great arabic turkish approximately kilometre long river flowing turkey iraq rises turkey near lake van joins iraq south drainage basin covers approximately square kilometres course rivers collects water tributaries river tributaries primarily fed rainfall result discharge highly year dams planned tributaries construction commenced halted gulf war occupied occupation great basin testified archaeological site historical records region available end millennium bce onward neo period provided water irrigation lands capital city battle ended took place near tributary valleys river provided shelter refugees conquest iraq 19th 20th centuries great basin saw frequent uprisings local tribes autonomy course rises turkey mountainous region east lake van elevation approximately metres joins left bank iraq turkey traverses provinces van iraq flows forms boundary upper reaches great flows steep rocky stretch gorge dam remains unfinished called valley large portion inundated water project completed numerous mountain streams join right left banks receives waters left bank tributaries length variously estimated kilometres kilometres approximately kilometres river course located iraq average discharge cubic metres second peak cubic metres second recorded average annual discharge cubic kilometres torrential nature medieval arab described possessed watershed estimates drainage basin vary widely low square kilometres high figure square kilometres approximately percent basin located iraq remainder turkey south basin borders east basin consists parallel limestone rising elevations metres valleys including great south western zone filled gravel sandstone result water erosion valley drainage basin largest valley iraqi rises highlands climate cold winter annual precipitation excess millimetres river flows zone rainfall drops millimetres year confluence average summer temperature zone generally higher zone mountains high characterized different area metres shrubs herbs dominate area metres past dominated open oak forest river valleys trees oak found forested zone including higher elevations ash maple intermediate elevations olive trees lower drier areas zone areas cultivated remain small patches natural vegetation dominated herbs genus river modifications date large dam partially constructed great iraq dam turkey controlled run river planned great basin turkey iraq turkey plans construct dams near dam near city dam power station final design dams support power stations respectively iraq commenced construction planned plans build dam great gorge flood control irrigation proposed feasibility study determined site suited dam construction plan abandoned study proposed different locations great including site suggested earlier study site eventually chosen work dam commenced construction dam interrupted outbreak gulf war dam remains unfinished war site dam looted plans called metre high dam underground hydroelectric power station housing turbines total capacity reservoir created storage capacity cubic kilometres flooded numerous villages archaeological site access road cave history evidence human occupation reaches lower evidenced discovery cave sites dating period iranian mountain range stone tool known cave site south iranian stone tool produced modern humans recently excavated occupied site cave site located yielded settlement sequence stretching period site particularly known occupation contemporary use stone tool oldest evidence modern human occupation great basin following occupation contemporary oldest occupation nearby open air site tributary small village hunter dating 10th millennium bce contemporary levant archaeological survey plain south lower course shown site continuously occupied 6th millennium bce upward earliest historical reference region dates dynasty king mentioned city ancient modern day great capitals located zone great flows great basin increasingly integrated neo capital empire bce located kilometres away confluence great king constructed canal called tapped water land canal restored successors canal ran right bank cut rock bluff means tunnel visible today fall neo empire gained control area followed bce bce decisive battles leading fall empire hands supposedly took place north great vicinity death bce control area shifted defeated battle banks tributary swept iraq 13th century sacked survivors sought refuge inaccessible valleys home christian muslim communities evidenced christian artefacts found 19th century area controlled local leaders world war heavy fighting took place area russian soldiers following world war episodes heavy fighting took place tribe establishment independent tribes uprisings started led heavy towns villages great basin
Great Zab