In this study, by monitoring carbon transportation and its rainfall-runoff process during the rainy season in Loess Plateau's Yangjuangou dam watershed, we analyzed changes in carbon transportation driven by rainfall and further evaluated the C loss flux for the dam watershed. Results showed that the monthly C wet deposition flux for the wet and dry seasons were 3.33 kg·hm-2and 2.18 kg·hm-2, respectively, which were only small contributions to C transportation for the watershed. C transportation under the rainfall-runoff process in this watershed can reach 944.89 kg·km-2 and 300.29 kg·km-2 in August and September, respectively. Different intensities of rainfall runoff lead to different C loss processes, wherein dissolved inorganic carbon (DIC) is the main C form. Under small rainfall events, the output of dissolved total carbon (DTC) in this watershed was 156.98 kg·km-2; and the output of moderate rainfall events was 284.60 kg·km-2. Finally, we determined that the C loss modulus of the Yangjuangou watershed was 1.89 kg·(km2·mon)-1 in the rainy season, thus the C loss modulus for the study area could reach 2.70 kg·(km2·a)-1.
Keywords: C transportation; Loess Plateau; carbon loss; dam watershed; rainfall runoff.