PRECIPITATION, RUN-OFF, EVAPORATION AND TRANSPIRATION
- The fall of moisture or water over the surface of the earth from atmosphere is knon precipitation.
- Precipitation includes rainfall, snow, hail, sleet, and frozen water in any form.
- Itis loss of water from surfaces of oceans, rivers, lakes, and moist soils.
- The water lost by evaporation is in form of vapours and is form of clouds.
- It is the process by which water leaves of the plants.
- Sometimes combined loss of water by evaporation and transpiration is referredas total evaporation of water.
- Unevaporated portion of precipitation is known as run-off.
- A part of precipitation water that falls on the surface gets evaporate and transpiratedan remaining partis call run-off.
- Run-off water ultimately runs to the ocean through surface and sub-surface streams of water.
- Water, flowing on the land is know surface run-off.
- This water first reaches the streams and river, and then ultimately joins sea.
- The portion of precipitation that infiltrates into the surface soil runs as subsurface run-off and joins streams and rivers.
- If precipitation is denot by P and total evaporation and various run-offs are denot by E and R respectively,
- Then all the three elements can be connect mathematically as follows:
P = R + E.