Takitakitoa Wetland Restoration Project
Client: Otago Fish and Game Council
Contract type: Wetland enhancement project
Completion date: June 2016
Capability: Environmental policy, conservation, sustainability, conservation awareness, health and safety, and operating heavy equipment in an environmentally sensitive area.
Fish and Game employed SouthRoads to help with the earthworks for the undertaking of the second largest wetland in New Zealand, Takitakitoa, the area was previously a wetland but had been drained in the 1960s.
Otago Fish and Game Council employed SouthRoads to help with the earthworks and infrastructure to restore around 70 hectares of farmland near Henley to a wetland and site for waddling birds and small fish species to flourish. The area had previously been part of a major series of wetland ranging from Mosgiel, through to Henley, but was previously drained in the 1950s and 60s. The land was offered to Otago Fish and Game in the late 1980s. A subsequent further land swap and some land held by a Maori Trust means that an area of approx. 70 hectares is now preserved in perpetuity.
The creation of the bund has been pivotal in re-flooding the 80ha wetland. By installing a 400m long, 1m high bund about 400m from the Taieri River, this allows an area of approx. 30ha of shallow, open-water about 50cm deep. This area of the wetland has allowed native plant species to flourish and created an excellent area ideal for dabbling ducks for nesting and brood-rearing, and an ideal hunting area for novice and junior duck hunters. The bund has also meant that, while in Summertime the water used to drain, now the area retains more of that water, allowing bird species to flourish and frequent the area.
SouthRoads worked on the installation of a drainage culvert and precast headwall, along with the construction of the wetland bund wall, the bund wall was approximately 3m across, with a core of low permeability fill (either borrow pits or marine silt or a blend) and it was bedded onto the marine clay layer. The undercut put in by SouthRoads also allows the area to maintain more water. A drainage culvert with precast headwall was also installed, and a fish ladder was installed in the culvert, ensuring access for the wildlife.
This project was challenging as it was a challenging environment for operators, with tussock and a very soft wetland area increasing the risk of sinkage for diggers and other heavy machinery that needed to operate. We overcame this with a stringent safety policy and highly trained staff. We also developed an environmental policy for the project, along with a quality policy to ensure that the environment would be protected.
This project led to SouthRoads receiving a Category award at the Hynds Construction Awards in 2017, which we are very proud to have received. The real reward comes from seeing the area now full with native plant species, frequented by a wide range of New Zealand birdlife, and used as a breeding ground for native fish, making it an incredibly valuable resource for future New Zealanders.
The recent completion of minor road maintenance and adjustment to the outlet stream of the bund structure brings an end to the physical works at Takitakitoa. There were no retentions involved and I understand you have now been paid in full which brings this contract to full conclusion.
The Otago Fish & Game Council is pleased that it has come in on budget and the work has been completed to a very high standard. We wish to extend our thanks to yourself and other Southroads Ltd staff for your practical and professional approach to this unorthodox project.
Wetland enhancement work, by its very nature, can be very unpredictable. Working remotely, around water and on soft ground increases the risks significantly in terms of safety, equipment, time and budget. All aspects were expertly managed.
This was one of the most ambitious construction projects Otago Fish & Game Council has undertaken so we appreciate the guidance provided in the practical and contractual aspects of the development. It has been a pleasure to do business with you and if there is any opportunity to recommend Southroads Ltd for similar projects, we would be happy to do that.
Finally, please also extend our thanks to the individual operators involved. I know some of them still have a personal interest in the project and as such, they are welcome to visit the wetland at any time.
Otago Fish & Game Council