Knowledge-based Ground Water ModelingAnd Parameter Validation

Abstract

Groundwater flow and particle transport can be described by mathematical groundwater simulation models, which turned out to be very good tools for analysing complex groundwater scenaries. These groundwater models gain in quality if they are combined with knowledge based systems. The problem with groundwater modeling often is not the connexion between model and knowledge based system rather than the knowledge itself. Getting true values of the input parameters required by the model can be very difficult, because these are correlated in a very complex manner. By discussing the input parameter macrodispersivity this paper discusses the importance of acquiring high quality input data for groundwater simulation models. Preliminary results of such long time large scale field experiments show that there is a functional relation between dispersivity, length of flow path and geological parameters. If this relation can be expressed quantitatively by evaluating a functionality very compact knowledge will be gained which can be placed directly into an algorithm for particle transport modeling. Transactions on Information and Communications Technologies vol 1, © 1993 WIT Press, www.witpress.com, ISSN 1743-3517 404 Artificial Intelligence in Engineering 1. ABILITIES OF NUMERICAL GROUND WATER MODELS Numerical groundwater models are an important tool in groundwater protection and analysis of complex groundwater scenaries (KinzelbaclP). This is mainly due to their ability of forecasting and calculating the worst case. Therefore they are very valuable in planification, taxing hazardous risks, analysing groundwater contaminations, security analyses for wells e.g.. Managed by an expert they represent the state of the art in groundwater modeling. Only by using such methods a complete view of the groundwater flow can be gained as well as prognostical statements. In the following the limits of traditional hydrogeological methods and in turn the advantegeous abilities of numerical models in the field of simulating the groundwater flow are discussed in brief by means of figures 1, 2 and 3 (Pfaff*). Fig. 1: By applying conventional hydrogeological methods only a linear interpolation can be made between two known altitudes of a groundwater table. But the linear interpolation is faulty if a water table is vaulted. For this reason a groundwater isohypse map often is inconsistent and of minor suitability for the examination of solute movement. Transactions on Information and Communications Technologies vol 1, © 1993 WIT Press, www.witpress.com, ISSN 1743-3517