Monitoring of region's swim spots keeps public informed over summer

Horizons Regional Council’s summer swim spot monitoring programme is underway to help inform the public about potential health risks and highlight over 80 recreational sites in the Manawatū-Whanganui Region.


The annual monitoring programme runs from November to the end of April and tests bacteria levels for freshwater rivers and lakes, and coastal beaches. Some freshwater sites are also regularly monitored for potentially toxic algae. 
Horizons natural resources and partnerships group manager Dr Jon Roygard says alongside New Zealand’s 15 other regional and unitary councils, Horizons collects, analyses and reports on swim spot monitoring over summer through the Can I Swim Here? module on the Land, Air, Water Aotearoa (LAWA) website to help the public decide when and where they can swim over summer.
“Weekly water samples collected from each site are sent to an independent accredited lab for testing,” says Dr Roygard.
“Results are received within 48 hours and are updated on LAWA and Horizons’ websites, where interactive maps show each of the swim spots marked by a red, amber or green location marker to indicate that week’s results.
The traffic light system used is part of the Ministry of Health and Ministry for the Environment guidelines that provide guidance to Councils and District Health Boards regarding how they should act when certain levels of indicator bacteria or algae are detected.
“For our lakes and rivers, a green/suitable for swimming result indicates a sample returned less than 260 E. coli per 100ml, the amber/caution advised result is between 261-550 E. coli per 100ml, and red results mean avoid swimming as a sample has greater than 550 E. coli per 100ml. If a site falls into the red category, information is provided to the public that the site is considered unsuitable for recreational use.
“Gravel bed river sites and lakes are also tested for cyanobacteria, which is an algae that can be potentially toxic. Horizons will be keeping an eye on this during summer and also reporting these results on the websites.
“However, we do urge public and their animals to stay out of the water if they are at a river and see black or dark brown, slimy mat-like growth on the stones that may also be musty smelling. In lakes, potentially toxic algae are visible as bright green “blooms” with surface scum often found at the lake edge.
“This year in collaboration with regional councils, the LAWA project has introduced new water quality historical displays on the swim spot page to help would-be-swimmers decide where’s suitable for a dip. The new donut graph display of results from the past five swim seasons is helpful for seeing the performance of a swim spot over time.
“In addition to water quality, LAWA’s website includes local weather, tides, surf, water temperature, flow-rate, whether a site is patrolled by lifeguards, and information on each site’s facilities such as camping and toilets, and factsheets on monitoring, algae and faecal indicators.
“We do want to remind people that water quality is just one factor in a number of potential health risks. We ask the public to be aware of hazards such as unstable banks and cliffs, submerged logs, and tsunami warnings and rips at beaches.
“Another thing to remember is that as sampling is weekly, the results may not always reflect the water quality for the whole week, especially if it has rained. A general rule is if the water looks clear and it’s three days after rainfall, you should be good to go.”
Dr Roygard says the results from the monitoring programme are used to help inform the Council’s policies, and the work programmes to enhance water quality which have been significantly increased through Jobs for Nature funding from central government this year.
“When looking at results from a year-round state and trend perspective continuing efforts to improve water quality is needed.
“The new long-term grading responds to the recent central government Freshwater National Policy Statement. The long-term grades allow swimmers to quickly identify swim spots that are excellent, and the ‘poor’ grade helps to signal sites where there may be an increased risk of getting sick because historical results have not always met swim guidelines.”