Residents raising a stink over bloom | Rotorua News | Local News in Rotorua

Residents of the Okere Arm of Lake Rotoiti are worried toxic algae will lower property prices and scare off holidaymakers.

They're calling for urgent action to resolve the problem.

Neighbours Joan Bracken and Steve Howard, who have owned property at the Okere Arm for 14 and 11 years respectively, say they had little problem with algal blooms until the Ohau Channel Diversion Wall was completed in September 2008.

The $10 million, 1275m-long wall, at the outlet of the Ohau Channel which links Lake Rotorua and Lake Rotoiti, diverts nutrient-rich water from Lake Rotorua down the Kaituna River, to prevent further degrading of Lake Rotoiti's water quality.

Environment Bay of Plenty says it does appear the algae is being funnelled into the Okere Arm but it can't be certain and is working to resolve the problem.

Mr Howard and Mrs Bracken said the wall had improved water quality in other parts of the lake but not in the Okere Arm, where it had worsened.

"Before the wall we only got a little bit of weed when the weather was bad and we accepted that," Mrs Bracken said.

"It's as if they have shifted the problem down to this end, when it's really bad it reaches 5m out into the water."

Mr Howard said he was worried the toxic bloom could poison people, especially holidaymakers who might be unaware of the problem. He was also concerned the problem could lower house prices.

"We have no problem with what they are trying to do, clean up our lakes. We told them when they built the wall this would be an issue but no one took any notice. I'm beginning to wonder if they actually know what they are doing," he said.

Mr Howard estimated the toxic bloom affected about 300 properties in the Okere Arm area on the northern edge of the lake.

Andy Bruere, Environment Bay of Plenty lakes programme manager, said the algal bloom in early 2009 was worse in Lake Rotorua than in the previous three years and coincided with the completion of the diversion wall.

"There's no denying that it's there and it looks like it's being funnelled into the area from Lake Rotorua, however, I can't be certain of this," Mr Bruere said.

"If the wall was not in place at that time this algae would have been transferred through a greater area of Lake Rotoiti.

"Environment Bay of Plenty recognise the issue with one arm of Lake Rotoiti. It is likely to be a problem at specific times of the year when blooms in [Lake] Rotorua are bad."

Mr Bruere said the regional council had initiated a trial harvesting of algae from the Ohau Channel during the next few weeks but it would not immediately resolve the issue.

Lake Rotoiti Holiday Camp co-owner Michelle Gray said they were always taking away algae, lake weed and rubbish from the beach in front of the camp.

"There are literally trailer loads of it and it's that thick the ducks can walk around on it," Mrs Gray said.

"I fully support the clean up of the lakes ... [the Regional Council] said it wouldn't affect us, but it has. It's costing us money and affecting our business."

Mrs Gray said she would like the regional council to pay part of her clean-up bill, which also included rubbish coming out of Lake Rotorua.

Mr Bruere said the council would be prepared to assist with the clean-up, if possible.

"This is a long-term problem and actions to address this have started with the construction of two phosphorus locking plants, the development of a denitrification plant, starting within the next two months and work being undertaken with respect to algae harvest trialling."

Major water quality improvement in Lake Rotoiti had brought with it problems of greater weed growth because of improved water clarity.

"Our programme is about recognising these issues and adapting to address the issues. In the main, the community has appreciated the complexity of the programme and assisted in addressing these matters."