Breach in channel 23, of Hub Canal has led to suspension of water supply to Karachi.
Sources in Water and Power Development Authority said that, due to the void, nearly 100 million gallons of water would not be supplied to the city for three days.
The situation has also resulted in inundation of Madinat-ul-Hikmat and Bhuray Khan Goth.
Chief Engineer Water Board Iftikhar Ahmed told a private television channel that rescue teams have been sent to the site to fill the void.