We cannot afford to ignore the state of our lakes and rivers - and it's not just a question of economics.
I have the greatest respect for Sir David Skegg, president of the Royal Society of New Zealand. Nevertheless, I think that the way he frames the debate over the state of waterways in his recent Dialogue article is mistaken.
Echoing the Parliamentary Commissioner for the Environment, Sir David argues that in choosing between intensive farming and dirty and degraded waterways, the country faces "a classic economy versus the environment dilemma".
This kind of framing, which speaks as though the interests of the economy and the environment are at odds, is based on a logic that splits mind from matter, subject from object, and people from the world around them.
The difficulty with this logic is that it has been rendered obsolete by the findings of contemporary science - brain science, quantum physics and the social and environmental sciences, for example.
Economics, too, has moved on. To quote Herman Daly, a senior economist at the World Bank, "the economy is a wholly owned subsidiary of the environment". As Daly points out, it is an oxymoron to separate people from the ecosystems that sustain us. This is certainly true in New Zealand, a country that derives so much of its wealth from the land, waterways and the sea.
Part of the problem is the structure of the sciences themselves, which have echoed this same outmoded logic by dividing the human from the natural sciences. As a result, scientific inquiry often fails to accurately grasp the complex dynamics of biophysical systems where human activities are implicated at every scale.
This kind of reasoning has also encouraged people to think that they can choose to damage waterways, for example, without putting their own lives and futures at risk. Unfortunately, however, given the fragmentation of our knowledge about water systems, we cannot accurately reckon what the costs of this degradation might be.
Remarkably, the first global study that sought to quantify the impact on human communities and aquatic biodiversity of the many stressors on river health, including agricultural runoff, pollution and invasive species, was published in Nature in 2010. This is despite the fact that according to this source, the waterways that serve 80 per cent of the world's population are threatened.
As we know from the Parliamentary Commissioner for the Environment's recent report on the state of waterways, many of them are in trouble. At present, we are conducting a very high risk experiment with our waterways and harbours, damaging aquifers, groundwater, wetlands, springs and lakes as well as streams and rivers with high flows of sediments and pollutants of various kinds.
As the leader of the Nature report on threats to the world's rivers, Professor Charles Vorosmarty concluded: "Our study demonstrates that diagnosing and then limiting threats at their local source, rather than through costly remedies and rehabilitation, is a more effective and sensible approach to assure global water security for both humans, and aquatic biodiversity."
I agree. The real challenge is to give up talking about trade-offs between the state of our waterways and the economy, and to pursue evidence-based approaches that traverse the natural and the human sciences, and seek prosperity for people and waterways alike.
As for the costs of damaged and degraded streams and rivers, the questions we should ask include the following: Is the current boom in dairying likely to lead to lasting prosperity, if we pollute or destroy rivers? Will consumers in other countries continue to trust our milk powder or other dairy products, or will they desert us for producers who seem more environmentally responsible and astute?
Will tourists continue to visit our shores, if they get ill from swimming in our rivers, lakes and harbours? What will happen to New Zealand's 100% Pure reputation if our rivers and lakes are choked with weed and algae?
Is the headlong pursuit of short-term prosperity at the expense of our waterways a rational choice, or is it a foolish, deluded gamble, based on a mistaken separation between people and the environment that is the source of our life, health and wealth?
Dame Anne Salmond is the project sponsor of Te Awaroa, aimed at enhancing waterways across New Zealand.