Examples
Examples
Try the starting example
- Horizontal tarp catchment area (m²)
- 20
- Total supplied rainfall scenario (mm)
- 10
- Rainfall duration (hours)
- 2
- Identical outlets sharing flow equally
- 2
- Supplied capacity per outlet (L/min)
- 1
- Collected water volume (L)
- 200
- Average combined outlet demand (L/min)
- 1.666667
- Average demand per outlet (L/min)
- 0.833333
- Average combined capacity shortfall (L/min)
- 0
Try another scenario
- Horizontal tarp catchment area (m²)
- 20
- Total supplied rainfall scenario (mm)
- 100
- Rainfall duration (hours)
- 2
- Identical outlets sharing flow equally
- 2
- Supplied capacity per outlet (L/min)
- 1
- Collected water volume (L)
- 2000
- Average combined outlet demand (L/min)
- 16.666667
- Average demand per outlet (L/min)
- 8.333333
- Average combined capacity shortfall (L/min)
- 14.666667
Calculation method
Calculation method
Collected water volume (L)
Horizontal projected catchment m² × rainfall mm = litres, assuming complete capture.
Average combined outlet demand (L/min)
Collected litres / duration minutes.
Average demand per outlet (L/min)
Combined average demand / outlet count.
Average combined capacity shortfall (L/min)
max(0,average combined demand − count×supplied capacity per outlet).
Symbols and units
- a
- Horizontal tarp catchment area (m²)
- b
- Total supplied rainfall scenario (mm)
- c
- Rainfall duration (hours)
- d
- Identical outlets sharing flow equally
- e
- Supplied capacity per outlet (L/min)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions & limits
Assumptions & limits
- An average complete-capture water-balance scenario, not a drainage design or peak-storm calculation. Horizontal area, equal outlet sharing and capacities must be supplied; splash loss, gusts, blockage and transient peaks are excluded.
Are these inputs private?
These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.
Further reading
OpenStax: arithmetic and geometry ↗
Background reading; this does not imply endorsement or independent review of SumFizz.