English: An annicut, or weir was built on the Son between 1869 and 1875 by constructing a mass of rubble stone masonry founded on shallow wells. It is 12,469 feet long and consists of scouring sluices positioned at each flank which are fitted with gates which can be opened or closed at any state of the river other than high flood. Through these the gates the level of water in the pool above the weir can be kept at the height required to supply the canals that branch off from the dam and traverse the plains. The Son canal system became one of the most important irrigation systems and provided water for a large tract and increased cultivation.