A lot to be done on lake pollution, but it’s a start

Some have been worrying about it for years, others denying it for years, now statistics show it has been happening for years. It is beyond doubt that the quality of the water in our high country lakes has been deteriorating. Intensifying farming, including more dairying, equals degenerating lakes – fact.

‘‘Polluted paradise’’ the Weekend Press headline said. A far more coarse, two-word phrase could be applied to the polluted state of the high country lakes, although in this instance it is not a creek we are talking about.

The purity of our alpine lakes has been seriously compromised, fouled by nutrient and phosphate-rich runoff from farming. The lakes, once pristine and blue, have, over the past decade, become green and murky.

Monitoring by Environment Canterbury (ECan) shows that of 14 lakes, only one – Lake Emma – is marginally less polluted now than in 2004. All the others, including some of the best-known, such as lakes Grasmere, Pearson, Lyndon, Ida, Coleridge and Clearwater, have become increasingly tainted.

In the five years since government-appointed commissioners took over the regional council, there has been some improvement to the picture, with purity in five lakes now better than in 2010, worse in eight lakes and much the same in one.

Cantabrians do not need official figures to let them know the wretched story. You can tell by simply looking. Try taking a dip in Lake Pearson and see how algae there has turned the water cloudy. Just up the road, Lake Grasmere offers similar unpleasant experiences. A letter writer to The Press said he had been fishing Grasmere for 65 years and had observed its inexorable deterioration.

Declining lake quality was just one concern Parliamentary Commissioner for the Environment Jan Wright warned about in her report on the high country in 2009. Federated Farmers at the time questioned her comments that lake pollution was due to intensive farming, saying alpine water quality was generally excellent.

ECan now says ‘‘nutrient loading’’ poses a significant threat to the health of 25 lakes in the upper Rakaia Gorge, the Ashburton basin and along the upper reaches of the Rangitata River. The shallowest are regarded as the most vulnerable to degradation from farming and contamination from bird droppings. Research by the Cawthron Institute came up with similar conclusions, that more intensive farming, dairying and growing crops for livestock created the right ingredients for more nutrient runoff into lakes.

Until the earthquakes, water was Canterbury’s biggest issue. It was such a hot topic – particularly when viewed in conjunction with the growing desires for irrigation to help the rapid intensification of the region’s agriculture, especially the boom in dairying – that it led to the downfall of a demo- cratically elected regional council.

So how much leadership have the commissioners, and by association the Government, shown on this critical issue? After all, Cabinet has trumpeted on several occasions how well the installed commissioners have been handling the water issues held up as the reason for their appointment and the sacking of councillors. And the National Government will hardly be remembered as at the forefront of environmental guardianship or protection efforts, to put it kindly.

Pleasingly there are early signs that farm management plans required by ECan may be starting to make a difference. Council staff have been working with high country farmers on how they might minimise nutrient seepage that changes the ecosystems of the waterways. These plans help determine how much fertiliser really is needed and consider ways to use irrigation more efficiently to reduce drainage.

The figures show a slow improvement, even if the purity of most lakes remains well below levels a decade ago. It will be a while before we can again swim and fish in pristine alpine lakes, but it may be a start.