The various aspects of water related to earth and their interaction can be explained in terms of a cycle known as hydrologic cycle.
Evaporation of water from the water bodies such as oceans and lakes, evapotranspiration, formation and movement of clouds, precipitation in the form of rainfall, snowfall, etc. surface runoff, stream flow and ground water movement are some dynamic aspects of water.
In each path of the hydrologic cycle there are further more aspects involve, which are
- Transportation of water,
- Temporary storage and
- Change of state.
The process of rainfall includes the change of state and transportation of water.
Ground water movement includes the temporary storage and transportation aspects.
Various Aspects or paths of Hydrologic cycle:
- Evaporation from ocean,
- Raindrop evaporation,
- Evaporation from land and water bodies,
- Surface runoff,
- Ground water,
- Deep Percolation.
The sequence of events describe above is the very simple form of a complex cycle that has been taking place since the formation of earth. It is a continuous recirculating cycle because there is neither a beginning nor an end or a pause. However, the convenient starting point to describe the cycle is from the oceans.
Engineering Applications of hydrologic cycle:
The knowledge of hydrologic cycle is important in the design of projects dealing with water supply, irrigation, coastal works, and salinity control etc.