We’re all responsible for water


The ODT brings some balance to bear on water woes:

. .  . evidence that farmers are not the only cause of such pollution may surprise some.

Urban-sourced pollution of waterways does not have the same public profile as that from farms, but one of the country’s great rivers, the Clutha, is still used to remove urban waste from several towns on its banks. Readers were reminded this week that treated sewage from Alexandra, Cromwell, Lawrence, Balclutha, Stirling, Tapanui, Kaka Point and Owaka all ends up in the Clutha, while treated sewage from Queenstown is discharged into the Shotover River. Dunedin waste is treated and discharged to sea through the Tahuna plant but most of the city’s stormwater – untreated – drains into Otago Harbour.

While dairy farmers have largely been the focus of recent attention about waterway pollution, a report carried by Fairfax this week showed some local authorities had struggled to abide by the conditions of their discharge consents. It reported this week that, in the past four years, fines of $153,000 for 123 breaches by 34 of the country’s 61 district and city councils had been issued.

These were made up of eight prosecutions, 47 infringement fines and 68 abatement notices.

In contrast, over the same period, there were 151 prosecutions of dairy farmers, with 1564 infringement notices and 1698 abatement notices. Dairy farmers paid court-imposed fines totalling more than $3.2 million. The heaviest fine for a farmer has been $90,000 and for a local authority $30,000, raising questions about consistency. In a similar vein, in the past six years, while 76 Otago dairy farmers have been prosecuted for illegal effluent discharge, for allowing livestock to access waterways or for pugging, no Otago councils have been fined for any breach of any kind (Environment Southland has recently taken successful cases against Invercargill city and Gore district councils). . .

Milking on the Moove has more on the causes of water pollution:

There are essentially 3 types of pollutants that affect our water ways:
  • Sediment -as a result of erosion and flooding, where large amounts of soil and gravel etc get washed into the water ways.
  • Bacteria– from animal and human waste being discharged into the water ways.
  • Excess Nutrients-when Nitrogen and Phosphorus find their way into the water ways.
Dairy farms main pollutant is Nitrogen from excess nutrients. This graph shows how much nitrogen is leached per ha from the different farming classes. Interestingly Horticulture is the worst offender, but Horticulture makes up a very small area so the overall effect is not as great as the dairy industry. You can see that a dairy farm leaches on average 50kg of N/ha/yr, which is less than horticulture. I have seen data that show vineyards leaching 80kg of N/ha/yr.
They’re-worse-than-us is no excuse but this does show that  urban discharges, horticulture and cropping are part of the problem.
We all use water, we all contribute to waste water which means we’re all responsible for its quality to a greater or lesser degree.


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