This document is a science practical report about water. It discusses how water is essential for life on Earth, but only 2.5% of water is freshwater. Most freshwater is frozen in glaciers or stored underground. Water pollution is increasing due to industrialization and human activities. Dams can store large amounts of water and generate electricity, but also displace local communities and cause environmental problems. Ancient water harvesting systems like the Khadin system in Rajasthan collected surface runoff water for agriculture using structures like earthen embankments and reservoirs.

1. Studentname -} prem r.rajput
subjectscience
rollno1022B
Sciencepractical

2. WATER
forall
Water is a basic necessity for all terrestrial form of lfe

3. •Water is one of the prime element responsible for life on earth .
•97 % of the water on the earth is salt water only 2.5 of the total water on
the earth is exists as fresh water .
•Around 70% of fresh water is frozen in glaciers and ice sheets.
•Only 30%of water is stored as ground water.
•The water pollution are caused by increasing industrialization and
human activites.
•Mostly the water bodies get polluted by industrial municipal and
agricultural wastes .
•Around 0.3 % of the total fresh water exists in rivers ,lack ,stream ,pond
and spring are natural resource of water.
Water
for
all

4. TABLE
OF
CONTENTS 01 Rainfallpatternsinindia
08
02 Rainsandirrigationpractices
07
03 dams
04 Benefitsoflargedams
Waterharvesting
05 Disadvantages ofconstructingdams
06 Issuesforconstruction ofdams
ANCIENTWATERHARVESTINGSYSTEM
KHADINSYSTEM
09

5. Rainfall
patterns
in
india
Rainfall pattern means the distribution of rain
geographically, temporally, and seasonally. The
tropics receive more rainfall than deserts. Cooler
places like the poles receive no rainfall, as it is
converted to snow before it falls to the ground

6. Rainfall
patterns
in
india

7. Rains
and
irrigation
practices Involveme
ntof
local
people
● Himachal Pradesh had a canal irrigation system
called kulhs where flowing stream water was
diverted to man-made channels which took it to
villages down the hillside.
● The water was used first by the village farthest
from the origin of the kulh. This helped water
percolate in the soil.
● It was made defunct after government irrigation
system took over.
● Dams
● Intervention of government to
pursue mega projects
neglected the local irrigation
methods
● Strict regulations on usage of
stored water and building
tanks, dams and canals
● Optimum cropping patterns
must be followed based on
water availability.

8. Dams
03

9. dams
● Dams can store large amounts of water and generate
electricity.
● Mismanagement of dams causes exploitation and there is
no equitable distribution of this resource.
● Criticism about large dams address:
(i) Displacement of tribals without compensation
(ii) Corruption and consumption of money without
generation of benefits
(iii) Environmental problems like deforestation.
Forirrigation,waterfromdamsisused.
Damwaterispurifiedandmadeavailablefordrinkingin neighbouringtowns andcities.
Hydroelectricpowerisproducedbydamsand utilisedtoproduceelectricity.
Damsstop floodingfrom takinglivesandproperty.
UsesofDams

10. Benefits
of
large
dams
Thebigdamsandthereservoirsalsoproviderecreationalareasforthepurpose
offishingandalsoboating.
Theyalsocaterinsecurityneedsofhumansbyreducingorpreventingfloods.
Duringthetimesof excessflowofwater,thedamsstorethewaterinthereservoir;
latertheyreleasethatwaterduringthetimesoflowflow,
alsowhenthenaturalflowsofwaterareinadequatetomeetthedemand.
Whenengineersdesignandalsomaintainthedams,
theyarekeenlyexpectedtomakesuretokeepallpurposesintheirmind.

11. Disadvantages
of
constructing
dams
Therearenumerousadvantagesofbuildingadam andthatisthereasonwhy a
governmentinvestssomuchmoneyintheconstructionandmaintenanceofDams.
Buttherearecertaindisadvantagesrelatedtoit.Someofthe disadvantagesare:
Buildingadamisveryexpensive,andthegovernmentneedstoensurethatstrict
guidelinesarefollowedandaveryhighstandardismaintained.
Theymustoperateformanyyearsinordertobecomeprofitableenoughto
compensateforthehighbuildingcost.
Peopleresidinginvillagesandtownsinthenearbyarea,wheretherearechances
offlooding,havetoberelocated.Theylosetheirbusinessesand farms.
Sometimespeopleareremovedforciblytoset uphydro-powerplantsanditposes
aseriousethicalconcern.
Thebuildingoflargedamscancauseseriouschangestotheearth’ssurfaceand
leadtogeologicaldamage.Itcantriggerfrequentearthquakes,however,modern
planninganddesignofdamshavereducedthepossibilityofoccurrenceof
certaindisasters.

12. Thechallengescausedduetoconstructionoflargedams:
Theproblemscanbecategorizedinto threecategories
SocialProblems:
Theconstructionofhigh-risedamsresults inavastareaoflandsubmergedunderwater.
Thepeoplecreateadisplacementofalargenumberofpeasantsand tribals without
adequatecompensationorrehabilitation.
Theothersocialproblemsaregeneratedduetomismanagementbytheofficials.
Ithasbeenobservedthatthepeopleclosetothesourcegrowwater-intensivecropslike
sugarcaneandricewhereaspeoplefartherdownstreamdonotgetsufficientwaterto
growthesecrops.
Thisalso causessocialproblemsresultingduetounequal distributionofwater.
EconomicProblems:
Theconstructionofahigh-risedamis anexpensiveprojectthatinvolves thespendingofa
hugeamountofpublicmoney.
EnvironmentalProblems:
Theconstructionofhigh-risedamscausesseveralproblemsincluding deforestation,loss
ofbiodiversityand displacementofpoor tribals.
Thelargereservoirsofwaterformedbythedams destroyplantsandanimals inthearea
whichgetsubmergedunderwater.
Alargenumberofpoortribals getdisplacedastheirlandsaresubmergedunderwater.

13. Water
harvesting Waterharvestingencouragessoiland water
conservationinordertosustainandincreasebiomass.
Increasesincomeforthelocalcommunitybutalso
alleviatesfloods anddroughts.
Examples:Rajasthan’stanks,Khadins,and Nadis,
Maharashtra’sTals and Bandharas,MadhyaPradesh’sand
UttarPradesh’sBundhis,Bihar’sPynes and Ahars,
HimachalPradesh’sKulhs,Kattasin Karnataka,pondsin
theKandibeltofJammuregion,andEris (tanks)inTamil
Nadu,Kerala’sSurangams.
Waterharvestingconstructionsarecrescent-shaped
earthenembankments/concretecheckdamsbuilt in areas
thatareseasonally flooded
Themainpurposeistorechargegroundwater.

14. Water
harvesting

15. advantages
of
a
rainwater
harvesting
system. Decreasesthedemandforwaterimports.
Encouragesenergyandwaterconservation.
Increasesgroundwateravailabilityand
quality.
Doesnotneedafilteringsystem for
irrigationingardens.
Thistechnologyiscomparatively
straightforwardandsimpletoinstalland
use.

16. ● ​A khadin is a construction that is designed to harvest surface
run off water for agriculture.
● It was first designed by the Paliwal Brahmins of Jaisalmer,
western Rajasthan in the 15th century.
● The 'Khadin' system of rainwater harvesting practised in
Rajasthan has a long earthen embankment known as bund,
which is built across the edges of sloping farmlands.
● The rainwater flows down the slope and is stopped by bund.
● It then flows into a reservoir.
● The water in the reservoir seeps into the land and can be used
for growing crops.
● It has a catchment area, bund, saline area and shallow dug well.
● The water from the catchment area flows down and stopped by
the bund.
● It forms a reservoir.
● If the reservoir overflows,the water goes into the shallow dug
well.
● This water from the reservoir and shallow dug well seeps down
the land and refills the ground water.
KHADIN
SYSTEM
.

18. THANK
YOU