Mathematical modelling and environmental decision-making

The primary role of a decision-maker is to make right decisions on the basis of available information and within the allowable time and resources constraints. The two basic types of models used for decision-making, technocratic and incremental, are discussed, and so are the common criteria of the decision-making process in a real world. The intensity and diversity of demands on our limited water resources have increased to such an extent that decision-makers are finding it increasingly difficult to consistently attain the needed flexibility and dexterity. Thus, even though decision-making has become exceedingly complex at present, and will become more so in the future, it is apparent that the average decision-maker has been provided with few, if any, new tools and concepts in the past several decades. One of these very few techniques is systems analysis.Even though modelling can add an important dimension to the decision-making process, surprisingly enough it still lacks credibility with the policy-makers. The several reasons that have given rise to this “credibility gap” are discussed in depth. Ten basic rules are suggested as guidelines for realistic model development. The positive and negative aspects of modelling as used for decision-making are discussed. Appropriate remedies are suggested to improve the image of modelling in the eyes of the decision-makers, which will reduce the proliferation of unvalidated, untested and unuseful models, much of which can be classified somewhere between dilettantism and academic exercises. It is concluded that even though some of our current models in this field are rather crude, and somewhat dependent on the experience and judgement of the analysts, the issue, in the final analysis, is very definitely on the side of having a model, even a crude one, against having no model at all.