New flow gate installed

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A new automatic flow gate has been installed and commissioned at Lake Tuakitoto-Robson Lagoon near Balclutha, which will enhance its natural values and offer improved land drainage.

The Lake Tuakitoto wetland is a ‘‘remaining example of what was once a widespread type of wetland’’ and has been recognised as New Zealand’s fifth most important wetland-habitat for its high diversity of indigenous flora and fauna, hosting a range of rare or threatened species, including about 50 bird species and threatened whitebait and fish populations.

‘‘Less than 15% of Otago’s original swamps still remain,’’ Otago Regional Council (ORC) engineering manager Michelle Mifflin said.

‘‘The aim of the project is to change the flow management system around the wetland to encourage the normal flows of tributaries Lovells Stream and Stoney Creek, which enter Robson Lagoon, while managing drainage in the area.’’

Human activity has impacted the wetland for generations, and the new infrastructure technology will help keep water at optimum levels for natural processes while aiding ongoing farming and council needs.

Consent was approved in 2020 for the $835,000 project, which was co-funded by the ORC and the Ministry of Business, Innovation and Employment’s (MBIE) Kanoa Covid Response and Recovery Fund ‘‘Shovel Ready’’ projects.

The official opening ceremony on April 19 was in te reo, led by ORC deputy chairman Lloyd McCall and attended by about 20 dignitaries and stakeholders.

Along with the solar-powered flow gate, other project works included installation of a flap-gate culvert at Stoney Creek, replacement of a sandbag weir at the lagoon’s eastern side and the replacement of the existing culvert vehicle crossing with new box culverts.

The MBIE had 54 climate and flood control projects worth $250 million of investment, spokesman Mark Aliprantis said.

‘‘[Lake Tuakitoto-Robson Lagoon is] a bit of a beachhead of community engagement with ORC and stakeholders — it’s instructive to other councils . . . The real benefits we may not see for another generation but it’s an investment for the future and it’s surprising how quickly things improve.’’

The gate is opened when there are higher flows from the tributaries, with water diverted past the lagoon through a drain into the lake, and in lower flows the gate is closed and the tributaries can flow into and replenish the lagoon.

An old gated culvert and other ageing structures have been removed and replaced with the new gate, and a lagoon (vehicle track) crossing and a separate sandbag weir have been upgraded.

The lagoon, lake and wetlands are described as a rush and sedge swamp and lowland lake with an artificial water level.

Ms Mifflin encouraged people to use the public walking track around the lagoon.