jheel

jheel jal ka vah sthir bhaag hai jo chaaro taraf se sthalakhandon se ghira hota hai. jheel ki doosari visheshata usaka sthaayitv hai. saamaanya roop se jheel bhootal ke ve vistrut gaddhe hain jinmein jal bhara hota hai. jheelon ka jal praay: sthir hota hai. jheelon ki ek mahatvapoorn visheshata unka khaaraapan hota hai lekin anek jheelein meethe paani ki bhi hoti hain. jheelein bhoopatal ke kisi bhi bhaag par ho sakti hain. ye uchch parvaton par milti hain, pathaaron aur maidaanon par bhi milti hain tatha sthal par saagar tal se neeche bhi pai jaati hain.

kisi antardesheeya gart mein pai jaanevaali aisi prashaant jalaraashi ko jheel kehte hain jiska samudra se kisi prakaar ka sambandh naheen rahata. kabhi-kabhi is shabd ka prayog nadiyon ke chaude aur vistrut bhaag ke liye tatha un samudra tateeya jalaraashiyon ke liye bhi kiya jaata hai, jinka samudra se apratyaksh sambandh rahata hai. inke vistaar mein bhinnata pai jaati hai; chhote chhote taalaabon aur sarovar se lekar meethe paaneevaali vishaal supeeriyr jheel aur lavanajaleeya kaispiyn saagar tak ke bhi jheel ke hi sanjnyaa di gayi hai. adhikaanshat: jheelein samudra ki satah se oopar parvateeya pradeshon mein pai jaati hain, jinmein mrut saagar, (ded si) jo samudra ki satah se neeche sthit hai, apavaad hai. maidaani bhaagon mein saamaanyat: jheelein un nadiyon ke sameep pai jaati hain jinki dhaal kam ho gayi ho. jheelein meethe paaneevaali tatha khaare paaneevaali, donon hoti hain. jheelon mein paaya jaanevaala jal mukhyat: varsh se, him ke pighlane se athva jharanon tatha nadiyon se praapt hota hai.

jheele banti hain, viksit hoti hain, dheere-dheere talachhat se bharakar daladal mein badal jaati hain tatha utthaan honne par sameepi sthal ke baraabar ho jaati hain. aisi aashanka hai ki sanyukt raajya America ki bruhat jheelein 45,000 varshon mein samaapt ho jaaengi. bhoo-tal par adhikaansh jheelein uttari golaardh mein sthit hain. Finland mein to itni adhik jheelein hain ki ise jheelon ka desh hi kaha jaata hai. yahaaain par 1,87,888 jheelein hain jismein se 60,000 jheelein behad badi hain.[1] pruthvi par anek jheelein krutrim hain jinhein maanav ne vidyut utpaadan ke liye, krushi-kaaryon ke liye ya apne aamod-pramod ke liye banaaya hai.

jheelein upayogi bhi hoti hain. sthaaneeya jalavaayu ko ve suhaavana bana deti hain. ye vipul jalaraashi ko rok leti hain, jisse baadh ki sambhaavana ghat jaati hai. jheelon se machhaliyaaain bhi praapt hoti hain.

anukram

jheelon ki utpatti

jheel ki utpatti ke anek kaaran hote hain jinmein mukhya nimnalikhit hain-

himaani ke kaaran

himaani pradeshon ke bhoodrushyon mein bhi anyadhik laakshanik hoti hain. vastut: vartamaan samay mein himaaniyon dvaara nirmit jheelein sankhya mein itni adhik hain ki unki tulana mein aur kaaranon se nirmit jheelein naganya hain. aisi jheelon ki utpatti ka mukhya kaaran yeh hai ki jab himaaniyaaain apni pighlane ki antim avastha mein aa jaati hain tab unamein paae jaanevaale himodh (moraine) rodhan ka kaarya karte hain jisse pighla hua jal, oobad khaabad sthal mein ekatrit hokar jheel ka aakaar le leta hai. hamaare desh mein is prakaar ki jheelein himaalaya mein pai jaati hain.

vivrtanik halchalon (tectonic movement) ke kaaran

pruthvi ke andar honevaali halchalon ke kaaran kabhi kabhi ant:krut garton ka nirmaan ho jaata hai, jo jal se bhar jaane par ant:krut jheelon ke janmadaata ho jaate hain. kaispiyn saagar iska udaaharan hai.

jvaalaamukhi parvaton ka kaaran

prasupt jvaalaamukhi parvaton ke jvaalaamukh (crater) bhi jal bhar jaane par jheelon ka roop le lete hain.

avarodh ke nikshep ke kaaran

kabhi kabhi parvateeya pradeshon mein bhooskhalan ho jaane par shailon ke vishaal bhookhand, nadiyon ke maarg mein gir padte hain, jinse unka pravaah avaruddh ho jaata hai aur ruka hua jal, jheel ka roop le leta hai.

avasaad ke kaaran

praaya: dekha jaata hai ki maidaani bhaag mein nadiyon mein chhaad (oxbow) ka nirmaan ho jaata hai. nadiyon ka visrpi mod (meander) iska pradhaan kaaran hai.

niraavaran (denudation) ke kaaran

choona patthar ke pradeshon mein choona patthar ke ghulane se bhoomi dhains jaati hai, jisse gart ban jaate hain. kaalaantar mein aise hi gart jal bhar jaane par jheel ban jaate hain.

jheelon ka jeevanakaal

adhikaanshat: jheelein asthaayi astitv ki hoti hain. manushya apne jeevanakaal mein hi unki utpatti, vikaas aur ant ki avasthaaeain dekh leta hai. parvateeya pradeshon mein jo jheelein avarodhan ke kaaran ban jaati hain, ve avarodhan hat jaane par sheegra hi lupt ho jaati hain. nam deshon mein jheelon ke tal mein avasaad (sediment) ekatr hone se ve chhichhli ho jaati hain aur yadi unamein se kisi nadi ka udgam hota hai, to ve sheegra hi vileen ho jaati hain.

sabse adhik

Tibet ki tiso sikroo sansaar ki sabse ooainchi jheel hai jo Tibet ke pathaar par 18,284 feet ki oonchaai par sthit hai. iske vipreet mrut saagar sansaar ki sabse neechi jheel hai, jo saagar tal se bhi 1,300 feet neechi hai.[2] iski tali saagar tal se 2,500 feet nichaai par hai.

kuchh jheelein adhik gahari hoti hain jaise saaiberiya ki baikaal jheel, jiski gaharaai 1.6 kilometer se adhik hai.[3] iske vipreet kuchh jheelein atyant uthali hoti hain. garmi ke mausam mein sookh jaane ke kaaran ye mausami jheel kahi ja sakti hain. kshetrafal mein jheelein chhoti-badi, sabhi tarah ki hoti hai himaaneekrut jheel (taarn jheel) kuchh varg meter tak hi vistrut hoti hain jabki laakhon varg kilometer kshetrafal waali vistrut jheelein hain. kaispiyn saagar ek vistrut jheel hai jiska kshetrafal 4,30,000 varg kilometer hai. mahaadveepon ke aantarik bhaagon mein sthit vistrut jheele jaise kaispiyn saagar, arab saagar, mrut saagar, sanyukt raajya America tatha Canada ki bruhat jheelein, Africa ki Victoria tatha saaiberiya ki baikaal jheele aakaar ki drushti se saagar ke samaan hain.

sandarbh