Arawhata Constructed Wetland Complex

The initial conceptual design for the Arawhata constructed wetland complex has been completed. You are able to give feedback on this design by either emailing horowhenua.wetlandcomplex@horizons.govt.nz or calling us on freephone 0508 800 800.

Currently, water from multiple sources in the Arawhata catchment flows onto the site of the wetland complex. 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 nitrogen, sediment and phosphorus within the water. This, combined with the other interventions within the catchment and the lake itself, will improve the water quality within Punahau.
 
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 2024. The constructed wetland complex will incorporate plants historically found in this area prior to its clearance, species such as harakeke (flax), carex, and rushes.
 
A Wetland Design Group and a Mātauranga Rōpu (Kāhui Ārahi) have been established to develop the wetland. A Community Stakeholder Group has also been formed, with input from this group to be considered in the process.
 
The wetland complex project was boosted by the Mahi mō te Taiao – Jobs for Nature Horowhenua (Waiopehu) Freshwater Management Unit Water Quality Interventions project (2021-2024). This support comes from Central Government funding and is complemented by Horizons Regional Council (a total of $12.5 million; $11.2 million from Central Government and $1.3 million from Horizons).
 
As further funding becomes available the following two phases will be considered. These phases will extend the constructed wetland complex with new drains, bunds, planting and a walking trail through the wetland.