Effect of Pilot-Points Location on Model Calibration: Application to the Northern Karst Aquifer of Qatar

<div><p>In hydrogeological modelling, two approaches are commonly used for model calibration: zonation and the pilot-points method. Zonation assumes an abrupt spatial change in parameter values, which could be unrealistic in field applications. The pilot-points method produces smoothly d...

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Main Author: Husam Baalousha (18140608) (author)
Other Authors: Marwan Fahs (18140611) (author), Fanilo Ramasomanana (18140614) (author), Anis Younes (18140617) (author)
Published: 2019
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_version_ 1864513520721199104
author Husam Baalousha (18140608)
author2 Marwan Fahs (18140611)
Fanilo Ramasomanana (18140614)
Anis Younes (18140617)
author2_role author
author
author
author_facet Husam Baalousha (18140608)
Marwan Fahs (18140611)
Fanilo Ramasomanana (18140614)
Anis Younes (18140617)
author_role author
dc.creator.none.fl_str_mv Husam Baalousha (18140608)
Marwan Fahs (18140611)
Fanilo Ramasomanana (18140614)
Anis Younes (18140617)
dc.date.none.fl_str_mv 2019-04-02T03:00:00Z
dc.identifier.none.fl_str_mv 10.3390/w11040679
dc.relation.none.fl_str_mv https://figshare.com/articles/journal_contribution/Effect_of_Pilot-Points_Location_on_Model_Calibration_Application_to_the_Northern_Karst_Aquifer_of_Qatar/25390969
dc.rights.none.fl_str_mv CC BY 4.0
info:eu-repo/semantics/openAccess
dc.subject.none.fl_str_mv Biological sciences
Biochemistry and cell biology
Engineering
Chemical engineering
groundwater flow
model calibration
PEST
pilot-points
MODFLOW
Qatar
dc.title.none.fl_str_mv Effect of Pilot-Points Location on Model Calibration: Application to the Northern Karst Aquifer of Qatar
dc.type.none.fl_str_mv Text
Journal contribution
info:eu-repo/semantics/publishedVersion
text
contribution to journal
description <div><p>In hydrogeological modelling, two approaches are commonly used for model calibration: zonation and the pilot-points method. Zonation assumes an abrupt spatial change in parameter values, which could be unrealistic in field applications. The pilot-points method produces smoothly distributed parameters compared to the zonation approach; however, the number and placement of pilot-points can be challenging. The main goal of this paper is to explore the effect of pilot-points number and locations on the calibrated parameters. A 3D groundwater flow model was built for the northern karst aquifer of Qatar. A conceptual model of this aquifer was developed based on MODFLOW software (United States Geological Survey). The model was calibrated using the parameter estimation and uncertainty analysis (PEST) package employing historical data of groundwater levels. The effect of the number and locations of pilot-points was examined by running the model using a variable numbers of points and several perturbations of locations. The calibration errors for all the runs (corresponding to different configurations of pilot-points) were maintained under a certain threshold. A statistical analysis of the calibrated parameters was then performed to evaluate how far these parameters are impacted by the pilot-point locations. Finally, an optimization method was proposed for pilot-points placement using recharge and observed piezometric maps. The results revealed that the pilot-points number, locations, and configurations have a significant effect on the calibrated parameter, especially in the high permeable regions corresponding to the karstic zones. The outcome of this study may help focus on areas of high uncertainty where more field data should be collected to improve model calibration. It also helps the placement of pilot-points for a robust calibration.</p><p> </p></div><h2>Other Information</h2> <p> Published in: Water<br> License: <a href="https://creativecommons.org/licenses/by/4.0/" target="_blank">https://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.3390/w11040679" target="_blank">https://dx.doi.org/10.3390/w11040679</a></p>
eu_rights_str_mv openAccess
id Manara2_e31172d4bf301db4a57f8b4b2ebcb968
identifier_str_mv 10.3390/w11040679
network_acronym_str Manara2
network_name_str Manara2
oai_identifier_str oai:figshare.com:article/25390969
publishDate 2019
repository.mail.fl_str_mv
repository.name.fl_str_mv
repository_id_str
rights_invalid_str_mv CC BY 4.0
spelling Effect of Pilot-Points Location on Model Calibration: Application to the Northern Karst Aquifer of QatarHusam Baalousha (18140608)Marwan Fahs (18140611)Fanilo Ramasomanana (18140614)Anis Younes (18140617)Biological sciencesBiochemistry and cell biologyEngineeringChemical engineeringgroundwater flowmodel calibrationPESTpilot-pointsMODFLOWQatar<div><p>In hydrogeological modelling, two approaches are commonly used for model calibration: zonation and the pilot-points method. Zonation assumes an abrupt spatial change in parameter values, which could be unrealistic in field applications. The pilot-points method produces smoothly distributed parameters compared to the zonation approach; however, the number and placement of pilot-points can be challenging. The main goal of this paper is to explore the effect of pilot-points number and locations on the calibrated parameters. A 3D groundwater flow model was built for the northern karst aquifer of Qatar. A conceptual model of this aquifer was developed based on MODFLOW software (United States Geological Survey). The model was calibrated using the parameter estimation and uncertainty analysis (PEST) package employing historical data of groundwater levels. The effect of the number and locations of pilot-points was examined by running the model using a variable numbers of points and several perturbations of locations. The calibration errors for all the runs (corresponding to different configurations of pilot-points) were maintained under a certain threshold. A statistical analysis of the calibrated parameters was then performed to evaluate how far these parameters are impacted by the pilot-point locations. Finally, an optimization method was proposed for pilot-points placement using recharge and observed piezometric maps. The results revealed that the pilot-points number, locations, and configurations have a significant effect on the calibrated parameter, especially in the high permeable regions corresponding to the karstic zones. The outcome of this study may help focus on areas of high uncertainty where more field data should be collected to improve model calibration. It also helps the placement of pilot-points for a robust calibration.</p><p> </p></div><h2>Other Information</h2> <p> Published in: Water<br> License: <a href="https://creativecommons.org/licenses/by/4.0/" target="_blank">https://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.3390/w11040679" target="_blank">https://dx.doi.org/10.3390/w11040679</a></p>2019-04-02T03:00:00ZTextJournal contributioninfo:eu-repo/semantics/publishedVersiontextcontribution to journal10.3390/w11040679https://figshare.com/articles/journal_contribution/Effect_of_Pilot-Points_Location_on_Model_Calibration_Application_to_the_Northern_Karst_Aquifer_of_Qatar/25390969CC BY 4.0info:eu-repo/semantics/openAccessoai:figshare.com:article/253909692019-04-02T03:00:00Z
spellingShingle Effect of Pilot-Points Location on Model Calibration: Application to the Northern Karst Aquifer of Qatar
Husam Baalousha (18140608)
Biological sciences
Biochemistry and cell biology
Engineering
Chemical engineering
groundwater flow
model calibration
PEST
pilot-points
MODFLOW
Qatar
status_str publishedVersion
title Effect of Pilot-Points Location on Model Calibration: Application to the Northern Karst Aquifer of Qatar
title_full Effect of Pilot-Points Location on Model Calibration: Application to the Northern Karst Aquifer of Qatar
title_fullStr Effect of Pilot-Points Location on Model Calibration: Application to the Northern Karst Aquifer of Qatar
title_full_unstemmed Effect of Pilot-Points Location on Model Calibration: Application to the Northern Karst Aquifer of Qatar
title_short Effect of Pilot-Points Location on Model Calibration: Application to the Northern Karst Aquifer of Qatar
title_sort Effect of Pilot-Points Location on Model Calibration: Application to the Northern Karst Aquifer of Qatar
topic Biological sciences
Biochemistry and cell biology
Engineering
Chemical engineering
groundwater flow
model calibration
PEST
pilot-points
MODFLOW
Qatar