Kopurererua Catchment

The Lower Catchment spans between the Waikareao Estuary and current extent of ongoing urban-industrial development in Tauriko and Pyes Pa. Land use is a mix of urban, industrial, and public open space (K-Valley wetland reserve).

The watercourses in these areas are heavily modified due to land use pressure. The Kopurererua main stream was straightened pre-1940, disconnecting the lower river reaches from its floodplain. Its associated wetlands were drained over the years in attempts to convert the Valley to pasture.

The Mid Catchment transitions to rural land use through upper Tauriko and Pyes Pa, with lifestyle blocks and farmland dominating the valley floors and orchards dominating the upper plateaus. Here, the Kopurererua stream still follows its natural, meandering course.

Land use practices over the last century have led to a loss of native forest cover and watercourse modification. Ongoing development is occurring in the Tauriko industrial estate along Kopurererua Stream and in Pyes Pa along Nanakau Stream. There is some lifestyle development in the valleys.

The Upper Catchment in Omanawa and Oropi includes orchards, lifestyle blocks and dry stock farmland with some dairy farming, and plantation forestry on the upper plateau. The steep gorges are largely covered in regenerating indigenous tawa-broadleaf forest.

Stream Re-alignment and wetland restoration

• We are supporting Tauranga City Council and Ngāi Tamarawaho with the Kopurererua re-alignment project which aims to realign and restore the natural path of the Kopurererua Stream. The main objectives of this project are to:
  • To reduce sediment entering the Waikareao estuary and harbour by allowing it to settle in the newly created wetland
  • To improve community access to the area
  • To enhance ecological and cultural values in the area

We are contributing $1.3million towards the project over the next 3 years and work commenced on 1 February 2022.

Wetland restoration for fish passage

At the bottom of the catchment, further downstream from the realignment project, council is working alongside Ngāi Tamarawaho, with the help of funding from the Port of Tauranga/Ngā Matarae Trust, to restore waterflow to the Koromiko wetland. The purpose of this project is to improve fish passage, (primarily for inanga) into the wetland and provide habitat for inanga spawning.

The lower part of this stream has been heavily modified over time, absent of any native riparian vegetation and has a heavy presence of the invasive weed glyceria which negatively impacts on spawning opportunities for inanga. This project aims improve habitat in the riparian zone and reinstate part of the original meander of the Kopurererua stream into the Koromiko wetland.

Work should commence on this project later in 2022.

There is recognition of the cultural values of the now-drained plains and the need for inclusion of matauranga Maori (traditional knowledge) in finding solutions.

We are working with smaller lifestyle block holders and horticulturalists to:

• Protect floodplain areas
• Control willows which are causing riverbank issues
• Protect and enhance existing wetlands
• Exclude stock from waterways

We are working with 4 out of 5 of the larger farms in the headwaters of the Kopurererua catchment to:

• Retire highly erodible hillslopes by fencing and planting
• Protect existing stands of native bush blocks
• Build detention bunds to trap sediment