Modeling Soil Solute Release into Runoff and Transport with Runoff on a Loess Slope

Dong, Wencai; Wang, Quanjiu

doi:10.1061/(asce)he.1943-5584.0000622

Cited by 12 publications

(11 citation statements)

References 33 publications

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“…where CO 2LW is the average concentration of CO 2L in overland flow. We assume an instantaneous complete mixing of solutes in overland flow (Dong and Wang, 2013). k L (m s −1 ) is the mass transfer coefficient between the soil upper boundary and overland flow.…”

Section: Hydrologic State 1: Soil Water Dynamics and Solute Transportmentioning

confidence: 99%

Ecohydrologic processes and soil thickness feedbacks control limestone-weathering rates in a karst landscape

et al. 2019

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A B S T R A C TChemical weathering of bedrock plays an essential role in the formation and evolution of Earth's critical zone. Over geologic time, the negative feedback between temperature and chemical weathering rates contributes to the regulation of Earth climate. The challenge of understanding weathering rates and the resulting evolution of critical zone structures lies in complicated interactions and feedbacks among environmental variables, local ecohydrologic processes, and soil thickness, the relative importance of which remains unresolved. We investigate these interactions using a reactive-transport kinetics model, focusing on a low-relief, wetland-dominated karst landscape (Big Cypress National Preserve, South Florida, USA) as a case study. Across a broad range of environmental variables, model simulations highlight primary controls of climate and soil biological respiration, where soil thickness both supplies and limits transport of biologically derived acidity. Consequently, the weathering rate maximum occurs at intermediate soil thickness. The value of the maximum weathering rate and the precise soil thickness at which it occurs depend on several environmental variables, including precipitation regime, soil inundation, vegetation characteristics, and rate of groundwater drainage. Simulations for environmental conditions specific to Big Cypress suggest that wetland depressions in this landscape began to form around beginning of the Holocene with gradual dissolution of limestone bedrock and attendant soil development, highlighting large influence of age-varying soil thickness on weathering rates and consequent landscape development. While climatic variables are often considered most important for chemical weathering, our results indicate that soil thickness and biotic activity are equally important. Weathering rates reflect complex interactions among soil thickness, climate, and local hydrologic and biotic processes, which jointly shape the supply and delivery of chemical reactants, and the resulting trajectories of critical zone and karst landscape development.

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Section: Hydrologic State 1: Soil Water Dynamics and Solute Transportmentioning

confidence: 99%

Ecohydrologic processes and soil thickness feedbacks control limestone-weathering rates in a karst landscape

et al. 2019

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“…All of these models assume that the soil surface is (nearly) horizontal, the thickness of the mixing layer is regarded as stable or constant, and lateral and return flows in the soil are negligible. Dong and Wang () considered an inclined soil surface and relied on the conceptual model of Gao et al (). They assumed that solute concentrations in the runoff and the mixing layer were to be identically affected by raindrop splash.…”

Section: Introductionmentioning

confidence: 99%

“…The main considered factors affecting Cr(VI) transfer from soil to surface runoff in the above referenced models include rain intensity (Gao et al, ), ponding water depth (Gao et al, ), soil characteristics (Tong et al, ), soil slope (Dong & Wang, ), and drainage conditions (Walker et al, ; Zhang et al, ). Adsorption of a chemically active solute is another important factor that affects solute loss.…”

Section: Introductionmentioning

confidence: 99%

Assessment of alternative adsorption models and global sensitivity analysis to characterize hexavalent chromium loss from soil to surface runoff

Xia

Tong

et al. 2018

Hydrological Processes

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We investigate our ability to assess transfer of hexavalent chromium, Cr(VI), from the soil to surface runoff by considering the effect of coupling diverse adsorption models with a two-layer solute transfer model. Our analyses are grounded on a set of two experiments associated with soils characterized by diverse particle size distributions.Our study is motivated by the observation that Cr(VI) is receiving much attention for the assessment of environmental risks due to its high solubility, mobility, and toxicological significance. Adsorption of Cr(VI) is considered to be at equilibrium in the mixing layer under our experimental conditions. Four adsorption models, that is, the Langmuir, Freundlich, Temkin, and linear models, constitute our set of alternative (competing) mathematical formulations. Experimental results reveal that the soil samples characterized by the finest grain sizes are associated with the highest release of Cr(VI) to runoff. We compare the relative abilities of the four models to interpret experimental results through maximum likelihood model calibration and four model identification criteria (i.e., the Akaike information criteria [AIC and AIC C ] and the Bayesian and Kashyap information criteria). Our study results enable us to rank the tested models on the basis of a set of posterior weights assigned to each of them.A classical variance-based global sensitivity analysis is then performed to assess the relative importance of the uncertain parameters associated with each of the models considered, within subregions of the parameter space. In this context, the modelling strategy resulting from coupling the Langmuir isotherm with a two-layer solute transfer model is then evaluated as the most skilful for the overall interpretation of both sets of experiments. Our results document that (a) the depth of the mixing layer is the most influential factor for all models tested, with the exception of the Freundlich isotherm, and (b) the total sensitivity of the adsorption parameters varies in time, with a trend to increase as time progresses for all of the models. These results suggest that adsorption has a significant effect on the uncertainty associated with the release of Cr(VI) from the soil to the surface runoff component.

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“…In PAWS, the one-dimensional Richards equation is used to describe soil moisture in the vadose zone and lateral moisture diffusion is ignored. Consistent with this description, the vertical transport of a linearly sorbing solute was modeled by the following 1D advection-disper sion-reaction equation (e.g., Dong and Wang, 2013;van Genuchten and Wagenet, 1989):…”

Section: Transport In the Vadose Zonementioning

confidence: 99%

“…The coupling of solute transport between overland flow and soil water in the vadose zone is simulated via a boundary condition, which at the underlying soil surface for Eq. (6) is related to two stages during rainfall-runoff (Dong and Wang, 2013):…”

Section: Interaction Between the Land Surface And Channelmentioning

confidence: 99%

Modeling watershed-scale solute transport using an integrated, process-based hydrologic model with applications to bacterial fate and transport

Niu

Phanikumar

2015

Journal of Hydrology

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Modeling Soil Solute Release into Runoff and Transport with Runoff on a Loess Slope

Cited by 12 publications

References 33 publications

Ecohydrologic processes and soil thickness feedbacks control limestone-weathering rates in a karst landscape

Ecohydrologic processes and soil thickness feedbacks control limestone-weathering rates in a karst landscape

Assessment of alternative adsorption models and global sensitivity analysis to characterize hexavalent chromium loss from soil to surface runoff

Modeling watershed-scale solute transport using an integrated, process-based hydrologic model with applications to bacterial fate and transport

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