A belated look back on work at Johns Hopkins

It has been too long since I last posted here. In the meantime, numerous major changes have occurred. My dissertation defense was in May 2023, after which I moved to Berlin, Germany for a postdoctoral position at GFZ Potsdam. I have been here for a year now, in which time dissertation papers have moved along, and several new projects have advanced. I also have a new group to play music with! Below is a summary of some of the non-musical projects from my time in Baltimore that are completed or ongoing.

Dissertation Papers

Stochastic recharge, variable source areas paper published

In May 2024 our wide-ranging paper describing the coevolution of runoff generation and topography was published. It extends our previous work to include stochastic storms, and examines not only patterns of topographic change, but hydrological function as well. Saturated areas, stormflow production, and watershed storage can all be linked together with factors like the uplift rate, and fluvial and hillslope erosion efficiency.

Field comparison paper submitted

From 2021-2023, I worked with my supervisor Ciaran Harman to set up an experimental watershed in a really unique setting that is part of the Soldiers Delight Natural Environment Area in Maryland. Its serpentine bedrock leads to very thin soils, and a grassland ecosystem that is strikingly different from the forests that surround it. I compared streamflow, saturation, and topographic metrics between this site and a nearby site on schist bedrock that forms the deep soil and saprolite that is more typical of the region. The theory from our model predicts that the serpentine site should produce much more storm runoff, and have more dynamic saturated areas than the schist site, and as a result, it should also have a higher drainage density. We found this was the case, but also found that the model couldn’t quite capture all of the aspects of the site runoff and geomorphology. A preprint was published in February 2024 and the paper is in review.

As a side note, toward the end of my time working at Soldiers Delight, nearly the entire study watershed burned in a wildfire. The grassland ecosystem there is dependent on fire to prevent woody plant encroachment, so while unplanned, the natural resource manager I talked with about it believed that the fire would be largely beneficial. The wildland fire teams were gracious enough to cut their fire line on the right side to protect our weather station, so nothing was damaged. It also occurred early enough in the spring that by mid-summer, much of the grasses had fully recovered. There was little effect on the hydrology of the site that we noticed – no abrupt changes in discharge behavior, and minimal soil hydrophobicity. Still, it was dramatic to be in cool eastern Maryland, and watch videos of flames leaping ten feet above the tops of trees around the watershed edges.

Outreach with research results

In the summer of 2023 I collaborated with the leaders of the GNOMES (Geophysics of the Near-surface an Outdoor Motivational Experience for Students) program to orient undergraduate student participants to the geologic and environmental setting of my two dissertation sites in Maryland. In the following weeks, the students conducted seismic, ERT, and GPR surveys at the sites. These were the first geophysical studies we know of at the serpentine site, and they confirmed just how close to the surface intact rock can be found. The work was presented at AGU Fall Meeting in 2023. The GNOMES group returned to these sites in summer 2024 to collect more data, so we have an even better picture of how the subsurface looks at this site! I’m excited to keep working on these data with the GNOMES students and leaders.