New Zealands 10 Most Polluted Rivers

18 October 2012

New Zealand is, OK, was not a place that I would associate with high levels of pollution.  From this country, apart from ideal film sets for movies about hobbits, come tales of super-clear lakes, with measureable transparencies in tens of meters!  During the last year or so, however, there has been an increasing litany of reports about impaired surface water quality.

Here’s a list of NZs 12 worst rivers (Source: Infonews)

1. WAIKATO RIVER: North of Huntly the river has high levels of E. coli and nitrogen caused by agricultural runoff. The river is used by duckshooters, whitebaiters and waterskiers.

2. TARAWERA RIVER, BAY OF PLENTY: Pulp and paper mills have reduced wastewater discharges into the river and oxygen levels are now high enough to support fish life. Still known as the “black drain”.

3. LAKE TAUPO: Nitrogen leaching into the lake — more than 90% of which comes from farming — has degraded water quality and colour. Environment Waikato last year forced sheep, beef and dairy farmers to get a resource consent and has capped how much nitrogen they use.

4. TUKITUKI RIVER, HAWKES BAY: A tributary, the Pah Flat stream, takes sewage, including heavy metals and bacteria. There are toxic blue-green algal blooms at Havelock North near fishing lodges and popular swimming holes.

5. MANAWATU RIVER: Dairy effluent, wastewater discharges from Fonterra’s Longburn milk processing plant and treated sewage from Palmerston North, Horowhenua, Tararua and Fielding. There are permanent “no swimming” signs downstream of discharge points.

6. WAIWHETU STREAM, WELLINGTON: Past discharge of toxic waste (including heavy metals) from industry has left a thick sludge of contaminants, with “mineable” quantities of lead, zinc and copper. In the Environment Minister Trevor Mallard’s own electorate, the stream is considered to be New Zealand’s most polluted urban waterway. A $6 million cleanup began this year.

7. NGAKAWAU RIVER, WEST COAST: Above the Stockton Plateau it is pristine, below the Stockton Opencast Mine it is contaminated by sediment and toxic chemicals — although a recent cleanup has reduced levels of metals. People fish and catch whitebait in the river’s lower reaches.

8. KAIAPOI, AVON AND HEATHCOTE RIVERS IN CANTERBURY: High E. coli counts regularly make these urban rivers unsuitable fro rowing, kayaking and swimming during summer — although rowers continue to use the Avon and Kaiapoi. The upper Kaiapoi runs through a rural catchment where grazing stock use the river as a toilet.

9. LAKE FORSYTH/WAIREWA, CANTERBURY: Toxicity from high levels of blue-green algal bloom over the past 15 years has killed animals and made people sick. Recreational use is strongly not sadvised in summer. Eating shellfish is never advised although people do catch eels.

10. SELWYN RIVER: High bacteria counts make the Selwyn unsafe for swimming at several spots. It has a farming catchment in the foothills and often runs dry.

11. LAKE ELLESMERE: An overload of nutrients has led to a massive decline in trout numbers at this former world class fishery. A series of dry summers and water extraction for irrigation has affected water flows.

12. MATAURA RIVER, SOUTHLAND: The upper to mid reaches of the Mataura get farming pollution as well as discharges from factories. Used for trout fishing and catching whitebait. Fishing and bathing are not recommended before and after rainfall because of increased E. coli bacteria levels.


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