Fredriksen, R. L. 1965. Sedimentation after logging road construction in a small western Oregon watershed. In: Proceedings of the federal inter-agency sedimentation conference; 1963; [Place of meeting unknown]. Misc. Publ. 970. Washington, DC: U.S. Department of Agriculture, Forest Service: 56-59.
During the summer of 1959, 1.65 miles of log-ging road were constructed in a 250-acre for-ested watershed that rises 2,000 feet in adistance of 1 mile. This study evaluates thechange in sedimentation subsequent to roadconstruction. Runoff from undisturbed water-sheds in this area remains clear during thesummer low-flow months and reaches concen-trations of 100 parts per million during winterstorm peaks. Runoff from the first rainstormsafter road construction carried 250 times theconcentration carried in an adjacent undis-turbed watershed. Two month; after construc-tion, sediment had diminished to levels slightlyabove those measured before construction.Sediment concentrations for the subsequent 2-year period were significantly different frompreroad levels. In about 10 percent of thesamples, sediment concentrations were far inexcess of predicted values, indicating a stream-bank failure or mass soil movement. Annualbedload volume the first year after constructionwas significantly greater than the expectedyield, but the actual increase was small. Atrend toward normalcy was evident the secondyear.