- Drainage basin
- Catchment area
A area drained by a river and all its tributaries.
An area or ridge of land that separates waters flowing to different rivers, basins, or seas.
- River system
A river system is defined as a group of rivers discharging water by way of a common flow or system of channels into a sea or lake. It usually consists of the main river (the trunk of the system) and primary, secondary and later-order tributaries.
- River Source
The River Source is the furthest point from which water could possibly flow
A tributary is a stream or river that flows into a main, or parent river.
A confluence, where two or more bodies of water meet together, usually refers to the joining of tributaries.
- River mouth
A river mouth or stream mouth is a part of a stream where it flows into the sea, river, lake, reservoir or ocean.
- Water table
The level below which the ground is saturated with water.
Water held underground in the soil or in pores and crevices in rock.
- Surface run-off
Surface run-off is water, from rain, snow-melt, or other sources, that flows over the land surface.