Showing posts with label WATER SUPPLY ENGINEERING. Show all posts
Showing posts with label WATER SUPPLY ENGINEERING. Show all posts

Tuesday 11 February 2014

Six components of the Hydrologic Cycle ==>>

Hydrologic Cycle

  • Evapotranspiration - is water evaporating from the ground and transpiration by plants. evapotranspiration is also the way that water vapor re-enters the atmosphere.
  • Condensation - is the process of water changing from a vapor to a liquid. Water vapor in the air rises mostly by convection. This means that warm, humid air will rise, while cooler air will flow downward. As the warmer air rises, the water vapor will lose energy, causing its temperature to drop. The water vapor then has a change of state into liquid or ice.
  • Precipitation - is water being released from clouds as rain, sleet, snow or hail. Precipitation begins after water vapor, which has condensed in the atmosphere, becomes too heavy to remain in atmospheric air currents and falls.
  • Infiltration - when a portion of the precipitation that reaches the Earth's surface seeps into the ground.
  • Percolation - is the downward movement of water through soil and rock. Percolation occurs beneath the root zone.
  • Runoff - is precipitation that reaches the surface of the Earth but does not infiltrate the soil. Runoff can also come from melted snow and ice.
for detail click here ==>>DETAIL DESCRIPTION OF HYDROLOGY CYCLE

Detail Description of the Hydrologic Cycle==>

Detail Description of the Hydrologic Cycle 

The Hydrologic Cycle
This is an education module about the movement of water on the planet Earth. The module includes a discussion of water movement in the United States, and it also provides specific information about water movement in Oregon.
The scientific discipline in the field of physical geography that deals with the water cycle is called hydrology. It is concerned with the origin, distribution, and properties of water on the globe. Consequently, the water cycle is also called the hydrologic cycle in many scientific textbooks and educational materials. Most people have heard of the science of meteorology and many also know about the science of oceanography because of the exposure that each discipline has had on television. People watch TV weather personalities nearly every day. Celebrities such as Jacques Cousteau have helped to make oceanography a commonly recognized science. In a broad context, the sciences of meteorology and oceanography describe parts of a series of global physical processes involving water that are also major components of the science of hydrology. Geologists describe another part of the physical processes by addressing groundwater movement within the planet's subterranean features. Hydrologists are interested in obtaining measurable information and knowledge about the water cycle. Also important is the measurement of the amount of water involved in the transitional stages that occur as the water moves from one process within the cycle to other processes. Hydrology, therefore, is a broad science that utilizes information from a wide range of other sciences and integrates them to quantify the movement of water. The fundamental tools of hydrology are based in supporting scientific techniques that originated in mathematics, physics, engineering, chemistry, geology, and biology. Consequently, hydrology uses developed concepts from the sciences of meteorology, climatology, oceanography, geography, geology, glaciology, limnology (lakes), ecology, biology, agronomy, forestry, and other sciences that specialize in other aspects of the physical, chemical or biological environment. Hydrology, therefore, is one of the interdisciplinary sciences that is the basis for water resources development and water resources management.
The global water cycle can be described with nine major physical processes which form a continuum of water movement. Complex pathways include the passage of water from the gaseous envelope around the planet called the atmosphere, through the bodies of water on the surface of earth such as the oceans, glaciers and lakes, and at the same time (or more slowly) passing through the soil and rock layers underground. Later, the water is returned to the atmosphere. 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.
The information presented below is a greatly simplified description of the major contributing physical processes. They include: 


EVAPORATION
Evaporation Icon
Evaporation occurs when the physical state of water is changed from a liquid state to a gaseous state. A considerable amount of heat, about 600 calories of energy for each gram of water, is exchanged during the change of state. Typically, solar radiation and other factors such as air temperature, vapor pressure, wind, and atmospheric pressure affect the amount of natural evaporation that takes place in any geographic area. 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. Heated buildings experience evaporation of water settled on its surfaces. Evaporated moisture is lifted into the atmosphere from the ocean, land surfaces, and water bodies as water vapor. Some vapor always exists in the atmosphere. 



CONDENSATION
Condensation Icon
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. The most active particles that form clouds are sea salts, atmospheric ions caused by lightning,and combustion products containing sulfurous and nitrous acids. Condensation is brought about by cooling of the air or by increasing the amount of vapor in the air to its saturation point. When water vapor condenses back into a liquid state, the same large amount of heat ( 600 calories of energy per gram) that was needed to make it a vapor is released to the environment. 


PRECIPITATION
Precipitation Icon
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. A falling drop leaves a turbulent wake behind which allows smaller drops to fall faster and to be overtaken to join and combine with the lead drop. The other sub-process that can occur is the ice-crystal formation process. It occurs when ice develops in cold clouds or in cloud formations high in the atmosphere where freezing temperatures occur. When nearby water droplets approach the crystals some droplets evaporate and condense on the crystals. The crystals grow to a critical size and drop as snow or ice pellets. Sometimes, as the pellets fall through lower elevation air, they melt and change into raindrops.
Precipitated water may fall into a waterbody or it may fall onto land. It is then dispersed several ways. The water can adhere to objects on or near the planet surface or it can be carried over and through the land into stream channels, or it may penetrate into the soil, or it may be intercepted by plants.
When rainfall is small and infrequent, a high percentage of precipitation is returned to the atmosphere by evaporation.
The portion of precipitation that appears in surface streams is called runoff. Runoff may consist of component contributions from such sources as surface runoff, subsurface runoff, or ground water runoff. Surface runoff travels over the ground surface and through surface channels to leave a catchment area called a drainage basin or watershed. The portion of the surface runoff that flows over the land surface towards the stream channels is called overland flow. The total runoff confined in the stream channels is called the streamflow. 


INTERCEPTION
Interception Icon
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.
When rain first begins, the water striking leaves and other organic materials spreads over the surfaces in a thin layer or it collects at points or edges. When the maximum surface storage capability on the surface of the material is exceeded, the material stores additional water in growing drops along its edges. Eventually the weight of the drops exceed the surface tension and water falls to the ground. Wind and the impact of rain drops can also release the water from the organic material. The water layer on organic surfaces and the drops of water along the edges are also freely exposed to evaporation.
Additionally, interception of water on the ground surface during freezing and sub-freezing conditions can be substantial. The interception of falling snow and ice on vegetation also occurs. The highest level of interception occurs when it snows on conifer forests and hardwood forests that have not yet lost their leaves. 



INFILTRATION
Infiltration Icon
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. Typically, the infiltration rate depends on the puddling of the water at the soil surface by the impact of raindrops, the texture and structure of the soil, the initial soil moisture content, the decreasing water concentration as the water moves deeper into the soil filling of the pores in the soil matrices, changes in the soil composition, and to the swelling of the wetted soils that in turn close cracks in the soil.
Water that is infiltrated and stored in the soil can also become the water that later is evapotranspired or becomes subsurface runoff. 



PERCOLATION
Percolation Icon
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. The boundary that separates the vadose and the saturation zones is called the water table. Usually the direction of water movement is changed from downward and a horizontal component to the movement is added that is based on the geologic boundary conditions.
Geologic formations in the earth's crust serve as natural subterranean reservoirs for storing water. Others can also serve as conduits for the movement of water. Essentially, all groundwater is in motion. Some of it, however, moves extremely slowly. A geologic formation which transmits water from one location to another in sufficient quantity for economic development is called an aquifer. The movement of water is possible because of the voids or pores in the geologic formations. Some formations conduct water back to the ground surface. A spring is a place where the water table reaches the ground surface. Stream channels can be in contact with an unconfined aquifer that approach the ground surface. Water may move from the ground into the stream, or visa versa, depending on the relative water level. Groundwater discharges into a stream forms the base flow of the stream during dry periods, especially during droughts. An influent stream supplies water to an aquifer while and effluent stream receives water from the aquifer. 



TRANSPIRATION
Transpiration Icon
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. Leaves undergoing rapid transpiration can be significantly cooler than the surrounding air. Transpiration is greatly affected by the species of plants that are in the soil and it is strongly affected by the amount of light to which the plants are exposed. Water can be transpired freely by plants until a water deficit develops in the plant and it water-releasing cells (stomata) begin to close. Transpiration then continues at a must slower rate. Only a small portion of the water that plants absorb are retained in the plants.
Vegetation generally retards evaporation from the soil. Vegetation that is shading the soil, reduces the wind velocity. Also, releasing water vapor to the atmosphere reduces the amount of direct evaporation from the soil or from snow or ice cover. The absorption of water into plant roots, along with interception that occurs on plant surfaces offsets the general effects that vegetation has in retarding evaporation from the soil. The forest vegetation tends to have more moisture than the soil beneath the trees. 



RUNOFF
Runoff Icon
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. Part of the subsurface flow enters the stream quickly, while the remaining portion may take a longer period before joining the water in the stream. When each of the component flows enter the stream, they form the total runoff. The total runoff in the stream channels is called streamflow and it is generally regarded as direct runoff or base flow. 



STORAGE
Storage Icon
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. Storage occurs as surface storage in oceans, lakes, reservoirs, and glaciers; underground storage occurs in the soil, in aquifers, and in the crevices of rock formations.
The movement of water through the eight other major physical processes of the water cycle can be erratic. On average, water the atmosphere is renewed every 16 days. Soil moisture is replaced about every year. Globally, waters in wetlands are replaced about every 5 years while the residence time of lake water is about 17 years. In areas of low development by society, groundwater renewal can exceed 1,400 years. The uneven distribution and movement of water over time, and the spatial distribution of water in both geographic and geologic areas, can cause extreme phenomena such as floods and droughts to occur. 

Tuesday 16 April 2013

==>>VARIOUS TYPES OF PUMPS OTHER THAN BASIC PUMPS==>>

OTHER TYPES OF PUMPS==>>

=>AIR LIFT PUMP
=>JET PUMP
=>HYDRAULIC RAM
For more types of pumps other than these three ==>>BASIC TYPES OF PUMPS

AIR LIFT PUMP==>>
Air lift pump working based on the mixture of water and air..IN such a pump , compressed air is forced into the well through a small air pipe and is released through a diffuser into the eduction pipe at the bottom of the well..
The air bubbles rise with water in eduction pipe ... The mixture of air and water is lighter in inside the pipe than the outside of the pipe, thats why it forced upward by hydrostatic pressure..
The reclaimed air is generally cooler than the atmospheric air and can be compressed more cheaply..
Air lift pumps can be used for high lifts upto 150 m..Their efficiency is generally low about 25 to 50 %...




JET PUMPS==>>
Jet pumps works same as airlift pump.. concept is same for both pumps bu arrangement is different.. Air is compressed in pipe by throat of pipe... and mixture of water and air upward the water due to hydrostatic pressure..




CONSIDERATIONS WHEN INSTALLING OR OPERATING JET PUMPS==>>



Installation==>>Penberthy Jet Pumps will operate in any position. They should be installed with minimum length of piping and with as few elbows and valves as possible to limit friction losses.


Inlet piping==>> Piping must be large enough to supply jet pump at maximum flow. Inlet pressure should be as specified in the performance data for the application.



Suction piping==>>To insure maximum capacity and highest possible vacuum, all suction piping must be airtight. When lifting liquids by suction, locate the jet as close to the liquid level as practical, with the
remainder of the elevation on the discharge side. Design pressure loss should not exceed two feet, including
strainer, foot valve and other piping at design suction flow rate.


Discharge piping==>> Piping should be equal in size to that of the pump. If discharge line is long, piping size should be increased to minimize the discharge head.


Start-up of steam jet pumps==>> When starting steam jet pumps, the steam valve should be opened slowly to enable the unit to start smoothly. All valves should then be adjusted to permit operation according to design conditions

                                                           AIRLIFT PUMP









HYDRAULIC RAM==>>
Hydraulic ram based on water hammer pressure ..water hammer pressure is the pressure applied in inside the pipe due to water..when we suddenly close valve ..in inside the pipe positive and negative wave generate and increase the pressure  in inside of pipe due to that pressure discharge increase..


==>>TYPES OF PUMPS==>>

TYPES OF PUMPS==>>
There are various types of pumps, but the two types which the hydraulic engineers generally encounter are :

1=> Roto -dynamic pumps
2=> Displacement pumps

ROTO-DYNAMIC PUMPS==>>
A rotodynamic pump has a wheel or a rotating element which rotates the water in a casing, and thus imparting energy to the water . The rotodynamic pumps do have a wheel type rotating element called impeller. The shape of the impeller may be such, as to force the water outward in a direction at right angles to its axis..

TYPES OF ROTO- DYNAMIC PUMPS=>
=> Centrifugal pump
=> Axial flow pump


IN general radial flow and mixed flow machines are commonly called centrifugal pumps.
whereas the axial flow machines are called axial flow pumps..



DISPLACEMENT PUMPS==>>
A displacement pump works on the principle of mechanically including vacuum in a chamber, thereby drawing in a volume of water which is then mechanically displaced and forced out of the chamber .

TYPES OF DISPLACEMENT PUMP=>
=>Reciprocating pump
=>Rotary pump

Reciprocating pump is a hand operated hand pump.....whereas in rotary pumps the rotary motion is used in place of a reciprocating motion ..The rotary motion is obtained by using two gears which mesh together and rotate in opposite directions.

OTHER TYPES OF PIPE ==>>

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