Weather events such as high rainfall are becoming more frequent and severe. ORC’s existing flood protection infrastructure provides a level of protection to our local communities from flood events.
Projects in the Climate Resilience Programme are critical works needed to help minimise the impacts of flooding on local communities in Otago. The programme also provides economic benefits to the region by creating jobs and protecting infrastructure and agricultural land.
ORC’s Climate Resilience Programme is a part of a national programme led by the Provincial Development Unit in the Ministry of Business, Innovation and Employment. It is a part of $3 billion investment in infrastructure to support New Zealand’s economic recovery from COVID-19, and will partially fund the four projects in Otago.
There are four projects that make up the Climate Resilience Programme. Two are located within the Lower Clutha flood protection scheme and two within the Lower Taieri flood protection scheme. These projects were chosen because planning for the work was already underway, meeting the shovel ready criteria and the projects provided environmental and social benefit.
West Taieri Contour Channel and bridges upgrade
This project will upgrade the currently existing Contour Channel, which is a part of the Lower Taieri Flood Protection Scheme in Mosgiel, Otago.
Contour Channel floodbank was originally constructed in the early 1900s using horse and cart construction techniques.
The channel intercepts runoff from the various steep streams located on the Maungatua Range and conveys this runoff by gravity to the Waipori River. The channel has an undulating longitudinal profile, which promotes concentration of overtopping during flood events, potentially exposing parts of the floodbank to relatively rapid failure.
Floodbank failure could potentially inundate 7,300 hectares of highly productive agricultural land and Dunedin International Airport. The proposed works are therefore necessary to bring the flood scheme up to a standard that can be relied upon as a flood defence.
Outram floodbank seepage mitigation
The Outram Floodbank experiences seepage during high river flows (e.g. 2017 flood). Seepage may threaten the integrity of the floodbank in the long run and this project will fix this by extending the stopbank toe with a weighting blanket, sealing or replacing culverts, constructing bottom stormwater drains, and refilling and sealing weak zones caused by tree roots.
This floodbank forms part of the Taieri Flood Protection Scheme that prevents inundation of up to 4,000 hectares of highly productive agricultural land, Dunedin International Airport, and State Highway 87.
Riverbank Road stopbank stabilisation
This project will stabilise critical flood protection stopbanks along Riverbank Road in the Lower Clutha delta, near Balclutha. The stopbank stabilisation was required due to flood damage caused by the February 2020 floods. Flood damage to stopbanks will be repaired at four critical locations on Riverbank Road, which runs 7km along the Mata-Au Branch of the Clutha River from the Riverbank Road bridge near Stirling.
Robson Lagoon flow control structures
This project will upgrade flow control structures for Robson Lagoon, located northeast of Balclutha. Infrastructure will be upgraded to assist with flood management around the Robson Lagoon area, whilst protecting its natural and cultural values. The regionally significant Lake Tuakitoto Wetland complex, which includes Robson Lagoon, is located in the Clutha-Mata Au catchment, approximately 7km east/northeast of Balclutha. The upgraded flow management structures will improve flow during flood events and provide a more sustainable habitat for local wildlife, such as native fish.
Lake Tuakitoto Wetland complex is a part of catchment serviced by the Lower Clutha Flood Protection and Drainage Scheme.