How does a stream-eroded landscape evolve as time passes?

Stream erosion occurs when running water (a stream or river) wears away at the Earth's surface, transporting sediments downstream. The process involves various types of erosion such as splash, hydraulic action, and abrasion. Various factors contribute to the rate of stream erosion, including the stream's velocity, the slope of the land, and the types and resistance of the rocks found along the stream's path.

As time goes on, a stream-eroded landscape evolves through distinct stages. These stages include youth, maturity, and old age. 1. Youth: In this early stage, the stream begins to erode its valley. The landscape is typically characterized by steep V-shaped valleys, with rapids and waterfalls common. The stream channel is narrow, and the stream works to deepen its channel through downcutting. The slope is steep, increasing the erosion rate. 2. Maturity: As the landscape continues to erode, the slopes gradually become less steep, allowing the stream to meander and create a wider channel. The valleys become more U-shaped, and the stream has a more sinuous path. During this stage, lateral erosion starts dominating, widening the channel. 3. Old age: In this final stage, the landscape becomes relatively leveled, and the stream's capacity to erode decreases. The slope is moderate, making the water flow more slowly. Meanders and oxbow lakes become more prevalent as the stream deposits its sediments evenly across the floodplain. The landscape is characterized by broad, flat valleys and extensive floodplains.

As a stream-eroded landscape evolves over time, the key characteristics to look for in each phase include: 1. Youth: V-shaped valleys, steep slopes, rapids, waterfalls, and a narrow channel. 2. Maturity: U-shaped valleys, more moderate slopes, meandering streams, and a wider channel. 3. Old age: Flat valleys, relatively low slopes, meanders, oxbow lakes, and an extensive floodplain. By observing these features, one can determine the stage of a given landscape and gain insight into how it has evolved over time due to stream erosion.