Information on the flood management and stormwater treatment projects within the Ōtākaro Avon River Corridor.
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Flood management and new stormwater treatment facilities will play a significant role in the future of the Ōtākaro Avon River Corridor, as we work to improve the quality of the water entering the awa and help the city prepare to live with sea-level rise in the future.
Waitaki Street stopbank and tidal wetland
Within the regeneration area, 22km of flood management is planned, including stopbanks and floodwalls. The first 472m section of the stopbank was completed in the Waitaki Street area in February 2024. This has allowed the area on the riverside of the stopbank to revert to tidal wetland.
Council assisted this process by removing some small sections of the temporary stopbank in the summer of 2024/2025, which allowed natural tidal processes to occur. Further minor works may be required as we monitor the wetland change over time.
Waitaki Street stormwater basin
Construction of a nine-hectare Waitaki Street stormwater treatment basin will begin in 2026. Situated between Anzac Drive, Pages Road and the Ōtākaro Avon River, the Waitaki Street stormwater basin will catch and treat all stormwater from a large area of Aranui before it's discharged into the river.
This is the first in a series of stormwater treatment systems that will be installed along the river to reduce the impact of the urban environment on the awa.
Bexley flood defence
The temporary stopbanks along the edge of the Ōtākaro Avon River in Bexley are nearing the end of their design life.
Contractors have now completed over 320m of sheet pile floodwall between SH74 and the estuary edge in Bexley. Paths will all be reinstated, and landscaping and planting of this section will follow, with the aim of leaving everything in a better condition than we found it in.
Designs for flood defences in the rest of the section between Pages Road and Bridge Street are underway, with work to commence once these are complete and consents are in place.
ANZAC Drive (SH74) to Waitaki flood defence
The flood defence section between ANZAC Drive (SH74) and the Waitaki Street stopbank is currently being consented. This will include a buried floodwall and a flood pump station.
Construction is scheduled to begin in the spring of 2026. The project team are working closely with the City to Sea team as the pathway will be on top of the flood defence in this reach.
Avondale to ANZAC flood defence and treatment wetland
The following section, between Avondale Road and ANZAC Drive, is in early design. Construction of this section is scheduled to commence in 2028.