Anna Marshall

Advisor: Dr. Ellen Wohl


Previous Education: Connecticut College, Environmental Science and Anthropology, 2016

About me: Growing up in northern Maine, I spent my childhood submerged in any form of water I could find, ranging from drainage ditches and mud puddles to forested streams and lakes. I developed an interest in fluvial geomorphology over the course of my undergraduate studies and began to question how river environments have been altered overtime after spending several field seasons looking at the long term impacts of coupled natural-human river systems in a variety of settings including Maine (logging impacts on channel morphology and salmon restoration), New Hampshire (channelization structures), Pennsylvania (mill dams and legacy sediments), and Cambodia (hydropower development impacts). I spent the last few years as a project manager for an environmental nonprofit in the Northeast where my work focused on restoring riverine and estuarine processes through dam removal, habitat restoration, and green infrastructure projects. I’m excited to explore the rivers of the west and the many complexities they offer!

Research Focus: Emergent Hydrological Properties Associated with Multiple Channel-Spanning Logjams

My research includes quantifying the manner in which hyporheic exchange flow (HEF) changes in relation to increasing channel complexity associated with channel-spanning logjams. Hyporheic zones are defined by the interchange of surface and ground water (HEF) in a river and are critically important for improved water quality, temperature, and ecosystem function. Existing studies examining the effects of large wood on HEF focus on single logs or single logjams. I am looking at whether multiple channel-spanning logjams produce and additive or nonlinear effect on HEF. My research includes using near-surface electrical resistivity (ER) imaging with an electrically conductive stream tracer to understand the spatial and temporal dynamics of HEF under different flow conditions and different levels of channel complexity. I’ll use this same field technique in a flume setting to experiment with the relationship between HEF and logjams.