On-line Abstracts
- Fedra, K., Diersch, H.J. and Härig, F. (1994)
- Interactive
Modeling of Groundwater Contamination: Visualization and Intelligent
User Interfaces. In D.C. Adriano, A.K. Iskandar and I.P. Murarka [Eds.]
Contamination of Groundwaters. Advances in Environmental Science.
Science Reviews. Northwood, UK. pp. 189-220.

Abstract
The management and remediation of groundwater contamination problems is
among the more complex tasks in environmental management and technology.
Not only is the available information usually sparse and the physical
processes very complex, i.e., dynamic and spatially distributed,
they are also difficult to analyze, understand, and communicate.
At the same time, problems are often of considerable urgency and
the economic and political stakes are usually high.
Numerical simulation models are certainly powerful tools with enormous
potential, but they are difficult to use and difficult to validate.
Their results are difficult to communicate and thus not easily
understandable by a non-technical audience.
Putting groundwater models into an interactive framework, with a
user-friendly interface, employing computer graphics for
problem visualization can help to improve this situation.
This makes available numerous support functions, such as
transparent data base handling that allows the efficient use of models
and at the same time the effective communication of model results.
The discussion centers on three basic concepts, i.e.,
- integration
of various sources of information and tools that go beyond the
immediate groundwater model, but are important components in a
problem-oriented application; examples include coupling to geographical
information systems or image processing of remote sensing data,
various data base management systems, models for related systems
such as surface water or land fills, or multi-criteria decision support
tools;
- interaction , i.e., the ability to run the models
interactively, produce
dynamic animated output, define scenarios interactively, run, modify, and
re-run a problem or set of problems, tune output and display options
in real time, etc., to get immediate answers in an exploratory and
experimental man--machine dialogue; and
- visualization, i.e., the graphical and symbolic representation
of the system and its behavior in time and space, but also including the entire
problem that goes beyond the basic physical system and includes economic
and socio-political dimensions and attributes.
This chapter introduces
an interactive approach to groundwater contamination modeling,
and discusses the approach, its philosophy, and concrete implementation
examples based on two 2D finite-element and finite difference
simulators respectively.
Combining groundwater flow and transport models with
an AI-based and symbolic, graphics user interface, selected functions of
geographical information systems (GIS), and transparent data and file handling,
the systems are designed to allow the easy and efficient use of complex
groundwater modeling technology in a problem- rather than model-oriented
style.
Using color-graphics super-microcomputer workstations,
the approach provides a problem manager with numerous built-in support
functions such as the selection of site-specific, as well as generic,
groundwater problems from problem libraries and GIS functions for the
comparative analysis of model runs, the preparation of topical background
maps, the interactive modification of a problem for extensive scenario analysis,
or the complete interactive design of a new problem.
Using either satellite imagery (such as LANDSAT or SPOT) or Digital Line
Graph (DLG) standard vector maps as a background, problems can be edited
and modified and then simulated under interactive user control.
The results are presented as dynamic graphical output, that can be
interactively controlled and configured.
Repeated simulations, comparing alternative assumptions on parameter
values or management options can be compared in a variety of analysis
functions such as GIS -based overlay techniques.
The systems also feature extensive problem-editing capabilities,
ranging from the interactive location of wells or sources of pollution to
a Computer Aided Design (CAD) component for the
interactive design of a complete problem geometry.
This allows the user to design very efficiently,
and parametrize, a new problem from the very beginning, using a map
or an auxiliary grid as a background for the definition of problem
geometry and hydrogeological parameters.
Building some of the knowledge of an experienced groundwater modeler
into the software system and its interface through the rule bases
driving, e.g., numerous transparent, error-correction functions and
an automatic mesh generator, allows for a very
fast and efficient formulation of a new problem, even by an inexperienced
user. Freed from the task of very detailed and demanding formalization of the
computer representation of the problem, the user can thus concentrate on,
e.g., the management, regulatory, economic, or technological aspects of
his problem.
Designed for complex applications such as hazardous waste management,
site evaluation, and groundwater contamination problems, ease of interactive
use, responsiveness, and efficiency in problem definition and comparative
analysis are the most important characteristics of this interactive
approach to groundwater simulation.
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