The Use of Terrestrial Laser Scanning to Assess the Mobilization of Contaminated Creekbank Soils in Oak Ridge, Tennessee

Streambank erosion contributes significantly to contaminant fluxes in contaminated freshwater streams, yet quantifying its extent and impacts remain challenging. This study employs Terrestrial Laser Scanning (TLS) to measure streambank erosion rates at multiple sites along East Fork Poplar Creek (EFPC) in Oak Ridge, Tennessee, a stream heavily contaminated with mercury. The research aims to address three objectives: The first objective is to quantify erosion rates using TLS and estimate mercury flux from streambank erosion. The second objective is to develop a consistent procedure for the application of TLS in streambank erosion studies and evaluate its feasibility and limitations, and the third objective is to correlate erosion patterns with site-specific factors. Terrestrial Laser Scanning is routinely applied in construction in forestry to track tree canopy changes, and in hydrology for overhead mapping of river networks. However, more studies are needed to evaluate its ability in detecting and quantifying topographic changes in natural environments. The findings in this thesis demonstrate that TLS technology is highly accurate and precise in measuring topographical change of creekbanks, enabling reliable estimation of erosion rates and associated mercury fluxes at several field sites in EFPC. The standardized TLS protocol established here enhances the reproducibility of erosion assessments. Furthermore, integrating erosion data obtained by TLS with site-specific characteristics can help elucidate key drivers of erosional trends. These results provide a robust framework for monitoring streambank erosion and inform targeted remediation strategies for contaminated streams.

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