APPLYING SYSTEMS-ANALYSIS IN MANAGING THE WATER ENVIRONMENT - TOWARDSA NEW AGENDA

The methods of systems analysis - principally, mathematical modelling, simulation, and optimisation - have been widely applied to solving pr oblems in managing the water environment for over three decades. These foundations of the subject remain just as relevant today as hitherto. The problems to which they might be applied, however, or the context in which they might be applied, seem to have changed in ways that coul d genuinely be described as ''radical''. In this survey stock is taken of these changes in perspective, especially over the past ten years: in the emergence of stakeholder participation, environmental ethics, l ife-cycle analysis, sustainability, industrial ecology, and design for ecological (as opposed to engineering) resilience. Whether the applic ation of systems analysis will require a new approach or new methods w ith which to address these new issues, is thus open to question. For t here are undoubtedly limits of method now discernible, even in respect of the more conventional problems of applying systems analysis to man aging water quality. For example, we shall be obliged to acknowledge t hat, were we to encode all our currently available hypothetical knowle dge into a model, this would not be verifiable in the conventional, ri gorous sense. Similarly, in spite of a wealth of apparently ever more powerful mathematical formulations of the problem of optimisation, heu ristics and intuition must still be called upon to reach even good sol utions, reasonably close to where the optimum is thought to lie. Circu mventing such methodological difficulties, while yet absorbing the cha nging currents in outlook on the man-environment relationship, is wher e candidate tasks for the ''new agenda'' of the next few years might b e found. This paper presents some personal observations on a handful o f such candidate tasks. (C) 1997 IAWQ. Published by Elsevier Science L td.