Distinguishing human and climate-induced contributions to the Columbia River hydrology

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Authors

Pradeep Naik¹ , David Jay²

Poster summary: Most hydrologic trends result from a combination of climatic and human influences, and analyses of hydrologic changes often do not differentiate these factors. Here, we separate human and climate influences on the Columbia River hydrologic cycle and sediment discharge. Human influences include water withdrawal for irrigation, flow regulation, reservoir manipulation, mining and deforestation. The Columbia’s streamflow and sediment discharge are strongly correlated with large-scale climate patterns, particularly the ENSO (El Niño Southern Oscillation) and PDO (Pacific Decadal Oscillation). The mean annual average Columbia River virgin flow at The Dalles has decreased ~16.5%, 8-9% due to climate change and 7-8% due to water withdrawal for irrigation. Climate impacts on the sediment discharge are larger than on streamflow because sediment discharge increases more than linearly with flow. Total sediment and sand transports have decreased >50% and >70% respectively, only a fraction of which is due to climate change.

Keywords: Streamflow, Sediment discharge, Climate change, El Nino Southern Oscillation, Pacific Decadal Oscillation, Flow regulation

Research areas: Environmental Sciences, Environmental Engineering, Civil Engineering, Earth Sciences, Ocean Sciences

Additional information

Data availability statement: The datasets generated during and / or analyzed during the current study are available from the corresponding author on reasonable request.

Creative Commons license: Copyright © 2023 Naik et al. This is an open access work distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.