Modelling Effects of Rainfall Patterns on Runoff Generation and Soil Erosion Processes on Slopes

Abstract

Rainfall patterns and landform characteristics are controlling factors in runoff and soil erosion processes. At a hillslope scale, there is still a lack of understanding of how rainfall temporal patterns affect these processes, especially on slopes with a wide range of gradients and length scales. Using a physically-based distributed hydrological model (InHM), these processes under different rainfall temporal patterns were simulated to illustrate this issue. Five rainfall patterns (constant, increasing, decreasing, rising-falling and falling-rising) were applied to slopes, whose gradients range from 5 • to 40 • and projective slope lengths range from 25 m to 200 m. The rising-falling rainfall generally had the largest total runoff and soil erosion amount; while the constant rainfall had the lowest ones when the projective slope length was less than 100 m. The critical slope of total runoff was 15 • , which was independent of rainfall pattern and slope length. However, the critical slope of soil erosion amount decreased from 35 • to 25 • with increasing projective slope length. The increasing rainfall had the highest peak discharge and erosion rate just at the end of the peak rainfall intensity. The peak value discharges and erosion rates of decreasing and rising-falling rainfalls were several minutes later than the peak rainfall intensity.

Advances in Modelling and Prediction on the Impact of Human Activities and Extreme Events on Environments

“…Results have identified a critical slope, 15 • , which was independent of the rainfall pattern and slope length. However, it has been found that the critical slope of soil erosion amounts decreased from 35 • to 25 • , with an increasing projective slope length [31].…”

“…Moreover, the changes in rainfall patterns and magnitudes generated by climate change may have also had an effect on runoff and soil erosion processes. Ran et al [31] have conducted a study aiming to understand how various rainfall patterns (constant, increasing, decreasing, rising-falling, and falling-rising) affect these processes, with a particular focus on the slopes with a wide range of gradients (5 • to 40 • ) and length scales (25 m to 200 m). Results have identified a critical slope, 15 • , which was independent of the rainfall pattern and slope length.…”

A high spatial resolution dataset of China’s biomass resource potential

“…It can be used to calculate the slope for each grid cell with the slope tool in ArcMap. As China's soil and water conservation law prohibits the cultivation of crops on a steep slope above 25 degrees, and many studies also show that severe soil erosion will occur in areas with a slope greater than 25 degrees [31][32][33] , this study excludes these areas for energy crop plantation. (4) net primary production dataset…”

Research on the Features of Rainfall Regime and Its Influence on Surface Runoff and Soil Erosion in the Small Watershed, the Lower Yellow River

“…as well as rainfall characteristics such as precipitation (P), rainfall duration (D), and rainfall intensity (I) [8]. Most of the above studies focus on the influence of single rainfall characteristics on runoff and sediment yield and lack of systematic evaluation [1], as runoff and sediment generation may vary greatly depending on different rainfall regimes [28]. Wei et al [29] used the K-mean clustering method to classify 131 rainfall events in the Loess Plateau region of China from 1986 to 1999 into 3 categories based on 3 indicators: precipitation (P), rainfall duration (D), and maximum 30 min rainfall intensity (I 30 ), and to analyze the effects of different rainfall regimes on the runoff and sediment yield.…”