ABCW-2 Under Technical Review Engine v0.9.0
Bioretention Basin (Rain Garden) calculator
Treatment area, maximum infiltration (filtration) rate, extended detention storage, underdrain and perforation capacity, and overflow pit capacity for a bioretention basin.
Not a PUB approval. This calculator is under technical review and is not yet validated against PUB's official calculation template. A passing calculation does not establish compliance with PUB requirements. ABC Waters design calculations must be prepared and endorsed by an ABC Waters Professional / Qualified Person and submitted to PUB in the required format.
Available after technical review
This module will open once it has been validated against PUB's official ABC Waters calculation template and independently reviewed. The method, inputs and references are listed below.
Inputs
- Project / feature reference
- Contributing catchment area (ha)
- Impervious fraction (-)
- Target treatment area (% of impervious area) (%)
- Runoff coefficient (treatment flow)
- Rainfall intensity for design treatment flow (mm/h)
- Filter surface length (m)
- Filter surface width (m)
- Filter media depth (m)
- Design saturated hydraulic conductivity of filter media (mm/h)
- Extended detention (ponding) depth (m)
- Filter media effective porosity (information) (-)
- Underdrain pipe internal diameter (mm)
- Number of underdrain pipes (no.)
- Manning n of underdrain pipe
- Underdrain longitudinal grade (%)
- Length of each underdrain pipe (m)
- Perforation open area per metre of pipe (mm2/m)
- Orifice discharge coefficient
- Perforation blockage factor (fraction open)
- Minor-system design flow to overflow pit (5-yr ARI) (m3/s)
- Overflow pit weir length (open perimeter) (m)
- Overflow pit grate open area (m2)
- Available head above overflow crest (m)
- Weir coefficient
- Overflow grate blockage factor (fraction open)