Yazoo Stream:
A tributary that parallels the main channel for a considerable distance. Joining of these streams is normally blocked by a natural levee along the larger stream.
Yellow Ground:
Oxidized kimberlite. A yellow soil that is characteristic of the area above a kimberlite diamond pipe.
Yield:
The quantity of water, coal, gold or other resource that can be produced from a deposit.
Youth:
The earliest stage in the development of a landscape. During this stage streams are actively downcutting and flowing straight for long distances with frequent waterfalls and rapids. The valleys are typically steep sided and v-shaped.