A $5 million upgrade to the Taieri contour channel is the largest bundle of work within the climate resilience programme co-ordinated by the Otago Regional Council.
Project delivery team leader Brett Paterson said the contour channel provided flooding protection and water conveyance to the Waipori pump station, protecting 7300ha of agricultural land surrounding communities and the Dunedin International Airport at risk from flooding in high rainfall events.
Use of the contour channel floodbank goes back more than a century, as it was originally constructed in the early 1900s, he said.
This stage of the upgrade works consists of reconstruction of a 2.4km section of the floodbank and bridge upgrades within the section.
The contour channel intercepts run off from various steep streams located on the Maungatua Range and conveys the runoff by gravity to the Waipori River.
Mr Paterson said the project was co-funded by Otago Regional Council and central government, through Kānoa, the regional economic development and investment unit within the Ministry of Business, Innovation and Employment.
The cost of the overall upgrade is $5 million, with the Ministry for Business, Innovation and Employment funding $3.2 million and ORC $1.8 million as part of central government’s 2020 budget, which included $210 million for climate resilience and flood protection projects across New Zealand.
The project is scheduled to be completed in 2025.
Mosgiel Taieri Community Board chairman Andrew Simms said the upgrade of the contour channel by the regional council was a major step in protecting the lower Taieri Plain from flooding.
"This is an important area for all of Dunedin as it encompasses several arterial routes and Dunedin Airport."
The board welcomed this important work undertaken by the regional council but was concerned about the integrity of the Taieri River stop banks, in particular the banks protecting Outram which appeared to be in need of urgent remediation, Mr Simms said.
The board was also concerned about maintenance of the Owhiro Stream and the Silver Stream in respect to keeping these waterways clear of vegetation, and the silting up of the Silver Stream channel.
"Both of these waterways pose significant threat to Mosgiel."
"The wider community are rightfully concerned about the potential for slash to impede the Silver Stream and the Taieri in the event of a major rain event."
The board was advocating for a survey of the catchment areas affecting the Taieri to determine if forestry slash was a significant risk, and it intended to write to the regional council asking for an update, Mr Simms said.
The Star put Mr Simms’ concerns to the regional council but it was unable to provide answers by time of publication.
