Author

Peter J. Vagt

Publication Date

1982

Document Type

Dissertation/Thesis

First Advisor

Flemal, Ronald C.

Degree Name

M.S. (Master of Science)

Department

Department of Geology

LCSH

Drainage--Illinois||Sedimentation and deposition||Stream channelization--Illinois

Abstract

Previous studies have shown that a number of streams in the midwest exhibit changes in channel geometry which are characteristic of stream disequilibrium. This study was undertaken to evaluate the equilibrium state of several streams in North Central Illinois, and to calculate the volume of sediment which results from the disequilibrium. Bridge blueprints and Soil Conservation Service (SCS) aerial photographs were used to document the vertical and horizontal locations of stream channels at various times since 1900. These known previous channel positions were then used as a datum against which to compare the present location of each. stream. Several conclusions were reached. 1) Streams from first to sixth order in North Central Illinois are currently degrading their channels at a rate of about 0.71 inches per year; they have been downcutting at approximately the same rate since at least 1900. 2) Concurrent downcutting and meandering produce a volume of sediment which is released downstream as pollution. The volume of pollution resulting from stream disequilibrium was found to be of the same order of magnitude as both the erosion losses reported by SCS, and the suspended sediment measured in regional streams by the USGS. The apparent causes of the disequilibrium are the changes in land use and changes in the natural drainage networks since European settlement.

Comments

Includes bibliographical references.||Includes illustrations and maps.

Extent

viii, 139 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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