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A fully subordinated linear flow model for hillslope subsurface stormflow
Author(s) -
Zhang Yong,
Baeumer Boris,
Chen Li,
Reeves Donald M.,
Sun HongGuang
Publication year - 2017
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2016wr020192
Subject(s) - flow (mathematics) , subsurface flow , hydrograph , scalar (mathematics) , hydraulic conductivity , scale (ratio) , soil science , surface runoff , advection , geology , soil water , hydrology (agriculture) , environmental science , geotechnical engineering , mathematics , groundwater , geometry , physics , ecology , quantum mechanics , biology , thermodynamics
Hillslope subsurface stormflow exhibits complex patterns when natural soils with multiscale heterogeneity impart a spatiotemporally nonlocal memory on flow dynamics. To efficiently quantify such nonlocal flow responses, this technical note proposes a fully subordinated flow (FSF) equation where the time‐ and flow‐subordination capture the temporal and spatial memory, respectively. Results show that the time‐subordination component of the FSF model captures a wide range of delayed flow response due to various degrees of soil heterogeneity (especially for low‐conductivity zones), while the model's flow‐subordination term accounts for the rapid flow responses along preferential flow paths. In the FSF model, parameters defining spatiotemporal memory functions may be related to soil properties, while other parameters such as scalar factors controlling the overall advection and diffusion are difficult to predict and can be estimated from subsurface stormflow hydrographs. These parameters can be constants at the hillslope scale because the spatiotemporal subordination, an upscaling technique, can capture the impact of system heterogeneity on flow dynamics, leading to a linear FSF model that might be applicable for various slopes. Valid scale, limitation and extension of the FSF model, and modification of the model for other complex hydrological dynamics are also discussed.