What is meant by a 'cross-profile' of a river?

A 'cross-profile' of a river refers to a vertical section cut across the river, providing a clear view of its shape, width, and depth at a specific location. This cross-sectional diagram is essential for understanding how a river channel varies, revealing key features such as the riverbed, banks, and any sediment deposits. By examining the cross-profile, geographers and hydrologists can analyze the physical characteristics of the river and how these may change over time due to various factors such as erosion or sedimentation.

The nuances of a cross-profile are important for students studying river systems as they directly relate to the river's behavior, environmental health, and the potential impact of human activity. This contrasts with other options, which either focus on flow rates, tributary relationships, or seasonal changes—none of which represent the structural aspect depicted in a cross-profile.