Water is hydrosphere is made up of all the water on Earth. This includes all of the rivers, lakes, streams, oceans, groundwater, polar ice caps, glaciers and moisture in the air (like rain and snow). The hydrosphere is found on the surface of Earth, but also extends down several miles below, as well as several miles up into the atmosphere. So, there is a need for study of water as a scarce resource.
WHAT IS HYDROLOGICAL CYCLE
SYSTEM APPROACH IN HYDROLOGY
HYDROLOGIC INPUT & OUTPUT
VARIATION IN HYDROLOGICAL CYCLE
COMPONENTS
EVAPORATION
EVAPOTRANSPIRATION
PRECIPITATION
INTERCEPTION
INFILTRATION
GROUND WATER
RUN-OFF
HUMAN IMPACT
EARTH SURFACE
CLIMATE CHANGE
ATMOSPHERIC POLLUTION
MULTI PURPOSE PROJECTS
WATER WITHDRAWAL
MANAGEMENT AND CONTROL
2. WATER & ITS STUDY
• Atmo (air) litho(land) and hydro(water)form bio(life)sphere .
• 97%salty,3%freshwater
• In all state solid ,liquid ,gas.
• Ocean is the major reservoir .
• Study reference from past geographers.
• Thales explain water is everything.
• wind & currents blows, temperature, gravity, the cycle form and reform and
existence of lives possible on earth.
• Water is hydrosphere is made up of all the water on Earth. This includes
all of the rivers, lakes, streams, oceans, groundwater, polar ice caps, glaciers
and moisture in the air (like rain and snow). The hydrosphere is found on
the surface of Earth, but also extends down several miles below, as well as
several miles up into the atmosphere.
• Chemical element (H,O).
4. WHAT IS HYDROLOGICAL CYCLE?
• Hydro + logy ,cycle(water cycle)
• It describes the continuous movement of water on, above and below the
surface of the Earth.
• Dynamic and continuous .
• The water moves from one reservoir to another, such as from river to ocean,
or from the ocean to the atmosphere, by the physical processes
of evaporation, condensation, precipitation, infiltration, surface runoff, and
subsurface flow. In doing so, the water goes through different forms: liquid,
solid (ice) and vapor.
5. SYSTEM APPROACH IN HYDROLOGY
• SYSTEM
the word derived from the Greek word “systema” which means a set of
rules that govern structure and/or behavior.
• A set of things working together as parts of a mechanism or an
interconnecting network; a complex whole.
• System analysis approach generating output from input .
• It distributed upon time and space into linear and non linear.
• Include the elements of water cycle that varies over space and time.
• Cyclic processes of input and resulted output .
6. HYDROLOGIC INPUT & OUTPUT
• INPUT:
1. Precipitation
• OUTPUT
I. Evaporation
II. Evapotranspiration
III. Runoff and Overland flow
IV. Infiltration
7. VARIATION IN HYDROLOGICAL
CYCLE
• General descriptions of the hydrologic cycle is simple, but the smaller-
scale aspects of the hydrologic cycle, is quite complex.
• Variations within the hydrologic cycle span a wide range of spatial and
temporal scales.
• precipitation also varies with altitude and orientation to local
mountains, creating an enormous diversity of microclimates across the
globe
• Result into Global Circulation, and climatic change.
9. Following are some of the important factors:
Type of Vegetation: Interception varies with the species, its age and density of stands.
coniferous trees intercept 25-35% of annual precipitation
deciduous trees intercept 15-25% of annual precipitation, but just as much as
coniferous trees during the growing season
grasses and forbs have high interception capacity during the growing but then either
die (annual plants) or loose mass (perennial plants); also they are grazed and
harvested.
Wind Velocity:
If the wind accompanies the precipitation the leaves become incapable of holding much water
as compared with the still air condition. Promotes interception loss by evaporation.
Duration of Storm:
Absolute interception storage increases with increasing storm duration.Interception will be
high due to evaporation when there’s short duration precipitation events that are spaced
sufficiently. However, if storms of long duration occur and if weather remains cloudy, relatively
interception loss will be less.
Season of the Year:
During summer or dry season the interception rate is quite high because of high evaporation.
Summer interception is 2 to 3 times more than the winter season interception.
Climate of the Area:
In arid and semiarid regions due to prevailing dry conditions the interception loss is more than
that occurring in humid regions.
10. EVAPORATION
• Evaporation is the process by which water changes from a liquid to a gas or
vapour. Evaporation is the primary pathway that water moves from the
liquid state back into the water cycle as atmospheric water vapour.
• Evaporation is an essential part of the water cycle. The sun (solar energy)
drives evaporation of water from oceans, lakes, moisture in the soil, and
other sources of water. In hydrology, evaporation and transpiration (which
involves evaporation within plant stomata) are collectively termed
evapotranspiration. Evaporation of water occurs when the surface of the
liquid is exposed, allowing molecules to escape and form water vapour; this
vapour can then rise up and form clouds. With sufficient energy, the liquid
will turn into vapour.
Water changes to vapour through the
absorption of heat.
Essential requirements in the process are -:
The source of energy to vapourize the
liquid water
(solar or wind),
The presence of gradient of concentration
between the
evaporating surface and the surrounding
area.
11. FACTORS AFFECTING EVAPORATION
1. TEMPERATURE -: The hotter the air is, the more kinetic energy the surface of the
liquid will absorb. This will help with the breaking of intermolecular bonds as well.
2. EXPOSED SURFACE AREA -: If more surface area is exposed of the liquid, more
water molecules are exposed to the surface, allowing foe more water molecules to
receive kinetic energy in order to evaporate.
3. HUMIDITY -: The humidity of the surrounding air shows how many water
molecules are already present. The more water molecules already present in the
air, the lesser the rate of evaporation.
4. PRESSURE -: The more pressure there is in the surrounding air of a liquid, the
harder it will be for the water molecules to break away from their intermolecular
bonds to mix with the atmosphere.
5. WIND -: If there is more wind around the liquid that is undergoing evaporation,
more variations of air will be present to absorb the new water molecules breaking
away from the surface of the water. The added kinetic energy also helps in this
process.
12. EVAPORATION DRIVES THE WATER CYCLE
Evaporation from the oceans is the primary mechanism supporting the surface-
to-atmosphere portion of the water cycle. After all, the large surface area of the
oceans (over 70 percent of the Earth's surface is covered by the oceans)
provides the opportunity for large-scale evaporation to occur. On a global scale,
the amount of water evaporating is about the same as the amount of water
delivered to the Earth as precipitation. This does vary geographically, though.
Evaporation is more prevalent over the oceans than precipitation, while over the
land, precipitation routinely exceeds evaporation. Most of the water that
evaporates from the oceans falls back into the oceans as precipitation.
Only about 10 percent of the water evaporated from the oceans is transported
over land and falls as precipitation. Once evaporated, a water molecule spends
about 10 days in the air. The process of evaporation is so great that without
precipitation runoff, and groundwater discharge from aquifers, oceans would
become nearly empty.
13. APPLICATION
Industrial applications include many printing and coating processes; recovering salts
from solutions; and drying a variety of materials such as lumber, paper, cloth and
chemicals.
The use of evaporation to dry or concentrate samples is a common preparatory step for
many laboratory analyses such as spectroscopy and chromatography. Systems used for
this purpose include rotary evaporators and centrifugal evaporators.
When clothes are hung on a laundry line, even though the ambient temperature is
below the boiling point of water, water evaporates. This is accelerated by factors such as
low humidity, heat (from the sun), and wind. In a clothes dryer, hot air is blown through
the clothes, allowing water to evaporate very rapidly.
The Matki/Matka, a traditional Indian porous clay container used for storing and cooling
water and other liquids.
The botijo, a traditional Spanish porous clay container designed to cool the contained
water by evaporation.
Evaporative coolers, which can significantly cool a building by simply blowing dry air
over a filter saturated with water.
14. TRANSPIRATION
Transpiration is the process by which water
vapour leaves the living plant body and enters
the atmosphere.
It involves continuous flow of water from soil in
to plant and out through stomata (leaves) to the
atmosphere.
Basically an evaporation process.
Transpiration ratio : The amount of water
transpired by a crop in its growth to produce unit
weight of dry matter.
15. ATMOSPHERIC FACTORS AFFECTING TRANSPIRATION
Temperature: Transpiration rates go up as the temperature goes up, especially during the
growing season, when the air is warmer due to stronger sunlight and warmer air masses.
Higher temperatures cause the plant cells which control the openings (stoma) where
water is released to the atmosphere to open, whereas colder temperatures cause the
openings to close.
Relative humidity: As the relative humidity of the air surrounding the plant rises the
transpiration rate falls. It is easier for water to evaporate into dryer air than into more
saturated air.
Wind and air movement: Increased movement of the air around a plant will result in a
higher transpiration rate. Wind will move the air around, with the result that the more
saturated air close to the leaf is replaced by drier air.
Soil-moisture availability: When moisture is lacking, plants can begin to senesce
(premature ageing, which can result in leaf loss) and transpire less water.
Type of plant: Plants transpire water at different rates. Some plants which grow in arid
regions, such as cacti and succulents, conserve precious water by transpiring less water
than other plants.
16. EVAPO-TRANSPIRATION
Evapotranspiration (ET) is the sum of evaporation and plant
transpiration from the Earth's land and ocean surface to
the atmosphere. Evaporation accounts for the movement
of water to the air from sources such as the soil, canopy
interception, and waterbodies.
Evapotranspiration is an important part of the water cycle.
An element (such as a tree) that contributes to
evapotranspiration can be called an evapotranspirator.
The transpiration aspect of evapotranspiration is
essentially evaporation of water from plant leaves.
Studies have revealed that transpiration accounts for about
10 percent of the moisture in the atmosphere, with
oceans, seas, and other bodies of water (lakes, rivers,
streams) providing nearly 90 percent, and a tiny amount
coming from sublimation (ice changing into water vapour
without first becoming liquid).
17. Why is Evapotranspiration Important?
Water continuously moves between the oceans, sky and land. This ongoing circulation
is fundamental to the availability of water on the planet and therefore to life on earth.
ET is a key process within this cycle, and is responsible for 15% of the atmosphere’s
water vapour. Without it clouds couldn’t form and rain wouldn’t fall.
Calculating ET
There are numerous ways to calculate ET to determine watering needs -:
The easiest way involves averaging ET values from the two nearest weather stations.
The resulting data, however, can be misleading. Microclimates even a few kilometres
apart can produce substantially different values. Some property owners and managers
purchase their own mini weather stations, but they tend to require frequent
calibration and are notoriously unreliable.
A relatively simple ET calculation method called Blaney-Criddle is popular, but tends to
be inaccurate in areas with higher humidity. The Makkink method requires weather
station calibration for each specific location.
Another frequently used method, called Hargreaves, uses a single sensor. Results can
be up to 60% different than other methods, calling their outcomes into serious
question.
18. FACTORS AFFECTING EVAPOTRANSPIRATION
1. Energy availability - The more energy available, the greater the rate of evapotranspiration.
It takes about 600 calories of heat energy to change 1 gram of liquid water into a gas.
2. The humidity gradient away from the surface - The rate and quantity of water vapour
entering into the atmosphere both become higher in drier air.
3. The wind speed immediately above the surface - The process of evapotranspiration moves
water vapour from ground or water surfaces to an adjacent shallow layer that is only a few
centimetres thick. When this layer becomes saturated evapotranspiration stops.
4. Water availability - Evapotranspiration cannot occur if water is not available.
5. Physical attributes of the vegetation - Such factors as vegetative cover, plant height, leaf
area index and leaf shape and the reflectivity of plant surfaces can affect rates of
evapotranspiration. For example coniferous forests and alfalfa fields reflect only about 25
percent of solar energy, thus retaining substantial thermal energy to promote transpiration;
in contrast, deserts reflect as much as 50 percent of the solar energy, depending on the
density of vegetation.
6. Stomatal resistance - Plants regulate transpiration through adjustment of small openings in
the leaves called stomata. As stomata close, the resistance of the leaf to loss of water
vapour increases, decreasing to the diffusion of water vapour from plant to the
atmosphere.
7. Soil characteristics - Soil characteristics that can affect evapotranspiration include its heat
capacity, and soil chemistry and albedo.
19. GEOGRAPICAL PATTERNS OF EVAPOTRANSPIRATION
Evapotranspiration varies with latitude, season of year, time of day, and cloud cover. Most of the
evapotranspiration of water on the Earth's surface occurs in the subtropical oceans. In these
areas, high quantities of solar radiation provide the energy required to convert liquid water into a
gas. Evapotranspiration generally exceeds precipitation on middle and high latitude landmass
areas during the summer season.
Estimates of average nationwide evapotranspiration for the conterminous United States range
from about 40 percent of the average annual precipitation in the Northwest and Northeast to
close to 100 percent in the Southwest.
The lower 5 miles of the atmosphere transports an average of about 40,000 billion gallons of
water vapour over the conterminous United States each day. Slightly more than 10 percent of this
moisture, however, is precipitated as rain, sleet, hail, or snow. The greatest proportion, about 67
percent, is returned to the atmosphere through evapotranspiration.
About 29 percent is discharged from the conterminous United States as surface-water flowing into
the Pacific and Atlantic Oceans and across the borders into Canada and Mexico, about 2 percent is
discharged as groundwater outflow, and about 2 percent is consumed by people, animals, plants,
and used for industrial and commercial processes. For most of the United States, evaporation
returns less moisture to the atmosphere than does transpiration.
21. PRECIPITATION
• Precipitation is any form of liquid or solid water particles that fall from the atmosphere
and reach the surface of the Earth. Precipitation is caused when a mass of warm, moist
air hits a mass of cold air. Condensation causes the moisture to form droplets that
become rain or crystals that become snow or ice. When these droplets or crystals
become too heavy to be suspended in the atmosphere, they fall to Earth as
precipitation. Different seasons and geographic locations see varying amounts of
precipitation in amount and intensity.
• There are two sub-processes that cause clouds to release precipitation,
A) The coalescence 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.
B) 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.
When rainfall is small and infrequent, a high percentage of precipitation is returned to
the atmosphere by evaporation.
22. Several Forms of precipitation:
Snow: Precipitation f white, opaque grains of ice
Rain: Precipitation of liquid water particles, in form of drops with dia 0.5 mm or more.
Drizzle: Precipitation of very fine drops of water with dia 0.5 mm or less.
Hail: Precipitation of small balls of ice with dia ranging from 5-50 mm or even more.
Sleet: Precipitation of small pellets of transparent/lucent ice of dia 5 mm or less.
Types of precipitation:
Convectional: Heavy showers for a short duration due to convection process. Major factors being
the intense heating of surface and abundant supply of moisture in the air.
Orographic: Concentrated precipitation on the windward side of a mountain or highland due to
adiabatic cooling.
Frontal: Precipitation due to meeting of cold and warm fronts.
24. 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 storages in puddles and in land formations.
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.
The amount of precipitation intercepted can be measured by placing several rain-gauges
below the vegetal canopy on the ground. Average precipitation that reaches this gauge can be
compared with the precipitation measured from a rain-gauge placed in an open area. The
difference between the two gauge readings gives the precipitation intercepted by the
vegetation.
The water caught by the vegetation gets disposed off in three ways namely:
i. Through fall;
ii. Flow along the stem; and
iii. Evaporation. Much of this intercepted rainfall evaporates before it hits the ground and
thus never makes it to the soil.
The highest level of interception occurs when it snows on conifer forests and hardwood
forests that have not yet lost their leaves.
25. INFILTRATION
• Infiltration is the process by which water on the ground surface enters
the soil.
• Infiltration rate in soil science is a measure of the rate at which soil is able to
absorb rainfall or irrigation.
• It is most often measured in millimetres per hour or inches per hour.
• The rate decreases as the soil becomes saturated. If the precipitation rate
exceeds the infiltration rate, runoff will usually occur unless there is some
physical barrier.
• The rate of infiltration can be measured using an infiltrometer.
27. FACTORS AFFECTING INFILTRATION
• Precipitation: The greatest factor controlling infiltration is the amount and characteristics (intensity,
duration, etc.) of precipitation that falls as rain or snow. Precipitation that infiltrates into the ground often
seeps into streambeds over an extended period of time, thus a stream will often continue to flow when it
hasn't rained for a long time and where there is no direct runoff from recent precipitation.
• Base flow: To varying degrees, the water in streams have a sustained flow, even during periods of lack of
rain. Much of this "base flow" in streams comes from groundwater seeping into the bed and banks of the
stream.
• Soil characteristics: Some soils, such as clays, absorb less water at a slower rate than sandy soils. Soils
absorbing less water result in more runoff overland into streams.
• Soil saturation: Like a wet sponge, soil already saturated from previous rainfall can't absorb much more ...
thus more rainfall will become surface runoff.
• Land cover: Some land covers have a great impact on infiltration and rainfall runoff. Vegetation can slow
the movement of runoff, allowing more time for it to seep into the ground. Impervious surfaces, such as
parking lots, roads, and developments, act as a "fast lane" for rainfall - right into storm drains that drain
directly into streams. Agriculture and the tillage of land also changes the infiltration patterns of a
landscape. Water that, in natural conditions, infiltrated directly into soil now runs off into streams.
• Slope of the land: Water falling on steeply-sloped land runs off more quickly and infiltrates less than water
falling on flat land.
• Evapotranspiration: Some infiltration stays near the land surface, which is where plants put down their
roots. Plants need this shallow groundwater to grow, and, by the process of evapotranspiration, water is
moved back into the atmosphere.
29. GROUND WATER
• Water in the saturated zone of soil–rock systems is commonly called
groundwater, and it represents the largest liquid water store of the terrestrial
hydrological cycle.
• Groundwater is the water present beneath Earth's surface in soil pore
spaces and in the fractures of rock formations.
• A unit of rock or an unconsolidated deposit is called an aquifer when it can
yield a usable quantity of water.
• The depth at which soil pore spaces or fractures and voids in rock become
completely saturated with water is called the water table.
• Groundwater is recharged from, and eventually flows to, the surface naturally;
natural discharge often occurs at springs and seeps, and can
form oases or wetlands.
• Groundwater is also often withdrawn for agricultural, municipal, and industrial
use by constructing and operating extraction wells. The study of the
distribution and movement of groundwater is hydrogeology, also called
groundwater hydrology.
30. • Not all run-off flows into rivers, though. Much of it soaks into the ground
as infiltration. Some of the water infiltrates into the ground and
replenishes aquifers (saturated subsurface rock), which store huge amounts
of freshwater for long periods of time.
• Some infiltration stays close to the land surface and can seep back into
surface-water bodies (and the ocean) as groundwater discharge, and some
groundwater finds openings in the land surface and emerges as
freshwater springs.
• Yet more groundwater is absorbed by plant roots to end up as
evapotranspiration from the leaves. Over time, though, all of this water
keeps moving, some to reenter the ocean, where the water cycle "ends" ...
Or where it "begins."
31. RUN OFF
• Surface runoff is water, from rain, snowmelt, or other sources, that flows over
the land surface, and is a major component of the water cycle.
• Runoff is precipitation that did not get (infiltrated) absorbed into the soil, or did
not evaporate.
• Runoff causes erosion, and also carry chemicals and substances on the ground
surface. It can cause water pollution too.
DETERMINANT
- Topography of the land
(slopes, hills and
valleys).
- The nature (make -up) of
the soil or ground.
- The amount of
precipitation.
32. RUNOFF IN NATURAL ENVIRONMENT
• A significant portion of rainfall in forested watersheds is absorbed into
soils (infiltration), is stored as groundwater, and is slowly discharged to
streams through seeps and springs.
• Flooding is less significant in these more natural conditions because
some of the runoff during a storm is absorbed into the ground, thus
lessening the amount of runoff into a stream during the storm.
33. URBAN RUNOFF
• Urban runoff is surface runoff of rainwater created by urbanization.
• This runoff is a major source of flooding and water pollution in urban
communities worldwide.
• Impervious surfaces (roads, parking lots and sidewalks) that are built from
(materials such as asphalt and concrete), carry polluted water during run off.
• This causes lowering of the water table (because groundwater recharge is
lessened) and flooding since the amount of water that remains on the surface is
greater.
• This excess water can also make its way into people's properties through
basement backups and seepage through building wall and floors.
• Also, road salt used to melt snow on sidewalks and roadways can contaminate
streams and groundwater aquifers.
• Because of fertilizer and organic waste that urban runoff often carries,
eutrophication often occurs in waterways affected by this type of runoff.
35. OVERLAND FLOW
• Runoff that occurs on surfaces before reaching a channel is also called overland
flow.
• Most water in our rivers and Underground reserves originates as overland flow
water.
• Horton overland flow - infiltration capacity and depression storage capacity.
• His more commonly occurs in arid and semi-arid regions, where rainfall
intensities are high and the soil infiltration capacity is reduced. This occurs
largely in city areas where pavements prevent water from infiltrating.
• Paved surfaces such as asphalt, which are designed to be flat and impermeable,
rapidly achieve Horton overland flow.
• Horton overland flow is most commonly encountered in urban construction sites
and unpaved rural roads, where vegetation has been stripped away, exposing
bare dirt.
• The process also poses a significant problem in areas with steep terrain, where
water can build up great speed and where soil is less stable, and in farmlands,
where soil is flat and loose.
36. HUMAN IMPACTS ON THE HYDROLOGIC CYCLE
• Many environmental problems stem from direct or indirect
impacts on the water cycle
• Five categories of impacts:
• Changes to Earth’s surface
• Changes to Earth’s climate
• Atmospheric pollution
• Withdrawals for human use
• Dams
38. 1. CHANGES TO THE SURFACE OF THE EARTH
• In natural systems, vegetation intercepts precipitation
• Water infiltrates into porous topsoil, filtering out debris
• Evapotranspiration sustains ecosystems and recycles water
• Recharged groundwater reservoirs release water through springs and seeps into
streams and rivers
• In cleared forests and overgrazed land, plants do not intercept rainfall
• Built-up area prohibits infiltration and making water to flow in drains.
• Water shifts from infiltration and recharge into runoff
39. EFFECTS OF FALLOW LAND
• Removing vegetation causes a sudden influx of water into rivers and streams
• Causing floods, pollutants from erosion, and less evapotranspiration and
groundwater recharge
• Resulting in dry, barren, lifeless streambeds
• Wetlands also store and release water
• Destruction leads to flooding and polluted waterways
• Wetlands dry up during droughts
• Massive flooding can take place due to filling wetlands and converting tallgrass
prairies to plowed fields
40. 2. CLIMATE CHANGE
• There is unmistakable evidence that Earth is warming
• Increasing greenhouse gases are changing the water cycle
• Evaporation increases with a warmer climate
• A wetter atmosphere means more and heavier precipitation and floods
• More hurricanes and droughts
• Water-stressed areas (e.g., East Africa) will get less water
• Global warming may be speeding up the water cycle
• Affecting precipitation, evapotranspiration, groundwater recharge, runoff,
snowmelt, etc.
42. 3. ATMOSPHERIC POLLUTION
• Aerosol particles form nuclei, enabling water to condense
into droplets
• More clouds form
• Anthropogenic particles are increasing
• From sulfates, carbon (soot), dust
• Form a brownish haze associated with industrial areas, tropical
burning, and dust storms
• Solar radiation is reduced
• Aerosols have a cooling effect
43. AEROSOLS AFFECT THE WATER CYCLE
• They promote smaller droplets
• They suppress rainfall, even though clouds form
• Aerosols suppress atmospheric cleansing
• They cause aerosols to remain in the air longer, further
increasing drier conditions
• Dust, smoke, and aerosols increase
• Aerosols work differently from greenhouse gases
• Aerosols have more local (vs. global) impacts
• They do not accumulate—they have a lifetime of days
44. 4. DAMS HAVE ENORMOUS IMPACTS
• Valuable freshwater habitats (waterfalls, rapids, fish runs) are lost
• Reduced waters at deltas.
• The waterway below the diversion is deprived of water
• Fish and other aquatic organisms are directly impacted
• Wildlife is adversely affected (e.g., food chains)
• Wetlands dry up and waterfowl die
• Fish (e.g., salmon) cannot swim upstream to spawn or downstream to return to
the ocean
• Even with fish ladders to help them pass the dams
• Juvenile salmon suffer 95% mortality going to sea
45. 5. WITHDRAWALS FOR HUMAN USE
USES OF WATER
• Worldwide, the largest use is for irrigation
• Then industry and direct human use
• Use varies by region, depending on:
• Natural precipitation
• Degree of development
• Most increases in withdrawal are due to increases in
agriculture
• Irrigation accounts for 65% of freshwater consumption in the U.S.
46. WATER: MANAGEMENT AND CONTROL
• Humans use 27% of all accessible freshwater runoff
• Global withdrawal will increase 10% each decade
• Americans use less water than in 1980
• No consumptive uses of water: water may be contaminated, but is still
available to humans
• Used in homes, industries, and electric power production
• Consumptive uses of water: the applied water does not return to the
water resource
• It is gone from human control
• Water for irrigation
47. NEED TO CHECK THE HUMAN IMPACT
• 37% of domestic water comes from groundwater sources- depleting fast
• 63% comes from surface water (rivers, lakes, reservoirs)- quality and quantity
deteriorating – affecting humans and biodiversity
• Rural people in developing nations get water where they can
• Women often have to walk long distances to get water
• Water in developing nations is often polluted with waste
• 1.1 billion people use polluted water
• 1.6 million (mostly children) die each year
• Millennium Development Goal 7: increase access to safe drinking water
48. EFFECTIVE WATER MANAGEMENT METHODS
Drip irrigation and other agricultural practices in Agriculture.
Tapping rain water resources through recharge pits.
Increasing awareness about effective water management.
Sustainable usage of Water.
Judicious usage of water in day to day life.
Sewage should be treated and clear water should be released into
the rivers.
Growing vegetation in Catchment Areas.
Effective usage in Industrial and Agricultural sectors.
49. THE POSSIBLE SOLUTIONS COULD BE
Afforestation
Reducing greenhouse gases.
Rain water harvesting
Watershed management
Manage and treat water starting at its source and at multiple locations
throughout the landscape
Protect natural systems and processes (water movement, vegetation, native
soils, sensitive/important features)
Incorporate natural features (wetlands, stream corridors, mature forests) as
design features into development plans
Re‐evaluate the cost and use of traditional building techniques and
infrastructure (lots, streets, curbs, sidewalks, storm drains)
Preserve open space and minimize land disturbance