Fluvial morphology in terms of slope, abrasion, and bed‐load

Abstract

Fluvial morphology may be defined as the science of the forms of river‐beds, their shapes in plan and in profile. There seems to be no satisfactory explanation of the cause of lateral migration of streams, that is, of the phenomenon of serpentining or meandering; and this is also true of the rhythm of change of the profile as seen in the downstream‐progression of its pools and concomitant shoals. Extant knowledge is generally qualitative; if quantitative, it is usually of empiric origin and applicable.only to a particular stream. Still there are some universal quantitative principles of fluvial morphology that have been developed theoretically. The purpose of this paper is to present, first, a very brief statement of some of the qualitative observations and, second, a more detailed statement of several quantitative laws and their use.

Concept of the Graded River

“…If a cutoff results in a "significant" break in the longitudinal profile the stream may be properly considered to be ungraded at that point; the height of the break that is "significant" depends simply on the point of view of the investigator. Schoklitsch's analysis of profile readjustments in the vicinity of a single cutoff, too long and not sufficiently pertinent to be summarized here, is an excellent illustration of readjustment on a small scale (1937, p. 153, 154; see also Shulits, 1936). The effect of a number of cutoffs was cited above, also from the engineering literature, to illustrate the very rapid headward propagation of a local steepening in the longitudinal profile.…”

“…Many other writers have advanced the theory that graded or adjusted river profiles are mathematical curves, often without Schoklitsch's qualifications as to the effect of tributaries. The most recent contribution in this country (Shulits, 1941) presents a so-called "Rational equation of river-bed profile". The theory that longitudinal profiles closely approximate simple logarithmic curves has been utilized in geomorphic studies, chiefly in England.…”

Worldwide correlations for subaerial aqueous flows with exponential longitudinal profiles

“…The exponential profile equation has also often been related to the well known exponential diminution in bed particle size in streams (Sternberg, 1875;Shulits, 1936;Schoklitsch, 1937). The latter phenomenon is known to apply to an even wider range of mobile bed subaerial aqueous flows (Morris and Williams, 1999) than the exponential profile equation.…”