Cargando…

A Bayesian Assessment of an Approximate Model for Unconfined Water Flow in Sloping Layered Porous Media

The prediction of water table height in unconfined layered porous media is a difficult modelling problem that typically requires numerical simulation. This paper proposes an analytical model to approximate the exact solution based on a steady-state Dupuit–Forchheimer analysis. The key contribution i...

Descripción completa

Detalles Bibliográficos
Autores principales: Chiachío, Juan, Chiachío, Manuel, Sankararaman, Shankar, Prescott, Darren
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Netherlands 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6390717/
https://www.ncbi.nlm.nih.gov/pubmed/30872878
http://dx.doi.org/10.1007/s11242-018-1094-2
_version_ 1783398194479104000
author Chiachío, Juan
Chiachío, Manuel
Sankararaman, Shankar
Prescott, Darren
author_facet Chiachío, Juan
Chiachío, Manuel
Sankararaman, Shankar
Prescott, Darren
author_sort Chiachío, Juan
collection PubMed
description The prediction of water table height in unconfined layered porous media is a difficult modelling problem that typically requires numerical simulation. This paper proposes an analytical model to approximate the exact solution based on a steady-state Dupuit–Forchheimer analysis. The key contribution in relation to a similar model in the literature relies in the ability of the proposed model to consider more than two layers with different thicknesses and slopes, so that the existing model becomes a special case of the proposed model herein. In addition, a model assessment methodology based on the Bayesian inverse problem is proposed to efficiently identify the values of the physical parameters for which the proposed model is accurate when compared against a reference model given by MODFLOW-NWT, the open-source finite-difference code by the U.S. Geological Survey. Based on numerical results for a representative case study, the ratio of vertical recharge rate to hydraulic conductivity emerges as a key parameter in terms of model accuracy so that, when appropriately bounded, both the proposed model and MODFLOW-NWT provide almost identical results.
format Online
Article
Text
id pubmed-6390717
institution National Center for Biotechnology Information
language English
publishDate 2018
publisher Springer Netherlands
record_format MEDLINE/PubMed
spelling pubmed-63907172019-03-12 A Bayesian Assessment of an Approximate Model for Unconfined Water Flow in Sloping Layered Porous Media Chiachío, Juan Chiachío, Manuel Sankararaman, Shankar Prescott, Darren Transp Porous Media Article The prediction of water table height in unconfined layered porous media is a difficult modelling problem that typically requires numerical simulation. This paper proposes an analytical model to approximate the exact solution based on a steady-state Dupuit–Forchheimer analysis. The key contribution in relation to a similar model in the literature relies in the ability of the proposed model to consider more than two layers with different thicknesses and slopes, so that the existing model becomes a special case of the proposed model herein. In addition, a model assessment methodology based on the Bayesian inverse problem is proposed to efficiently identify the values of the physical parameters for which the proposed model is accurate when compared against a reference model given by MODFLOW-NWT, the open-source finite-difference code by the U.S. Geological Survey. Based on numerical results for a representative case study, the ratio of vertical recharge rate to hydraulic conductivity emerges as a key parameter in terms of model accuracy so that, when appropriately bounded, both the proposed model and MODFLOW-NWT provide almost identical results. Springer Netherlands 2018-06-09 2019 /pmc/articles/PMC6390717/ /pubmed/30872878 http://dx.doi.org/10.1007/s11242-018-1094-2 Text en © The Author(s) 2018 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Article
Chiachío, Juan
Chiachío, Manuel
Sankararaman, Shankar
Prescott, Darren
A Bayesian Assessment of an Approximate Model for Unconfined Water Flow in Sloping Layered Porous Media
title A Bayesian Assessment of an Approximate Model for Unconfined Water Flow in Sloping Layered Porous Media
title_full A Bayesian Assessment of an Approximate Model for Unconfined Water Flow in Sloping Layered Porous Media
title_fullStr A Bayesian Assessment of an Approximate Model for Unconfined Water Flow in Sloping Layered Porous Media
title_full_unstemmed A Bayesian Assessment of an Approximate Model for Unconfined Water Flow in Sloping Layered Porous Media
title_short A Bayesian Assessment of an Approximate Model for Unconfined Water Flow in Sloping Layered Porous Media
title_sort bayesian assessment of an approximate model for unconfined water flow in sloping layered porous media
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6390717/
https://www.ncbi.nlm.nih.gov/pubmed/30872878
http://dx.doi.org/10.1007/s11242-018-1094-2
work_keys_str_mv AT chiachiojuan abayesianassessmentofanapproximatemodelforunconfinedwaterflowinslopinglayeredporousmedia
AT chiachiomanuel abayesianassessmentofanapproximatemodelforunconfinedwaterflowinslopinglayeredporousmedia
AT sankararamanshankar abayesianassessmentofanapproximatemodelforunconfinedwaterflowinslopinglayeredporousmedia
AT prescottdarren abayesianassessmentofanapproximatemodelforunconfinedwaterflowinslopinglayeredporousmedia
AT chiachiojuan bayesianassessmentofanapproximatemodelforunconfinedwaterflowinslopinglayeredporousmedia
AT chiachiomanuel bayesianassessmentofanapproximatemodelforunconfinedwaterflowinslopinglayeredporousmedia
AT sankararamanshankar bayesianassessmentofanapproximatemodelforunconfinedwaterflowinslopinglayeredporousmedia
AT prescottdarren bayesianassessmentofanapproximatemodelforunconfinedwaterflowinslopinglayeredporousmedia