Stream power

About: Stream power is a research topic. Over the lifetime, 1135 publications have been published within this topic receiving 51324 citations.

Quantifying the Contribution of Sediment Load to Soil Detachment Rate by Sediment-Laden Rill Flow

Abstract: Sediment load changes with downslope distance during rill erosion process, and thus quantifying the potential contribution of sediment load on soil detachment rate is essential to accurately model the rill erosion process. A standardization-based method was adopted to quantify the contribution for the first time, and the rill flume with a soil-feeding hopper was specifically designed to insulate the effect of sediment load on detachment rate. Loessial soil was quantitatively fed into rill flow to produce different sediment loads. Seven flow discharges were combined with six slopes. Soil detachment rate was measured for each combination under five sediment loads (10, 25, 50, 75, and 90% of the sediment transport capacity, respectively). The results showed that soil detachment rate by sediment-laden rill flow decreased linearly with the increase in sediment load. Stream power is the best hydrodynamic parameter in relation to the detachment rate under different sediment loads compared with shear stress and unit stream power. The comprehensive response relationship of soil detachment rate to sediment load and stream power is a binary linear equation (R² = 0.9482). The contribution rate of sediment load to soil detachment rate is 30.43% and that of stream power is 64.39%. The negative effect of sediment load on soil detachment rate accounts for almost one-third of the total contribution. It is important to draw sediment load as a negative factor into process-based rill erosion model. This study can provide a feasible way for researchers to quantify the contribution rate of factors and can help to understand rill erosion process sufficiently.

Determination of Watershed Infiltration and Erosion Parameters from Field Rainfall Simulation Analyses

Abstract: Realistic modeling of infiltration, runoff and erosion processes from watersheds requires estimation of the effective hydraulic conductivity (Km) of the hillslope soils and how it varies with soil tilth, depth and cover conditions. Field rainfall simulation (RS) plot studies provide an opportunity to assess the surface soil hydraulic and erodibility conditions, but a standardized interpretation and comparison of results of this kind from a wide variety of test conditions has been difficult. Here, we develop solutions to the combined set of time-to-ponding/runoff and Green– Ampt infiltration equations to determine Km values from RS test plot results and compare them to the simpler calculation of steady rain minus runoff rates. Relating soil detachment rates to stream power, we also examine the determination of “erodibility” as the ratio thereof. Using data from over 400 RS plot studies across the Lake Tahoe Basin area that employ a wide range of rain rates across a range of soil slopes and conditions, we find that the Km values can be determined from the combined infiltration equation for ~80% of the plot data and that the laminar flow form of stream power best described a constant “erodibility” across a range of volcanic skirun soil conditions. Moreover, definition of stream power based on laminar flows obviates the need for assumption of an arbitrary Mannings “n” value and the restriction to mild slopes (<10%). The infiltration equation based Km values, though more variable, were on average equivalent to that determined from the simpler calculation of steady rain minus steady runoff rates from the RS plots. However, these Km values were much smaller than those determined from other field test methods. Finally, we compare RS plot results from use of different rainfall simulators in the basin and demonstrate that despite the varying configurations and rain intensities, similar erodibilities were determined across a range of infiltration and runoff rates using the laminar form of the stream power equation.

The influence of channel steps on coarse bed load transport in mountain torrents: case study using the radio tracer technique ‘PETSY’

Abstract: Direct measurements of the movements of bed load particles in a mountain torrent, using the radio tracer technique ‘PETSY’, show the influence of channel (bottom) steps on coarse bed load transport. This effect is demonstrated through an analysis of the step length of tagged cobbles. A significant change in the mean step length of particle is noted and the effect of marked channel slope changes on mean particle travel velocity revealed. The empirical results lead to the conclusion that particle transport is clearly controlled by local channel slope changes and that these are of fundamental importance in the transport of coarse bed load material.

Sediment transport capacity in erodible beds with reconstituted soils of different textures

Abstract: Precise estimation of sediment transport capacity and wide applicability of a prediction equation could provide a positive response to increasing challenges of soil erosion. Currently, the models developed by many researchers are focused on a few or single soils. In this study, a prediction equation of sediment transport capacity was attempted to establish from the flume experiments performed on erodible beds under the experimental settings of two slopes (5.6%, 16.7%), four unit width discharges (6.67 × 10−5, 1.33 × 10−4, 2.00 × 10−4 and 2.67 × 10−4 m2 s−1) and five reconstituted soils (sand contents of 0%, 30%, 50%, 70%, 100%). Here, the sediment transport capacity under clay-sand mixture of different soil texture were analyzed, and a prediction equation for sediment transport based on soil cohesion and hydraulic variables was established. The experiments confirmed that the sediment concentration and transport capacity increased with the unit width discharge and slope gradient as a power function, and was more dependent on slope gradient. Besides, the hydrological and erosive processes on the beds with reconstituted soils varied with soil texture, the beds with a high clay content had a stable channel of sediment transport. Comparatively, unit stream power was the most suitable hydraulic variable to describe the sediment transport capacity (r = 0.951, P