Kouli_etal_2008_Groundwater modelling_BOOK.pdf - Pantelis ...

In: Groundwater: Modelling, Management… ISBN: 978-1-60456-832-5
Editors: L.F. Konig and J.L. Weiss, pp. 291-308 © 2008 Nova Science Publishers, Inc.
Chapter 11
FLOW SIMULATION AND OPTIMAL MANAGEMENT
OF GROUNDWATER RESOURCES. THE BALANCE
BETWEEN ACCURACY AND COMPUTATIONAL
EFFICIENCY
K.L. Katsifarakis *
Department of Civil Engineering, Aristotle University of Thessaloniki
GR-54124, Thessaloniki, Greece
Abstract
This paper presents some thoughts on the overall accuracy of the combination of flow
simulation and optimization models, which are used to optimize management of groundwater
resources.
Approximations introduced at different stages during the construction, or selection, of
groundwater flow and mass transport models are discussed first, together with their effect on
computational volume. Then the role of the optimization tool is presented, since the best
choice of model for a flow simulation problem, when considered alone, might not be that
good in the frame of an optimization procedure, when the respective calculations should be
repeated many times. This case arises, when evolutionary methods are used as the
optimization tool. To clarify this point, the method of genetic algorithms, the most popular
evolutionary technique, is briefly outlined.
Finally the paper focuses on the integration of simplified flow (and mass transport)
simulation models in the optimization procedure, which is illustrated through a number of
examples. In the first, a simple conceptual model for optimization of coastal aquifer
management is presented. In the second an approximate form of the method of images is
introduced, which offers analytical calculation of hydraulic head drawdowns at the expense of
relaxing observation of the boundary conditions. Finally, in the last two examples, ways to
simplify simulation models of mass transport are discussed.
* E-mail address: klkats@civil.auth.gr