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U.S. GEOLOGICAL SURVEY
Open File Report 2008–1217

Annotated Definitions of Selected Geomorphic Terms and Related Terms of Hydrology, Sedimentology, Soil Science and Ecology

Prepared in cooperation with the Office of Surface Water, U. S. Geological Survey, Reston, VA

By W.R. Osterkamp

Preface

Terminology used in fluvial geomorphology, hydrology, sedimentology, soil science, climatology, and ecology is often inconsistent among the disciplines and within a discipline. The terms defined and described herein were compiled to:

1. recognize the overlapping needs of fluvial geomorphologists and hydrologists and the related perspectives of sedimentologists, soil scientists, climatologists, and ecologists.
2. describe the earth-surface processes that result in landforms or hydrologic events that affect each of the disciplines.
3. extend many of the definitions and provide explanations of how landforms and the landscape change in response to the processes that act upon them.
4. provide different definitions for terms that are used differently by different disciplines, and
5. include specialty terms that are commonly used by practitioners of the several disciplines but are rarely if ever defined in most glossaries or dictionaries, or are inconsistently defined.

As with any list of technical words, many terms have been overlooked, but future revisions to the list may be a start to correcting this deficiency. Many of the annotated definitions given below represent original expressions of the meaning of present-day terms as applied by scientists and technicians of the several disciplines considered. Many others are modifications and elaborations of definitions available in numerous pertinent glossaries. Most of the sources that were used in support of this list, however, emphasize features, such as landforms, and techniques to provide field personnel tools for conducting geomorphic and hydrologic data collection and investigations. A principal intent in developing many of the extended definitions of this list has been to indicate what earth-surface processes were required to result in the landform or feature observed.

Numerous sources, including personal communications, were consulted to generate the definitions listed below. Several, however, were especially helpful and provided foundations from which the extended definitions could be constructed. W. B. Langbein and K. T. Iseri authored U. S. Geological Survey Water-Supply Paper 1541-A (1960), General introduction and hydrologic definitions, as part of the Survey's Manual of Hydrology for general surface-water techniques. The list of definitions accentuated hydrologic terms commonly used by Water Resources Division personnel at the time, but also necessarily included numerous fluvial-geomorphic terms. A much more comprehensive list, periodically updated, of definitions related to the earth sciences is the Glossary of Geology, published by the American Geological Institute (Neuendorf and others, 2005, 5th edition); this excellent resource of information includes many definitions for geomorphological, hydrological, and ecological terms but, owing to a need for brevity, many of those terms are not thoroughly defined.

Other important sources of natural-science definitions with emphases on geomorphology, hydrology, soil science, climatology, and ecology include encyclopedias of geomorphology (Fairbridge, ed., 1968; Goudie, ed., 2003), The Encyclopedic Dictionary of Geography (Goudie, ed., 1994), A Dictionary of the Natural Environment (Monkhouse and Small, 1978), Limited Glossary of Selected Terms (MacArthur and Hall, 2008), Glossary of terms relating to the phreatophyte problem (Phreatophyte Subcommittee PSIAC, 1962), and Bulletin 17B of the Hydrology Subcommittee, Interagency Advisory Committee on Water Data (1982). Appendix 1 lists references for the information sources cited above; others were used less extensively and are not listed.

Contents

Preface
Definition and description of selected terms
Major sources of information

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Send questions or comments about this report to the author, W.R. Osterkamp, (520) 670-6821 ext. 113.