Drainage Basin : Key Words Flashcards
Define : Precipitation
Rain, snow or hail, formed when cloud droplets or ice crystals join together and become too heavy to remain in the cloud.
Define : Interception
When precipitation is caught by vegetation before it reaches the ground.
Define : Surface Storage
When precipitation reaches waterlogged ground, it forms puddles on the surface.
Define : Soil Storage
When water is trapped and stored in the pores in the soil.
Define : Groundwater Storage
When water becomes trapped and stored in the natural pores and cracks withing the bedrock below the soil.
Define : Stem Flow
Some precipitation flows down twigs and tree trunks on the ground.
Define : Infiltration
When water reaches the ground it soaks into the soil through holes, cracks and worm tunnels etc. There is a maximum rate at which infiltration can occur, which depends on the size of the holes and pores in the soil.
Define : Percolation
Water flows down through the pores and cracks in the bedrock under the soil.
Define : Through-flow
Once water is in the soil, it flows through spaces such as pores and natural cracks left by decayed plant roots
Define : Groundwater Flow
The movement of water sideways to lower levels where it reappears on the surface at springs and the sides of river channels
Define : Surface Run-Off
Water flowing across the surface. This happens when the soil is saturated, or the rate of the infiltration is too slow.
Define : Transpiration
Soil moisture and ground water is drawn up into trees via their roots and released as water vapour into the atmosphere through their leaves.
Define : Evaporation
Water trapped as surface storage changes from liquid into gas and enters the atmosphere as water vapour.
Define : Evapotranspiration
The combination of transpiration and evaporation.
Define : River Output
This is water that flows out of a drainage basin via a river.
