The transportation of large amounts of dissolved organic carbon (DOC) down a stream within a 15.51-km2 catchment in Alberta, Canada, related directly to events, such as high rainfall and beaver (Castor canadensis) dam failures, that created major disturbances. A 2.3-km section of the stream was drastically altered in June 1994 when a flood wave resulting from a breached beaver dam deposited large amounts of debris and sediment within the section. Results from stream DOC-storage analyses, in which a difference method was used, suggest that the organic-debris dams created by the failed dam event served as both sources and sinks for DOC. Discharge and DOC measurements at hydrometric stations located at intervals along the stream indicated that storage of DOC on the catchment was strongly influenced by the presence of wetlands and beaver. In 1994 and 1995, disturbances occurring during periods totalling 17 days and 28 days accounted for 94% (1374 kg·km2) and 84% (204 kg·km2), respectively, of the amount of DOC exported from the catchment. DOC concentrations in the stream were greatest (77.0 mg·L1) near the top of the catchment and decreased progressively downstream to the catchment outlet, where the mean concentration was 23.3 mg·L1.
Riparian alder fens — source or sink for nutrients and dissolved organic carbon? — 2. Major sources and sinks