Avoid water contact: Swimming spots unsafe
Waterways likely contaminated after heavy rainfall
Almost all of the Bay of Plenty’s swimming spots are unswimmable after heavy rains swept the region this week. According to Toi Te Ora Public Health, it is “the rule of thumb” not to swim for at least 48 hours after heavy rain in order to avoid issues such as diarrhoea, vomiting, skin infections or ear infections.
“There is likely to be contamination from rural and urban run-off in waterways.”
Toi Te Ora’s health warning is reflected in environmental body Lawa’s (Land, Air, Water Aotearoa) recreational water quality data which, as of yesterday afternoon, showed all but one swimming spot in the region was unsuitable for swimming.
In late January before the latest heavy rain, 20 of the region’s 80 swimming spots were too unsafe to swim in.
Local residents called on visitors and boaties to stop ignoring health warnings and take greater care as health authorities issued warnings advising people to stay out of key areas in Rotorua lakes because of extensive algal bloom.
Lawa data is used by Bay of Plenty Regional Council and Toi Te Ora Public Health to determine whether certain areas are safe to enter.
Lake Rotoiti’s Okawa Bay and several locations around Lake Rotorua were among those “unsuitable for swimming” due to algal blooms.
Lake Rotoiti Community Association deputy chairman Jim Stanton said the health warnings issued around Lake Rotoiti over January had been “frustrating for everyone”, especially property owners and visitors.
“[They] come to enjoy a break over the summer holiday season only to find a blanket health warning against coming into contact with the lake water due to toxic algal blooms,” he said.
Stanton said many lake users either ignored or were unaware of the warnings and continued with normal on-water activities such as skiing, using paddle boards and towing biscuits.
He said watercraft users, in particular, needed to adopt “comprehensive” cleaning of equipment when moving between waterways.
Lake Rotoiti Classic and Wooden Boat Association commodore Richard Amery said algal growth happened once or twice a year and usually did not last more than a couple of days.
“These recent warnings were right on Christmas and the two areas mentioned, Okawa Bay and Te Weta Bay, turned green and people heeded the warnings.”
Amery said about four days after the warnings a storm meant the water reverted to normal colour.
“Despite no one lifting the algae warnings, everyone went back to water sports and swimming and, as in the past, we have not heard of anyone suffering any aftereffects,” Amery said.
Bay of Plenty Regional Council science manager Rob Donald said the criteria for deciding whether water was safe for swimming were based on microbiological guidelines in place since 2002.
“From late October through to the end of March, Bay of Plenty Regional Council collects weekly water samples from more than 70 popular coastal, river and lake recreation sites.
“The samples we collect are tested in our lab specifically for faecal contamination (E. coli or Enterococci bacteria) and for toxin-forming algae (cyanobacteria).”
Donald said the region had been “unlucky” this year.
“We have experienced a significant algal bloom in all four of the lakes we monitor. This resulted in all sites on these lakes (Rotorua, Rotoiti,
Rotoehu, Okaro) ¯ being classed as unswimmable as a precaution because toxic algae can be moved rapidly across water by wind currents.”
Donald said the blooms were subsiding but the health warnings still stood.
“There are lots of factors that contribute to whether a site is swimmable or not, with the weather playing a significant role.”
Bay of Plenty Regional Council Rotorua catchments manager Helen
Creagh said algae were essential to freshwater ecosystems but became problematic when they reached high levels.
“Pollution from urban areas, excessive nutrients, lack of water circulation in calm conditions, extreme weather events and higher water temperatures can all alter the natural composition of algae in the lakes,”
Creagh said.
“If the natural balance is disturbed an algae overgrowth or ‘bloom’ may occur, causing discolouration, scum, odours and even toxic effects.”
Creagh said algal blooms could happen suddenly.
“So a warning may not be in place when you’re out swimming. Remember to always check for signs, is the water pea green or discoloured? Does it have slime on the surface, like paint scum? Is it smelly? If in doubt, stay out,” Creagh said.
He said the council’s goal for lakes with regular algal blooms was to reduce nutrient outputs from sewage and septic tanks and to reduce nutrients from land use.
“We support and encourage the retirement of riparian areas beside streams by fencing and planting trees, the conversion of land to native bush and forestry to remove livestock and to reduce fertilisers, and more environmentally acceptable farming methods with funding and advice,”
The rain is so bad and it's not viable to open. Nobody goes to the lakefront
when it rains. Chris Senerpida, Teariffic Bubble Milk
Tea owner
continue to monitor the situation and contractor crews are continuing clean-up,” it said in a statement.
In the 24 hours from 12.01am on Wednesday, Fire and Emergency’s communication centres received 413 calls across the country, 14 of which were in the Bay of Plenty with one priority two incident where there was a potential risk to people.
The final stage of the Rotorua lakefront boardwalk opened to the public in August 2022.
The boardwalk was the latest stage of construction and part of the $40 million lakefront redevelopment.
Work began on the final section of the boardwalk in September 2021 which has involved an additional 50 metres of boardwalk being built out over the water at the western end of the lakefront reserve.