scholarly journals Impact of degrading permafrost on subsurface solute transport pathways and travel times

2015 ◽  
Vol 51 (9) ◽  
pp. 7680-7701 ◽  
Author(s):  
Andrew Frampton ◽  
Georgia Destouni
Keyword(s):  
Solute Transport ◽  
Travel Times ◽  
Transport Pathways ◽  
Subsurface Solute Transport

scholarly journals An experimental evaluation of the solute transport volume in biodegraded municipal solid waste

1999 ◽  
Vol 3 (3) ◽  
pp. 429-438 ◽  
Author(s):  
H. Rosqvist ◽  
D. Bendz
Keyword(s):  
Solute Transport ◽  
Solid Waste ◽  
Volume Fraction ◽  
Tracer Tests ◽  
Travel Times ◽  
Volume Fractions ◽  
Rapid Flow ◽  
Set Up ◽  
Log Normal ◽  
Transport Volume

Abstract. A large undisturbed sample (3.5 m3) of 22-year-old, biodegraded solid waste set up to estimate the volume fraction participating in the transport of solutes through the waste material. Altogether, five tracer tests were performed under ponding and sprinkling conditions, and under steady-state and transient conditions. The experimental break through curves (BTCs), which indicated a non-equilibrium transport of the solute by early peaks and long right-hand tails, were used to parameterize log-normal solute travel time probability density functions. The expected solute travel times (i.e. the median solute travel times) were assessed and the corresponding fraction of the experimental volumes active in the transport of solutes was estimated. The solute transport volume fractions defined by the median solute travel times were estimated to vary between 5 and 10% of the total experimental volume. Further, the magnitudes of the solute transport volume fractions defined by the modal (peak) solute travel times were estimated to vary between 1 and 2% of the total experimental volume. In addition, possible boundary effects in terms of rapid flow along the wall of the experimental column were investigated.

Flow transiency on analytical modeling of subsurface solute transport

2020 ◽  
Vol 27 (31) ◽  
pp. 38974-38986 ◽  
Author(s):  
Xu Li ◽  
Zhang Wen ◽  
Qi Zhu ◽  
Hamza Jakada
Keyword(s):  
Solute Transport ◽  
Analytical Modeling ◽  
Subsurface Solute Transport

An exploration of coupled surface–subsurface solute transport in a fully integrated catchment model

2015 ◽  
Vol 529 ◽  
pp. 969-979 ◽  
Author(s):  
Jessica E. Liggett ◽  
Daniel Partington ◽  
Sven Frei ◽  
Adrian D. Werner ◽  
Craig T. Simmons ◽  
...  
Keyword(s):  
Solute Transport ◽  
Fully Integrated ◽  
Subsurface Solute Transport ◽  
Catchment Model

scholarly journals Preferential Pathways for Fluid and Solutes in Heterogeneous Groundwater Systems: Self-Organization, Entropy, Work

2021 ◽  
Author(s):  
Erwin Zehe ◽  
Ralf Loritz ◽  
Yaniv Edery ◽  
Brian Berkowitz
Keyword(s):  
Fluid Flow ◽  
Steady State ◽  
Hydraulic Conductivity ◽  
Solute Transport ◽  
Energy Input ◽  
Self Organization ◽  
Saturated Porous Media ◽  
Concentration Gradients ◽  
Transport Pathways ◽  
Preferential Pathways

Abstract. Patterns of distinct preferential pathways for fluid flow and solute transport are ubiquitous in heterogeneous, saturated and partially saturated porous media. Yet, the underlying reasons for their emergence, and their characterization and quantification, remain enigmatic. Here we analyze simulations of steady state fluid flow and solute transport in two-dimensional, heterogeneous saturated porous media with a relatively short correlation length. We demonstrate that the downstream concentration of solutes in preferential pathways implies a downstream declining entropy in the transverse distribution of solute transport pathways. This reflects the associated formation and downstream steepening of a concentration gradient transversal to the main flow direction. With an increasing variance of the hydraulic conductivity field, stronger transversal concentration gradients emerge, which is reflected in an even smaller entropy of the transversal distribution of transport pathways. By defining "self-organization" through a reduction in entropy (compared to its maximum), our findings suggest that a higher variance and thus randomness of the hydraulic conductivity coincides with stronger macroscale self-organization of transport pathways. While this finding appears at first sight striking, it can be explained by recognizing that emergence of spatial self-organization requires, in light of the second law of thermodynamics, that work be performed to establish transversal concentration gradients. The emergence of steeper concentration gradients requires that even more work be performed, with an even higher energy input into an open system. Consistently, we find that the energy input necessary to sustain steady-state fluid flow and tracer transport grows with the variance of the hydraulic conductivity field as well. Solute particles prefer to move through pathways of very high power, and these pathways pass through bottlenecks of low hydraulic conductivity. This is because power depends on the squared spatial head gradient, which is in these simulations largest in regions of low hydraulic conductivity.

scholarly journals Investigating the relationship between subsurface hydrology and dissolved carbon fluxes for a sub-arctic catchment

2010 ◽  
Vol 7 (2) ◽  
pp. 1677-1703
Author(s):  
S. W. Lyon ◽  
M. Mörth ◽  
C. Humborg ◽  
R. Giesler ◽  
G. Destouni
Keyword(s):  
Surface Water ◽  
Dissolved Inorganic Carbon ◽  
Water System ◽  
Travel Times ◽  
Catchment Scale ◽  
Transport Pathways ◽  
Subsurface Hydrology ◽  
Natural Systems ◽  
Dissolved Carbon ◽  
Northern Latitudes

Abstract. In recent years, there has been increased interest in carbon cycling in natural systems due to its role in a changing climate. Northern latitude systems are especially important as they may serve as a potentially large source or sink of terrestrial carbon. There are, however, a limited number of investigations reporting on actual flux rates of carbon moving from the subsurface landscape to surface water systems in northern latitudes. This study estimates dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) fluxes from the subsurface landscape for a sub-arctic catchment located in northern Sweden. Estimates are based on observed annual in-stream flux-averaged concentrations of DOC and DIC at the outlet of the 566 km2 Abiskojokken catchment and from catchment-scale transport modeling based on advective solute travel times and their spatial distributions. We also demonstrate the importance of correctly representing the spatial distribution of the advective solute travel times along the various flow and transport pathways. For the sub-arctic catchment considered in this study, there is a relative balance between the flux of DOC and DIC from the subsurface landscape to the surface water system. This balance between DOC and DIC fluxes could shift under future climatic changes that influence the hydrological and biogeochemical system.

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