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Efficiency of the Summer Monsoon in Generating Streamflow Within a Snow‐Dominated Headwater Basin of the Colorado River
Author(s) -
Carroll Rosemary W. H.,
Gochis David,
Williams Kenneth H.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl090856
Subject(s) - streamflow , snowpack , monsoon , evapotranspiration , environmental science , snow , drainage basin , east asian monsoon , hydrology (agriculture) , climatology , snowmelt , structural basin , geology , geography , ecology , paleontology , cartography , geotechnical engineering , geomorphology , biology
The North American Monsoon occurs July–September in the central Rocky Mountains bringing significant rainfall to Colorado River headwater basins. This rain may buffer streamflow deficiencies caused by reductions in snow accumulation. Using a data‐modeling framework, we explore the importance of monsoon rain in streamflow generation over historical conditions in an alpine basin. Annually, monsoon rain contributes 18 ± 7% water inputs and generates 10 ± 6% streamflow. The bulk of rain supports evapotranspiration in lower subalpine forests. However, rains have the potential to produce appreciable streamflow at higher elevations where soil moisture storage, forest cover, and aridity are low and rebound late season streamflow 64 ± 13% from simulated reductions in spring snowpack as a function of monsoon strength. Interannual variability in monsoon efficiency to generate streamflow declines with low snowpack and high aridity, implying the ability of monsoons to replenish streamflow in a warmer future with less snow accumulation will diminish.