The Asan Barrage is a barrage suited in the Uttarakhand-Himachal Pradesh border region of the Dehradun District, Uttarakhand. Barrage means a type of low-head diversion dam which includes several large gates that can be opened or closed to control the amount of water passing through.
The barrage is 287.5m long and contains water fed from the river Asan and the discharge channel of the river Yamuna. It was declared a Ramsar Site on July 21, 2020, making it the first protected site of Uttarakhand.
History of the Place
Asan Barrage was constructed from 1965 to 1967 by the UP Irrigation Department. It is named after the Asan river.
Asan Barrage, also spelled- Assan or Aasan Barrage, was created in 1967 as a small man-made wetland on the confluence of two mighty rivers, namely Eastern Yamuna and Asan river. Since it is located near Dhalipur Power Plant, it is sometimes referred to as Dhalipur lake.
The barrage is flocked by many birds, some of which are globally endangered species that are listed in the International Union for the Conservation of Nature and Natural Resources (IUCN) Red Data Book.
The Reservoir is a small wetland of approximately 4 square kilometers with a 403.3 m maximum water level. The official name of this Ramsar Wetland is Asan Conservation Reserve. The barrage is also called Dhalipur Lake.
Access to the Wetland
Assan Barrage has located about 40 km from Dehradun. The best month to visit this place is October, November, February, and March. The Jolly Grant Airport in Dehradun is the nearest airport to the site. This is only 28 kilometers from the place. The nearest railway station to reach the place is through the Dehradun Station, which is only 2 kilometers away.
Public and private buses are available. The barrage is open from 8 am to 6 pm throughout the week.
Topography of Area
The length of the dam is 287.5 m (943 ft). The Reservoir surface area is almost 4 km2 (2 sq mi).
Geology of Area
According to the geographical coordinate system, the place is located at 30°26′09″N 77°39′56″E. Assan Barrage experiences a pleasant climate, with a maximum of 38° C to a minimum of 14°C temperature during summer.
Monsoon in Assan Barrage is from June to September with 250 cm rainfall. Winters are fascinating for bird lovers with chill weather, with a maximum of 21°C to a minimum of 2°C during winter.
Hydrology of the Land
The catchment area at the barrage site is 685 sq km. Water from this river is used in hydroelectricity. Hence, it has turbines: the Kushal, a 3 x 10 MW Kaplan-type, and the Khara, a 3 x 24 MW Francis-type.
The water regime remains almost stable. There is a continuous impoundment of water. The Reservoir’s water level is maintained and regulated to supply water to two downward hydropower stations.
The site lies in the foothills of the outer Himalayas, hence the surface is bouldery and sandy. The flowing water recharges the groundwater.
Aquatic vegetation of the Reservoir includes Eichhornia crassipes, Potomageton pectinatus, Typha elephantine, and Ceratophyllum demersum. Surrounding bushes include Ipomea fistulosa and Lantana Camara.
On the southern side agricultural field surrounds the barrage. There is a mixed forest in Siwaliks comprising of Shorea robusta, Anogeissus latifolia, Lannea coromandel, Dalbergia sissoo, and Bombax ceiba.
The damming of the river and consequent siltation above the dam wall has developed a satisfactory environment for avian species.
Asan wetland is home to around 330 species of birds (including some rare species). Critically endangered species that can be found in the area are white-rumped vulture (Gyps bengalensis), Red-headed vulture (Sarcogyps calvus), and Baer’s pochard (Aythya baeri).
Almost 53 species of water birds can be found here, including red-crested poacher, mallard, coot, pintail, common teal, tufted duck, and so on. These species are frequented by almost nineteen European and Asian migratory birds. Birds like Shoveller, Mallard, Red Chested Poacher, Ruddy Shelduck, Wagtails, Coot, Pochards, Pintail, Wigeon, Gadwalls, Tufted Duck, and Teals, etc. are some of the common visitors.
From May to September, the area caters to local migratory birds like Painted Stork, Open Billed Stork, and Night Heron.- crested pochard. A total of 49 fish species have been known to inhabit the site, and it serves as feeding, migration path, and spawning ground.
Islands in the Lake
The are no islands in the lake but a dam developed the Asan Reservoir. It is also called Dhalipur Lake. Asan barrage has been built across river Asan, a major tributary of River Yamuna in Dehradun District of Uttrakhand.
Economic Evaluation of the Lake’s Resources
Tourism around this place helps the residents to fulfill their financial needs. Bird Watching Safari was mostly preferred by the visitors. The fishery also plays a vital role.
Asan Conservation Reserve has multiple tenures. Despite having a very small area, several agencies control or use the land resources of the Reserve. These include the Uttarakhand Jal Vidyut Nigam Limited (UJVNL), the Forest Department, the Forest Development Corporation, the Tourism Department (through Garhwal Mandal Vikas Nigam), surrounding villages that own some areas of the Reserve as Gram Samaj lands, and private landowners practicing subsistence agriculture on the land pattas allotted to them.
Deterioration of the lake environment
According to the Times of India, these are the major threat to the Dam.
- Uncontrolled siltation and weed infestation
- Uncontrolled discharge of wastewater
- Industrial effluents
- Surface run-off results in the proliferation of aquatic weeds, which adversely affect the flora and fauna
According to one report of WWF, 70 percent of wetlands in the state have degraded due to negligence. Excessive tourism pressure with trekkers camping at the site, spreading filth and pollutants in the water body. On top of that, extreme grazing pressure by shepherds has contributed to the destruction of these wetlands.
Asan Barrage Conservation Reserve was declared a ‘Wetland of International Importance’ under the Ramsar Convention. It’s the 38th site to get this recognition in India. This will protect the birds from the hunters.
The aim of the Ramsar list is “to develop and maintain an international network of wetlands which are important for the conservation of global biological diversity and sustaining human life through the maintenance of their ecosystem components, processes, and benefits”.
There is also an ongoing special rehabilitation work of Asan barrage and other associated structures. Construction of bridge (35 m span, steel girder bridge over land owned by UJVN Ltd) across power channel & parallel to HR bridge of Asan barrage has also begun.
The conservation plan also includes repairing the damaged portions of the power channel and repairing pitching on both banks.
Major repair/refurbishment of hoisting arrangement of HR gates of the barrage is ongoing.
Providing and fixing chequered plates at Hoist Bridge of barrage gates and HR gates, including miscellaneous fabrication and protective coating (cold galvanized/polypoxy coating) on barrage and head regulator gates at Asan barrage, are also part of the plans.