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UNDERGRADUATE STUDENT LAB GROUP
UNDERGRADUATE STUDENT LAB GROUP
Lab group in May 2024 (L-R): Key Hatch, Rachel Harris, Emma Ferm, Gabby Matejowsky, Lauren Best, and Kaden Cusack.
I am very excited to work with undergraduate students from a diversity of backgrounds who are interested in the themes of quantitative hydrology and the impact of climate warming on water resources. I aim to have my students publish their research in peer-reviewed journals, present at academic conferences, and find jobs in the fields of environmental consulting, non-profit water resources, and/or continue on to graduate studies. Prospective students should contact me at: evanssg@appstate.edu.
Current undergraduate research students:
Kaden Cusack, B.Sc. Quantitative Environmental Science, expected 2025
Gabby Matejowsky, B.Sc. Quantitative Geoscience, expected 2026
Emma Ferm, B.Sc. Environmental Science, expected 2025
Key Hatch, B.Sc. Environmental Science, expected 2025
Prior undergraduate research students listed by graduation date:
Lauren Best, B.Sc. Environmental Science, December 2024
Rachel Harris, B.Sc. Environmental Science and Geology, May 2024
Aaron Lubkemann, B.Sc. Mathematics (co-advised), May 2023
Alexander Brodie, B.Sc. Environmental Science, expected 2025
Caroline Moore, B.Sc. Environmental Science, May 2021
Connor Miller, B.Sc. Environmental Geology, December 2020
Connor Stephens, B.Sc. Geology, May 2020
Brandon Yokeley, B.Sc. Quantitative Geoscience, May 2019
Nicholas Hammond, B.Sc. Environmental Science (co-advised with Chuanhui Gu), May 2018
Sarah Larson, left Appalachian State University
Daniela Presas, left Appalachian State University
RECENTLY FUNDED GRANTS
RECENTLY FUNDED GRANTS
National Science Foundation, Division of Earth Sciences, Hydrologic Sciences and NSF Office of Polar Programs, Arctic Natural Sciences, CAREER: Hydrogeologic implications of permafrost thaw – Developing a process-based understanding of biophysical controls and educational tools for rural communities [Lead PI.] $499,727 (2024-2028).
National Science Foundation, Division of Earth Sciences, Collaborative Research: RUI: Zero-order to first-order: Hydrologic drivers of surface-subsurface storage dynamics in thawing permafrost landscapes [Lead PI. Co-PIs: Dr. Sarah Godsey (ISU), Dr. Clara Chew (UCAR), and Dr. Ben Crosby (ISU)] $686,742 ($276,373 to ASU) (2022-2024).
Project website: https://sites.google.com/appstate.edu/h2cold
CURRENT RESEARCH
CURRENT RESEARCH
HOW DOES THE HYDROLOGY OF REGIONS UNDERLAIN BY FROZEN GROUND RESPOND TO WARMING?
Seasonally frozen ground and perennially frozen ground known as permafrost underlay approximately half of the land surface in the Northern Hemisphere (Figure 1). In my research, I utilize coupled groundwater and heat transport models that included freeze/thaw dynamics to predict future changes to hydrologic cycling and groundwater flow in regions of permafrost and seasonally frozen ground. Results suggest that groundwater discharge to streams will increase in these cold regions but that this increase will be mediated by recharge amounts. On-going research is examining how groundwater discharge and soil saturation vary in Arctic regions with water tracks and thermoerosional gullies, two of the most common hydrologic features in the Arctic.
Related publications:
Evans, S. G., Godsey, S.E., Rushlow, C.R., and Voss, C. (2020), Water tracks enhance water flow above permafrost in upland Arctic Alaska hillslopes, Journal of Geophysical Research: Earth Surface, 125, doi:10.1029/2019JF005256.
Evans, S. G., Ge, S., Voss, C., and Molotch, N. (2018), The role of frozen soil in groundwater discharge predictions for warming alpine watersheds, Water Resources Research, 54, 1599-1615, doi:10.1002/2017WR022098.
Evans, S. G. and Ge, S. (2017), Contrasting hydrogeologic responses to warming in seasonally frozen ground and permafrost hillslopes, Geophysical Research Letters, 44, 1803-1813, doi:10.1002/2016GL072009.
Evans, S. G., Ge, S., and Sihai, L. (2015), Analysis of groundwater flow in mountainous, headwater catchments with permafrost, Water Resources Research, 51, 9564-9576, doi:10.1002/2015WR017732.
Figure 1. Northern hemisphere extent of permafrost [Brown et al., 1997] and 2010 maximum extent of seasonally frozen ground (SFG). SFG extent is derived from Willmott and Matsuura [2012].
Figure 2. Schematic diagram illustrating groundwater movement in an alpine catchment (left) without permafrost and (right) with permafrost. Black lines are groundwater flow paths. Grey dashed line indicates low magnitude groundwater flow.
WHAT GOVERNS PERMAFROST THAW RATES IN THE WARMING ARCTIC?
The Arctic has warmed at three times the rate of the global average, resulting in extensive perennially frozen ground or permafrost thaw. While it is well understood that permafrost thaw will continue and likely accelerate, thaw rates are non-uniform. This thrust of my research aims to explore what factors control permafrost thaw and how thaw rates, in turn, affect groundwater flow (Figure 2).
Related publications (*denotes undergraduate student advisee):
Evans, S. G., Raberg, J.H., Crump, S.E., Raynolds, M.K., Sugg, M.M., *Brodie, A.R., and Miller, G.H. (2022), Control of short-stature vegetation type on shallow ground temperatures in permafrost cross the eastern Canadian Arctic, Journal of Geophysical Research: Biogeosciences, 127, doi:10.1029/2022JG006941.
Evans, S.G., *Yokeley, B., *Stephens, C., and *Brewer, B. (2020), Potential mechanistic causes of increased baseflow across northern Eurasia catchments underlain by permafrost, Hydrological Processes, 34: 2676– 2690, doi:10.1002/hyp.13759.
DO INCREASING SOIL WATER TEMPERATURES AFFECT BOG TURTLE HABITAT IN APPALACHIAN FENS?
Wetlands serve as critical habitat for a diverse array of plant and animal communities. In the Appalachian highlands of the southern United States, many wetlands are classified as fens (Figure 3), alkaline wetlands sustained primarily by groundwater flow. Southern Appalachian fens provide a unique habitat for bog turtles who utilize the thermally-buffered wetland soils to thermoregulate during the summer and keep their body temperatures above freezing during the winter. As a warming global climate will likely alter the thermal regime of fens, my recent work has begun to quantify the effects of groundwater flow on fen seasonal temperatures and the resulting consequences for wetland habitats.
Related publications (*denotes undergraduate student advisee):
*Moore, C. and Evans, S.G. (2022) Shallow soil temperatures are heterogeneous across small a mountain fen, Wetlands, doi:10.1007/s13157-022-01566-2.
Figure 3. Research student Sarah Larson surveying a highland fen in June, 2018.
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