Motueka River is country's clearest

The Motueka River at the Gorge is the best river in the country for recreational use, with the clearest water and the fourth-least amount of contamination by E.coli bacteria, according to Ministry for the Environment league tables.

The tables used 2007 data gathered from 77 national network sites on 35 rivers to rank water clarity and levels of E.coli bacteria to build an overall picture of river health for recreational use.

At the Gorge, the water clarity was 12.93m with levels of E.coli at 18.4 cells per 100ml. Clarity for the worst river, the Waitara in Taranaki, was 1.02m, with levels of E.coli there at 4426.6 cells per 100ml.

The Nelson-Tasman region fared well in the tables, with two other sites in the top 10 for recreational water quality: the Motueka at Woodstock and the Buller at Longford. The worst rivers in the country were in the Manawatu/Wanganui region, which had five river sites in the bottom 10.

Tasman District Council resource scientist Trevor James said the council's data backed up the survey "absolutely". In 10 years of council monitoring, he said, only four samples had ever tested above detection for E.coli, with the highest ever at 30 cells per 100ml.

He said a possible reason was that much of the catchment started in the Red Hills, which did not support many warm-blooded mammals because of a lack of vegetation.

Lack of soil in the area may also be one reason the water had good clarity because there was less suspended sediment in the water, he said. However, he said water clarity was still identified as a "major issue" for the region.

The ministry tables also ranked rivers for nutrient levels and macroinvertebrate activity. Nutrient levels showed the Motueka deteriorated along its length: at the Gorge it was ranked 10, but by the time it reached Woodstock it was ranked 34th.

Motueka Integrated Catchment Management research programme leader Andrew Fenemor said that at the Gorge there had been relatively little disturbance upstream, but by the time the river reached Woodstock, two-thirds of the way down the catchment, there was likely to be an impact from tributaries and pastoral land.

Minister for the Environment and Nelson MP Nick Smith said transparent reporting of water quality was part of the Government's intention to "manage what it can measure". There had been "very piecemeal data" in the past that was not nationally comparable. He said rivers in the region were facing greater pollution pressures, but was particularly pleased as a local that the Motueka had topped the report, which he thought was partly due to a low level of intensive farming in its catchment.

"Those communities should take a bow, and those where river standards are bad should make sure they lift their game," he said.

However, Green Party co-leader Russel Norman said the water-quality league tables painted a "clear but ugly picture". In the Green Party's weblog, he said that on one hand, the tables were "great news".

"The first step towards cleaning up our rivers is knowing how bad the problem is, and the information in these league tables gives a clear overall snapshot of national river water quality," he wrote.

However, while it was a clear picture, it was also an ugly one. "Many of our rivers are in a dire state."

- © Fairfax NZ News

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