Fundamentals of Fluvial Geomorphology and Channel Processes
Axis of bend
Point of inflection
L = Meander length (wave length)
A = Amplitude
rm = Mean radius of curvature
Figure 2.9 Definition Sketch for Channel Geometry (after Leopold et al.,
220.127.116.11 Channel Slope
The slope (longitudinal profile) of a stream is one of the most significant parameters
in the study and discussion of river behavior. The slope is one of the best indicators of the
ability of the river to do work. Rivers with steep slopes are generally much more active with
respect to bank erosion, bar building, sediment movement, etc., than lower slope channels.
Slope can be defined in a number of ways. If sufficient data exists, then the water
surface slope may be calculated using stage readings at gage locations along the channel.
However, in many instances, particularly in small streams, gage information is non-existent.
In these cases, the thalweg slope is generally calculated. The thalweg refers to the deepest
point in a cross section. The thalweg slope not only provides a good expression of the energy
of the stream, but also may aid in locating areas of scour and fill, geologic controls, and
outcrops of non-erodible materials.