Appeal gone, wetland back on track

Appeal gone, wetland back on track

Construction of one of New Zealand’s largest wetlands near Punahau/Lake Horowhenua is to start later this year.

An appeal in the Wellington High Court against resource consents granted for the Arawhata Wetland has been withdrawn.

Horizons Regional Council says the appeal “has been resolved between the parties.” Horizons will now progress detailed design and construction for the 2025/26 construction season.

The council didn’t elaborate on how the issue was resolved.

Resource consents were granted in November last year, but were then appealed by a neighbouring farmer.

The aim of the wetland is to improve the water quality of the lake, while ensuring that any effects on groundwater are appropriately managed. The project has been boosted
by the Mahi mō te Taiao – Jobs for Nature Horowhenua (Waiopehu Freshwater Management Unit Water Quality Interventions project).

This support comes from central government funding ($11.2 million) and Horizons ($1.3 million).

Water from multiple sources in the Arawhata catchment currently flows onto the site of the wetland. That water contains nitrogen, sediment and phosphorus, which contributes to poor water quality in Punahau/Lake Horowhenua.

The constructed wetland complex will help to reduce the concentrations of pollutants in the water. This, combined with other interventions within the catchment and the lake itself, will improve the water quality within Punahau, Horizons says.

The conceptual design includes a master plan for the constructed wetland complex, with construction split into three phases.

The first phase aims to convert at least 15 hectares of farmland into a constructed wetland complex by December 2026. It will incorporate plants historically found in the area before its clearance – species such as harakeke (flax), carex, and rushes.

As further funding becomes available the following two phases will be considered. These would extend the constructed wetland complex with new drains, bunds, planting and a walking trail.

At the time of the consent, Horizons chair Rachel Keedwell, who is also co-chair of the governance group that will oversee the project, said the fast-track consenting process was extremely robust.

“While fast-tracking means the process as a whole is sped up and more streamlined, the effects of the proposal put forward are assessed as robustly as they would be through the normal process,” she said. “This will include the proposal being heard by an expert consenting panel to which the Environmental Protection Authority (EPA) provides advice and administrative support.

“This means the application will essentially go through the most stringent critiquing like it would through the Environment Court – by no means is it a way to cut corners.”

Once completed, the Arawhata wetland complex is expected to be one of the largest constructed wetlands in the country, creating improved habitats for native bird and fish species, along with better environmental outcomes through nutrient reduction in the Arawhata Stream, and in turn within Punahau.

The complex will be built on a former dairy farm adjacent to the lake.

The governance group includes representation from the Lake Horowhenua Trust, Muaūpoko Tribal Authority, Te Rūnanga o Raukawa, Horowhenua District Council, Ministry for the Environment, and Horizons Regional Council.