KEY POINTS:
A Danish water quality expert has warned that degradation of the country's lakes is likely to get worse because a "time bomb" of polluting nitrates exists in the ground.
Erik Jeppesen, from Denmark's National Environmental Research Institute, said years of intensive farming in New Zealand meant high concentrations
of nitrogen and phosphorous would continue leaching into lakes and waterways for several decades yet.
"It's simply because you have a time bomb from the past."
Professor Jeppesen was a speaker at the first day of the Rotorua Lakes 2008 symposium yesterday and told guests that tough national regulation on farmers was needed to limit water degradation in the future.
"Farming is an industry and has to be treated as an industry," he said.
"Don't repeat our mistakes because you have a lot to clean up afterwards."
He said Denmark had introduced measures including taxing fertilisers and reducing stock density which had gone some way to cleaning up its waterways, but further regulation was also needed there.
He recommended caps on nitrogen use in particular in New Zealand, but dairy farmers at the symposium said such caps were already threatening to put them out of business.
Mike Barton, chairman of Taupo Lake Care - a society which represents 120 farmers in the Taupo region - said his farm was already subject to nutrient caps as part of a study and they were economically destructive.
"Over the next 10 years, we are unlikely to survive financially."
Mr Barton told the Herald he was not opposed to caps, but if farmers were unable to maintain their income, it would have a huge flow-on effect to consumers because of the amount the industry contributed to the economy.
"We can have the cleanest lakes in the world but we may not be able to afford a kilo of cheese or a pound of mince."
He said the caps would cost Taupo farmers $185 million over 10 years, which in turn would cost the local economy $500 million because of money farmers would no longer spend.
"And Taupo's just a microcosm of what's going to happen in the rest of the country."
Carbon emissions regulations would also take a toll, and Mr Barton said that even now, farmers needed to increase production by 4 per cent a year to make up for the loss of income from nutrient caps.
He believed the survival of farming depended on science or extracting higher prices from the international market by trading on a sustainable image.
The symposium, hosted by the Lakes Water Quality Society, finishes today. The first day coincided with the signing of a deed of funding to help to clean up Rotorua's worst-polluted lakes, which suffer from toxic algal blooms resulting from high nutrient levels.
The deed sets out a $72.1 million commitment from the Government to improve the water quality in Lakes Rotorua, Rotoiti, Rotoehu and Okareka in the next 10 years.
Environment Minister Trevor Mallard and representatives of local councils signed the deed in the presence of Te Arawa Lakes Trust chairman Toby Curtis, who said it recognised the importance of the lakes to iwi.
The total cost of the restoration programme is $144.2 million and it includes extending sewage systems, diverting nutrient flows away from polluted lakes, and constructing wetlands.
The Government is also in the process of formulating a national policy statement on fresh water management.