Research on the Impact of Using a Combination of Rigid and Flexible Vegetation on Slope Hydrological Properties in Loess Regions.

Slope vegetation is a key component of soil erosion control. Rigid vegetation improves slope stability, while flexible vegetation reduces water velocity, and the combination of both improves erosion resistance; however, there are few studies on how the combination of rigid and flexible vegetation affects the hydraulic characteristics of slope flow. In order to investigate the effect of this combination on the hydraulic characteristics of slopes, a mathematical model of the coefficient of resistance under the cover of rigid–flexible vegetation was established by using theoretical analysis and indoor tests, and the indoor tests were conducted with different rigid–flexible vegetation combinations (single-row interlocking (IS), double-row interlocking (IT), upstream rigid–downstream flexible (RF), and bare slope (BS)). The results showed that the rigid–flexible vegetation combination had a significant effect on the slope water flow. With the increase in flow, the water depth and flow velocity of slope flow showed an increasing trend, the flow velocity of the bare slope was significantly larger than that of the vegetation-covered slope, and the value of the water depth increment of the vegetation-covered slope was 0.086~0.22 times that of the bare slope. The Reynolds number showed a good linear increasing relationship with flow rate, and with the gradual increase in flow rate and slope, the flow pattern gradually changed from slow flow to fast flow. When the slope was 2°, the drag coefficient increased and then decreased. The pattern of erosion reduction capacity was IS > RF > IT > BS. The results of this study provide strong theoretical support for understanding the mechanism of vegetation-controlled erosion and provide scientific guidance for optimizing vegetation design in the Loess Plateau region. [ABSTRACT FROM AUTHOR]