Sideways erosion usually on outside of a meander.

Sideways erosion usually on outside of a meander.

• A. Meander
• B. Lateral Erosion
• C. Gorge
• D. Flood Plain

Answer: (B)

Lateral erosion is the process at work. When a river meanders, the flow is fastest on the outside bend, so that outside bank is eroded horizontally, widening the channel and slowly moving the bend downstream. The inside bend, by contrast, has slower flow and tends to deposit material, forming features like point bars. Over time this sideways erosion causes the river to migrate and widen its valley, which is why the term lateral erosion fits the statement about erosion on the outside of a meander. The other terms describe the bend itself (meander), a deep downward-cut valley (gorge), or a flat area formed by flood deposits (flood plain) and don’t describe the process of sideways widening.

Lateral erosion is the process at work. When a river meanders, the flow is fastest on the outside bend, so that outside bank is eroded horizontally, widening the channel and slowly moving the bend downstream. The inside bend, by contrast, has slower flow and tends to deposit material, forming features like point bars. Over time this sideways erosion causes the river to migrate and widen its valley, which is why the term lateral erosion fits the statement about erosion on the outside of a meander. The other terms describe the bend itself (meander), a deep downward-cut valley (gorge), or a flat area formed by flood deposits (flood plain) and don’t describe the process of sideways widening.