CHAPTER 2
FUNDAMENTALS OF FLUVIAL GEOMORPHOLOGY
AND
CHANNEL PROCESSES
2.1 FLUVIAL GEOMORPHOLOGY
Webster's New World Dictionary defines fluvial as: of, found in, or produced by a
river or rivers. The same reference defines morphology as: any scientific study of form and
structure, as in physical geography, etc. With a little guess work, we can correctly
extrapolate that fluvial geomorphology is the study of the form and structure of the surface
of the earth (geo) as affected by flowing water. Another definition, although given in jest,
may be the one most remembered after this next section. Geomorphology is the triumph of
terminology over common sense. An equally important term is the fluvial system. A system
is an arrangement of things to form a whole. The primary goal on which we want to focus
in this section is that you are working with a system and the complete system must be
considered.
2.1.1 BASIC CONCEPTS
Six basic concepts that should be considered in working with watersheds and rivers
are: 1) the river is only part of a system, 2) the system is dynamic, 3) the system behaves with
complexity, 4) geomorphic thresholds exist, and when exceeded, can result in abrupt changes,
5) geomorphic analyses provide a historical prospective and we must be aware of the time
scale, and 6) the scale of the stream must be considered. Is the stream a small, mountain
meadow trout stream, or is it the Mississippi River?
2.1.1.1 The Fluvial System
Schumm (1977) provides an idealized sketch of a fluvial system (Figure 2.1). The
parts are referred to as:
Zone 1 -
the upper portion of the system that is the watershed or drainage
basin; this portion of the system functions as the sediment supply.
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