Water Shapes the LandIn the beginning of this Aspect, I explained that gravity is part of the erosion. The gravity pulls sediment and water downhill. This process is called deposition. Erosion begins when runoff carries small particles of soil downhill. When particles bounce along a stream bottom, it is called a saltation. Channels join together to form large channels and it is called a gully. In the end, streams flow together and reach the ocean. These sediments scrape rocks and change their form. When rocks scrape or grind against one another, it is called a abrasion. In every process of erosion, abrasion is causing the land to change their form. A stream's ability to erode depends mainly on its speed. Water erosion forms V-shaped valleys, waterfalls, meanders, and oxbow lakes.
|
V-shaped Valleys• Mass movement on the stream slopes
• Harder layers resist erosion=forming the top of the waterfall • Softer rock layers downstream are worn away=leaving the cliff over which the waterfall rumbles |
Meanders• Loop-like bend in the river
• Outside of the curve=faster=more erosion • Inside of the curve=slower |
Oxbow Lakes• Curved lakes
• New channel made by flood |
Features deposited by flowing water include alluvial fans and deltas.
Alluvial Fans |
Alluvial fan is a fan-shaped deposit of sediment on land. They grow into thick deposits of sediment.
|
Deltas |
A mass of sediment deposited where a river enters a large body of water (triangular shape).
|
The processes of chemical weathering causes much groundwater erosion, including the formation of caves and sinkholes.
Sinkhole |
The erosion weakens a layer of limestone so the entire portion of the ground can suddenly collapse, which create a hole.
|
Stalactite |
Water that drips from the cavern ceiling hardens and an icicle-like formation will be created.
|