Linear scaling of precipitation-driven soil erosion in laboratory flumes

Abstract

The proportionality between raindrop-driven soil erosion delivery and area of soil exposed to raindrops under a uniform precipitation rate was investigated in terms of individual size classes using laboratory flume experiments. In particular, we examined the dependence of soil erosion on the area exposed to raindrop detachment. Twelve experiments were performed on the same laboratory flume, filled with the same soil. The experiments entailed different (constant) precipitation rates (28 and 74 mm h -1 , 2-5 h duration) and various fractions of exposed surface (20, 30, and 40%, created using rock fragment cover). In addition, different initial soil conditions (dry hand-cultivated, wet sealed-compacted and dry compacted) were considered. The discharge rates and the sediment concentrations of seven individual size classes (< 2, 2-20, 20-50, 50-100, 100-315, 315-1000 and > 1000 µm) were measured at the flume exit. Results showed that the proportionality of soil erosion to the area exposed appears to always hold at steady state independently of the initial conditions and rainfall intensity.Across all experiments the data indicate that this proportionality holds approximately during entire erosive events and for all individual size classes. However, the proportionality for short times is less clear for the larger size classes as the data show that for these classes the erosion was sensitive to the soil's antecedent conditions and further influenced by additional factors such as surface cohesion, surface compaction and soil moisture content.

Probability Models and Statistical Tests for Extreme Precipitation Based on Generalized Negative Binomial Distributions

“…In particular, the issue of determining threshold values, the excess of which leads to the extreme events, for example, in daily rainfalls or their intensities, is the key point of the study. Precipitation intensities are important not only for forecasting floods but also for solving problems such as runoff and soil erosion [50,51]. It can be explained by the contemporary climate change scenarios that predict a significant increase in the frequency of high intensity rainfall events, primarily in the dry areas.…”

Use of geophysical methods to evaluate soil sediments behind gabion check dams in the dry regions of southern Tunisia.

“…Cependant, dans des conditions contrôlées au laboratoire, il a été constaté que la perte en sol est proportionnelle à la surface exposée pendant l'équilibre et lorsque le mécanisme d'érosion en rigole est dominant. En même temps, au début de l'événement érosif, la relation est moins claire en raison de l'influence prononcée des conditions antécédentes du sol (Jomaa et al, 2012(Jomaa et al, , 2017. Par conséquent, lors de fortes évènements, l'érosion concentrée en rigoles devient le processus d'érosion du sol dominant, en particulier dans des conditions de couche arable compactée et nue, entraînant une perte en sol substantielle.…”

Impact of Accessibility to Cities at Multiple Administrative Levels on Soil Conservation: A Case Study of Hunan Province

“…Vegetation is able to increase soil organic matters, improve aggregate stability and reduce soil erosion [ 27 ]; it can be easily altered by human activities and changes soil conservation magnificently within a few years [ 28 ]. Precipitation is one of the kinetic energy sources of soil erosion [ 29 ]; it was originally determined by the local climate, but has been polarized by global warming in recent years [ 30 ]. The steeper the terrain, the greater the potential gravitational energy it provides for soil erosion [ 31 ]; on a micro scale, the construction of traffic infrastructures will weaken the original stability of the terrain [ 32 ], which furtherly increases soil erosion.…”