Fast-moving outer bank of a stream with high erosion is best described by which term?

• A. Lotic Ecosystem
• B. Erosional Zone
• C. Depositional Zone
• D. Riparian Zone

Answer: (B)

In stream geomorphology, the outer bank of a bend carries the highest flow velocity and shear stress, which erodes the bank and removes material. The term that describes a region where erosion dominates is the erosional zone. This is the opposite of a depositional zone, where the flow slows and sediments settle, often on the inner bend forming deposits like point bars. A lotic ecosystem simply refers to the flowing-water system as a whole, and the riparian zone is the land–water interface along the banks, not the active process of erosion itself. So, the fast-moving, highly eroding outer bank is best described as an erosional zone.