No abstract

Abstract. Dissolved organic carbon (DOC) loading from lands to rivers in response to rainfall events are the major carbon sources to aquatic ecosystem. We used high-resolution measurements to determine the runoff exports of DOC from the Chippewa River and watershed which was largely dominated by agricultural land-uses. It was found that DOC concentrations in spring were higher than in autumn and discharges in spring affected by snowmelt were larger and varied more widely than in autumn in this mixed watershed. We focused on the effect of antecedent 10-day rainfall on DOC variation and exports for the different magnitudes rainfall events. It showed that the antecedent precipitation (field moisture conditions) greatly determined the extent of DOC export. It was also shown that the DOC-Discharge distributions for storm-events were generally asymmetric, whereby they were positively skewed and it was greatly different between different seasons.