Degradational Landforms of Stream Erosion
Glossary

Annular drainage

A concentric stream pattern that drains the interior of an excavated geologic dome.

Antecedent stream

A river exhibiting transverse drainage across a structural feature that would normally impede its flow because the river predates the structure and kept cutting downward as the structure was uplifted around it.

Butte

Small, steep-sided, caprock-protected hill, usually found in dry environments; an erosional remnant of a plateau.

Cuesta

A long ridge with a steep escarpment on one side and a gently dipping slope and rockbeds on the other.

Cycle of erosion

The evolutionary cycle proposed by William Morris Davis that purportedly affects all landscapes.

Dendritic drainage

A tree-limb-like stream pattern that is the most commonly observed; indicates surface of relatively uniform hardness or one of flat-lying sedimentary rocks.

Drainage density

The total length of the stream channels that exist in a unit area of a drainage basin.

Geologic structure

Refers to landscape features originally formed by geologic processes, which are sculpted by streams and other erosional agents into characteristic landforms.

Hogback

A prominent steep-sided ridge whose rockbeds dip sharply.

Interfluve

The ridge that separates two adjacent stream valleys.

Mesa

Flat-topped, steep-sided upland capped by a resistant rock layer; normally found in dry environments.

Monadnock

A prominent, not-yet-eroded remnant of an upland on a peneplain.

Pediplane

A surface formed by the coalescence of numerous pediments after a long period of erosion has led to parallel slope retreat.

Peneplain

The concept of a “near plane” developed by William Morris Davis to describe the nearly flat landscape formed by extensive erosion over long periods of time.

Radial drainage

A stream pattern that emanates outward in many directions from a central mountain.

Rectangular drainage

A stream pattern dominated by right-angle contacts between rivers and tributaries, but not as pronounced as in trellis drainage.

Stream piracy

The capture of a segment of a stream by another river.

Superimposed stream

A river exhibiting transverse drainage across a structural feature that would normally impede its flow because the feature was at some point buried beneath the surface on which the river developed; as the feature became exposed, the river kept cutting through it.

Trellis drainage

A stream pattern that resembles a garden trellis; flows only in two orientations, more or less at right angles to each other; often develops on parallel-folded sedimentary rocks.

Water gap

A pass in a ridge or mountain range through which a stream flows.

Links

River Channel Surveys
This USGS webpage describes river channel erosion in several areas of the Pacific Northwest. Specific monitoring techniques are described, and links to other hydrologic monitoring pages are provided.