Even before large-scale irrigation began , high summer evaporation meant that not all of this discharge reached the Aral Sea - though there is some evidence the large Pamir glaciers provided enough melt water for the Aral to overflow during the 13th and 14th centuries .
Even before large-scale irrigation began , high summer evaporation meant that not all of this discharge reached the Aral Sea - though there is some evidence the large Pamir glaciers provided enough melt water for the Aral to overflow during the 13th and 14th centuries A.D. Historical records state that in different periods , the river flowed into the Aral Sea ( from the south ) , the Caspian Sea ( from the east ) or both , similar to the Syr Darya ( Jaxartes , in Ancient Greek ) .