Seven major rivers along with their numeroustributariesmake up the river system of India. The largest basin system of the rivers pour their waters into theBay of Bengal; however, some of the rivers whose courses take them through the western part of the country and towards the east of the state ofHimachal Pradeshempty into theArabian Sea. Parts ofLadakh, northern parts of theAravallirange and the arid parts of theThar Deserthave inland drainage.

All major rivers of India originate from one of the following mainwatersheds:

1.Aravalli range

2.HimalayaandKarakoramranges

SahyadriorWestern Ghatsin western India

3.VindhyaandSatpuraranges

As far as lakes are concerned there are many kinds of lakes in India. On the basis of salt concentration they are of two types : fresh water, eg- kedartal (uttarakhand) and Salt water, eg- Sambar lake (Rajasthan)

On the basis of origin they could be classified into following types:

a) Tectonic- mostly found among young fold mountain i. e. himalayan Eg. wular (kashmir)

b) Meteorite lake - formed by impact of Meteorites. Eg - lonar lake (Maharashtra)

c) Ox bow lakes - mostly associated with mature course of himalayan rivers. Eg- Kanwar lake (associated with Ganga river)

d) Lagoons - formed along coasts and are adjacent to seas /oceans. They have rich biodiversity. Eg- Chilika lake (Odisha)

e) Manmade lakes - mostly constructed in Western India to cater to human needs. Eg - Rajsamand lake

f) Glacial lakes - Cholamu lake(sikkim)

g) Dams and reservoirs - again Manmade. There are many of these across India. Eg- Bhakra dam