River Drainage Basins and Hydrological Cycle Flashcards
Transpiration
Loss of water from vegetation.
Precipitation
All forms of water that falls from the sky e.g. rain or snow.
Percolation
Downward vertical movement of water within rock. The rate depends on the size of the pores through which the water travels.
Evaporation
Liquid is converted into vapour by heating.
Evapotranspiration
Amount of moisture removed by evaporation and transpiration from a land surface.
Infiltration
Passage of water into the surface layers of soil by gravity and capillary action. It takes place at a higher rate at the start of a rainstorm, then falls steadily as the soil becomes more saturated
Ground water storage
Water stored beneath the earth’s surface in permeable rock and soil.
Groundwater flow
Water that moves downslope through groundwater storage, usually emerging as a spring on the side of a valley.
Overlandflow
Outcome of rainfall intensity on a slope being greater than the rate at which the water can infiltrate into the soil.
Interception
Precipitation that is prevented from falling directly onto the soil surface by a layer of vegetation, and its leaves, stems and branches.
Water table
If permeable rock exists under the soil, this gets saturated with water. This is therefore the name given to the upper boundary of this saturated area.
Surface storage
Store of water that forms on surface of ground, and can be due to high levels of rainfall e.g. lakes, ponds, puddles.
River discharge
Volume of water in a river passing a measuring point at a given time. It is calculated by multiplying velocity of the river by cross sectional area. It is measured in cubic metres per second or cumecs.
Source
Where a river starts
Watershed
An area of high land which divides two drainage basins.
