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Travel time distribution in a hillslope: Insight from numerical simulations
Year:
2008
Source of publication :
Water Resources Research
Authors :
רוסו, דוד
;
.
Volume :
44
Co-Authors:
Fiori, A., Dipartimento di Scienze dell'Ingegneria Civile, Università di Roma Tre, Rome, Italy, Dipartimento di Scienze dell'Ingegneria Civile, Università di Roma Tre, via V. Volterra 62, I-00146 Roma, Italy
Russo, D., Department of Environmental Physics and Irrigation, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel, Department of Environmental Physics and Irrigation, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel
Facilitators :
From page:
To page:
(
Total pages:
1
)
Abstract:
Solute transport in a three-dimensional, heterogeneous hillslope is analyzed through a series of detailed, three-dimensional numerical simulations. The investigation focuses on the transport of a pulse of a passive solute, taking into account realistic features of the relevant flow domain (i.e., the spatial heterogeneity of the soil hydraulic properties and records of the time-dependent meteorological data and evapotranspiration). The scope of the present work is to analyze a few issues regarding the travel time probability density function (pdf) f(τ) of solute, with particular reference to the following: (1) the suitability of the time invariance assumption and the circumstance under which it may represent a valid approximation, (2) the shape of the resulting travel time pdf f(τ), and (3) the difference between f(τ) and the instantaneous unit hydrograph. It is found that in many cases of practical interest the transport of contaminants in catchments can be analyzed by assuming the time-invariant approximation for f(τ), provided that the calendar time is replaced by a flow-corrected time. Here f(τ) is calculated through the analysis of the breakthrough curve represented in terms of flux-averaged concentration versus cumulate discharge. The rescaling of time with respect to the cumulated outflow takes care in an approximate way of the transient processes occurring in the porous medium. The derived f(τ) is weakly dependent on various attributes, like the level of heterogeneity, presence of evaporation or transpiration, and injection period. The main exception regards the cases in which plant transpiration is intense in the vicinity of the channel after relatively long periods of low rain. The impact of the parameters' heterogeneity on f(τ) is generally quite limited, the dispersion being ruled by the distribution of length paths within the hillslope. The derived f(τ) seems compatible with the Gamma distribution, being characterized by both fast and slow responses, with a pronounced power law early peak and an exponential-like tail. Comparison of f(τ) with the often employed Gamma instantaneous unit hydrograph emphasizes the differences between water and solute dynamics after rainfall events. Copyright 2008 by the American Geophysical Union.
Note:
Related Files :
Catchments
computer simulation
Probability densities
Soil hydraulic properties
Time invariances
transpiration
עוד תגיות
תוכן קשור
More details
DOI :
10.1029/2008WR007135
Article number:
Affiliations:
Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
20332
Last updated date:
02/03/2022 17:27
Creation date:
16/04/2018 23:35
Scientific Publication
Travel time distribution in a hillslope: Insight from numerical simulations
44
Fiori, A., Dipartimento di Scienze dell'Ingegneria Civile, Università di Roma Tre, Rome, Italy, Dipartimento di Scienze dell'Ingegneria Civile, Università di Roma Tre, via V. Volterra 62, I-00146 Roma, Italy
Russo, D., Department of Environmental Physics and Irrigation, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel, Department of Environmental Physics and Irrigation, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel
Travel time distribution in a hillslope: Insight from numerical simulations
Solute transport in a three-dimensional, heterogeneous hillslope is analyzed through a series of detailed, three-dimensional numerical simulations. The investigation focuses on the transport of a pulse of a passive solute, taking into account realistic features of the relevant flow domain (i.e., the spatial heterogeneity of the soil hydraulic properties and records of the time-dependent meteorological data and evapotranspiration). The scope of the present work is to analyze a few issues regarding the travel time probability density function (pdf) f(τ) of solute, with particular reference to the following: (1) the suitability of the time invariance assumption and the circumstance under which it may represent a valid approximation, (2) the shape of the resulting travel time pdf f(τ), and (3) the difference between f(τ) and the instantaneous unit hydrograph. It is found that in many cases of practical interest the transport of contaminants in catchments can be analyzed by assuming the time-invariant approximation for f(τ), provided that the calendar time is replaced by a flow-corrected time. Here f(τ) is calculated through the analysis of the breakthrough curve represented in terms of flux-averaged concentration versus cumulate discharge. The rescaling of time with respect to the cumulated outflow takes care in an approximate way of the transient processes occurring in the porous medium. The derived f(τ) is weakly dependent on various attributes, like the level of heterogeneity, presence of evaporation or transpiration, and injection period. The main exception regards the cases in which plant transpiration is intense in the vicinity of the channel after relatively long periods of low rain. The impact of the parameters' heterogeneity on f(τ) is generally quite limited, the dispersion being ruled by the distribution of length paths within the hillslope. The derived f(τ) seems compatible with the Gamma distribution, being characterized by both fast and slow responses, with a pronounced power law early peak and an exponential-like tail. Comparison of f(τ) with the often employed Gamma instantaneous unit hydrograph emphasizes the differences between water and solute dynamics after rainfall events. Copyright 2008 by the American Geophysical Union.
Scientific Publication
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