Rainwater Roof Yield Greenhouse Calculator

Reconcile actual greenhouse roof rain events with event capture/first flush and no-between-event storage withdrawal; plan area not roof slope surface, no potable-water quality or future rainfall guarantee.

Description

Rainfall depth over roof plan area gives a water-volume budget.

Rainfall depth over roof plan area gives a water-volume budget. Capture losses, first flush and available storage reduce usable collection.^[1]

Enter aligned nonempty nonnegative rain/flush records, fractions 0–1 and nonnegative plan area/storage. Return event collection, stored liters and overflow, assuming no withdrawals between events.

When to use Rainwater Roof Yield Greenhouse Calculator

Use Rainwater Roof Yield Greenhouse Calculator when you need to evaluate the supplied records under the calculation and evidence rules below. Use horizontal plan area rather than sloping roof surface. No future rainfall or water quality is predicted.

Prepare the measured crop, container, lighting or inventory records requested. Supply verified local catalogs, calibration factors and crop-stage limits; keep units and dates consistent.

How to use Rainwater Roof Yield Greenhouse Calculator and understand its results

Prepare the measured crop, container, lighting or inventory records requested. Supply verified local catalogs, calibration factors and crop-stage limits; keep units and dates consistent.
Enter observedRainMmByEvent, measuredRoofPlanAreaM2, callerRunoffCaptureFractions, firstFlushLitersByEvent, freeStorageLiters using the field table and calculation rules, then run the tool.
Read netCollectedRainwaterLitersByEvent, capturedIntoStorageLiters, overflowRainwaterLiters. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
observedRainMmByEvent	Observed rain mm by event	list of number	Required
measuredRoofPlanAreaM2	Measured roof plan area m2	number	Required
callerRunoffCaptureFractions	Caller runoff capture fractions	list of number	Required
firstFlushLitersByEvent	First flush liters by event	list of number	Required
freeStorageLiters	Free storage liters	number	Required

Enter aligned nonempty nonnegative rain/flush records, fractions 0–1 and nonnegative plan area/storage. Return event collection, stored liters and overflow, assuming no withdrawals between events.

eventLiters=max(0,rainMm×planArea×captureFraction−flush); stored=min(total,freeStorage)

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
netCollectedRainwaterLitersByEvent	Net collected rainwater liters by event	list of number
capturedIntoStorageLiters	Captured into storage liters	number
overflowRainwaterLiters	Overflow rainwater liters	number

json

{
  "input": {
    "observedRainMmByEvent": [
      10,
      20
    ],
    "measuredRoofPlanAreaM2": 100,
    "callerRunoffCaptureFractions": [
      0.8,
      0.5
    ],
    "firstFlushLitersByEvent": [
      100,
      0
    ],
    "freeStorageLiters": 1000
  },
  "output": {
    "netCollectedRainwaterLitersByEvent": [
      700,
      1000
    ],
    "capturedIntoStorageLiters": 1000,
    "overflowRainwaterLiters": 700
  }
}

Limitations and assumptions

Use horizontal plan area rather than sloping roof surface. No future rainfall or water quality is predicted.

Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Numeric lists are limited to 10,000 entries; string lists to 128 strings of at most 128 characters each. The rules above may impose smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Capillary Mat Reservoir Days Calculator: Reservoir duration can be estimated from recorded daily mat draw plus independently measured other losses. Reserved stock reduces usable water. For a complementary task, use Hydroponic Reservoir Size Plants Calculator: Reservoir autonomy combines measured plant draw with fixed loop hold-up. Nominal tank size also depends on its usable fraction.

References

Rainwater Roof Yield Greenhouse Calculator — tool.io

Similar or alternative tools

Capillary Mat Reservoir Days Calculator
Reservoir duration can be estimated from recorded daily mat draw plus independently measured other losses. Reserved stock reduces usable water.
Hydroponic Reservoir Size Plants Calculator
Reservoir autonomy combines measured plant draw with fixed loop hold-up. Nominal tank size also depends on its usable fraction.