2006
Darcy Lecture
All
Models Are Wrong: How Do We Know Which Are Useful?
by
Eileen Poeter
Abstract:
Hydrology is modeling, starting from the
moment a hydrologist stands on a hill and develops a concept of the
system; continuing with application of an analytical model such as
Darcy's law, the Theis equation, or chemical equilibria; and sometimes
extending to elaborate numerical models. Darcy created the first
quantitative ground-water model in 1856, driven by the practical goal
of providing clean water supply to Dijon, France. It was clearly useful
because it not only served his immediate purpose, but hydrologists
still call on it daily. Today we strive to solve complex ground-water
flow and transport problems and we are asked to use model results to
make decisions without the luxury of a long assessment period.
Consequently, the ground-water profession is searching for appropriate
approaches for developing conceptual models, evaluating which models
are useful, and describing the uncertainty associated with their
predictions. Formulation of a reasonable set of alternative conceptual
models, coupled with quantitative representation (which may range from
simple to complex), is critical to the process. In spite of its
apparent simplicity, this task is more difficult than numerical
modeling because it reaches beyond consideration of scientific
principles and quantitative algorithms into the realm of human nature
and judgment. The problem is exacerbated by the dense, opaque character
of the subsurface that makes data acquisition expensive, causing us to
accomplish the work with sparse, uncertain information. Nevertheless,
movements to meet this challenge are gaining momentum in the
ground-water profession. Currently available practical approaches to
the problem are presented in down-to-earth terms and future challenges
are considered.
Come join us at
a lecture to learn more about the following important concept
Speaker Bio: Eileen P. Poeter is currently a Professor of
Geological Engineering at Colorado School of Mines and Director of the
International Ground Water Modeling Center (IGWMC, Dept. GE, CSM, 1500
Illinois St., Golden CO, 80401; 303-273-3829, fax 303-384-2037;
epoeter@mines.edu; http://www.mines.edu/~epoeter/). She obtained her
Ph.D. in Engineering Science in 1980 and an M.S. in Engineering in
1978, both from Washington State University, and a BS in Geology from
Lehigh University in 1975. She worked for Golder Associates in the
early 80's before moving to academia and continues to work as an
independent consultant to stay in touch with the needs of industry. Her
research focuses on groundwater modeling and parameter estimation (she
is first author of UCODE_2005, a universal inversion code, and
associated codes for evaluating the results of the parameter
estimation; and of MMRI, a multi-model ranking and inference code)
water resource evaluation, and evaluation of heterogeneous and
fractured aquifers. She is, a part of the JUPITER (Joint Parameter
IdenTification and Evaluation of Reliability) development team. JUPITER
is an application-programming interface for evaluating sensitivity,
assessing data needs, estimating parameters, selecting/ranking models,
and evaluating uncertainty currently under development by the USGS, in
coordination with EPA to interface with their contemporary software
modeling frameworks.
Thanks to:
National Ground Water
Association, for organizing
and providing financing for this lecture tour
CSM Hydrologic Science and
Engineering Program, Students and
Professors for inspiration throughout the years and making my time
available for the lecture tour