1. 1st century BC The water harvesting system that taps the flood waters of the Ganga River was at Shringaverapura, located in the present-day Allahabad district of Uttar Pradesh state of India.

2. The system was composed of three percolation-cum-storage tanks, fed by an 11-meter wide and 5-meter deep canal, which diverted flood water from the monsoon-swollen Ganga.

3. During the reign of Chandragupta Maurya, large-scale dams, irrigation systems and harvesting systems were constructed throughout his kingdom.

1. Narmada River is the fifth largest river of India which flows through Madhya Pradesh and Gujarat.

2. The Narmada River (Rewa) serves as a traditional boundary between North and South India.

3. It originates from the Amarkantak peak of Maikal mountain and flows 1,312 km towards the west and joins the Gulf of Khambhat.

4. Major tributaries from the right side are Hiran, Tendori, Barna, Kolar, Maan, Uri, Hatni and Orsang.

5. Major left tributaries are- Berner, Banjar, Sher, Shakkar, Dudhi, Tawa, Ganjal, Chhota Tawa, Kundi, Goi and Karjan.

6. Narmada River Basin is home to fishes, turtles, crocodiles, beautiful birds and other wildlife.

7. The largest dam built on the Narmada River is "Sardar Sarovar Dam", which is built in Narmada district of Gujarat.