$170m to improve Rotorua water quality

The cost of improving water quality in the Rotorua lakes is now estimated to be $170 million over 20 years.

Rotorua Mayor Kevin Winters yesterday described the figure as horrendous and said neither the local nor the regional communities could afford to pay that much.

A high-level call would be going out to the Government for assistance.

Mr Winters said the updated price to restore the sick lakes was the result of five years' research.

"We are now able to pinpoint the cost rather than give a ballpark figure," he said.

There was "a very real risk" that financing the remedial work would be beyond the region's financial capability.

"It would be a huge burden, and unfair, especially when we remember that significant areas of the Bay of Plenty are among the most deprived in the country," said Mr Winters, who chairs the Rotorua Lakes Strategy joint committee.

The strategy partners - Rotorua District Council, Environment Bay of Plenty and Te Arawa Maori Trust Board - would urgently seek an indication of the level of commitment they could expect from the Government.

"We have been saying to them all along that we are going to come to them with a figure and a strategy," Mr Winters said.

Discussions would be held with Environment Minister Marian Hobbs when she visited Rotorua next month.

In late 2003, the minister committed up to $36.7 million to a joint fund for preserving Lake Taupo.

"We realise the Government did not want to set a precedent by doing this, but we think we have an extremely good case to put to them," Mr Winters said.

"The Rotorua lakes are iconic and are clearly special to the whole nation. They are appreciated by and belong to all New Zealanders, not just those who live near them."

A year ago the Government pledged $7.2 million towards short-term measures aimed at a rapid improvement in Lake Rotoiti's water quality.

That included diversion at the Ohau Channel of contaminated water from Lake Rotorua directly down the Kaituna River and out to sea.

At present, the nutrient-rich water goes into Lake Rotoiti.

Although the help was appreciated, it was always considered an initial contribution, said Mr Winters.

The updated cost estimates for wide-ranging Rotorua lakes' protection and restoration projects included a major programme of sewerage reticulation that would cost Rotorua District more than $90 million over the next 10 years.

Environment Bay of Plenty's work was likely to reach at least $80 million for wetland construction, the use of minerals to improve water quality, the Lake Rotoiti diversion wall and other measures.

Nitrogen danger

* Nitrogen from fertiliser is one of the main polluters of lakes and rivers.

* When too much nitrogen is applied to plants it cannot be absorbed and leaches into waterways.

* This encourages weed and algal growth that kills off other plant and animal life.