Experimental analysis of size and distance of travel of unconstrained particles in interrill flow

Abstract

Abstract. The travel distances of particles ranging in size from 2.88 mm to 10.63 mm were investigated in !.?•.boratory simulations of interrill overland flow. Using travel distances scaled for differences,: among the experiments in flow and rainfall energy, a relationship between distance traveled and particle size is obtained that shows a steep reduction in travel distance with increase in particle size. Travel distance is the outcome of two probabilities: that of moving and that of coming to rest. In interrill flow, the former is controlled by rainfall energy, but the latter is controlled by flow energy. Analysis of subsets of the data in which only rainfall or flow energy varied shows that the steep reduction in travel distance with particle size is primarily due to sensitivity to flow energy. Although particle movement (entrainment) by rainfall energy does vary with particle size, the sensitivity is less. ( 1) in which M is particle mass (grams), L is distance moved in unit time (cm min-•), Er is rainfall energy (J m -2 S -1) and Ef is flow energy (J m -2 s-1). This relationship indicates thatsmaller particles are transported farther than larger particles and that effective particle transport is achieved in interrill flow only when both rainfall and flow energy are significant because the combined effect of rainfall energy and flow energy on particle transport is multiplicative. While this study demonstrates the importance of both rainfall and flow energy to particle transport, it describes only the relationship between rate of transport and total energy available. No data have been presented that clearly demonstrate the relationship between particle size and transport distance.

Simulation of soil loss processes based on rainfall runoff and the time factor of governance in the Jialing River Watershed, China

“…Studies have shown that soil loss would occur due to the interception of the plant residues and roots as well as the aggradation of billabongs, ditches, ponds, reservoirs, weirs, and dams in the process of transport (Parsons and Stromberg 1998). To this end, the SDR was introduced and used to explain the spatial and temporal heterogeneity of sediment transport processes and their interactions with rainfall and catchment characteristics within the watershed (Walling 1983;Wang et al 2008).…”

Understanding the relationship between heavy metals in road-deposited sediments and washoff particles in urban stormwater using simulated rainfall

“…Future studies should consider how the road smoothness affects the relationship of heavy metals with different chemical fractions between RDS and washoff particles. In addition, all results of washoff particles in this study were based on simulated rainfall experiments; therefore, the findings presented herein should be verified based on natural rainfall in future studies [41].…”

Scaling Soil Erosion Models in Space and Time

“…Torri et al (1987) suggested that this function is a negative exponential of flow depth to a power. The median travel distance of particles in shallow flows can be considered to be a non-linear function of rainfall energy and flow energy as well as particle mass (Parsons & Stromberg, 1998). On a planar, uniform slope with a uniform infiltration rate and uniform roughness, flow hydraulics can be considered to be simple functions of distance downslope (discharge increases linearly, so that depth increases with x 2/3 , flow velocity with x 1/3 and flow energy with x 5/3 ).…”

“…Wainwright et al (2001) relaxed the assumption that all particles travel the same distance under the same flow conditions. It has long been recognized that particles travel a range of different distances as a result of flow variability (especially turbulent bursts where transitional or turbulent flows occur), microtopographic variations and other factors (Wainwright & Thornes, 1991;Hassan et al, 1992;Parsons & Stromberg, 1998). Travel distance of particles can thus be considered to follow a distribution function, with individual particles moving different distances with a given probabilistic form.…”