The death of 10 cattle after drinking lake water contaminated by toxic algae highlighted two things - the terrible state of Waikato lakes, and that cattle had access to the water.

This column has sought to raise awareness of the first: the second has been hammered nationally by Fish and Game's "dirty dairying" campaign.

On the face of it, the news that Lake Rotongaro is poisonous enough to kill large animals suggests neither people who care deeply about Waikato's lakes, nor the Fish and Game campaign have made much headway.

Rotongaro, too, is just one of five lakes that are currently the subject of health warnings. So are Lakes Hakanoa, Kainui, Ngaroto, Waahi and Whangape.

And if we are looking for a reason they are in such a state we probably need look no further than the comments by Waikato University professor David Hamilton, who is heading the research into Rotorua's sick lakes.

Hamilton told the Herald that Waikato lakes were in a much worse state than those in Rotorua.

Almost a forgotten icon of the area, Waikato lakes were in a "severely degraded state", he said.

Intensive farming was responsible for some of the problem, causing a build-up of nutrients from animal effluent, fertilisers and other run-off into the lakes.

But why, if Waikato lakes are as iconic as those in Rotorua, and are more heavily polluted for exactly the same reason, do they not rate a similar rescue mission?

The obvious answer - few Waikato lakes are on a well-trodden tourist trail - raises important questions for those with a duty of care for the environment - regional councils, and Government departments. Are their priorities and actions led by the needs of the environment they are sworn to protect or the almighty dollar?

Who decides what needs protection - foreign tourists or New Zealanders?

Perhaps surprisingly, around Lake Rotongaro it is definitely the locals and they have been prompted to action, not by campaigns or damning newspaper headlines but by their memories.

George Blair, whose bull farm runs down to Rotongaro's water's edge, remembers rowing boats on wetlands that today are parched pastures. His neighbour Rob Beverland, whose land drops down to Lake Whangape, remembers it as healthy and teeming with wildlife.

"In the 1950s and 60s we were all guilty of clearing gullies, which are absolutely no use for farming," Beverland says.

"We would've been better to have left them alone but we were here to develop and get as much land as we could."

Underscoring the fast rate at which swamps were drained, land stripped of trees and sheep and cattle replaced wetland wildlife, neither man is talking of long ago. They can recall huge transformations in land and lakes within the past 50 years.

When they add the stories of their fathers and grandfathers, who settled the land west of Huntly, the vast scale of farming's impact on bush and wetland, and the speed with which it happened is breathtaking.

Now that the consequences are to be seen in sick lakes and silent bush, some farmers are taking on board new thinking.

Beverland began fencing his 2.5km of lake front 10 years ago. With Environment Waikato funding, designed to help farmers with conservation fencing projects, he's also fenced off gullies that feed into the lake.

The benefits of the tree planting and natural regeneration are now emerging. The treed gullies and bushy lake edge act as filters for run off. Eliminating boundary fences that used to run into the lake has removed a major maintenance headache.

Trees on the lake's edge act as a windbreak and geese that used to walk straight off the water to eat pasture now face a few barriers.

Beverland says he now feels more comfortable about using fertiliser because a better filtering system is in place.

Blair called a meeting in 1998 that was attended by 15 neighbourhood farmers whose land bordered lakes. With help from Environment Waikato, the Conservation Department, Fish and Game, Forest and Bird and Ducks Unlimited, fences have been voluntarily going up along lake edges and trees planted at a steady rate ever since.

Now there is a stark contrast between farms with bushy, green lake edges - some of them fenced only recently - and those where heavy cattle can walk right out into the shallow water.

It's a small but significant start toward combating a big problem. The recent cattle deaths show there is more to be gained than reversing environment degradation.

The dead cattle were valued at around $12,000. "You could put in a lot of fencing for that," said Blair.