Stream capacity is defined as

• A. The size of particles a stream can carry
• B. The total amount of sediments a river is capable of transporting
• C. The speed of the water downstream
• D. The mineral content of the sediment

Answer: (B)

Stream capacity refers to how much sediment a stream can transport under its current flow conditions. It represents the maximum sediment load the channel could carry, not just what is actually moving at the moment. This is why the best choice is the total amount of sediments a river is capable of transporting. It’s different from velocity or the size of particles the stream can move (which relate to how fast water flows and to the largest particle that can be moved, respectively). Actual transport may be less than capacity if sediment supply is limited, or up to capacity if plenty of sediment is available.