What is the definition of aggradation in relation to streams?

Aggradation refers to the process in which the elevation of a streambed increases due to the deposition of sediment. This occurs when the transport capacity of the stream reduces, leading to the accumulation of materials such as sand, silt, and gravel within the channel. As sediment builds up over time, it raises the streambed, which can impact the flow of water, potentially leading to a wider or shallower stream. Understanding aggradation is essential in the context of river morphology and sediment dynamics, as it plays a crucial role in shaping the landscape and influencing aquatic ecosystems.