Spatial Patterns and Sensitivity of Intermittent Stream Drying to Climate Variability

Intermittent streams comprise much of the global river network, and are expected to become more prevalent with climate change. Characterizing the expansion and contraction of intermittency in stream networks, and understanding how sensitive these dynamics are to climatic variability, is critical for...

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Bibliographic Details
Published in:	Water resources research 2021-11, Vol.57 (11), p.n/a
Main Authors:	Moidu, H., Obedzinski, M., Carlson, S. M., Grantham, T. E.
Format:	Article
Language:	eng
Subjects:	Annual precipitation Antecedent precipitation Biodiversity Climate change Climate prediction Climate variability Contraction Creeks & streams Dry season Drying Dynamics Ecosystem services Hydrologic regime Hydrology Interannual variability Intermittency intermittent Intermittent streams Land cover Land use Mathematical models Mediterranean Precipitation Risk assessment River networks Rivers Seasons Stability Statistical analysis Statistical models Streams Surface water Variability Watersheds wetted channel
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Summary:	Intermittent streams comprise much of the global river network, and are expected to become more prevalent with climate change. Characterizing the expansion and contraction of intermittency in stream networks, and understanding how sensitive these dynamics are to climatic variability, is critical for predicting the trajectory of hydrologic regimes in a changing climate. Here, we consider the spatial patterns of stream intermittency, focusing on wetted channel conditions at the end of the dry season, and identify land cover, physiographic, and climate variables that influence surface water presence and variability across years. We trained statistical models with wetted channel mapping data from 25 streams over 7 years to predict both the spatial and interannual variability of the wetted channel network. We then used the models to assess intermittent stream dynamics across the Russian River watershed in northern California, USA. We found that an average of 3.7% of the stream network was reliably dry, while 16.1% was reliably wet at the end of the dry season, with the remainder of the network exhibiting variability in wetted conditions in response to antecedent precipitation. Both climatic and landscape characteristics controlled the extent of the wetted network, particularly antecedent precipitation at seasonal and annual time scales, highlighting the role of hydrologic memory in this system. Given predictions of increased climate volatility, an improved understanding of the spatial patterns and stability of dry season conditions in intermittent streams can inform climate risk assessments and strategies for protecting biodiversity and the ecosystem services that intermittent streams support. Key Points We evaluate patterns of intermittent stream drying and identify variables that influence surface water presence and variability across years We developed models to characterize streams based on their sensitivity to climate variability Physical watershed characteristics and precipitation at multiple time scales controlled the spatial and temporal variation of intermittency
ISSN:	0043-1397 1944-7973