Past, present, and future erosion in a post-glacial landscape

When hazardous waste material sits in a location that may be susceptible to erosion, how do we estimate the likelihood of future contaminant release? This is a question that Greg Tucker’s group has been grappling with, in the context of a former nuclear fuel reprocessing plant in western New York State. During its operational life in the late 1960s and early 1970s, the plant generated a variety of radioactive waste products; much of this material remains entombed at the site today. The plant lies atop a plateau underlain by soft late Pleistocene glacial sediments. Active erosional processes, including landsliding and gully propagation, are gradually gnawing at the plateau edges. In a project spearheaded by Geological Sciences and CIRES postdoc Katy Barnhart (PhD ‘15; now at USGS Landslide Hazards Group) and including CU Boulder researchers and (then) graduate students Charlie Shobe (PhD '19), Rachel Glade (PhD '19), and Matt Rossi, the project team undertook a computational modeling study of past and future long-term erosion at the site. They took advantage of a unique aspect of the site’s recent geologic history: the last recession of glacial ice about 13,000 years ago left behind a relatively smooth surface that has subsequently been deeply incised by stream valleys. By reconstructing this smooth post-glacial surface and running a suite of erosion models forward in time from the late Pleistocene to the present day, the team was able to test and calibrate a collection of alternative models. The models were crafted using Landlab Toolkit, a Python-language modeling framework developed by Greg’s group and CSDMS. In addition to providing a basis for making projections of future erosion, the results shed new light on the key principles of long-term landscape evolution in this type of post-glacial environment, and yielded a new method for testing quantitative models.

References:

Barnhart, K.R., Hutton, E.W.H., Tucker, G.E., Gasparini, N.M., Istanbulluoglu, E., Hobley, D.E.J., Lyons⁠, N.J., Mouchene, M., Nudurupati*, S.S., Adams, J.M., and Bandaragoda, C. (2020) Short communication: Landlab 2.0: A software package for Earth surface dynamics. Earth Surface Dynamics, 8, 379–397, https://doi.org/10.5194/esurf-8-379-2020.

Barnhart, K.R., Tucker, G.E., Doty, S.G., Glade, R. C., Shobe, C.M., Rossi, M., and Hill, M.C. (2020) Projections of landscape evolution on a 10,000 year timescale with assessment and partitioning of uncertainty sources. Journal of Geophysical Research: Earth Surface, 125, 7, https://doi.org/ 10.1029/2020JF005795.

Barnhart, K.R., Tucker, G.E., Doty, S.G., Shobe, C.M., Glade, R. C., Rossi, M., and Hill, M.C. (2020) Inverting topography for landscape evolution model process representation: Part 1, conceptualization and sensitivity analysis. Journal of Geophysical Research: Earth Surface, 125, 7, https://doi.org/10.1029/2018JF004961.

Barnhart, K.R., Tucker, G.E., Doty, S.G., Shobe, C.M., Glade, R. C., Rossi, M., and Hill, M.C. (2020) Inverting topography for landscape evolution model process representation: Part 2, calibration and validation. Journal of Geophysical Research: Earth Surface, 125, 7, https://doi.org/10.1029/2018JF004963.

Barnhart, K. R., Tucker, G.E., Doty, S.G., Shobe, C.M., Glade, R. C., Rossi, M., and Hill, M.C. (2020) Inverting topography for landscape evolution model process representation: Part 3, Determining parameter ranges for select mature geomorphic transport laws and connecting changes in fluvial erodibility to changes in climate. Journal of Geophysical Research: Earth Surface, 125, 7, https://doi.org/10.1029/2019JF005287.

Barnhart, K. R., Glade, R. C., Shobe, C.M., and Tucker, G.E. (2019) Terrainbento 1.0: a Python package for multi-model analysis in long-term drainage basin evolution, Geosci. Model Dev., 12, 1267-1297, https://doi.org/10.5194/gmd-12-1267-2019.

Hobley, D. E., Adams, J. M., Nudurupati, S. S., Hutton, E. W., Gasparini, N. M., Istanbulluoglu, E., & Tucker, G. E. (2017) Creative computing with Landlab: an open-source toolkit for building, coupling, and exploring two-dimensional numerical models of Earth-surface dynamics. Earth Surface Dynamics. https://doi.org/10.5194/esurf-5-21-2017.