Effects of Dynamic Forcing on Hillslope Water Balance Models

Kees, Christopher E.; Band, Lawrence E.; Farthing, Matthew W.

doi:10.21236/ada446725

Cited by 3 publications

(3 citation statements)

References 40 publications

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“…In the alternative, one can work in well instrumented research catchments to develop the closure relations, as we do in the present study. In such cases the numerical simulation approach can nevertheless be a good starting point for developing closure relations at the catchment scale that are accurate to first order Kees et al, 2002;Kees et al, 2004). Zehe et al (2005a) and Kees et al (2004) presented examples of the development of closure relations for a hillslope scale water balance model with a transient numerical solution of continuum-scale model.…”

Section: Analytical Approach To the Derivation Of Closure Relationsmentioning

confidence: 99%

Predictions of rainfall-runoff response and soil moisture dynamics in a microscale catchment using the CREW model

Lee

Zehe

Sivapalan

2007

Hydrol. Earth Syst. Sci.

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Abstract. Predictions of catchment hydrology have been performed generally using either physically based, distributed models or conceptual lumped or semi-distributed models. In recognition of the disadvantages of using either of these modeling approaches, namely, detailed data requirements in the case of distributed modeling, and lack of physical basis of conceptual/lumped model parameters, Reggiani et al. (1998Reggiani et al. ( , 1999 derived, from first principles and in a general manner, the balance equations for mass, momentum and energy at what they called the Representative Elementary Watershed (or REW) scale. However, the mass balance equations of the REW approach include mass exchange flux terms which must be defined externally before their application to real catchments. Developing physically reasonable "closure relations" for these mass exchange flux terms is a crucial pre-requisite for the success of the REW approach. As a guidance to the development of closure relations expressing mass exchange fluxes as functions of relevant state variables in a physically reasonable way, and in the process effectively parameterizing the effects of sub-grid or sub-REW heterogeneity of catchment physiographic properties on these mass exchange fluxes, this paper considers four different approaches, namely the field experimental approach, a theoretical/analytical approach, a numerical approach, and a hybrid approach combining one or more of the above. Based on the concept of the scaleway (Vogel and Roth, 2003) and the disaggregation-aggregation approach (Viney and Sivapalan, 2004), and using the data set from Weiherbach catchment in Germany, closure relations for infiltration, exfiltration and groundwater recharge were derived analytically, or on theoretical grounds, while numerical experiments with a detailed fine-scale, distributedCorrespondence to: H. Lee (haksu.lee@noaa.gov) model, CATFLOW, were used to obtain the closure relationship for seepage outflow. The detailed model, CATFLOW, was also used to derive REW scale pressure-saturation (i.e., water retention curve) and hydraulic conductivity-saturation relationships for the unsaturated zone. Closure relations for concentrated overland flow and saturated overland flow were derived using both theoretical arguments and simpler process models. In addition to these, to complete the specification of the REW scale balance equations, a relationship for the saturated area fraction as a function of saturated zone depth was derived for an assumed topography on the basis of TOPMODEL assumptions. These relationships were used to complete the specification of all of the REW-scale governing equations (mass and momentum balance equations, closure and geometric relations) for the Weiherbach catchment, which are then employed for constructing a numerical watershed model, named the Cooperative Community Catchment model based on the Representative Elementary Watershed approach (CREW). CREW is then used to carry out sensitivity analyses with respect to various combinations of climate,...

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Section: Analytical Approach To the Derivation Of Closure Relationsmentioning

confidence: 99%

Predictions of rainfall-runoff response and soil moisture dynamics in a microscale catchment using the CREW model

Lee

Zehe

Sivapalan

2007

Hydrol. Earth Syst. Sci.

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show abstract

“…So one either has to work with assumptions or has to focus on well instrumented research catchments, as we do in the present study. In such cases the numerical simulation approach can nevertheless be a good starting point for developing closure relations at the catchment scale (Zehe et al, 2005a;Kees et al, 2002Kees et al, , 2004 that are accurate to first order. Zehe et al (2005a) and Kees et al (2004) presented examples of the development of closure relations for a hillslope scale water balance model with a transient numerical solution of continuum-scale model.…”

Section: Numerical Simulation Approach To the Derivation Of Closure Rmentioning

confidence: 99%

Predictions of rainfall-runoff response and soil moisture dynamics in a microscale catchment using the CREW model

Lee¹,

Zehe²,

Sivapalan³

2006

Preprint

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Abstract. Predictions of catchment hydrology have been performed generally using either physically based, distributed models or conceptual lumped or semi-distributed models. In recognition of the disadvantages of using either of these modeling approaches, namely, detailed data requirements in the case of distributed modeling, and lack of physical basis of conceptual/lumped model parameters, Reggiani et al. (1998, 1999) derived, from first principles and in a general manner, the balance equations for mass, momentum and energy at what they called the Representative Elementary Watershed (or REW) scale. However, the mass balance equations of the REW approach include mass exchange flux terms which must be defined externally before their application to real catchments. Developing physically reasonable "closure relations'' for these mass exchange flux terms is a crucial pre-requisite for the success of the REW approach. As a guidance to the development of closure relations expressing mass exchange fluxes as functions of relevant state variables in a physically reasonable way, and in the process effectively parameterizing the effects of sub-grid or sub-REW heterogeneity of catchment physiographic properties on these mass exchange fluxes, this paper considers four different approaches, namely the field experimental approach, a theoretical/analytical approach, a numerical approach, and a hybrid approach combining one or more of the above. Based on the concept of the scaleway (Vogel and Roth, 2003) and the disaggregation-aggregation approach (Viney and Sivapalan, 2004), and using the data set from Weiherbach catchment in Germany, closure relations for infiltration, exfiltration and groundwater recharge were derived analytically, or on theoretical grounds, while numerical experiments with a detailed fine-scale, distributed model, CATFLOW, were used to obtain the closure relationship for seepage outflow. The detailed model, CATFLOW, was also used to derive REW scale pressure-saturation (i.e., water retention curve) and hydraulic conductivity-saturation relationships for the unsaturated zone. Closure relations for concentrated overland flow and saturated overland flow were derived using both theoretical arguments and simpler process models. In addition to these, to complete the specification of the REW scale balance equations, a relationship for the saturated area fraction as a function of saturated zone depth was derived for an assumed topography on the basis of TOPMODEL assumptions. These relationships were used to complete the specification of all of the REW-scale governing equations (mass and momentum balance equations, closure and geometric relations) for the Weiherbach catchment, which are then employed for constructing a numerical watershed model, named the Cooperative Community Catchment model based on the Representative Elementary Watershed approach (CREW). CREW is then used to carry out sensitivity analyses with respect to various combinations of climate, soil, vegetation and topographies, in order to test the reasonableness of the derived closure relations in the context of the complete catchment response, including interacting processes. These sensitivity analyses demonstrated that the adopted closure relations do indeed produce mostly reasonable results, and can therefore be a good basis for more careful and rigorous search for appropriate closure relations in the future. Three tests are designed to assess CREW as a large scale model for Weiherbach catchment. The first test compares CREW with distributed model CATFLOW by looking at predicted soil moisture dynamics for artificially designed initial and boundary conditions. The second test is designed to see the applicabilities of the parameter values extracted from the upscaling procedures in terms of their ability to reproduce observed hydrographs within the CREW modeling framework. The final test compares simulated soil moisture time series predicted by CREW with observed ones as a way of validating the predictions of CREW. The results of these three tests, together, demonstrate that CREW could indeed be an alternative modelling framework, producing results that are consistent with those of the distributed model CATFLOW, and capable of ultimately representing processes actually occurring at the larger scale in a physically sound manner.

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“…Various model structures, such as physics-based, index-based, and conceptual models, are available to describe rainfall-runoff processes in ungauged watersheds [1]. Physicsbased models can effectively assess and predict overland flow [27]. Two-dimensional models applying shallow water equations may accurately predict runoff and flood occurrence timing and duration [28].…”

Section: Introductionmentioning

confidence: 99%

Improving Flash Flood Hydrodynamic Simulations by Integrating Leaf Litter and Interception Processes in Steep-Sloped Natural Watersheds

Ámon,

Bene,

Ray

et al. 2024

Water

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More frequent high-intensity, short-duration rainfall events increase the risk of flash floods on steeply sloped watersheds. Where measured data are unavailable, numerical models emerge as valuable tools for predicting flash floods. Recent applications of various hydrological and hydrodynamic models to predict overland flow have highlighted the need for improved representations of the complex flow processes that are inherent in flash floods. This study aimed to identify an optimal modeling approach for characterizing leaf litter losses during flash floods. At a gauged watershed in the Hidegvíz Valley in Hungary, a physical-based model was calibrated using two distinct rainfall–runoff events. Two modeling methodologies were implemented, integrating canopy interception and leaf litter storage, to understand their contributions during flash flood events. The results from the model’s calibration demonstrated this approach’s effectiveness in determining the impact of leaf litter on steep-sloped watersheds. Soil parameters can estimate the behavior of leaf litter during flash flood events. In this study, hydraulic conductivity and initial water content emerged as critical factors for effective parametrization. The findings underscore the potential of a hydrodynamic model to explore the relationship between leaf litter and flash flood events, providing a framework for future studies in watershed management and risk-mitigation strategies.

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Effects of Dynamic Forcing on Hillslope Water Balance Models

Cited by 3 publications

References 40 publications

Predictions of rainfall-runoff response and soil moisture dynamics in a microscale catchment using the CREW model

Predictions of rainfall-runoff response and soil moisture dynamics in a microscale catchment using the CREW model

Predictions of rainfall-runoff response and soil moisture dynamics in a microscale catchment using the CREW model

Improving Flash Flood Hydrodynamic Simulations by Integrating Leaf Litter and Interception Processes in Steep-Sloped Natural Watersheds

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