per day in the zone editor to override the derived value; the field’s placeholder shows the number in effect. The cap does not decay older rain by ET: the weekly target already accounts for typical ET, and decaying the credit would count it twice.

When a zone looks off plan: persistently dry means runs are being skipped or are too short, and the zone’s “Why this duration?” panel shows the throughput and whether the run hit its cap. Persistently soggy means rain is doing the work and the engine should be skipping more, or the precipitation rate is set too low.

This budget is what decides watering for weekly-governed zones. Its per-zone remainder sizes each session, and when the remainder reaches zero, or forecast rain is imminent, or the session spacing has not elapsed, the zone plans zero seconds for the day and says which of those it was. A zone in that state reads ON HOLD on the zone card and detail with the reason beside it.

The session length that remainder buys is not the last word. The seasonal dial, engine.seasonal_adjust_pct, scales it before the zone’s maximum run time clamps the result, so the planned minutes you see already carry the dial. At 100% you get the depth this ledger computed, and you turn the dial down for a wet stretch or up for a heat wave instead of re-editing every weekly target; the full treatment is under the seasonal water budget.

The soil model is the other scheduling model, and the shipped default: a zone it governs waters when its own soil deficit crosses the trigger and each run refills the deficit, so both the trigger and the size come from the soil instead of this weekly ledger. engine.scheduling_model picks the default and the zone editor pins it per zone, so a weekly-governed zone is one you pinned to weekly, one on an install whose engine.scheduling_model is weekly that carries no per-zone pin, or one with no zone config at all: an env-var install, or a controller zone you never configured in LocalSky. That last kind has no texture and no species to size a bucket from, so it stays on this ledger whatever the engine default says. Under the soil model, a Weekly target you set by hand stays honored as a rolling-7-day delivery ceiling, and Sessions per week stops steering because cadence follows soil texture and roots. The soil deficit computes for a zone that has a zone config, whichever model governs it, once its trailing window carries at least three evidenced days (a resolved ET0 day, a rain day, or a completed run); below that the zone publishes no soil fields and the weekly ledger sizes it, which is where a fresh install starts. A zone with no zone config gets no soil fields at all, and no zone gets them on a tick where the runs read failed. The zone detail’s Soil model block shows what it plans.