Treatment MeasuresWetlands : Treatment Performance

The curves below show pollutant removal performance expected for constructed wetland systems for varying extended detention depths. These curves are based on the Melbourne hydrological region and it is expected that different hydrological regions will result in varying treatment performances. The size of the treatment measure can be simply adjusted to ensure suitable performance in other regions throughout greater Victoria. These adjustment factors are provided in Chapter 2 of the WSUD Engineering Procedures (PDF 691kb).

These curves are the basis to the STORM tool, a web based system for assessing the performance relative to best practice objectives for TN.

Melbourne (reference site) Wetlands TN Removal Melbourne (reference site) Wetlands TSS Removal

The curves were derived using the Model for Urban Stormwater Improvement Conceptualisation (MUSIC) (Cooperative Research centre for Catchment Hydrology 2003).

The curves were derived assuming the systems receive direct runoff (ie no pre-treatment) and have the following characteristics:

Treatment Measure Values used in Music 3.0
  Wetland treatment nodes were modelled for 200mm and 400mm extended detention depths using the following parameters:
Wetlands (200mm) TSS: k=1500, c*=6
TP: k=1000, c*=0.06
TN: k=150, c*=1
Extended Detention = 200mm
Inlet Pond Volume = 0.1 x Surface Area
Permanent Pool Volume = 0.4 x Surface Area
Overflow Weir Width = 200m
Notional Detention Time = 72hrs
Wetlands (400mm) TSS: k=1500, c*=6
TP: k=1000, c*=0.06
TN: k=150, c*=1
Extended Detention = 400mm
Inlet Pond Volume = 0.1 x Surface Area
Permanent Pool Volume = 0.4 x Surface Area
Overflow Weir Width = 200m
Notional Detention Time = 72hrs