SEDIMENT TRANSPORT IN A SMALL STREAM FOLLOWING 2 SUCCESSIVE FOREST-FIRES

The transport of stream bedload sediment was monitored continuously in a small stream from 1975 to 1982 following forest fires in 1974 and 1 980. The stream is located in the east subcatchment (170 ha) of Lake 2 39 in the Experimental Lakes Area, northwestern Ontario. Precipitation , stream discharge, bedload transport, and concentration of suspended materials were measured quantitatively and organic debris was observed and collected. Bedload transport increased 20-fold following the firs t fire and threefold after the second. Particle sizes tended to increa se during the period of study. Bedload data suggest a recovery period of 5-6 yr following the first fire and a shorter one following the sec ond. A mass budget of material load transported in a single year follo wing recovery indicated a dominance of dissolved load (87%), followed by suspended load (10%), and bedload (3%).