| A | B |
|---|
| Runoff | Water that flows over the ground surface rather than soaking into the ground. |
| Rill | A tiny groove in soil made by flowing water. |
| Gully | A large channel in soil formed by erosion. |
| Stream | A channel through which water is continually flowing downhill. |
| Tributary | A stream that flows into a larger stream. |
| Flood plain | A wide valley through which a river flows. |
| Meander | A looplike bend in the course of a river. |
| Oxbow lake | A meander cut off from a river. |
| Alluvial fan | A wide, sloping deposit of sediment formed where a stream leaves a mountain range. |
| Delta | A landform made of sediment that is deposited where a river flows into an ocean or lake. |
| Groundwater | Water that fills the cracks and spaces in underground soil and rock layers. |
| Stalactite | A calcite deposit that hangs from the roof of a cave. |
| Stalagmite | A cone-shaped calcite deposit that builds up from the floor of a cave. |
| Karst topography | A region in which a layer of limestone close to the surface creates deep valleys, caverns, and sinkholes. |
