Moving ahead with solutions for Lakes
Moving ahead with solutions for Lake Rotoiti and Lake Rotorua
Friday 2 April 2004
A major engineering project aimed at improving water quality in Lake Rotoiti will move into its next phase later this year.
Rotorua Lakes Protection and Restoration Action Programme coordinator Paul Dell expects resource consents will be lodged within six months for a groyne in Lake Rotorua at the entrance to the Ohau Channel. The Ohau Channel flows into Lake Rotoiti.
However, a detailed study of the environmental impacts of the structure will need to be carried out first, Mr Dell says. If all goes well, the groyne could be built early next year at a cost of more than $1 million. Environment Bay of Plenty has already allocated funding for various engineering options, including the groyne.
Rotorua mayor Graeme Hall, chairman of the lakes joint committee, says the groyne should have “a fairly immediate positive effect” on Lake Rotoiti’s water quality.
Rotorua District Council and Environment Bay of Plenty have worked intensively on different aspects of the groyne project since it was mooted as an option late last year. While the regional council has focused on scientific investigation, the district council has taken up the engineering challenge.
The groyne will create a defined channel through which water can flow from Lake Rotorua into the Ohau Channel. Currently, Lake Rotorua water passes over a shallow area before entering the channel. In windy conditions, the water stirs up the lake floor and picks up nutrients held in the sediment. These nutrients then end up in Lake Rotoiti.
Water from Lake Rotorua is responsible for more than 70% of Lake Rotoiti’s nutrient load. It is nutrients - nitrogen and phosphorus – that feed algal growth, which degrades water quality.
Rotorua District Council, Environment Bay of Plenty and Te Arawa Trust Board are working with the local community to implement the Rotorua Lakes Protection and Restoration Action Programme and solve water quality problem in key Rotorua lakes, including Lake Rotorua and Lake Rotoiti. A working party, now being established, will develop a community-led Action Plan for Lakes Rotorua and Rotoiti. It is likely to involve a variety of solutions, including both short-term options like engineering works and long-term solutions such as land use changes. A focus group will probably be set up to handle the groyne proposal.
Rotorua District Council councillor Glenys Searancke and Environment Bay of Plenty councillor Bill Cleghorn will represent their councils on the working party, with nominations now being sought from other groups. Mr Cleghorn, the working party’s chairman, welcomes the progress being made on Lake Rotorua and Lake Rotoiti.
Another major project related to the two lakes’ water quality is a plan by Rotorua District Council to connect Rotorua’s eastern areas by pipeline to the existing sewerage scheme for Rotorua. Rotorua District Council is now seeking public feedback on the scheme. It is expected to cost $14.7 million.
Mr Hall says good quality and effective sewerage schemes are expensive but “that is a price we have to pay for getting the lakes water quality back to a safe and sustainable condition”. Replacing septic tanks with sewerage connections will stop nutrients seeping into the lakes, he says.
“It is one important element in the complex plan to remedy lake water quality. We have to commit ourselves to the future of our lakes, the future of our local economy and the future lifestyle of our residents.”
Last month, for the first time, a single health warning was issued for the whole of Lake Rotorua, Lake Rotoiti and the Kaituna River, which runs from Lake Rotoiti and reaches the sea near Maketu.