2022 CSDMS meeting-062


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Modeling icy riverbank erosion into permafrost

Josie Arcuri, (she/her/hers),University of Colorado Boulder Boulder Colorado, United States. Josephine.Arcuri@colorado.edu
Irina Overeem, University of Colorado Boulder Boulder Colorado, United States. irina.overeem@colorado.edu

Rivers flowing across permafrost limit the residence time of floodplain soil organic carbon (SOC) by transferring riverbank material to the fluvial network. In this way, permafrost riverbank erosion limits production of greenhouse gases (GHG) in a deepening permafrost active layer. Concurrently, arctic riverbanks are laden with permafrost ice wedges and channels themselves are seasonally occupied by ice; these factors are known to affect fluvial potential to erode and remove material from floodplains. However, we do not know how ice impacts rates of riverbank migration through permafrost, especially in small arctic watersheds where observations are limited. We hypothesize that bank migration into permafrost is best described by melting of bank ice but is also described by slumping of the active layer, and fluvial carrying capacity. First, we develop a model of thermal riverbank erosion. Next, we detail plans to incorporate slumping and mechanical erosion into a holistic icy riverbank erosion model. We will characterize riverbanks along the Canning this field season and use or measurements to calibrate our model. Then, we will test which mechanisms are most significant in forming permafrost riverbanks, as well as describe their evolution under warming mean annual air temperatures. This work is also useful for predicting the future contribution of the arctic rivers to their basin-wide carbon budget. This work has immediate importance for people who traverse or depend on arctic landscapes, but especially those who live within them. Arctic landscape response to climate change is just as much a story about the loss of place and vanishing resources as it is about a dynamic earth system.