Catchments


 * __Definition of a Catchment: -__** A structure in which water is collected
 * Confluence: - The meeting/merging of two or more bodies of water
 * Tributary: - A stream that flows to a larger stream, or body of water

//The total area of the drainage basin// __**Catchment area:**__ Also called a **drainage basin**, an area drained by a river and all its tributaries
 * __Key Elements:__**
 * Its boundaries are marked by ridges of higher lands which is known as a **Watershed**.
 * **Drainage Density: -**
 * __//The total length of all the streams in the drainage basin//__
 * The density is higher on impermeable rocks and clay.
 * The density is lowest on permeable rocks and sand.
 * Higher density - more risk of flooding.
 * part of the water cycle, but is an **open system** (water can be gained and lost)