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Streamflow from small watersheds on the western slope of the Cascade Range of Oregon
Author(s) -
Rothacher Jack
Publication year - 1965
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr001i001p00125
Subject(s) - streamflow , hydrology (agriculture) , watershed , precipitation , environmental science , vegetation (pathology) , surface runoff , acre , range (aeronautics) , cascade , geology , drainage basin , geography , meteorology , ecology , agroforestry , medicine , chemistry , materials science , cartography , geotechnical engineering , pathology , chromatography , machine learning , computer science , composite material , biology
Streamflow from small watersheds on the western slopes of the Oregon Cascade Range is strongly influenced by a maritime climate (wet winters and dry summers). Although annual precipitation is high (94 inches in the study area), overland flow is almost unknown. Peak flows result largely from subsurface flow and under conditions in which both retention and detention reservoirs are almost filled during extended periods of low‐intensity rainfall. Under these conditions, vegetation appears to exert a minimum influence on high streamflow. Lowest Streamflow occurs from late August to mid‐November and may follow a 60− to 100‐day period with little or no rain. The dense vegetation 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 in minimum streamflow. On a 237‐acre watershed on which 80% of the trees were cut, the increase in low flow was 85%.