Flood protection work at Transpower’s Stoke Substation not only helped keep the power on during last year’s severe weather but also protected threatened native fish living in the stream that runs through the site.
The upgrade, completed in 2024, was designed to meet flood mitigation requirements and strengthen electricity supply into Nelson Tasman.
It proved it’s worth when the June 2025 storms hit, executive general manager grid delivery Mark Ryall says.
“The work was designed to ensure the substation can continue to operate through major floods. This was tested last year when the substation came through the terrible storms and flooding in June without any issues.”
The project also created an opportunity to work with mana whenua and the Department of Conservation to improve the stream habitat, which supports lamprey, shortjaw kōkopu, koaro, giant kōkopu, inanga and longfin eels.
Transpower planned work around fish migration and breeding, and specialists helped relocate species while construction was underway. Contractors also checked nets daily for koura and eels, sending photos to ecologists as part of the monitoring process.
The Stoke Substation connects Transpower’s national grid to Network Tasman’s local network and is a key part of the region’s electricity system. Streambank erosion from the 2022 Nelson floods had made reinforcing the site a priority.
Network Tasman operations manager Robert Derks says collaboration was central to the project’s success.
“This project made a real difference to security of electricity supply in the region through last year’s floods. And we’re all really proud of how we could combine this critical work with something of such enormous benefit to biodiversity and local communities.”
Eight iwi with connections to the stream supported the project, represented by Ārewa and Ngāti Tama ki Te Waipounamu Trust. Ngāti Tama environmental manager Dayveen Stephens says the work showed Transpower’s commitment to meaningful engagement.
Mark says strong relationships with mana whenua will be crucial as more infrastructure is built to support Aotearoa’s energy transition.
