Drainage basin as an open system

Drainage basin as an open system

an area of land drained by a river and it's tributaries. It's watershed is marked by ridges of high land betong which rainfall will drain into neighbouring basins. 

The drainage basin system:

• forms a subsystem of the water cycle
• open system as energy and matter is transfered in and out of the system. 
• composed of precipitation (input), throughfall, stemflow, infiltration, percolation, overland flow and ground water flow (flows and transfers) and evapotranspiration (output). 

Precipitation - rain, hail, sleet or snow. Duration and intensity will impact processes within the system. 

Evapotranspiration - combined loss of water through evaporation and transpiration by plants

Run Off - the output of water from the drainage basin as it moves across the land surface either as overland flow or channel flow. 

Interception store - Vegetation cover intercepts the precipiation and a store may be held on leaves and branches.Density of vegetation will affect this. Tropical rainforests can intercept 58% of rainfall. 

Surface storage - This mainly occurs in built…