Asan Barage Bird Sanctuary is situated in the Districts of Dehradun and recently declared as a Bird Sanctuary. The wetland at Assan Barrage, is situated near the confluence of two rivers Assan and Yamuna. It's a paradise for the Bird Watchers. The Assan Reservoir is a small man-made wetland of Approx. 4 SQ. K.M. area. Assan Barrage serves as a winter passage halt for trans-Himalayan migratory birds. These birds are spotted here on their way to southern India (October-November) and again on their way back (late February-March).

Temperature : summer, max.38o C, min. 14o C; winter max. 21o C, min. 2o C
Average Rainfall : 250 cm; South West monsoon during June to September.

Birding Season
Arrival & Departure
October November December March-end
Or Early April, Sometimes April- end

The Asan reservoir exists throughout the year and is fed from the river Asan and the discharge channel of Yamuna through Dhalipur powerhouse. Although the water level is controlled, it often goes down, and swampy islands in the middle become visible, attracting a variety of marsh-loving birds like Egrets, Herons and Lapwings, etc.

Wildlife Species
At the Asan Barrage Bird Sanctuary a total number of 53 species of water birds visit the Asan reservoir, of which 19 are winter migrants from Eurasia. During winter months 90% of the waterbird population comprises of 11 migratory species, namely Brahminy Duck, Pintail, Red Crested Pochard, Shoveller, Tufted Duck , Mallard, Coot, Wigeon, Common Teal, Common Pochard and Gadwall. The Asan reservoir exists throughout the year and is fed from the river Asan and the discharge channel of Yamuna through Dhalipur powerhouse. Although the water level is controlled, it often goes down, and swampy islands in the middle become visible, attracting a variety of marsh-loving birds like Egrets, Herons and Lapwings etc.

Vegetation & Flora
The aquatic vegetation of the reservoir consists of Eichhornia crassips, Potamogeton pectinatus, Typha elephantina, and Ceratophyllum demersum. The surrounding bushes include Xanthium strumarium, Eclipta prostrata, Ipomoea sp., Mimosa pudica, Achyranthus aspera, Polygonum glabrum, P. lanigerum, Aeschynomene sp., Ageratum conyzoides, phyllanthus sp., Monochoria hastata, Mosla dianthera, and Lantana camara. On the southern side, agricultural fields surround the barrage. Further south there is mixed forest in Siwaliks comprising principally Shorea robusta, Anogeissus Latifolia, Lannea coromandelica, Dalbergia sissoo, and Bombax ceiba.