Laboratory Investigation on Rainfall-Runoff-Erosion Characteristics Under Varying Vegetation Layouts

This laboratory study is aimed to assess the impact of different plant types and varying rainfall levels on the runoff and sediment erosion on slopes. The study employed a 2 × 1 m soil bed in conjunction with a rainfall simulator. Various plant layouts were tested including scenarios with no vegetation, full vegetation coverage, and distinct patterns such as upstream, downstream, and checkerboard. Rainfall was applied at three different intensities (100, 150, and 200 mm/h) for a total duration of 16 min, with data collection continuing until runoff ceased into the collection tank. This comprehensive approach enabled the researchers to gain insights into how different plant arrangements influenced erosion dynamics. Upon drying the sediment for 24 h, results of the study revealed that vegetation cover played a significant role in reducing both runoff and sediment. Intriguingly, downstream vegetation was found to be more effective than upstream vegetation in mitigating erosion. Furthermore, the placement of vegetation on the lower part of the slope proved more efficient in erosion prevention than having it higher up. These findings hold substantial importance for the development of erosion control and land management strategies, particularly in regions with diverse plant configurations. Notably, the absence of vegetation (bare soil) resulted in the highest sediment output, while a uniform vegetation pattern across the area exhibited a significant reduction in sediment compared to bare soil. Among the various layouts tested, the scenario with uniform vegetation (at a density of 2.5 cm) emerged as the most effective in sediment reduction. When vegetation was placed on one side with bare soil on the other (either upside or downside), a moderate reduction in sediment was observed compared to entirely bare soil. However, the checkerboard pattern had only a marginal effect on sediment reduction and proved less effective than the uniform vegetation layout.