Drainage system means the draining of rivers and their subsidiaries. Chambal is the only perennial river in Rajasthan. It is the Aravalli mountain ranges which determine the drainage system of Rajasthan. These mountain ranges divide the rivers system of Rajasthan into two parts, besides the Inland rivers. 

Thus the rivers of Rajasthan are grouped into three parts:

1. The Bay of Bengal Drainage system. 

2. The Arabian Sea Drainage system. 

3. The Inland Drainage system.

1. The Bay of Bengal Drainage System, i.e. the rivers draining into the Bay of Bengal. These rivers are Chambal, Banas, Banganga and their subsidiary rivers. 

(а) Chambal River: 

It was known as the Chamanvati in the ancient period. It originated from Janapaw hill near Manpur (Mhow), Madhya Pradesh. It enters Rajasthan near Chaurasigarh (Chittorgarh district), crosses the, Kota- Bundi districts, passes through Sawai Madhopur, Karauli and Dhaulpur districts and merges finally with Yamuna river. Gandhi Sagar, Jawahar Sagar and Rana Pratap sagar dams, and Kota Barrage have been constructed on the river Chambal. Its main subsidiary rivers are Banas, Kali Sindh and Parvati. 

(b) Banas River: 

It originates in Khamnor hills of the Aravalli range, which is 5 km far from Kumbhalgarh. It flows southwards from Kumbhalgarh, Gogunda plateau, crosses Nathdwara, Rajsamand, Rail Magara, runs through Chittorgarh, Bilwara, and Tonk districts, then merges with Chambal in Sawai Madhopur. River Banas is also known as the Van-ki-Asha. Its main auxiliary rivers are Berach, Kothari, Khari, Mainal, Bandy, Dhundh and Morel. 

(c) Kali-Sindh River: 

It originates near Devas in Madhya Pradesh, flows through Jhalawar and Baran districts and merges with Chambal near Nanera. Its main subsidiaries are Parvan, Ujaar, Niwaz and Aahu. 

(d) Parvati River: 

It arises in the Sihore area of Madhya Pradesh, runs through Baran district and merges with the Chambal river near Palia in Sawai Madhopur district. 

(e) Vapani (Brahmani) River: 

Originating near Haripur village in Chittorgarh district, the river merges with Chambal near Bhainsorgarh. 

(f) Maze River: 

It originates in Bhilwara district and merges with river Chambal near Lakheri in Bundi.

(g) Banganga River: 

It originates in the Bairath hills of Jaipur district. From here it turns eastwards and flows through Sawai Madhopur district and then Bharatpur district.

2. The Arabian Sea Drainage System: 

The Rivers Luni, Alahi and Sabarmati drain into the Arabian sea. 

(a) Luni River: 

It originates in the Nag hill of Ajmer, then flows through Jodhpur, Pali, Barmer and Jalore covering the distance of 320 km, before draining, finally, into the Rann of Kutchh.Jt is the rainy season river. Its special feature is that its water remains sweet till Balotara and after that it became saline. Its subsidiaries are Jawai, Leelari, Muhari, Sukhari-I, II and III, Bari I and II and Saagi. 

(b ) Mahi River: 

It originates in Mhow hills of Madhya Pradesh, enters Banswara in Rajasthan, forms the boundary of Dungarpur-Banswara districts, enters Gujarat and then drains into the Bay of Khambhat. Mahi Bajaj Sagar Dam has been built on it near Banswara. Its main subsidiaries are Som, Jakham, Annas, Chap and Moren. 

(c) Sabarmati River: 

It originates in the south-west Udaipur, flows through Udaipur and Sirohi districts, and enters Gujarat to drain into the Bay of Khambhat. 

3. Inland Drainage System: 

There are small rivers in Rajasthan, which flow through a small distance and then disappear in sand or mud. They are known as the inland drainage rivers. They are Katali, Sabi and Kakani rivers. 

(a) Katali River: 

It arises from the Khandela hills of Sikar district, flows through Sikar and Jhunjhunu districts upto 100 km and disappears in the sands. 

(b) Sabi River: 

It originates in the Sewar hills of Jaipur, passes through Banasur, Behror, Kishangarh, Mandavar and Tijara tehsils and then becomes extinct in Haryana. 

(c) Kalani or Kakneya River: 

It originates in Kotari village, 27 km south of Jaisalmer, flows a few km and then disappears.

Ghaggar River: It is the river which is considered to be the remnant of the ancient Sarswati river. It originates in Haryana, passes through Hanumangarh, Ganganagar, Suratgarh and Anupgarh, to end, finally, in Pakistan. It receives water during the rainy season and spreads it all over. Presently this river is known as ‘Naati’ in the local dialect. Besides the above Inland rivers, rivers of Banganga and Sambhar lake areas also fall in this category.