valley

A valley is a low area between hills or mountains, often containing a river or stream. Valleys form through a combination of processes, including river erosion, glaciation, and tectonic activity, and they vary widely in size and shape. The valley floor is typically lower than the surrounding terrain and may be lined with fertile alluvial soils that support vegetation and crops. Valleys are common in many climates and landscapes, from arid basins to temperate valleys with lush riparian zones.

Valley shapes are commonly described as V-shaped or U-shaped. V-shaped valleys are carved primarily by river erosion in landscapes with active downcutting, producing steep sides and a narrow floor. U-shaped valleys are formed or enlarged by glacier activity, resulting in a broad, flat floor and steep, straight sides. Other forms include troughs or glacial valleys, which are wide and flat at the bottom, and hanging valleys, where tributary valleys meet a deeper main valley, often creating waterfalls after glaciation. Intermontane valleys lie between mountain ranges, while rift valleys form where tectonic plates pull apart, creating long, narrow basins.

Ecology and human use: Valleys commonly host diverse ecosystems and are favorable for agriculture due to soil richness and consistent water supply. They are frequently preferred sites for settlements, transportation routes, and economic activity. Flooding and sedimentation can be important considerations in valley management and land use.

In cultural and linguistic contexts, the term can appear in various forms, such as dale or vale, reflecting local naming traditions.