Hydrologic Cycle (Water Cycle)

Hydrologic Cycle

Evapotranspiration Evapotranspiration (ET) is the sum of evaporation and plant transpiration from the Earth's land surface to atmosphere.

Precipitation Hail Snow Sleet Rain

Surface Runoff

Technical words Evaporation involves adding energy to molecules of a liquid so that it becomes a gas in which the molecules are further apart. Condensation is the reverse process in which molecules of a gas give up energy, get closer together and become a liquid. The water vapor in the air moves across the surface of the earth as the atmosphere circulates. As warm, moist air cools, water droplets form and fall to the land as precipitation. Surface water that move across the surface of the land and enters streams and rivers is known as Runoff.

Technical words The water that fills the space in the substrate is called groundwater. The porous layer that becomes saturated with water is called an aquifer.

Technical words A recharge zone is an area where water is added to the aquifer. Infiltration is the process by which water on the ground surface enters the soil. Percolation concerns the movement and filtering of fluids through porous materials. The water cycle, also known as the hydrological cycle or H2O cycle, describes the continuous movement of water on, above and below the surface of the Earth. Soil water is water contained in pore spaces of soil or adsorbed to the surface of soil particles. Transpiration: the root systems of plants absorb water from the surrounding soil in various amounts. Most of this water moves through the plant and escape into the atmosphere through the leaves.

Fig. The composition of the soil

Fig. Infiltration of water into the soil

Examples of soil structure with pore space (line drawing from USDA.)

Putting into order of Hydrologic Cycle starting from the 1st occurring process through the final one Surface runoff Infiltration Precipitation Condensation Evaporation + Transpiration (Evapotranspiration) Sun energy