Ken Liao from Jack and Di's Lakefront Motel and Lodge hopes the lake pollution issue is cleaned up as soon as possible for the sake of his guests and children. Photo / Andrew Warner
Ken Liao from Jack and Di's Lakefront Motel and Lodge hopes the lake pollution issue is cleaned up as soon as possible for the sake of his guests and children. Photo / Andrew Warner
Continuing levels of bacteria in Lake Rotorua may mean other factors are causing pollution on top of last week's wastewater spill, according to Rotorua Lakes Council.
Council officials are trying to figure out why bacteria levels in Lake Rotorua haven't reduced as expected. Last week a maintenance hole overflowed andspilt wastewater near Arnold St and Waiteti Rd at Ngongotahā.
The wastewater, described by locals as brown water "spraying like a fountain", flowed from a manhole at a property, across the ground and into the lake.
The spill, blamed on a computer fault at the pump station, happened at 7pm on October 18. It is estimated that up to 20 cubic metres of wastewater may have reached the lake over three hours.
A public health warning is in place for Lake Rotorua following a wastewater overflow. Photo / NZME
A public health warning is in place and locals in the area say they hope the issue is sorted out quickly.
They say their children can't swim or use the lake and guests in accommodation facilities on the lake edge are annoyed to discover the lake is out of bounds.
Council three waters services manager Eric Cawte said the council did not think there was another wastewater leak somewhere.
He said discussion with the Bay of Plenty Regional Council officials had raised other possible factors including background bacteria in the lake and stream related to animal or birdlife, activities up stream and erosion.
"The lingering levels of bacteria could also be attributed to natural conditions in the lake such as wind and water currents restricting movement for dispersion and dilution. Investigation and testing is still underway to try and pinpoint a reason."
The water was tested again yesterday morning and results would be known by this morning.
The health warning would remain in place until bacteria contamination levels had fallen below the recommended level for safe swimming.
Bacteria levels were expected to rise in the coming days with rain forecast.
Cawte clarified the health warning applied only to the spill area in Ngongotahā, within about a 400m radius of the Waiteti Stream mouth.
Rotorua Lakes Council building. Photo / NZME
Cawte said in a council social media post on Tuesday that the lingering levels of bacteria in the water were not consistent with what typically followed a limited overflow into a large body of water.
He said normally the contaminants would disperse and become diluted into the lake after a few days. Bacteria levels would then normally reduce to below the recommended safe swimming levels.
"What we are seeing is slightly elevated levels of bacteria around the Waiteti stream mouth, further upstream and in areas that are some way from the overflow site. We are considering whether there are other factors contributing towards the elevated levels."
Ken Liao, from Jack and Di's Lakefront Motel and Lodge on Arnold St, described seeing the spill last week.
"Brown water came out [of the manhole] spraying everywhere like a fountain."
He said big trucks and machinery were brought in to clean up the mess.
His children, aged 8 and 4, and motel guests were disappointed they couldn't use the lake.
"My boys love playing in the lake but we have been telling them they can't. The guests can't even kayak because there's a sign there saying don't enter the lake.
"When you look at the lake it looks beautiful and clean. But what happened happened - the issue for us is if the kids can't enjoy the water as much."
Aria Hamiora said her son, 11, was swimming with his cousins, aged 3 and 8, on Tuesday afternoon at Hannah's Bay - on the opposite side of Lake Rotorua - and they weren't clear whether the health warning applied to them.
"If we had known there was a warning about the water we wouldn't have let them in and we won't be going back there until we know the lake is safe."
Professor Russell Death. Photo / NZME
Medical officer of health for Toi Te Ora Public Health Dr Jim Miller said gastro illnesses and skin infections caused by direct contact with the contaminated water or land were the main health risks associated with sewage spills.
Other health risks can include localised contamination of sources of drinking water as well as contamination of food sources collected from the environment.
Bay of Plenty Regional Council compliance manager Stephen Mellor said the regional council was investigating the incident which would determine their compliance and enforcement actions.
Meanwhile, Rotorua Lakes Council is awaiting sentencing by Judge Jeff Smith in the Rotorua District Court after pleading guilty to discharging a dangerous substance from the city's dump on April 6, 2017.
The discharge was leachate, which was described in court documents as having a bacteria equivalent to that of raw sewage. In a diluted state, it entered Tureporepo Stream, which flows into Puarenga Stream and Lake Rotorua.
Although the charge related to a single discharge, the court process heard how the council had been repeatedly warned by the regional council about discharges from the landfill over several years.
Leachate overflowing at the Rotorua Landfill in 2017. Photo / NZME
