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A modified Eulerian method for snowdrifts was proposed by introducing the snow particle capture efficiency. The relationships between the modified method and the previous methods were discussed, the results showed that the previous methods are special cases of the modified method. Based on the modified method, the impacts of the location and the height of the interfering building on the snow distribution on the target building were studied. The location of the interfering building seriously affects the snow distribution on the roof of the target building. Four typical interference modes were found through simulations. Significant interference effects on snow load occur when the interfering building is higher than the target building, and it becomes more powerful with the increase of the height of the interfering building. • A modified erosion and deposition model is proposed, introducing the capture efficiency of the falling snow phase. • The Impacts of the location of the interfering building on the snow distribution on the target building are investigated. • The Impacts of the height of the interfering building on the snow distribution on the target building are investigated. [ABSTRACT FROM AUTHOR]

Abstract: Rill erosion can be a serious problem on cultivated slopes. Understanding the mechanisms of the detachment process in eroding rills is important in developing and improving process-based erosion prediction models. The detachment rate, defined as the sediment amount detached from a unit area in a unit time, is a crucial parameter in most physical erosion prediction models. Most current studies on rill detachment rates use spatially averaged soil erosion data, which provides little information about soil erosion dynamics due to the lack of spatially distributed, contemporaneous rill erosion data. The objective of this study was to estimate the net detachment rate in eroding rills using a rare earth element (REE) tracing method. Flume experiments were conducted with ten REE oxides (Ho2O3, Tb4O7, Eu2O3, Yb2O3, Dy2O3, Sm2O3, La2O3, Tm2O3, CeO2, and Nd2O3) as tracers mixed with soil in different sections of five slopes (8.74%, 17.62%, 26.78%, 36.38%, and 46.6%) exposed to three water flow rates (2, 4, and 8 L min− 1). Regulated water flow was introduced to the upper end of flumes, 8 m long and 0.1 m wide, which were divided into 10 equal segments, each containing a different REE–soil mixture. The net detachment rate from each rill segment was calculated from the REE concentrations in the eroded and transported material. The detachment rates from different segments along the rills, at different slope gradients and flow rates, were compared with those estimated directly from previous studies, and were found to increase with increasing slope gradient and flow rate. Results also showed that the net rill detachment rates decreased linearly with an increase in sediment concentration, and decreased exponentially with an increase in rill length. The REE-derived detachment data and their relationship with sediment concentrations are consistent with the detachment function used in the WEPP model, and are helpful in understanding the processes of rill erosion. Using REEs to trace detachment rates in continuous rills is a valid and advantageous technique for estimating the spatial distribution of the rill detachment rates. [Copyright &y& Elsevier]

Abstract: Measurement of the velocity of shallow water flow on a hill slope is of great importance in soil erosion studies. Electrolyte tracers have been tried to estimate mean velocity of water flow with the velocity of the leading edge of the solute propagation multiplied with a somewhat arbitrary correction factor. In this study, an analytical solution of solute (tracer) transport was formulated to serve as the mathematical foundation for measuring shallow water flow velocity. To estimate the flow velocity, a procedure was advanced. In the procedures, the analytical solution is fitted with the measured propagation curve and given the ‘the least square’ estimation of velocity. A detailed mathematical description is outlined for this purpose. Experimental results are given to show the feasibility of the method, including the analytical solution and the estimation procedures. This study provides the theoretical foundation for measuring the velocity of shallow water flow and for studies of overland solute transport. [Copyright &y& Elsevier]

• Soil erosion due to livestock and climate in QTP was assessed using 137Cs and 210Pb ex. • Net erosion in the last 50 years was 19 t ha−1 yr−1 but 0.25 t ha−1 yr−1 over 100 years. • Erosion significantly correlated with grazing but not with climate change. • Livestock grazing accelerates soil erosion more than climate change in QTP. Livestock grazing and climate change accelerate soil erosion in the grassland of Qinghai-Tibet Plateau (QTP), China. However, the linkage of the two factors to accelerated erosion in the region has never been separated. Thus, this study was set up to determine the contribution of livestock grazing and climate change to soil erosion in the grassland of QTP. Five sites (Tuotuohe, Maduo, Maqin Dongqinggou (MQDQG), Maqin Junmuchang (MQJMC), and Maqin Jungongzhen (MQJGZ)) across 1100-km East-West transect in the Three-River Headwaters Region (TRHR) of QTP were selected for this study. The 137Cs and 210Pb ex techniques were used to determine soil redistribution rates, covering a time scale of 50 and 100 years, respectively. In the last 100 years, soil accumulation was obvious in four sites (Tuotuohe, Maduo, MQDQG and MQJMC) except one site (MQJGZ), where soil erosion occurred along the transect. In the entire transect, almost no soil erosion but soil accumulation (0.25 t ha−1 yr−1) occurred over a period of 100 years. In contrast, soil erosion significantly increased by 75 times at a rate of 18.68 t ha−1 yr−1 in the last 50 years. Net soil redistribution varied significantly from −99 t ha−1 yr−1 in MQJGZ to 14.2 t ha−1 yr−1 in MQDQG over a period of last 50 years. Accelerated soil erosion across QTP significantly correlated with livestock numbers and intensive grazing activities but not significantly correlated with precipitation. Our results suggest that livestock grazing play a key role in accelerating soil erosion more than climate change in the grassland of Qinghai-Tibet Plateau. [ABSTRACT FROM AUTHOR]