Date of Graduation

Spring 2011

Degree

Master of Science in Geospatial Sciences

Department

Geography, Geology, and Planning

Committee Chair

Robert Pavlowsky

Abstract

Historical mining operations were responsible for large scale contamination of floodplain deposits along the Big River in eastern Missouri. These contaminated deposits represent potential sources of future pollution due to remobilization by erosion and weathering. The purpose of this study is to evaluate the distribution and rates of contaminated sediment storage and remobilization in the lower 24 km of the Big River. Specifically, the objectives are to (i) assess and quantify historical channel planform change, (ii) identify spatiotemporal trends and determine bank erosion and bar deposition rates, and (iii) create a sediment- Pb budget to evaluate the role of stored alluvium and Pb as contemporary sources acting as threats to endangered mussel beds in the lower Big River. Results show that bank erosion occurs within localized disturbance reaches along 32% of the study reach. Bank erosion rates within disturbance reaches vary from 0.11 to 0.19 m/yr and lead (Pb) concentrations range from approximately 250 to 3,000 ppm. Total gravel bar surface area varies spatiotemporally in the study segment and ranges from approximately 70,000-120,000 m2. Floodplain erosion within the lower Big River is the main source of contaminated fine-grained sediment to the study reach and represents an important source of future pollution. Approximately 31,000 Mg of sediment is being released from floodplains per year, and approximately 21 Mg of this is Pb.

Keywords

river disturbance, sediment budget, bank erosion, Missouri, mining

Subject Categories

Hydrology | Mining Engineering | Sedimentology

Copyright

© Benjamin Michael Young

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