Marlborough's Swimming Water Quality

Marlborough has been identified as one of five regions where swimming water quality needs greatest improvement but in fact Marlborough’s water quality has been showing an improving trend for the last five years both at river and coastal swimming spots.

The Ministry for the Environment has released gradings from sites at beaches and rivers in areas where five years of data is available. The grades are based on bacteria levels and associated risk. Coastal water quality consistently returns a higher quality grade than river water sites in New Zealand.

A total of 13 river sites and 18 coastal sites are monitored across Marlborough.

Marlborough Mayor Alistair Sowman says it is well known that some of Marlborough’s rivers are affected by run-off but a great deal of work has been done in recent years to identify sources of contamination.

Five years ago 69% of Marlborough’s monitored river swimming sites were considered poor or very poor but today that’s down to 60% so improvement is occurring, he said.

However, Mr Sowman said he hopes to see greater advances in the next year or two as a great deal of effort and resource is now going into improving water quality.

“Earlier this year I noted that clean water should be one of our region’s priorities and I can assure you the Council is working on this issue. We want clean rivers which are free from bacterial contamination and I believe most people accept that is desirable.”

A great deal of work is being done with dairy farm plans near the Rai and Pelorus rivers where it has been established that most of the bacterial contamination is from cattle but it will take time for the effect of that work to filter through, he said.

Council staff believe the source of bacteria in the town’s Taylor River is likely to be more complex as the river takes a lot of run-off from roads and car parking areas as well as from parkland.

“The Council has adopted a stormwater strategy which is designed to improve water quality in both the Taylor and Opawa rivers and I hope we begin to see the effect of that soon,” said Mr Sowman.

He said work is well underway investigating the likely sources of pollutants.

“In the meantime, one constructive thing that everyone can do is to accept that contaminants should not go down our stormwater drains. That means no paint or oils, no sediments or detergents going down these drains,” he said.

Mr Sowman said water quality was an important issue for Marlborough and it was closely monitored and results regularly published on the Council’s website.

“Remember, not all councils across the country actually participate in the grading of their swimming sites so the Ministry for the Environment figures do not provide a true national picture, just a snapshot of those areas which do grade their swimming spots. We don’t know how Marlborough really compares to the rest of the country but we do know we want to improve our local gradings,” he said.

In 2010-11, river water quality in Marlborough compared favourably with river water quality nationally, with most sites suitable for swimming nearly all of the time.

Approximately 8% of sites in Marlborough were high-risk compared with the national figure of 13%. However there are more sites nationally (40%) which are almost always low-risk, compared with those in Marlborough which are almost always low-risk (23%).

In Marlborough, most sites (69%) showed low risk with an occasional high risk.