An analysis of total phosphorus transport in river systems

Verhoff, F. H.; Melfi, David A.; Yaksich, Stephen M.

doi:10.1007/978-94-009-8009-9_25

Cited by 8 publications

(5 citation statements)

References 2 publications

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“…Partheniades, 1972;Cahill et al, 1974;Piest et al, 1975;Verhoff et al, 1980Verhoff et al, , 1982Bonniwell et al, 1999). Routing of sediment movement by any flow process follows the steepest descent algorithm of the flow-routing algorithm.…”

Section: Model Structurementioning

confidence: 99%

A transport‐distance approach to scaling erosion rates: 1. Background and model development

Wainwright

Parsons

Müller

et al. 2008

Earth Surf Processes Landf

127

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The process basis of existing soil-erosion models is shown to be ill-founded. The existing literature builds directly or indirectly on Bennett's (1974) paper, which provided a blueprint for integrated catchment-scale erosion modelling. Whereas Bennett recognized the inherent assumptions of the approach suggested, subsequent readings of the paper have led to a less critical approach. Most notably, the assumption that sediment movement could be approximated by a continuity equation that related to transport in suspension has produced a series of submodels that assume that all movement occurs in suspension. For commonly occurring conditions on hillslopes, this case is demonstrably untrue both on theoretical grounds and from empirical observations. Elsewhere in the catchment system, it is only partially true, and the extent to which the assumption is reasonable varies both spatially and temporally. A second ground-breaking paper -that of Foster and Meyer (1972) -was responsible for subsequent uncritical application of a first-order approximation to deposition based on steady-state analysis and again a weak empirical basis. We describe in this paper an alternative model (MAHLERAN -Model for Assessing Hillslope-Landscape Erosion, Runoff And Nutrients) based upon particle-travel distance that overcomes existing limitations by incorporating parameterizations of the different detachment and transport mechanisms that occur in water erosion in hillslopes and small catchments. In the second paper in the series, we consider the sensitivity and general behaviour of MAHLERAN, and test it in relation to data from a large rainfall-simulation experiment. The third paper of the sequence evaluates the model using data from plots of different sizes in monitored rainfall events. From this evaluation, we consider the scaling characteristics of the current form of MAHLERAN and suggest that integrated modelling, laboratory and field approaches are required in order to advance the state of the art in soil-erosion modelling. Wainwright et al., 2001;Parsons et al., 2004Parsons et al., , 2006b. We have argued elsewhere (Parsons et al., 2004) that these problems arise from a fundamental misconception, and thus misrepresentation, of the component processes that make up soil erosion. The aim of this paper is, therefore, to review the conceptual basis of existing models and to propose an alternative model that addresses the problems inherent in existing approaches. Figure 2. Comparison of information on (a) travel distances and (b) virtual velocities from Hassan et al. (1992) for concentrated flows and Parsons et al. (1998) for unconcentrated flows. See the text for further discussion.822 J. Wainwright et al.Figure 4. Summary of the calculation algorithm used in MAHLERAN. The main components in terms of detachment and the use of travel distance and virtual velocity to estimate sediment discharge are highlighted. 824 J. Wainwright et al.appropriate erosion and deposition rates have been calculated. The sediment mass-balance Equation (6) is equiva...

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Section: Model Structurementioning

confidence: 99%

A transport‐distance approach to scaling erosion rates: 1. Background and model development

Wainwright

Parsons

Müller

et al. 2008

Earth Surf Processes Landf

127

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“…The relative decoupling of the particulate and solution forms of P, the spatial discontinuity of transfers [35,72], and the time and spatial variability in P speciation characterise the P dynamics of diffuse transfer in rural watersheds. These properties are a challenge for process-based modelling.…”

Section: Prospectsmentioning

confidence: 99%

Soluble phosphorus dynamics in an agricultural watershed

Jordan‐Meille

Dorioz²

2004

Agronomie

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-Both particulate phosphorus (PP) and soluble phosphorus (SP) contribute to the eutrophication of water bodies. This research focuses on the mechanisms and factors controlling SP exports at the watershed scale in a case study located in Southern France. Variability in the P concentrations and fluxes was analysed over a period of 6 years in a 302-ha rural watershed. During most of the hydrological periods, reservoirs and pathways for PP and SP seemed to be different both in time and space; differences were greatest during storm flows of the early wet season. Their high SP fluxes and concentrations were due to the P released from agricultural soils as shown by a P mass balance downstream/upstream. During these flushing periods, soluble forms of P follow a hydrochemical behaviour quite similar to solutes and are transferred in relationship to subsurface flows, as shown by a detailed monitoring of the transition from dry to wet season on an agricultural sub-watershed. soluble phosphorus / watershed / no point source / storm flows / losses Abbreviations: PP, particulate phosphorus; SP, soluble phosphorus; SRP, soluble reactive phosphorus; TSS, total suspended solids; TP, total phosphorus.

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“…Equation (1) implies that surface runoff depends directly on the soil moisture content. This movement of phosphorus is a discontinuous process and mainly occurs during high flow events (Verhoff et al, 1982). Exponent a in the formula is a variable depending upon rainfall intensity.…”

Section: Runoff and Phosphorus Loadingmentioning

confidence: 99%

Simulation of runoff and phosphorus transport in a Carpathian catchment, Slovakia

et al. 2006

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A comprehensive, GIS-based modelling approach is developed to estimate runoff and phosphorus transport within a watershed at a daily time step. The approach relies on the use of GIS data for deriving major critical model parameters that exhibit distinct spatial variability over the catchment. Surface runoff is calculated by a modified rational method, which depends upon rainfall intensity, soil moisture status, slope, land-use and soil characteristics. Phosphorus loading is estimated as a function of the runoff volume and the event mean concentration for different land use categories. A diffusive approximation method is used to trace runoff and phosphorus transport to the basin outlet. The modelling approach is tested in the Margecany catchment, Hornad River basin, Slovakia, to simulate runoff, phosphorus loading, and its transport on a daily time scale using data observed between 1995 and 2000. Satisfactory results of the hydrographs and phosphorus concentration at the basin outlet are obtained, though more efforts regarding the phosphorus cycling and its biochemical reactions need to be clarified by further research. Figure 4. Unit response functions with l ¼ 0.0003/s: (a) IUHs for a fixed travel time of 3600 s and different standard deviations, and (b) IUHs for a fixed standard deviation of 3600 s and different travel times

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An analysis of total phosphorus transport in river systems

Cited by 8 publications

References 2 publications

A transport‐distance approach to scaling erosion rates: 1. Background and model development

A transport‐distance approach to scaling erosion rates: 1. Background and model development

Soluble phosphorus dynamics in an agricultural watershed

Simulation of runoff and phosphorus transport in a Carpathian catchment, Slovakia

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