The Marlborough Rivers Too Dirty To Swim In

Tuesday, 7 October 2025, 5:36 pm
Article: Kira Carrington - Local Democracy Reporter

With summer fast approaching, some waterways have been given a big thumbs down for swimming in the Marlborough District Council’s river health report card. 

After monthly monitoring at 54 sites, the latest report has graded 29% of Marlborough rivers as having unacceptable water quality. 

Popular swimming hole Craiglochart, in the Mid Waihopai, was among the waterways with poor results.

Catchments in the west and northwest of the region were more likely to have “fair” or “good” quality water, while intensive land use had caused “marginal” or “poor” water quality in streams and rivers in the lower Wairau and Awatere valleys. 

Urban rivers, such as the Taylor River in Blenheim, also had poor quality water due to runoff into stormwater drains. 

The Taylor River was one of 15 waterways not clean enough for swimming, fishing or harvesting, nor for aquatic ecosystems. 

It had high E coli levels and problematic phosphate levels. Peter Hamill, the council’s land and water team leader, said high levels of E coli indicated faecal matter in the water, which could contain other more dangerous bacteria such as campylobacter and salmonella. 

“If you've just found like one E. coli [cell] in the waterway, it's not so bad for recreational bathing, but [if] the level gets up ... the risk of getting sick through some of the other pathogens is starting to get elevated,” Hamill said. 

“There's definitely an elevated risk of swimming in the Taylor. 

“Look for signs because if we do see that things are elevated, then we will put signs up there to say that it is a higher risk at that time.” 

Hamill’s advice to people wanting to swim in the Taylor River was to find a spot upstream of Blenheim.

Hamill said children and the elderly were at particular risk if swimming in poor quality water. 

“It's people with young children and elderly people, people with lower immune systems, that's what all these systems are [for].” 

The other 14 waterways with poor results were the Lower Awatere, Omaka River, Marchburne River, Lower mid Wairau, Mid Waihopai, Lower Ōpaoa, Linkwater Stream, Murphy’s Creek, Tuamarina River, Mill Creek, Pukaka Stream, Doctors Creek, Flaxbourne River, and the Riverlands Coop Drain. 

Murphy’s Creek in Springlands, which fed the Taylor River, made the list for its particularly high nitrate levels. Linkwater Stream had particularly high E coli levels, and Pukaka Stream, Doctors Creek and Riverlands Coop Drain had high ammonia levels. 

Eight sites technically met the council’s standards but were at risk of falling below them: Timms Creek, Medway River, Lower Waihopai, Grey River, Rongā River, Mid Ōpaoa, Oyster Bay Stream and Mid Awatere. Elsewhere, Cullen Creek had high ammonia levels, and Ngākuta Bay Stream had high E coli levels. 

They were not on the list of waterways with poor results because dips in their water quality were generally tied to rainfall, Hamill said. 

“Ngākuta Bay is flagged because when we get rainfall events, as soon as you get some surface runoff, anything that’s had a poo on the land basically, whether it's a cow or a bird or a septic tank .... it washes into the stream,” he said. 

“[It’s] good to swim at, but if there has been rainfall events ... you shouldn't go out and swim in one of the rivers or the sea, ideally it’d be [for] 48 hours.” 

People could help to protect water quality by being mindful of what went down stormwater drains, Hamill said. 

“If you look ... at the stormwater drains, you'll see little blue fish on them. This [means] rain only. 

“We don't want to be pushing dog poos or anything else into those stormwater grates, or washing your paintbrushes, or any of that kind of stuff down there, because all of our stormwater systems just take the quickest route into the river.” 

Swimmers wanting to check the latest water quality results could check the Can I Swim Here? page at www.lawa.org.nz. 

-LDR is local body journalism co-funded by RNZ and NZ On Air.

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