Evolution of rock cover, surface roughness, and flow velocity on stony soil under simulated rainfall
Abstract
Erosion pavement is one result of hillslope evolution on semiarid watershed hillslopes. It is anticipated that the accumulated rock as erosion pavement develops will affect both the surface morphology and hydraulic processes. This study aimed to quantify the spatiotemporal evolution of rock cover and surface roughness as erosion pavement develops, and measure their effects on the flow velocities. A series of rainfall simulations were made on a soil plot (2 by 6.1 m) under three slope treatments (5%, 12% and 20%) with surface elevation, rock cover and flow velocity measurements. The results showed: 1) rock cover increased as rainfall was progressed and the terminal rock cover was not slope gradient dependent; 2) surface roughness was positively correlated with rock cover in the upper and middle plot sections, wherein the increasing surface roughness and rock cover reduced the flow velocity following power functions; 3) in the lower section, surface roughness did not uniformly increase with increasing rock cover due to the rill incisions; 4) steeper slopes had greater terminal surface roughness; 5) the terminal velocities reached a relative constant value that was a function of unit flow rates for a given section; 6) there was no unique hydraulic coefficient for a give surface condition. These results improve our understanding of the evolution of semiarid hillslopes.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H11N1705L
- Keywords:
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- 1809 Desertification;
- HYDROLOGY;
- 1812 Drought;
- HYDROLOGY;
- 1833 Hydroclimatology;
- HYDROLOGY;
- 1834 Human impacts;
- HYDROLOGY