Giant Rotoiti wall gets 9-year consent

A $12 million diversion wall to improve Lake Rotoiti's water quality has been given the go ahead - but could be torn down after nine years.

If there is no notable improvement in the water quality within that time, the Ohau Channel wall could be scrapped.

Environment Bay of Plenty applied for a 20-year resource consent but was granted one for only nine years, at which time it will have to reapply at a cost of about $300,000.

Nutrients flowing from Lake Rotorua through the Ohau Channel are a major cause of water-quality problems in Lake Rotoiti.

The 1.25km-long structure will divert water flowing into Lake Rotoiti from Lake Rotorua down the Kaituna River and out to sea.

It will start near the Ohau Channel outlet which links the two lakes and extend to Te Akau Point, 75m offshore, parallel to State Highway 33.

The nine-year timeframe has prompted the regional council to appeal to the Environment Court, but has pleased others who believe the wall may have adverse effects on fishing, as well as the water quality downstream.

Environment Bay of Plenty regulation and resource manager Paul Dell said work was due to start on the diversion in the middle of next year but given the appeals, was unlikely to start before December. The diversion is expected to take six to nine months to build and it will be four or five years before results will be visible.

The decision to grant consent received mixed reaction from the public. Many, especially those living around the lakes, were pleased it could provide an emergency solution to the ailing lakes, plagued by algal blooms each summer.

But others were angry the dirty water would be diverted down the Kaituna River and into the Maketu River - both of which are grounds for gathering food.

Fish and Game also has concerns about the effect the diversion could have on trout. Eastern Region manager Steve Smith said fish might not be able to find the Ohau Channel to spawn in, affecting population numbers.

Young fish from Lake Rotorua could get caught in the diversion and washed straight down the Kaituna River, he said.


Te Arawa Maori Trust Board chairman Anaru Rangiheuea said he did not believe diverting the water would add any further pollution to the Kaituna or Maketu rivers.

He was confident the diversion would be in the lake for more than nine years.

- NZPA