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VARIATIONS IN NORTHERN SIERRA NEVADA STREAMFLOW: IMPLICATIONS OF CLIMATE CHANGE 1
Author(s) -
Pupacko Alex
Publication year - 1993
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.1993.tb03208.x
Subject(s) - streamflow , snowmelt , snowpack , surface runoff , snow , water year , climate change , environmental science , climatology , hydrology (agriculture) , drainage basin , structural basin , physical geography , geology , geography , oceanography , cartography , geotechnical engineering , ecology , paleontology , geomorphology , biology
Historical records of streamflow for an eastward‐ and a westward‐draining stream in the northern Sierra Nevada have been analyzed for evidence of changes in runoff characteristics and patterns of variability. A trend of increasing and more variable winter streamflow began in the mid‐1960s. Mean monthly streaniflow during December through March was substantially greater for water years 1965–1990 compared to water years 1939–1964. Increased winter and early‐spring streamflow during the later period is attributed to small increases in temperature, which increase the rain‐to‐snow ratio at lower altitudes and cause the snowpack to melt earlier in the season at higher altitudes. The timing of snowmelt runoff on the western slope of the Sierra Nevada is more sensitive than it is on the eastern slope to changes in temperature, owing to predominantly lower altitudes on the west side. This difference in sensitivity suggests that basins on the east side of the Sierra Nevada have a more reliable water supply (as snow storage) than western‐slope basins during warming trends.