TY - JOUR

T1 - Field-Scale Subsurface Flow Processes Inferred From Continuous Gravity Monitoring During a Sprinkling Experiment

AU - Reich, Marvin

AU - Mikolaj, Michal

AU - Blume, Theresa

AU - Güntner, Andreas

N1 - Funding information: The authors would like to thank Thomas Klügel, Hartmut Wziontek and Stefan Lüdtke for fruitful discussions, critical views and useful comments. We thank Stephan Schröder for his technical support and companionship on field trips and Daniel Beiter for instructions on using BERT inversion software. Furthermore a big thank you goes to Hadley Wickham, the R?core team and the stackoverflow community for helping out with programming struggles, supplying packages, maintenance and support. The presented hydro?gravimetric model, for both conversion and inversion mode, is accessible and applicable via installing the R?package “gravityInf” (Reich, 2021 ). A therein supplied example script can be adjusted to individual needs in order to analyze sprinkling experiments in terms of infiltration modeling and comparison to measured gravity signal. The authors thank Don Pool, Ty Ferre and a third anonymous reviewer for their helpful comments and suggestions. Open access funding enabled and organized by Projekt DEAL. This work has partly been funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) ? Project?ID 434617780 ? SFB 1464. The authors would like to thank Thomas Kl?gel, Hartmut Wziontek and Stefan L?dtke for fruitful discussions, critical views and useful comments. We thank Stephan Schr?der for his technical support and companionship on field trips and Daniel Beiter for instructions on using BERT inversion software. Furthermore a big thank you goes to Hadley Wickham, the R-core team and the stackoverflow community for helping out with programming struggles, supplying packages, maintenance and support. The presented hydro-gravimetric model, for both conversion and inversion mode, is accessible and applicable via installing the R-package ?gravityInf? (Reich,?2021). A therein supplied example script can be adjusted to individual needs in order to analyze sprinkling experiments in terms of infiltration modeling and comparison to measured gravity signal. The authors thank Don Pool, Ty Ferre and a third anonymous reviewer for their helpful comments and suggestions. Open access funding enabled and organized by Projekt DEAL. This work has partly been funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Project-ID 434617780 - SFB 1464.

PY - 2021/9/28

Y1 - 2021/9/28

N2 - Field-scale subsurface flow processes are difficult to observe and monitor. We investigated the value of gravity time series to identify subsurface flow processes by carrying out a sprinkling experiment in the direct vicinity of a superconducting gravimeter. We demonstrate how different water mass distributions in the subsoil affect the gravity signal and show the benefit of using the shape of the gravity response curve to identify different subsurface flow processes. For this purpose, a simple hydro-gravimetric model was set up to test different scenarios in an optimization approach, including the processes macropore flow, preferential flow, wetting front advancement (WFA), bypass flow and perched water table rise. Besides the gravity observations, electrical resistivity and soil moisture data were used for evaluation. For the study site, the process combination of preferential flow and WFA led to the best correspondence to the observations in a multi-criteria assessment. We argue that the approach of combining field-scale sprinkling experiments in combination with gravity monitoring can be transferred to other sites for process identification, and discuss related uncertainties including limitations of the simple model used here. The study stresses the value of advancing terrestrial gravimetry as an integrative and non-invasive monitoring technique for assessing hydrological states and dynamics.

AB - Field-scale subsurface flow processes are difficult to observe and monitor. We investigated the value of gravity time series to identify subsurface flow processes by carrying out a sprinkling experiment in the direct vicinity of a superconducting gravimeter. We demonstrate how different water mass distributions in the subsoil affect the gravity signal and show the benefit of using the shape of the gravity response curve to identify different subsurface flow processes. For this purpose, a simple hydro-gravimetric model was set up to test different scenarios in an optimization approach, including the processes macropore flow, preferential flow, wetting front advancement (WFA), bypass flow and perched water table rise. Besides the gravity observations, electrical resistivity and soil moisture data were used for evaluation. For the study site, the process combination of preferential flow and WFA led to the best correspondence to the observations in a multi-criteria assessment. We argue that the approach of combining field-scale sprinkling experiments in combination with gravity monitoring can be transferred to other sites for process identification, and discuss related uncertainties including limitations of the simple model used here. The study stresses the value of advancing terrestrial gravimetry as an integrative and non-invasive monitoring technique for assessing hydrological states and dynamics.

KW - Hydrogravimetry

UR - http://www.scopus.com/inward/record.url?scp=85118246756&partnerID=8YFLogxK

U2 - 10.1029/2021WR030044

DO - 10.1029/2021WR030044

M3 - Article

AN - SCOPUS:85118246756

VL - 57

JO - Water resources research

JF - Water resources research

SN - 0043-1397

IS - 10

M1 - e2021WR030044

ER -