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Evidence of Hydrological Intensification and Regime Change From Northern Alaskan Watershed Runoff
Author(s) -
Arp C. D.,
Whitman M. S.,
Kemnitz R.,
Stuefer S. L.
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 - 10.1029/2020gl089186
Subject(s) - snowmelt , surface runoff , environmental science , hydrology (agriculture) , hydrograph , watershed , permafrost , flood myth , water year , precipitation , streamflow , climate change , geology , water resources , drainage basin , oceanography , geography , meteorology , ecology , geotechnical engineering , cartography , archaeology , machine learning , computer science , biology
Snowmelt‐dominated runoff regimes have defined northern Alaskan rivers. Discharge records from three watersheds within the National Petroleum Reserve in Alaska (NPR‐A) span 19 years and capture three notable periods of changing runoff. In the first, 2001–2008, mean annual runoff (MAR) averaged 90 mm, characterized by sharp snowmelt runoff and summer drought. Over the next 7 years, larger MAR averaged 120 mm driven by high and early snowmelt runoff. The most recent 4 years, 2016–2019, had even higher MAR of 163 mm with high and sustained late summer flows. Hydrograph analysis suggests a shift toward rainfall‐dominated runoff in the most recent period compared to snowmelt‐dominated hydrographs in the previous two. Declining sea ice appears closely linked to increasing late summer precipitation and a shift toward rainfall runoff. Future development in the NPR‐A will require continued hydrological monitoring and planning to mitigate flood and erosion hazards, permafrost degradation, and ecosystem impairment.