Water quality results at Lyttelton Harbour/Whakaraupō - what's the story?

Long-term grades for Corsair Bay, Diamond Harbour Beach, Rāpaki Bay and Purau Bay changed to poor prior to this summer. This is understandably concerning for Cantabrians who love to swim at these summer hot spots. 

From November to March, we monitor more than 100 popular swim and recreation sites in Canterbury. At coastal sites, we check for bacteria (enterococci) weekly, results can be found on the Can I Swim Here? section of the Land Air Water Aotearoa (LAWA) website. 

Our surface water science team leader Shirley Hayward said each site is given a long-term grade prior to each summer monitoring season for suitability for swimming and recreation, based on the last five years of bacteria sampling. 

“The Corsair Bay, Diamond Harbour Beach, Rāpaki Bay, Purau Bay long-term grades changed to poor after the 2021/22 season. They are not recommended for swimming because there is an elevated risk of getting sick from bacteria," Hayward said.

We will continue weekly monitoring of the sites and we are investigating the potential sources of bacteria.

Nearby bays with good long-term grades

Cass Bay has a grassy area with houses around and a swimming pontoon.

Cass Bay in Te Whakaraupō/Lyttelton Harbour

Other sites nearby at Cass Bay, Church Bay and Charteris Bay have long-term grades that are suitable for swimming. These sites are also monitored weekly and if high faecal bacterial concentrations are found, Te Mana Ora may issue a temporary health warning notice until the water quality has improved. 

“It’s best to check the LAWA website before going swimming, you can find weekly sampling results and information on the risk of illness.

“We do not have an answer on what has caused high faecal bacteria in the harbours, but we urge everyone to do their bit to improve the water quality when out swimming and using the water.

“Simple steps can help reduce bacteria in the water - use the public toilets provided, use swim nappies for babies and toddlers, pick up your dog’s poo and dispose of any toilet waste from boats and campervans responsibly.

“The bays that we all love to swim in are small and shallow which unfortunately increases the risk of any discharge having an impact,” Hayward said.

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