Bioretention swale design
assessment checklist
Asset I.D
Bioretention Location:
Hydraulics:
Minor flood (m²/s):
Major flood (m²/s):
Area:
Catchment area (ha)
Bioretention area (m²/s):
TREATMENT
Y
N
Y
N
Y
N
Treatment performance verified?
SWALE COMPONENT
Longitudinal slope of invert >1% and <4%?
Manning’s 'n' selected appropriate for proposed vegetation type?
Overall flow conveyance system sufficient for design flood event?
Maximum flood conveyance width does not impact on traffic requirements?
Overflow pits provided where flow capacity exceeded?
Energy dissipation provided at inlet points to the swale?
Velocities within bioretention cells will not cause scour?
Set down of at least 60mm below kerb invert to top of vegetation incorporated?
BIORETENTION COMPONENT
Design documents bioretention area and extended detention depth as defined by
treatment performance requirements?
Overflow pit crest set at top of extended detention?
Maximum ponding depth and velocity will not impact on public safety (v x d <0.4)
Bioretention media specification includes details of filter media, saturated zone (if
required), drainage layer and transition layer (if required)?
Design saturated hydraulic conductivity included in specification?
REVISION DATE >> 7 MAY 2014
Townsville City Plan Table SC6.4.3.9.6
Design of saturated zone included in specification?
Transition layer provided where drainage layer or saturated zone consists of gravel
(rather than coarse sand)?
Perforated pipe capacity > infiltration capacity of filter media?
Saturated zone outflow weir/up-turned pipe capacity > infiltration capacity of filter
media?
Selected filter media hydraulic conductivity > 10 x hydraulic conductivity of
surrounding soil?
Maximum spacing of collection pipes <1.5m?
Collection pipes extended to surface to allow inspection and flushing?
Liner provided if selected filter media hydraulic conductivity > 10x hydraulic
conductivity of surrounding soil?
Maintenance access provided to invert of conveyance channel?
LANDSCAPE AND VEGETATION
Y
N
Y
N
Plant species selected can tolerate periodic inundation and design velocities?
Bioretention swale landscape design integrates with surrounding natural and/ or built
environment?
Planting design conforms with acceptable sight line and safety requirements?
Top soils are a minimum depth of 300 mm for plants and 100 mm for turf?
Existing trees in good condition are investigated for retention?
Detailed soil specification included in design?
COMMENTS
REVISION DATE >> 7 MAY 2014
Townsville City Plan Table SC6.4.3.9.6
REVISION DATE >> 7 MAY 2014
Townsville City Plan Table SC6.4.3.9.6
REVISION DATE >> 7 MAY 2014
Townsville City Plan Table SC6.4.3.9.6