Streamflow from small watersheds on the western slope of the Cascade Range of Oregon

Year: 
1965
Publications Type: 
Journal Article
Publication Number: 
320
Citation: 

Rothacher, Jack. 1965. Streamflow from small watersheds on the western slope of the Cascade Range of Oregon. Water Resources Research. 1(1): 125-134.

Abstract: 

Abstract. Streamflow from small watersheds on the western slopes of the Oregon Cascade Rangeis strongly influenced by a maritime climate (wet winters and dry summers). Although annual pre-cipitation is high (94 inches in the study area), overland flow is almost unknown. Peak flows resultlargely from subsurface flow and under conditions in which both retention and detention reservoirsare almost filled during extended periods of low-intensity rainfall. Under these conditions, vegeta-tion appears to exert a minimum influence on high streamflow. Lowest streamflow occurs from lateAugust to mid-November and may follow a 60- to 100-day period with little or no rain. The densevegetation of this part of the Douglas-fir region appears to exert its major influence at such times.Removal of vegetation from only 30% of a 250-acre watershed has caused a 12-28% increase inminimum streamflow. On a 237-acre watershed on which 80% of the trees were cut, the increase inlow flow was 85%.