|Central coordinates||77o 42.00' East 30o 26.00' North|
|IBA criteria||A1, A4i|
|Year of IBA assessment||2004|
Site description The Asan Barrage, near village Dhalipur 38 km from Dehra Dun, is located at the confluence of the Yamuna hydel canal (from Dak Pathar which was built in the mid 1970s) and river Asan (a small rainfed tributary of the Yamuna). It is under the control of the Irrigation Department and has an area of 250 ha. When the water level is low, it provides good habitat for waterfowl. The dominant aquatic vegetation comprises of Potamogeton pectinatus, Typha elephantina and Ceratophyllum demersum. The southern side of the barrage is surrounded by agricultural fields. Further south, there is mixed forest typical of the Siwalik hills, consisting chiefly of Shorea robusta, Anogeissus latifolia, Lannea coromandelica, Dalbergia sissoo and Bombax ceiba. Some parts of the reservoir are covered by weeds Eichhornia crassipes and Ipomea fistulosa (Kumar and Porwal 1998).
AVIFAUNA: This IBA has a 30-year old nesting site of the Vulnerable Pallas’s Fishing Eagle Haliaeetus leucoryphus. During winter, it is not unusual to count up to 5,000 waterfowl, with high species diversity, as Asan Barrage has both shallow and deep water and the River Yamuna flows close by. Brahminy Duck Tadorna ferruginea, Mallard Anas platyrhynchos, Red-crested Pochard Rhodonessa rufina, Common Pochard Aythya ferina, Tufted Pochard A. fuligula, Wigeon Anas penelope, Northern Shoveller A. clypeata and Common Teal A. crecca are commonly seen. It is one of the best sites for large congregations of Brahminy Ducks (Kumar and Porwal 1998) and other birds (Gandhi and Singh 1995a, b and Singh 2000). On 12 February, 2003, more than 2,000 were seen (Arun P. Singh pers. comm. 2003). The 1% threshold for this species is 500 (Wetlands International 2002) so the population in this IBA exceeds the threshold four times, thus this site also qualifies A4i criteria. Raptors recorded in this IBA include the Osprey Pandion haliaetus, Marsh Harrier Circus aeruginosus, Steppe Eagle Aquila nipalensis, Oriental Honey Buzzard Pernis ptilorhynchus and Changeable Hawk Eagle Spizaetus cirrhatus. Being located towards the northwest and serving as a halt for Trans-Himalayan migratory birds, the Asan Barrage receives waterfowl migrants which are rare elsewhere. These include the Black-necked Grebe Podiceps nigricollis and Great Crested Grebe P. cristatus. Other rare records include Common Shelduck Tadorna tadorna, Black-necked Stork Ephippiorhynchus asiaticus, and Black-bellied Tern Sterna acuticauda. Altogether, more than 150 species have been recorded in this IBA, including many globally threatened and Near Threatened ones.
OTHER KEY FAUNA: Except for Common Otter Lutra lutra, there is no mammal of conservation concern. The Fishing Cat Prionailurus viverrina could be present but there are no confirmed record.
|Species||Season||Period||Population estimate||Quality of estimate||IBA Criteria||IUCN Category|
|Baer's Pochard Aythya baeri||winter||2004||present||-||A1||Critically Endangered|
|Ruddy Shelduck Tadorna ferruginea||-||2004||present||-||A4i||Least Concern|
|Marbled Teal Marmaronetta angustirostris||winter||2004||present||-||A1||Vulnerable|
|Pallas's Fish-eagle Haliaeetus leucoryphus||resident||2004||present||-||A1||Vulnerable|
|White-rumped Vulture Gyps bengalensis||non-breeding||2004||present||-||A1||Critically Endangered|
|Greater Spotted Eagle Clanga clanga||winter||2004||present||-||A1||Vulnerable|
|Slender-billed Vulture Gyps tenuirostris||non-breeding||2004||present||-||A1||Critically Endangered|
|2003||high||not assessed||not assessed|
|Good - based on reliable and complete / representative data|
|Biological resource use||hunting & collecting terrestrial animals - intentional use (species being assessed is the target)||happening now||some of area/population (10-49%)||slow but significant deterioration||medium|
|Human intrusions and disturbance||recreational activities||happening now||some of area/population (10-49%)||slow but significant deterioration||medium|
|Human intrusions and disturbance||work and other activities||happening now||some of area/population (10-49%)||slow but significant deterioration||medium|
|Invasive & other problematic species, genes & diseases||invasive non-native/alien species/diseases - named species||happening now||some of area/population (10-49%)||moderate to rapid deterioration||high|
|Natural system modifications||dams & water management/use - abstraction of surface water (agricultural use)||likely in long term (beyond 4 years)||majority/most of area/population (50-90%)||slow but significant deterioration||medium|
|Pollution||agricultural & forestry effluents - soil erosion, sedimentation||happening now||majority/most of area/population (50-90%)||moderate to rapid deterioration||high|
|IUCN habitat||Habitat detail||Extent (% of site)|
|Artificial - aquatic||-|
|Artificial - terrestrial||-|
|Land-use||Extent (% of site)|
Acknowledgements Key contributors: Arun P. Kumar, Dhananjai Mohan and S. S. Gandhi.
Gandhi, S. S. and Singh, S. K. (1995a) Avifauna of Asan Barrage. Cheetal 34(1): 29–34.
Gandhi, S. S. and Singh, S. K. (1995b) Birds at Asan Baraj. Newsletter for Birdwatchers 35: 65–68.
Kumar, A. and Porwal, M.C. (1998) Habitat evaluation of migratory waterfowls using remote sensing techniques. Project Report, Zoological Survey of India and National Remote Sensing Agency, Dehra Dun. Pp. 1-20.
Singh, A. P. (2000) Birds of the lower Garhwal Himalayas: Dehra Dun valley and neighbouring hills. Forktail 16: 101–123.
Wetlands International (2002) Waterbirds Population Estimates: Third Edition. Wetlands International Global Series No. 12, Wageningen, The Netherlands.
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