ravines

A ravine is a narrow, steep-sided valley formed primarily by the erosive action of running water. Ravines are typically smaller than canyons or gorges and often have a V-shaped cross-section in their early stages, becoming more complex as erosion and mass wasting continue. They occur wherever streams or rivers cut down into bedrock or unconsolidated material, leaving steep walls and a narrow bottom.

Formation results from a combination of processes. Sustained downcutting by a stream removes rock and soil, while weathering weakens material on the sides. Gravity-driven mass wasting, such as landslides or rockfalls, can widen the walls. In humid regions, persistent flow shapes the ravine; in arid areas, episodic flash floods can carve and redefine channels rapidly. Headward erosion at the source of a stream can also extend a ravine upstream over time.

Characteristics of ravines include steep, often bare or sparsely vegetated walls, a bottom that may contain a stream or a dry channel, and soils that are thin or absent on the slopes. The landscape can support microhabitats for specialist plants and animals and may act as a corridor for wildlife. Ravines can be prone to erosion, slope instability, and sudden flash flooding, particularly after heavy rainfall.

Distinctions from related terms vary regionally. Ravines are generally smaller and more deeply incised than broad valleys, and narrower than many canyons. Humans use ravines for footpaths, routes to water, and agricultural margins, but development can increase erosion and destabilize slopes. Conservation efforts often focus on slope stabilization and preserving native vegetation to reduce further erosion.