THE EVOLUTION OF EQUATIONS FROM HYDRAULIC DATA .1. THEORY

Even as hydroinformatics continues to elaborate more advanced operatio nal tools, languages and environments for engineering and management p ractice, it necessarily also promotes a number of concepts and methodo logies that are eminently applicable within the more traditional areas of hydraulic research. Among the many new possibilities thereby intro duced, that of evolving equations from hydraulic data using evolutiona ry algorithms has a particularly wide range of applications. The prese nt paper is in two parts, the first of which introduces the subject an d outlines its theory, while the second is given over to four represen tative applications and to some of the most immediate lessons that may be drawn from these. The first of the applications is derived from a hydrologic model but provides equations with purely hydraulic interpre tations. The second, taken from sediment transport studies, raises the question of ambiguity in the identification of ''thresholds'' in phys ical processes. It also provides a means for analyzing the significanc e of variables and indicates the need, or otherwise, for introducing f urther variables. A third example, based upon physical observations of salt water intrusion in estuaries, introduces the application of the present methods to accelerating prediction processes, while the fourth example extends this kind of application to cover numerically generat ed data, in this case appertaining to the case of flow resistance in t he presence of vegetation.