**2. Study area**

Kosi River watershed extending between 29° 18<sup>0</sup> N–79° 02<sup>0</sup> E and 29° 51<sup>0</sup> N–79° 51<sup>0</sup> E is located in the Kumaon Lesser Himalaya (**Figure 1**). The Kosi River flows North– South in the northern and southern parts of the watershed while in the middle part, it follows the East–West trend incising the bedrocks and forming broad valleys, strath as well as unpaired terraces. The Kosi River mainly receives its water from several springs, aquifers, and tributaries in its course. Kosi river watershed falls within Almora and Nainital districts of Uttarakhand. The word Kosi refers to "river." Kosi is a Himalayan river that originates from Koshimool near Kausani and flows in the central part of Almora and the western part of Nainital district. River Kosi has the total catchment area of 3,420 sq. km. Kumaon is a mountainous region of eastern Uttarakhand in India. This region consists of the great Himalayan tract. Many rivers and their tributaries got their course from Kumaon. Four major rivers Kali, western Ramganga, Kosi, and Gaula make the surface drainage of Kumaon Himalaya. Kosi is the main river of Almora and Nainital districts. It is an important river flowing in the hills of the Kumaon region and drains central part of Almora and western part of Nainital district. The soil of the watershed falls under the loamy to clay categories. The major agricultural crops in the watershed are wheat, paddy, barley, pulses, and vegetables. The study area is also rich in the temperate horticulture fruit crops.

**Figure 1.** *Kosi river basin.*

The average annual rainfall at different locations of the watershed ranges from 850 to 1100 mm. About 75% of annual rainfall is received between June and September due to southwest monsoon. The river Kosi is the major source of water supply to cities of Almora, Pithoragarh, and other cities in the Kumaon region of Uttarakhand.
