The Difference Between Rivers & Streams

The majority of Earth's landscape is shaped by the erosion caused by flowing water, be it streams and rivers or rainfall and its runoff. As streams and rivers flow over the Earth's surface, they form both erosional landforms (such as canyons and valleys) and depositational landforms (such as deltas and floodplains, which are flood-prone areas of flat land adjacent to streams).

A stream is any body of water that moves through a narrow, defined channel downslope over the Earth's surface under the influence of gravity. They are also found in caves and inside glaciers. They move in three different types of channels: straight (which involves little side-to-side movement), meandering (which move in a series of S-shaped bends) and braided (in which one large channel breaks into smaller ones, which cross each other like hair braids).

A river is defined as a large stream. These may also be straight, meandering or braided. A river erodes the landscape in two ways. One is hydraulic action, in which the water itself exerts change upon the land, and the other is abrasion, in which the sediment carried by the river scrapes and sculpts the land along the river beds.

A stream may be defined as youthful, mature or old. A youthful stream has a high velocity, a generally straight channel and little to no floodplain. A mature stream is slower, with a deeper gradient. It also meanders more, having carved out curves into its banks. An old stream has reached its base level, or the level beyond which it can no longer erode. It meanders wildly, and its waters flow very slowly.