Available rainwater volume (ABNT NBR 15527:2019) — rh_available

Computes the theoretical volume of rainwater available for capture, using the equation given in ABNT NBR 15527:2019, item 4.1.6:

Usage

rh_available_volume(precip, area, runoff = 0.8, efficiency = 0.85)

Arguments

precip: Numeric vector of precipitation depths, in millimetres (mm). Each element is one time step (typically a day).
area: Catchment area in square metres (m2). May be a vector of per-block areas, in which case the total sum(area) is used.
runoff: Runoff coefficient C (the coeficiente de escoamento superficial), dimensionless in [0, 1]. Scalar or vector recycled to length(precip). Default 0.8.
efficiency: System efficiency eta (dimensionless, [0, 1]), accounting for the first-flush diverter/solids-discard device. Scalar or vector recycled to length(precip). ABNT NBR 15527:2019 recommends 0.85 when no data are available (the default).

Value

A numeric vector, the same length as precip, of available volumes in cubic metres (m3).

Details

$$V_{disp} = P \times A \times C \times \eta$$

The result is converted from litres to cubic metres (division by 1000).

Examples

# Daily available volume for a 775.53 m2 roof over three days
rh_available_volume(precip = c(0, 12, 30), area = 775.53)
#> [1]  0.000000  6.328325 15.820812