The physical processes of sediment transport and deposition by confined unidirectional flow are produced only in a fluvial environment. The physical properties resulting from these processes provide unique criteria for recognition of fluvial deposits. Characteristic physical properties include (1) surface texture, (2) particle shape, (3) texture, (4) fabric, (5) sedimentary structures, (6) bedding, (7) sequence of structures, bedding, and textures, (8) scour surfaces, and (9) local and regional geometric patterns. Other aspects, including mineralogy, detrital clasts and fragments, physical character of the associated sediments, and fauna and flora, may aid in the identification of fluvial environments.

Point-bar deposits resulting from channel migration are the most commonly preserved type of fluvial sandstone bodies. These geomorphic features are nearly universal in all meandering streams, and they control clastic deposition. The commonly developed sequence of festoon, current-laminated, and ripple cross-bedded sedimentary units is developed in response to flow across point bars. Other types of fluvial sand bodies, such as those deposited in alluvial fans, braided streams, and deltaic distributaries, exhibit many fluvial characteristics, but they lack the sequence of sedimentary structures related to point-bar deposition.

Unidirectional currents produce characteristic grain-size distributions, which suggest a predominance of saltation and suspension modes of particle transport. Current transport produces elliptical-shaped particles with smooth surfaces. Detrital clay clasts commonly are preserved, many altered to clay-ironstone concretions. Minerals chemically stable in fresh, oxidizing, slightly acid water are commonly characteristic, such as kaolinite, feldspar, and ferric iron. The absence of other minerals such as calcite, glauconite, and ferrous iron compounds is significant.

The external geometry of fluvial deposits is probably the least characteristic physical attribute. Individual outcrops may not show channeling, and fluvial sand bodies may be of a blanket type. Boundaries of channels, however, show abrupt pinchouts, commonly within a few hundred feet. Trends of sand bodies in connection with paleocurrent and slope indicators provide strong supporting evidence for identifying fluvial environments.

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