ABSTRACT
Although the river and the hillside . . . do not resemble each other at first sight . . . one may fairly extend the river all over its basin and up to its very divides.
(Davis, 1899)
To protect your rivers, protect your mountains. (Attributed to Emperor Yu of China, 1600 )
Catchments are thus unknowable in objective terms. (Ison et al., 2007)
These quotations serve to re-emphasise the huge appetite for data, information and knowledge inherent in our ambition to coordinate the human exploitation of the resources of any river basin ecosystem and to make that exploitation sustainable. Our penchant for constructing myths (Chapter 3) illustrates a basic desire for rationality, one denied to us by catchments being inherently ‘unknowable’! We might recall the words of the philosopher Bertrand Russell, who remarked that ‘Uncertainty . . . must be endured if we wish to live without the support of comforting fairy tales.’ As Hillman and Brierley (2002) put it, ‘Expectations of certainty are placed on the biophysical sciences because of a widespread public perception that they can provide black-and-white answers’ (p. 625). Whatever the expectations, two roles remain central for the biophysical sciences: policy formulation and decision support, but to perform either demands more than simply ‘writing up’ research results. Scientific outputs require careful translation into the more or less reliable (in a legal sense) ‘tools’ of evidence-based public policies. In legal parlance, evidential proof is divided into ‘beyond reasonable doubt’ and ‘on the balance of probabilities’; much of the scientific guidance we have discussed in this book has fallen into the latter category. Our first challenge is to understand the broad societal context into which the science is to be translated: hence the need, once again, to ‘have a go’ at understanding sustainability.
