The Drainage Basin System Flashcards
Drainage basin definition
subset of global hydrological cycle, catchment area forming part of earth’s surface area
watershed
dividing line between adjacent basins
What type of system is the drainage basin?
open system - transfers across boundary from external sources
drainage basin flows
through fall - rainwater dripping through vegetation
stemflow - water flows to ground via stem/trunks
infiltration - water moves from ground surface into soil
through flow - lateral movement of water through soil pores
percolation -transfer of water into underlying bedrock
groundwater flow - vertical/lateral movement of water through drainage basin rock due to gravity and pressure
importance of overland flow
ground fully saturated, flooding in urban areas
not all water able to infiltrate, common on hard-baked ground and high rainfall, flash flood occur
drainage basin stores
interception - leaf and plant surface
vegetation - water held in biomass of plants
surface - water collected on ground surface
soil moisture - water held in pore spaces in soil
channel - water held in river channel
groundwater - water soaked in solid rock and deposits
importance of interception
delays or staggers precipitation falling
tropical rainforest - ‘drip tip’ leaves encourage through fall
coniferous trees - sloping branches allowing snow to slide off
soil moisture store
hydroscopic water = water adhering by molecular attraction to surface soil particles , creating a thin film
capillary water = water occupying smaller pore spaces, available for plants to use
gravitational water = excess water occupying large soil spaces
drainage basin outputs
evaporation (liquid to gas) - influenced by temp, humidity
transpiration (water from vegetation to gas through stomata)
larger leaves e.g. rainforest = greater transp
needle leaves e.g. coniferous = lower transp
