Best environmental/revegetation project - Kūmānu Environmental

Kūmānu Environmental’s epic undertaking helped transform a flood-ravaged valley into a thriving public asset and ecological success story

An ambitious ecological restoration effort on Nelson’s eastern fringe has earned accolades at this year’s awards, with Kūmānu Environmental’s Mahitahi and Groom Creek Redevelopments winning the Premier Environmental/Revegetation Award for a project that has revitalised an entire river corridor.

Complex project done well

What began as a storm-damaged, weed-infested site has become a restored riverine ecosystem, supporting native biodiversity, community recreation and long-term flood resilience. The judges praised the scale and execution of the work, calling it “a huge restoration project” that “enriched local ecosystems, restored key habitat types and improved the site as an asset for the community”.

The works followed devastating storms in August 2022, which caused severe damage to riverbanks, deposited sediment and gravel across wide areas, and left the site vulnerable to noxious weeds. Civil and ecological teams responded with a multi-stage plan supported by the Jobs for Nature programme – ultimately bypassing the entire Maitai River flow using eight pumps, relocating over 1,000 native fish and invertebrates, removing 7,000m³ of gravel and placing 2,500 tonnes of stabilising rock.

A total of 75,000 native plants were installed to re-establish wetland margins, streambanks and forest edges, with selection based on pre-European vegetation records and site-specific soil and water profiles. The result is a diverse, location-sensitive planting scheme that has taken hold without irrigation and with no signs of stress – even through Nelson’s peak summer.

“This is not just about planting, it’s about long-term restoration,” said Will Morrison, senior landscape architect. “The site was overrun with willow, blackberry, broom and Himalayan honeysuckle. We’ve returned it to a functioning ecosystem, using ecologically appropriate species, tailored planting grades and careful ground preparation with reclaimed organic material.”

A transformed space

The judges were particularly struck by the practical complexity behind the transformation. “The photos of the project don’t convey the complexity and scale of the work involved,” they noted. “The extensive plant list had the judges reaching for our plant apps.”

Cover crops of clover, rye and fescue were used to suppress weeds, while plant guards and soil depressions supported young plants through their first critical establishment phase. A flexible replacement regime was initially used to manage losses but is now largely retired due to the success of the original planting.

“All the works held up with complete structural integrity during the most recent weather events and throughout the length of the construction site,” Morrison added.