The Narmada, the largest flowing Westward, rises near Amarkantak range of mountains in Madhya Pradesh. It is the fifth largest river in the country and the largest one in Gujarat. It traverses Madhya Pradesh, Maharashtra and Gujarat and meets the Gulf of Cambay. The total length of the river from source to sea is 1312 kilometers (815 miles) while the length up to dam site is 1163 kilometers. (723 miles). The width of the river channel at dam site during high floods is 488 meter (1600 feet) and that during summer is 45.70 meter. (150 feet). The maximum recorded flood on 7th September 1994 was 70,847 cusecs (2.5 million cusecs) while minimum recorded flow in summer was 8.5 cusecs (300 cusecs.)
The dam is designed for 87,000 cusecs (3.07 million cusecs) flood.

The total basin area of the river is 97,410 square kilometer comprising 85,858 square kilometer in Madhya Pradesh, 1658 square kilometer in Maharashtra and 9894 square kilometer in Gujarat. The drainage area up to dam site is 88,000 square kilometer. The mean annual rainfall in the basin is 112 centimeters. The annual run of the dam site at 75 percentage of dependability is 27.22 MAF. The World Bank computed the yield of 28.57 MAF while the yield computed in May 1992 by the Central Water Commission, Government of India is of 26.60 MAF, i.e. about 27.00 MAF. The utilisation of Narmada River basin today is hardly about 10%. Thus water of the Narmada continue to flow to the sea unused.