The effects of numerical-model complexity and observation type on estimated porosity values

Hydrogeology Journal
By: , and 

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Abstract

The relative merits of model complexity and types of observations employed in model calibration are compared. An existing groundwater flow model coupled with an advective transport simulation of the Salt Lake Valley, Utah (USA), is adapted for advective transport, and effective porosity is adjusted until simulated tritium concentrations match concentrations in samples from wells. Two calibration approaches are used: a “complex” highly parameterized porosity field and a “simple” parsimonious model of porosity distribution. The use of an atmospheric tracer (tritium in this case) and apparent ages (from tritium/helium) in model calibration also are discussed. Of the models tested, the complex model (with tritium concentrations and tritium/helium apparent ages) performs best. Although tritium breakthrough curves simulated by complex and simple models are very generally similar, and there is value in the simple model, the complex model is supported by a more realistic porosity distribution and a greater number of estimable parameters. Culling the best quality data did not lead to better calibration, possibly because of processes and aquifer characteristics that are not simulated. Despite many factors that contribute to shortcomings of both the models and the data, useful information is obtained from all the models evaluated. Although any particular prediction of tritium breakthrough may have large errors, overall, the models mimic observed trends.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title The effects of numerical-model complexity and observation type on estimated porosity values
Series title Hydrogeology Journal
DOI 10.1007/s10040-015-1289-3
Volume 23
Issue 6
Year Published 2015
Language English
Publisher Springer
Publisher location Berlin
Contributing office(s) Connecticut Water Science Center
Description 8 p.
First page 1121
Last page 1128
Country United States
State Utah
Other Geospatial Salt Lake Valley
Online Only (Y/N) N
Additional Online Files (Y/N) N