Semester

Summer

Date of Graduation

2023

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Geology and Geography

Committee Chair

Charles Shobe

Committee Member

Leslie Hopkinson

Committee Member

Aaron Maxwell

Abstract

Increased erosion following human land disturbance is a global issue for ecosystem health and land management. Mountaintop removal (MTR) mining – a type of surface mining predominately found in the Central Appalachian Coalfields region – is one of the most significant examples of human perturbation to a natural landscape. A post-MTR landscape, when compared to its natural state, has significantly different erosive potential due to the rearrangement of topography from mining and reclamation practices. Removal of vegetation and alterations to soil further influence erosion by raising the effective erodibility of substrate subjected to MTR. We quantify the changes in erosion from MTR mining by forecasting landscape evolution for 10000yrs on five catchments, using available pre-MTR and post-MTR topographic data. We then constrain ranges of sediment erodibility from gully features on mine margins to model the impacts of ecologic recovery trends on erosion. Model runs that do not use the observations of altered erodibility values show a reduction in total sediment flux due to the mining disturbances on topography alone. Model runs that incorporate the disturbances and recovery of vegetation and material properties in mined watersheds show higher total sediment flux in mined catchments than natural catchments. The results suggest a sensitivity of erosion rate and total sediment flux to vegetation recovery extents. All model runs show that mining controls the spatial trends in erosion. Post-MTR catchments show increased fluvial incision concentrated on the hillslopes adjacent to mined areas, and in headwater valleys that have been filled with mine overburden materials. Gullies incising into hillslopes and valley fills on post-MTR landscapes have erosion rates that are orders of magnitude higher than incision rates on the natural landscapes. We attribute these spatial trends to altered flow accumulation on post-MTR landscapes and over steepened headwater valleys from mine reclamation practices. This study highlights the locations in post-MTR landscapes that are most problematic for rapid erosion on medium geologic timescales and reinforces the importance of vegetation recovery on reclaimed land.

Embargo Reason

Publication Pending

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Available for download on Wednesday, July 24, 2024

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