Modeling the dynamics of soil erosion and size‐selective sediment transport over nonuniform topography in flume‐scale experiments

Abstract

[1] Soil erosion and the associated nutrient fluxes can lead to severe degradation of surface waters. Given that both sediment transport and nutrient sorption are size selective, it is important to predict the particle size distribution (PSD) as well as the total amount of sediment being eroded. In this paper, a finite volume implementation of the Hairsine-Rose soil erosion model is used to simulate flume-scale experiments with detailed observations of soil erosion and sediment transport dynamics. The numerical implementation allows us to account for the effects of soil surface microtopography (measured using close range photogrammetry) on soil erosion. An in-depth discussion of the model parameters and the constraints is presented. The model reproduces the dynamics of sediment concentration and PSD well, although some discrepancies can be observed. The calibrated parameters are also consistent with independent data in the literature and physical reason. Spatial variations in the suspended and deposited sediment and an analysis of model sensitivity highlight the value of collecting distributed data for a more robust validation of the model and to enhance parametric determinacy. The related issues of spatial resolution and scale in erosion prediction are briefly discussed.

Modeling fine‐scale soil surface structure using geostatistics

“…Therefore, by using the length scale as a guide, it is possible to quantify surface variance at a number of spatial scales within a specified area, in order to consider the appropriate geomorphological scale and its environmental or hydrological influence (Table 1). Given the computing power that is available to model land surface processes, it is clear that the recent development of fine spatial resolution rainfall-runoff and erosion models is well supported technologically [Heng et al, 2009[Heng et al, , 2011. Data-capture techniques (proximal and terrestrial laser scanning, high-definition total station surveying) now exist to produce digital elevation models at very fine spatial resolutions [Jomaa et al, 2010].…”

Forest harvesting impacts on micrometeorological conditions and sediment transport activities in a humid periglacial environment

“…Following forest harvesting, sediment flux decreased during rainfall periods in site CC, while differences in the sediment flux in NC before and after harvesting were not significant (Table 4). Decreases in the sediment flux of fine sediment, which is selectively transported by overland flow (Heng et al, 2011;Zhao et al, 2014), was clear during the rainfall seasons (Fig. 11).…”

Constraining the relative importance of raindrop‐ and flow‐driven sediment transport mechanisms in postwildfire environments and implications for recovery time scales

“…Since the influence of raindrop impact on the bed is known to vary with overland flow depth [Proffitt et al, 1991;Gabet and Dunne, 2003;Dunne et al, 2010], many modeling studies [e.g., Heng et al, 2009Heng et al, , 2011Kim et al, 2013] prescribe the raindrop detachment and redetachment coefficients, a and a d , respectively, as decreasing functions of flow depth. In this study, we let…”