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