Sone Basin
The river Sone is an important right bank tributary of the river Ganga. It originates from Amarkantak high lands in hills of Maikala range in Bilaspur district of Chhattisgarh at an elevation of 640 m and latitude 20°44’ N and longitude 82°4’E. The river outfalls into the Ganga at about 16 km. upstream of Patna at latitude 25°14’ N and longitude 84°42’ E . The total length of the river is 881 km. The total catchment area of river system is 70,055 sq.km.
The catchment of the whole river system is surrounded by the Vindhachal range in the North, the Punpun river system and the Chotanagpur plateau on the East, the Baghelkhand plateau and the Mahadeva hills on the South and the forest clad Maikal and Bhamver ranges on the West . After flowing a distance of 655 km.through the states of Chhattisgarh, Madhya Pradesh and Uttar Pradesh, the river Sone enters in Jharkhand. Its important tributaries lying in ther states of Chhattisgarh, Madhya Pradesh, Uttar Pradesh and Jharkhand are Johilla, Mahanadi, Banas, Gopad, Rihand, Ghagher , Kanhar and North Koel. The river Kanhar which flows South to North and in the downstream reach forms boundaries between Jharkhand and Madhya Pradesh. After meeting with the river Kanhar, the river Sone enters Jharkhand and joined by the river North Koel on its right bank. The river, thereafter, takes a sharp North-East turn and finally joins the river Ganga.
North Koel Sub Basin
It is the second largest right bank tributary of the river Sone and originates from Ranchi district (latitude 23°4”N, longitude 84°28’ E) of Jharkhand at an elevation of 900 m. The river initially flows in the northern direction through the narrow valley of Bishupur in Palamu district and thereafter turns towards west and flows in this direction for about 32 km. It then takes an almost right angle turn through a gorge at Kutku and flows in north-east direction upto its confluence with the Auranga river . It later turns towards north-west and is met by the Amanat river just downstream of Daltonganj. After flowing for another 30 to 40 km. in the north west direction it turns towards north and meets the river Sone at an elevation of 140 m in Palamu district of Jharkhand, a few kilometers north-west of Haidarnagar, opposite the famous hill fort of Rohtasgarh (latitude 24°30’N, longitude 83°55’ E).
The total length of the river is 259 km. and its catchment area is 11100 sq.km. It has three important tributaries namely the Auranga, the Amanat and the Tahle.