Table of Contents
Rivers: Features of a drainage basin
Features of a drainage basin: watershed, source, mouth, channel network.
Drainage basin
- The area drained by a river and its tributaries, bounded by a watershed
- An open system – has inputs and outputs (the amount of water in the system is not fixed)
- Inputs of a drainage basin:
- Energy from the sun
- Precipitation formed from moisture picked up outside the basin
- Water from tributaries
- Outputs
- River’s discharge
- Water in its drainage basin from which evapotranspiration take place and eventually falls as precipitation in another drainage basin. (Evapotranspiration- the process by which water is transferred from land to the atmosphere by evaporation (from soil, lakes, ponds) and by transpiration of plants. Transpiration is when plants take up water from soil and release it into the atmosphere as water vapour.)
Watershed
- The dividing line between one drainage basin and another. Basically a boundary.
Stores in a Drainage Basin
- The atmosphere exists as water vapour or as droplets in clouds
- The land- stored in rivers, lakes and reservoirs. Taken up by plants and stored in vegetations. Stored below soil/ bedrock, i.e. groundwater store. They can also exist as snow or ice.
Tributaries
- Smaller streams
- Enter the main river channel at confluences
Mouth/ estuary
- River flows out to the sea
- An estuary is where the river meets the sea (i.e. mouth) and the surrounding area.
Confluence
- Where tributaries joins the main river
Channel network
- The system of surface and underground channels that collect and transport the precipitation falling on the drainage basin.
