The northern section of Nerrigen Brook living stream is situated on the banks of the Wungong River in the Springtime Estate along Coomal Road in Haynes (Wungong Urban Water Precinct C). The section of Nerrigen Brook west of Coomal road was constructed in 2017, after the design received approval from Metropolitan Redevelopment Authority, the Water Corporation, City of Armadale and Departments of Water and Environmental Regulation and Biodiversity, Conservation and Attractions.
The development includes median swales which are designed to manage the first 15mm of rainfall runoff from impervious ground within the development. The landscaping design for the Neerigen Brook Foreshore includes extensive revegetation throughout the corridor outside of the baseflow channel with footpaths, play equipment and some areas of turf located outside the 5 year ARI ‘floodway’ in accordance with the requirements of the Wungong Foreshore Management Plan. Turfed areas have been situated high in the cross section so that they remain well drained and functional throughout the year.
The stream design consists of three levels to convey increasing ARI events:
- Stream channel (~3m wide) – includes baseflow channel to convey approximately 350 L/s (winter baseflow) which periodically overtops into a broader conveyance channel designed to contain channel forming flows (1 in 1.5 year ARI).
- Vegetated floodway – sized to accommodate the 1 in 5 year ARI event (~9m3/s) within the Water Corporation’s landholdings (~15m wide).
- Floodplain – the remainder of the Neerigen Brook foreshore area(up to 60m wide) safely accommodates the 100 year ARI event (~11.5m3/s)