Introduction
Mahi River Basin is located in south-eastern Rajasthan, between latitudes 23004' and 24o35' and longitudes 73o18' and 74o52'. It lies south of Banas Basin, its eastern edge borders Chambal Basin in Madhya Pradesh, and its western edge borders Sabarmati Basin.

Mahi River Basin extends over parts of Banswara, Chittorgarh, Dungarpur and Udaipur Districts.
The total catchment area of the Basin is 16,985 km2 according to the 1:250,000 scale topographical maps published by the Survey of India.

Orographically, the Basin is marked by hilly terrain belonging to the Aravali chain. Ground elevations in the southern hilly part range from +465 to +1046 m amsl approximately, while the alluvial plain elevations range from +208 to +262 m approximately.

The main urban agglomeration is Banswara situated at the southeastern end of the Basin. The second largest urban centre is Dungarpur.

Drainage
Mahi River originates in the Mahi Kanta hills in the Vindhyachal range, in the western part of Madhya Pradesh, and enters Rajasthan in Banswara District, near Chandangarh. It leaves the State at Salakari village. On an average the river is about 100 - 130 m wide and it flows mostly through rocky terrain. Its banks may be steep, though not very high.

The main tributaries of the Mahi River are the Anas, Hiran, Eru and Chap Rivers, in Banswara District. Of these, only the Anas River is perennial.

The Jakam and Gomti Rivers are the next most important downstream tributaries of the Mahi River, originating from Chittorgarh and Udaipur Districts, respectively.

In Dungarpur District, the last lap of the Mahi River in Rajasthan, the main tributary is the Som River. Another tributary, the Moran, a seasonal river, also flows through this District.

Rainfall
The mean annual rainfall over the Mahi Basin is around 700 mm, of which about 94% falls during the four Monsoon months (June-September).

Existing Surface Water Projects
There are three Major projects (Mahi Bajaj Sagar, Jakham and Jaisamand), two Medium and 220 Minor irrigation projects in the Mahi River Basin, as well as some small irrigation systems (covering less than 20 ha) constructed and operated by Panchayat Samities (PS).

Ongoing Surface Water Projects
38 irrigation projects, including Som Kamla Amba (Major), with a total live storage capacity of 333 Mm3, are under construction in the Basin. An additional area of 31.7 kha will be irrigated on completion of these projects, expected between the years 1997 and 2015.

Proposed Surface Water Projects
308 irrigation projects, with a total live storage capacity of 283 Mm3, have been proposed in this Basin. An additional area of 55 kha will be irrigated on completion of these projects, expected in between the years 2005 and 2015.