Date of Graduation

Spring 2017

Degree

Master of Science in Geospatial Sciences

Department

Geography, Geology, and Planning

Committee Chair

Robert Pavlowsky

Abstract

Geomorphic characteristics of headwater streams draining the Missouri Ozarks have not been studied as much as larger rivers in the region. Further, while the effects of historical logging on channel form and sediment supply have been identified, no studies have investigated the effects of logging tramways constructed along Ozark headwater rivers. This study examines the geomorphic characteristics and channel disturbances of Tram Hollow (1.67 km2) within the Mark Twain National Forest in the Ozark Highlands. The purpose of this study is to classify and quantify natural and disturbed channel morphology in Tram Hollow which has been affected by confinement, flow obstruction, and channel straightening from the construction of a historical logging tramway. The tram bed confines the valley in disturbed reaches by reducing the effective valley width to 2-3 times less than the effective valley widths in undisturbed reaches. Tram bed-affected reaches have higher incision ratios ranging from 1.1 to 1.3, higher channel enlargement ratios ranging from 1.9 to 5.4, and relatively large headcuts up to 0.6 m deep from tram bed effects. The tram bed alters the hydrology in disturbed reaches including the splitting of surface drainage and the pirating of flow from natural channels. Incised channels along tram beds cut into colluvium composed of 2-27% boulder substrates. Natural morphology at Tram Hollow has little to no incision and contains stable bed substrates. The tram bed in Tram Hollow disconnects the river system laterally through confinement, incision, headcut development, and floodplain fragmentation. Headwater streams at this scale can be sensitive to human modifications and can affect larger downstream reaches due to their positions in drainage networks.

Keywords

geomorphology, headwater, logging, disturbance, Missouri

Subject Categories

Geomorphology

Copyright

© Nickolas Salvatore Bradley

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Geomorphology Commons

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