如何写英语作文关于使用水的作文

UsesofWater

WaterisoneofthemostvitalnaturalresourcesforalllifeonEarth.Theavailabilityandqualityofwateralwayshaveplayedanimportantpartindeterminingnotonlywherepeoplecanlive,butalsotheirqualityoflife.EventhoughtherealwayshasbeenplentyoffreshwateronEarth,waterhasnotalwaysbeenavailablewhenandwhereitisneeded,norisitalwaysofsuitablequalityforalluses.Watermustbeconsideredasafiniteresourcethathaslimitsandboundariestoitsavailabilityandsuitabilityforuse.

resultbetweenandamongthevarioususes.

Thebalancebetweensupplyanddemandforwaterisadelicateone.Theavailabilityofusablewaterhasandwillcontinuetodictatewhereandtowhatextentdevelopmentwilloccur.Watermustbeinsufficientsupplyforanareatodevelop,andanareacannotcontinuetodevelopifwaterdemandfaroutstripsavailablesupply.Further,awatersupplywillbecalledupontomeetanarrayofoffstreamuses(inwhichthewateriswithdrawnfromthesource)inadditiontoinstreamuses(inwhichthewaterremainsinplace).Figure1representsthedemandsonwaterasatug-of-waramongthevariousoffstreamandinstreamuses.

Traditionally,watermanagementintheUnitedStatesfocusedonexpandingormanipulatingthecountry'ssuppliesoffreshwatertomeettheneedsofusers.Anumberoflargedamswerebuiltduringtheearlytwentiethcenturytoincreasethesupplyoffreshwaterforanygiventimeandplace.Thiseraofbuildinglargedamshaspassed.Inthetwenty-firstcentury,thefinitewatersupplyandestablishedinfrastructurerequirethatdemandbemanagedmoreeffectivelywithintheavailablesustainablesupply.Water-useinformationcanbeusedtoevaluatetheimpactsofpopulationgrowthandtheeffectivenessofalternativewatermanagementpolicies,regulations,andconservationactivities.

TheWater-UseCycle

Waterisconstantlyinmotionbywayofthehydrologiccycle.Waterevaporatesasvaporfromoceans,lakes,andrivers;istranspiredfromplants;condensesintheairandfallsasprecipitation;andthenmovesoverandthroughthegroundintowaterbodies,wherethecyclebeginsagain.*

Thewater-usecycleiscomposedofthewatercyclewiththeaddedinfluenceofhumanactivity.Dams,reservoirs,canals,aqueducts,withdrawalpipesinrivers,andgroundwaterwellsallrevealthathumanshaveamajorimpactonthewatercycle.Inthewater-usecycle,watermovesfromasourcetoapointofuse,andthentoapointofdisposition.Thesourcesofwaterareeithersurfacewaterorgroundwater.Wateriswithdrawnandmovedfromasourcetoapointofuse,suchasanindustry,restaurant,home,orfarm.Afterwaterisused,itmustbedisposedof(orsometimes,reused).Usedwateriseitherdirectlyreturnedtotheenvironmentorpassesthroughatreatmentprocessingplantbeforebeingreturned.