Philippa Stevenson: Lakes and rivers choke as the talk goes on and on

It would take about five million people - nearly 50 Hamilton cities - to generate the same amount of waste produced by the 3000 dairy herds that graze land draining into the Waikato River.

It's an interesting statistic to consider as the Waikato hosts the Agriculture Fieldays, where anyone taking a break from spending the profits of the land can stroll alongside the Waikato River as it runs past the Mystery Creek site.

They'd find the river cleaner than in the 1950s and 60s when it was used as the handy escape route for industrial and city waste.

When it came to cleaning up the river these easily identified polluters were tackled first. The effort was so successful that now the main contributors to river pollution are urban and rural runoff.

Rural runoff and leaching are the main sources of nitrogen, the nutrient that gives us choking plant growth and toxic algal blooms. Around 25 per cent of the runoff of nitrogen is thought to be natural. The rest comes from pasture - mostly cow urine.

Next Monday, after the Fieldays' tents are packed away for another year, the Environment Court will begin a two-week hearing in Hamilton prompted by an appeal by the Ecologic Foundation (formerly the Maruia Society) to provisions in Environment Waikato's proposed regional plan related to fertiliser use and runoff.

Ecologic stepped into the debate with submissions on the plan in 1998. Foundation senior fellow Jim Sinner is frustrated that so much nitrogen has flowed unchecked since then.

Ecologic wants Environment Waikato to require those in sensitive river catchments to have farm management plans approved by the council to reduce their farm's impact on water quality.

The case has nationwide implications, Sinner says, because it seeks to establish that farmers, like factories and sewage plants before them, must take responsibility for the harm they cause the country's rivers, lakes and streams.

Farmer John Fisher, who recently stepped down as Waikato Federated Farmers president, says the organisation will be in court arguing for more consultation on the issue and against the imposition of council-approved management plans.

He says a lot of effort has been put into improving farm practices and that education and encouragement will make more progress than heavy-handed regulation.

He does concede, though, that progress has been glacial and voluntary schemes have their drawbacks because, under voluntary management plans, farmers could still be "sneaking on more fertiliser and fiddling the figures between farms".

But with scientists still working on fertiliser additives that could slow nitrogen loss, the wholesale adoption of farm practices to lessen impacts such as feed pads and wintering stock off farms would bring sudden and costly changes to traditional farming.

"We should make incremental gains all the time because anything else will rock the economy," Fisher says.

Although farmers want the voluntary system to continue, Ecologic and Environment Waikato agree that regulation is required.

The council's disputed plan includes the proposal that from this year farmers have a nutrient budget to plan nitrogen fertiliser application where it's being applied at rates greater than 60kg a hectare a year - about half the rate used on most dairy farms. Such budgets must be designed to predict nutrient leaching rates and be approved by the council.

The council wants full community consultation, a process that could take years. Ecologic would like it brought in this year but suggests farmers in priority catchments such as those from Karapiro to Taupo have until 2007 to get their plans approved.

Council spokesman Robert Brodnax says next week's court case has come down to a very narrow issue.

"It's put it [the rule] in place and mop up public opinion afterwards or work through the issues now.

"We believe that if we are going to impose rules on the community the community has the right to have their say on those rules."

Sinner believes the council's consultation will sound the death knell for already damaged waterways.

The council's process could take at least another 10 years, "by which time it will probably be too late for the rivers and lakes that are vulnerable."