@ Hydro-logical Modeling @

What is Hydrology ?

 

Hydrology is the scientific study of the movement, distribution, and quality of water on Earth and other planets, including the hydro-logic cycle, water resources and environmental watershed sustainability. A practitioner of hydrology is a hydrologist, working within the fields of earth or environmental science,physical geography, geology or civil and environmental engineering.

Hydrology subdivides into surface water hydrology, groundwater hydrology (hydro-geology), and marine hydrology. Domains of hydrology include hydro-meteorology, surface hydrology, hydro-geology, drainage-basin management and water quality, where water plays the central role.

Description of the Hydrologic Cycle

 A fundamental characteristic of the hydrologic cycle is that it has no beginning an it has no end. It can be studied by starting at any of the following processes: evaporation, condensation, precipitation, interception, infiltration, percolation, transpiration, runoff, and storage. 

Evaporation Process  

Evaporation :-   Evaporation occurs when the physical state of water is changed from a liquid state to a gaseous state.Evaporation can occur on raindrops, and on free water surfaces such as seas and lakes. It can even occur from water settled on vegetation, soil, rocks and snow. There is also evaporation caused by human activities.

Condensation :- Condensation is the process by which water vapor changes it's physical state from a vapor, most commonly, to a liquid. Water vapor condenses onto small airborne particles to form dew, fog, or clouds.

Precipitation :- Precipitation is the process that occurs when any and all forms of water particles fall from the atmosphere and reach the ground. There are two sub-processes that cause clouds to release precipitation, the coalescence process and the ice-crystal process. As water drops reach a critical size, the drop is exposed to gravity and frictional drag.7th Grade Science-Groundwater & Surface Water

Interception :- Interception is the process of interrupting the movement of water in the chain of transportation events leading to streams. The interception can take place by vegetal cover or depression storage in puddles and in land formations such as rills and furrows.The water layer on organic surfaces and the drops of water along the edges are also freely exposed to evaporation.

Infiltration :-  Infiltration is the physical process involving movement of water through the boundary area where the atmosphere interfaces with the soil. The surface phenomenon is governed by soil surface conditions. Water transfer is related to the porosity of the soil and the permeability of the soil profile. 

Percolation :-Percolation is the movement of water though the soil, and it's layers, by gravity and capillary forces. The prime moving force of groundwater is gravity. Water that is in the zone of aeration where air exists is called vadose water. Water that is in the zone of saturation is called groundwater. For all practical purposes, all groundwater originates as surface water. Once underground, the water is moved by gravity.

Transpiration :-Transpiration is the biological process that occurs mostly in the day. Water inside of plants is transferred from the plant to the atmosphere as water vapor through numerous individual leave openings. Plants transpire to move nutrients to the upper portion of the plants and to cool the leaves exposed to the sun.

Runoff :-Runoff is flow from a drainage basin or watershed that appears in surface streams. It generally consists of the flow that is unaffected by artificial diversions, storages or other works that society might have on or in a stream channel. The flow is made up partly of precipitation that falls directly on the stream , surface runoff that flows over the land surface and through channels, subsurface runoff that infiltrates the surface soils and moves laterally towards the stream, and groundwater runoff from deep percolation through the soil horizons.

Storage :- There are three basic locations of water storage that occur in the planetary water cycle. Water is stored in the atmosphere; water is stored on the surface of the earth, and water stored in the ground. Water stored in the atmosphere can be moved relatively quickly from one part of the planet to another part of the planet. The type of storage that occurs on the land surface and under the ground largely depend on the geologic features related to the types of soil and the types of rocks present at the storage locations.

Canopy interception :- The precipitation that is intercepted by plant foliage, eventually evaporates back to the atmosphere rather than falling to the ground.

Snowmelt :-The runoff produced by melting snow.

Sublimation :-The state change directly from solid water (snow or ice) to water vapor.

Deposition :-This refers to changing of water vapor directly to ice.

Advection :- The movement of water — in solid, liquid, or vapor states — through the atmosphere. Without advection, water that evaporated over the oceans could not precipitate over land.

Condensation :- The transformation of water vapor to liquid water droplets in the air, creating clouds and fog.

Percolation :- Water flows vertically through the soil and rocks under the influence of gravity.

Plate tectonics :- Water enters the mantle via subduction of oceanic crust. Water returns to the surface via volcanism.

Water covers 70% of the Earth's surface.