西南喀斯特地区不同岩面形态下岩面径流特征OACSTPCD

[Objective]The aims of this study are to examine the characteristics of rainfall-runoff under differ-ent rock surface morphologies under natural rainfall conditions,and to provide a scientific basis for further understanding the rainfall erosion pattern in karst slopes.[Methods]Four typical rock surface morphologies of smoothness,fissure,karst cave,and solution dish in this study area were selected as the research objects.In-situ observational tests on field run-off plots were used to monitor rock surface runoff generation under various rock surface morphologies after rainfall.[Results](1)Among the four kinds of rock surface morphology,the runoff coefficient of rock surface decreased in the order:smoothness(0.74)＞solution dish(0.57)＞karst cave(0.35)＞fissure(0.19).The average runoff coefficient of smoothness was significantly higher than those of other types,being 3.89,2.11,and 1.30 times higher than those of the fissure,solution dish,and karst cave,respectively.(2)With the increase in rainfall grade,the runoff coefficients of different rock surfaces showed an increasing trend.During heavy rainfall and above rainfall events,the runoff coefficients were significantly different for the 4 rock surface morphologies.(3)Preciptation was the main rainfall factor affecting the runoff depth of rock.The critical value of rainfall causing rock surface runoff was fissure(1.8 mm)＞smoothness rock surface(1.5 mm)＞solution dish(1.1 mm)＞karst cave(1.0 mm).[Conclusion]Rock surface morphology and rainfall are important factors affecting rock surface runoff.Large rock surface runoff is a vital component of runoff in karst slopes.The effect of rock surface runoff should be considered in the prevention of soil and water loss on karst slopes.