ISLAMABAD  : Water storage capacity of Tarbela Dam has been reduced down to 33 percent raising the threat of reduction in water supply to more than one million acre land. As per report of Tarbela dam graphic survey, stored water capacity of dam has been reduced due to filling of silt which could deprive off 1,10,000 acre piece of land from water supply. As per survey, annual storage of water has been decreased to 55,000 acre per foot, while since construction of dam this capacity has been decreased to more than 3m acre per foot. On the other side sources from IRSA said that Chashma Barrage has been also filled with 62 percent of sand and soil which has reduced its storing capacity to 44,000 acre per foot.