Year of Award


Document Type


Degree Type

Master of Science (MS)

Degree Name


Department or School/College

College of Forestry and Conservation

Committee Chair

Donald F. Potts


University of Montana


The purpose of this study was to 1) document changes in suspended sediment and turbidity associated with road construction and logging on Belt series metasediments, and 2) measure the magnitude of organic debris loading, and evaluate the significance of debris as an agent of stream equilibrium.

Forest management activities in a 2nd order drainage increased suspended sediment yields 7.7 fold in the first year following road construction, and 2 fold following logging in the second year. Severely limited sediment supplies resulted in poor correlations between suspended sediment and discharge. Sediment transport was strongly hysteretic, with highest concentrations of sediment occurring on the rising limbs of the snowmelt hydrograph as well as on individual peaks. Sediment-turbidity relationships were strongly discharge dependent, reflecting the changing composition of suspended load with stream power and sediment supplies.

Organic debris loads within the active channel were inversely proportional to stream order. All channels tended to concentrate debris; channels contained 1.8 to 5 times as much debris per unit area as the adjacent bank. The percentage of organic debris within the active channel which was involved in storage of sediments increased with stream order.

Additionally, channel obstructions shifted from debris (< 10 cm) to logs as stream order increased. Organic obstructions stored from .009 to .021 m3 of sediment /m2 of active channel, and dissipated from 21% to 37% of the stream energy.



© Copyright 1985 Bruce Konrad Muir Anderson