Final answer:
Downcutting is the process of erosion that deepens a riverbed. Elevated rates can be caused by factors such as increased water volume and steep gradients.
Step-by-step explanation:
Downcutting refers to the process by which a riverbed deepens as the water flow erodes the bedrock or sediment. It is a form of erosion that occurs in streams and rivers, resulting in the formation of canyons or gorges.
Elevated rates of downcutting can be influenced by various conditions. These can include increased water volume due to heavy rainfall or melting snow, steep gradients, presence of resistant bedrock, or tectonic uplift. For example, during a period of intense rain, a river may experience higher rates of downcutting as the increased water flow accelerates erosion of the riverbed.
Overall, downcutting plays a significant role in shaping the landscape, and understanding the factors that contribute to its accelerated rates can help predict and manage potential risks associated with river erosion and flooding.