Sara Warix, CSM Geology & Geological Engineering/ Geophysics PhD Candidate 2023 Student Research Fair Winner, 4-5PM, Berthoud 241

‘Impacts of Climate Change on Headwater Stream Discharge and Chemistry’

Abstract: In the western U.S., climate change is causing more precipitation to fall as rain rather than snow and it is currently unclear how, where, and when this shift is going to impact groundwater contributions to streams. As stream chemistry is dependent on the unique flowpaths of contributing groundwater, it is also unclear how climate change will impact stream chemistry. In this study, we instrumented a small, high-elevation stream in Colorado, USA to determine (a) how much groundwater is contributing to streamflow, (b) how long groundwater spends traveling through the subsurface before reaching streams, and (c) how stream chemistry varies through time and space. We show that streamflow source is most dynamic in steep areas with high streambed hydraulic conductivity. Despite observed variability in the ability of groundwater to contribute to streamflow, we observe that stream chemistry is relatively constant as it is primarily sourced by old groundwater at geochemical equilibrium. We conclude that in future climate scenarios, hydrologic fluxes are expected to vary more than geochemical fluxes where groundwater is old.

This lecture is scheduled in a hybrid format. If you would like to join the meeting please:

Join from PC, Mac, Linux, iOS or Android: https://mines.zoom.us/j/95550030997?pwd=d1FUMmlMaTFHc1hlUm1BaW1OQmtFUT09
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Pizza and sodas will follow the lecture in Berthoud 243.