Incipient subsurface heterogeneity and its effect on overland flow generation – insight from a modeling study of the first experiment at the Biosphere 2 Landscape Evolution Observatory
Evolution of landscape heterogeneity is controlled by coupled Earth system dynamics, and the resulting process complexity is a major hurdle to cross towards a unified theory of catchment hydrology. The Biosphere 2 Landscape Evolution Observatory (LEO), a 334.5 m<sup>2</sup> artificial h...
| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-05-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | http://www.hydrol-earth-syst-sci.net/18/1873/2014/hess-18-1873-2014.pdf |
| _version_ | 1817983503781855232 |
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| author | G.-Y. Niu D. Pasetto C. Scudeler C. Paniconi M. Putti P. A. Troch S. B. DeLong K. Dontsova L. Pangle D. D. Breshears J. Chorover T. E. Huxman J. Pelletier S. R. Saleska X. Zeng |
| author_facet | G.-Y. Niu D. Pasetto C. Scudeler C. Paniconi M. Putti P. A. Troch S. B. DeLong K. Dontsova L. Pangle D. D. Breshears J. Chorover T. E. Huxman J. Pelletier S. R. Saleska X. Zeng |
| author_sort | G.-Y. Niu |
| collection | DOAJ |
| description | Evolution of landscape heterogeneity is controlled by coupled Earth system
dynamics, and the resulting process complexity is a major hurdle to cross
towards a unified theory of catchment hydrology. The Biosphere 2 Landscape
Evolution Observatory (LEO), a 334.5 m<sup>2</sup> artificial hillslope built with
homogeneous soil, may have evolved into heterogeneous soil during the first
experiment driven by an intense rainfall event. The experiment produced
predominantly seepage face water outflow, but also generated overland flow,
causing superficial erosion and the formation of a small channel. In this
paper, we explore the hypothesis of incipient heterogeneity development in
LEO and its effect on overland flow generation by comparing the modeling
results from a three-dimensional physically based hydrological model with
measurements of total mass change and seepage face flow. Our null hypothesis
is that the soil is hydraulically homogeneous, while the alternative
hypothesis is that LEO developed downstream heterogeneity from transport of
fine sediments driven by saturated subsurface flow. The heterogeneous case
is modeled by assigning saturated hydraulic conductivity at the LEO seepage
face (<i>K</i><sub>sat,sf</sub>) different from that of the rest (<i>K</i><sub>sat</sub>). A range of
values for <i>K</i><sub>sat</sub>, <i>K</i><sub>sat,sf</sub>, soil porosity, and pore size distribution
is used to account for uncertainties in estimating these parameters,
resulting in more than 20 000 simulations. It is found that the best runs
under the heterogeneous soil hypothesis produce smaller errors than those
under the null hypothesis, and that the heterogeneous runs yield a higher
probability of best model performance than the homogeneous runs. These
results support the alternative hypothesis of localized incipient
heterogeneity of the LEO soil, which facilitated generation of overland
flow. This modeling study of the first LEO experiment suggests an important
role of coupled water and sediment transport processes in the evolution of
subsurface heterogeneity and on overland flow generation, highlighting the
need of a coupled modeling system that integrates across disciplinary processes. |
| first_indexed | 2024-04-13T23:34:00Z |
| format | Article |
| id | doaj.art-f7efc24a7ded40e59c39bd19f3fe049b |
| institution | Directory Open Access Journal |
| issn | 1027-5606 1607-7938 |
| language | English |
| last_indexed | 2024-04-13T23:34:00Z |
| publishDate | 2014-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Hydrology and Earth System Sciences |
| spelling | doaj.art-f7efc24a7ded40e59c39bd19f3fe049b2022-12-22T02:24:49ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382014-05-011851873188310.5194/hess-18-1873-2014Incipient subsurface heterogeneity and its effect on overland flow generation – insight from a modeling study of the first experiment at the Biosphere 2 Landscape Evolution ObservatoryG.-Y. Niu0D. Pasetto1C. Scudeler2C. Paniconi3M. Putti4P. A. Troch5S. B. DeLong6K. Dontsova7L. Pangle8D. D. Breshears9J. Chorover10T. E. Huxman11J. Pelletier12S. R. Saleska13X. Zeng14Biosphere 2, University of Arizona, Tucson, AZ, USAInstitut National de la Recherche Scientifique, Centre Eau Terre Environnement (INRS-ETE), Université du Québec, Quebec City, CanadaInstitut National de la Recherche Scientifique, Centre Eau Terre Environnement (INRS-ETE), Université du Québec, Quebec City, CanadaInstitut National de la Recherche Scientifique, Centre Eau Terre Environnement (INRS-ETE), Université du Québec, Quebec City, CanadaDepartment of Mathematics, University of Padova, Padova, ItalyBiosphere 2, University of Arizona, Tucson, AZ, USABiosphere 2, University of Arizona, Tucson, AZ, USABiosphere 2, University of Arizona, Tucson, AZ, USABiosphere 2, University of Arizona, Tucson, AZ, USASchool of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USADepartment of Soil, Water and Environmental Science, University of Arizona, Tucson, AZ, USAEcology and Evolutionary Biology, University of California, Irvine, CA, USADepartment of Geosciences University of Arizona, Tucson, AZ, USAEcology and Evolutionary Biology, University of Arizona, Tucson, AZ, USADepartment of Atmospheric Sciences, University of Arizona, Tucson, AZ, USAEvolution of landscape heterogeneity is controlled by coupled Earth system dynamics, and the resulting process complexity is a major hurdle to cross towards a unified theory of catchment hydrology. The Biosphere 2 Landscape Evolution Observatory (LEO), a 334.5 m<sup>2</sup> artificial hillslope built with homogeneous soil, may have evolved into heterogeneous soil during the first experiment driven by an intense rainfall event. The experiment produced predominantly seepage face water outflow, but also generated overland flow, causing superficial erosion and the formation of a small channel. In this paper, we explore the hypothesis of incipient heterogeneity development in LEO and its effect on overland flow generation by comparing the modeling results from a three-dimensional physically based hydrological model with measurements of total mass change and seepage face flow. Our null hypothesis is that the soil is hydraulically homogeneous, while the alternative hypothesis is that LEO developed downstream heterogeneity from transport of fine sediments driven by saturated subsurface flow. The heterogeneous case is modeled by assigning saturated hydraulic conductivity at the LEO seepage face (<i>K</i><sub>sat,sf</sub>) different from that of the rest (<i>K</i><sub>sat</sub>). A range of values for <i>K</i><sub>sat</sub>, <i>K</i><sub>sat,sf</sub>, soil porosity, and pore size distribution is used to account for uncertainties in estimating these parameters, resulting in more than 20 000 simulations. It is found that the best runs under the heterogeneous soil hypothesis produce smaller errors than those under the null hypothesis, and that the heterogeneous runs yield a higher probability of best model performance than the homogeneous runs. These results support the alternative hypothesis of localized incipient heterogeneity of the LEO soil, which facilitated generation of overland flow. This modeling study of the first LEO experiment suggests an important role of coupled water and sediment transport processes in the evolution of subsurface heterogeneity and on overland flow generation, highlighting the need of a coupled modeling system that integrates across disciplinary processes.http://www.hydrol-earth-syst-sci.net/18/1873/2014/hess-18-1873-2014.pdf |
| spellingShingle | G.-Y. Niu D. Pasetto C. Scudeler C. Paniconi M. Putti P. A. Troch S. B. DeLong K. Dontsova L. Pangle D. D. Breshears J. Chorover T. E. Huxman J. Pelletier S. R. Saleska X. Zeng Incipient subsurface heterogeneity and its effect on overland flow generation – insight from a modeling study of the first experiment at the Biosphere 2 Landscape Evolution Observatory Hydrology and Earth System Sciences |
| title | Incipient subsurface heterogeneity and its effect on overland flow generation – insight from a modeling study of the first experiment at the Biosphere 2 Landscape Evolution Observatory |
| title_full | Incipient subsurface heterogeneity and its effect on overland flow generation – insight from a modeling study of the first experiment at the Biosphere 2 Landscape Evolution Observatory |
| title_fullStr | Incipient subsurface heterogeneity and its effect on overland flow generation – insight from a modeling study of the first experiment at the Biosphere 2 Landscape Evolution Observatory |
| title_full_unstemmed | Incipient subsurface heterogeneity and its effect on overland flow generation – insight from a modeling study of the first experiment at the Biosphere 2 Landscape Evolution Observatory |
| title_short | Incipient subsurface heterogeneity and its effect on overland flow generation – insight from a modeling study of the first experiment at the Biosphere 2 Landscape Evolution Observatory |
| title_sort | incipient subsurface heterogeneity and its effect on overland flow generation ndash insight from a modeling study of the first experiment at the biosphere 2 landscape evolution observatory |
| url | http://www.hydrol-earth-syst-sci.net/18/1873/2014/hess-18-1873-2014.pdf |
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