Date of Graduation

Summer 2021

Degree

Master of Natural and Applied Science in Geography, Geology, and Planning

Department

Geography, Geology, and Planning

Committee Chair

Robert Pavlowsky

Keywords

logging, land use change, LiDAR, General Land Office, Missouri Ozarks, fluvial geomorphology, aerial photography

Subject Categories

Geomorphology

Abstract

It is well known that watershed disturbances due to land clearing and agricultural settlement during the early 1800s changed the hydrology and geomorphology of stream systems in the Midwestern USA. However, little is known about the impacts of historical logging on stream systems in forested watersheds. This study evaluates channel width measurements from 38 General Land Office (GLO) surveys completed in 1821, aerial photographs from the 1930’s to present, and LiDAR imagery from 2016/17 to evaluate changes in channel morphology in Big Barren Creek in Mark Twain National Forest in the Ozarks Highlands of southeast Missouri. The area was heavily logged for pine between 1880 and 1920 and today is being managed for both pine forest restoration and cyclical tree harvesting. Overall, modern channel widths have increased by an average of 2.6 times since 1821. The largest increases occurred in second order streams averaging a 3.4-fold increase, while no change in width occurred in a 2 km long 4th order confined bedrock-controlled segment. It is suggested that the primary cause of channel widening was the increase in runoff due to deceased canopy interception of rainfall after removal of short-leaf pine by exploitive logging and replacement by hardwoods. Apparently, recent climate change resulting in more intense rains and frequent floods has caused channel width to increase at some sites by an average of 1.6 times since 2007.

Copyright

© Sierra N. Casagrand

Open Access

Included in

Geomorphology Commons

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