Implications of climate variability and changing seasonal hydrology for subarctic riverbank erosion
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Implications of climate variability and changing seasonal hydrology for subarctic riverbank erosion Dana R. N. Brown 1 & Todd J. Brinkman 1 & W. Robert Bolton 2 & Caroline L. Brown 3 Helen S. Cold 3 & Teresa N. Hollingsworth 4 & David L. Verbyla 5
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Received: 8 April 2019 / Accepted: 20 May 2020/ # Springer Nature B.V. 2020
Abstract
Warmer climatic conditions have been associated with numerous hydrologic changes that may impact riverbank erosion in cold regions, but the net effect is not well understood. We used regression and correlation analyses to examine the relationships among subarctic riverbank erosion and seasonal hydrology, the impact of climate change and variability, and the societal implications. Geomorphic change (loss and gain of vegetated land) was mapped along several river reaches in the Yukon River Basin, Alaska, throughout 1984 and 2017 using Landsat satellite imagery. Annual erosion rates were estimated from these spatial data. At most study sites, erosion rates (km2/year) were either positively correlated (r = 0.68–0.84, p = 0.0085–0.061) with monthly mean discharge within the cold season or inversely correlated (r = − 0.74 – −0.62, p < 0.10) with river ice breakup date in the spring. These proximate controls on erosion, in turn, were influenced both by climate variability and long-term climatic change. We conclude that increased cold season discharge and earlier freshet that occurs under warmer conditions enhance riverbank erosion in most areas. Climate-related changes to fluvial dynamics may impact communities through effects on infrastructure, travel safety, channel navigability, fish and wildlife habitat, and access to subsistence resources. Keywords Climate change . Subsistence . Riverbank erosion . Fluvial geomorphology . Hydrology . River ice
1 Introduction Most rural communities in the Arctic are mixed cash-subsistence economies where people depend on hunting, trapping, and gathering as an important source of subsistence (Brinkman Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10584-02002748-9) contains supplementary material, which is available to authorized users.
* Dana R. N. Brown [email protected] Extended author information available on the last page of the article
Climatic Change
et al. 2016). Many communities are located off of the road system, but adjacent to waterways. People rely on rivers for travel, subsistence fishing, and access to subsistence resources (Brabets et al. 2000; Johnson et al. 2016). River channels change over time due to continual erosion and fluvial deposition. However, studies with rural communities across the region reveal a widespread perception that riverbank erosion, bar deposition, and channel change have increased in recent decades (Alaska Native Tribal Health Consortium 2016; Carothers et al. 2014; Herman-Mercer et al. 2011; Wilson et al. 2015). In addition to the direct impacts of erosion on infrastructure and land (Larsen et al. 2008), the addition of debris to channels and the shifting o
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