Geography Chapter 5.6 Flashcards

Base Level

• Base level is the lowest elevation to which a stream can erode its channel.
• Ultimate base level is typically sea level, representing the lowest point for stream erosion.
• Temporary base levels can include lakes, resistant rock layers, and main streams affecting tributary erosion.

V-Shaped Valleys

• V-shaped valleys are often formed from fast-moving water eroding the landscape.
• Stream flow in these valleys leads to the creation of rapids and waterfalls due to steep gradients and narrow channels.
• Increased velocity in these areas contributes to erosion, resulting in the formation of sudden drops and turbulent water flows.

Erosional Floodplain Development

• An erosional floodplain develops as a stream cuts laterally into its banks while eroding vertically.
• Over time, sediment is transported and deposited during periods of high flow, influencing the landscape.
• This process can widen the valley and create a flat area adjacent to the stream known as a floodplain.

Incised Meanders and Base Level Changes

• Incised meanders occur when a stream cuts deeply into the landscape, often due to a drop in base level.
• Lowering of base level, such as from tectonic uplift or decreases in sea level, results in increased erosion.
• The stream adjusts by deepening its channel, leading to pronounced, steep-sided meanders in the landscape.

Test your knowledge on the concept of base level in river systems with these flashcards. Distinguish between ultimate and temporary base levels and understand their significance in shaping stream valleys. Perfect for geography students looking to reinforce their learning.