Loktak Lake - WikiHQ

thumb|Loktak Lake in December 2016

thumb|Loktak Lake, December 2016

Loktak Lake () is the largest freshwater lake in Northeast India. It is a pulsating lake, with a surface area varying from 250 km2 to 500 km2 during the rainy season with a typical area of 287 km2. The etymology of Loktak is Lok = "stream" and tak = "the end" in Meitei language (Manipuri language).

The Loktak Day is observed every year on the 15th of October at the periphery of the Loktak lake, in Manipur.

This ancient lake plays an important role in the economy of Manipur. It serves as a source of water for hydropower generation, irrigation and drinking water supply. The lake is also a source of livelihood for the rural fishermen who live in the surrounding areas and on phumdis, also known as "phumshangs". Human activities have led to severe pressure on the lake ecosystem. 55 rural and urban hamlets around the lake have a population of about 100,000 people.

Considering the ecological status and its biodiversity values, the lake was initially designated as a wetland of international importance under the Ramsar Convention on 23 March 1990.

Geography

Topography

Of the two river systems, which drain the Manipur state—the Barak River and the Manipur River—the Manipur River flows through the Manipur Valley. The river rises in the north at Karong, flows south of Imphal and hence is also known as the Imphal River. Along its course through the valley downstream of Imphal, the bed slope of the river is gentle. The drainage pattern is sub-dendritic, sub-parallel and sub-radial, dictated by the structure and lithology of the area. Imphal, Iril and Thoubal River valleys also exhibit a meandering river course. The area of the lake is , comprising large pockets of open water and marshy land formed at the southern part of the Imphal valley up to the confluence of Manipur River and Khuga River in the district of Imphal West. The Lake is divided into two zones, namely, the "Core Zone" which is the no-development zone or totally protected zone comprising and the balance area is called the "Buffer Zone".

Within the lake and on its periphery, there are 14 hills of varying size and elevation; in the southern part of the lake are the Sendra, Ithing and Thanga islands.

Lake zonation

Geographically, in terms of biodiversity and pressure of human activities, the lake is broadly divided into northern, central and southern zones as elaborated below.

Climate

With an average annual rainfall of tropical monsoon climate prevails in the valley. Temperatures range from . February and March are the driest months.

Hydrology

The Loktak Lake is fed by the Manipur river and several tributaries and ‘Ungamel Channel’ (Ithai Barrage) is its only outlet now. The downstream Loktak Power Project in cascade to utilize the regulated releases from the upper project for further power generation of 90 MW is proposed to be taken up for joint implementation by NHPC and the Government of Manipur.

The project has invited severe criticism since the water level in the lake at the Ithai barrage is maintained throughout the year at FRL from considerations of power generation from the well planned water conductor system. The problem in the lake is, however, diverse; economic activities in and around the lake, and encroachments by 50,400 fishermen for extensive fishing activity are also cited to be some reasons. Other reasons for the distress situation in the lake are a) jhum (shifting) cultivation, b) extensive deforestation and unscientific land use practices in the catchment areas which bring large amount of silt into the lake and c) undefined ownership of the lake where the stakeholders are the districts of Imphal west district, Bishnupur and Thoubal causing lack of integrated approach to the lakes potential for providing benefits. The lake’s rich biological diversity comprises 233 species of aquatic macrophytes of emergent, submergent, free-floating and rooted floating leaf types. Also recorded were 425 species of animals—249 vertebrates and 176 invertebrates). The list includes rare animals such as the Indian python, sambhar and barking deer. Keibul Lamjao National Park is the natural habitat of one of the most endangered deer, the brow-antlered deer (Cervus eldi eldi) which was once thought to be extinct, which was declared a national park only to preserve and conserve this species of Eld's deer.

;Aqua fauna

Fish yield from the lake is reported to be about 1,500 tonnes (6,600,000 lb) every year. The State Fishery Department has introduced millions of fingerlings of Indian and exotic major carps. Natural capture fishery without the requirement of any lease or licence was also in vogue in the lake. The lake fishery is now a mixture of capture and culture systems. Nine mini-hatcheries opened by the State Government has the capacity to produce one million fish fingerlings in a day. Fifty percent of the fingerlings produced were released into the Loktak Lake and the balance were distributed to beneficiary fishing committees. The new fish varieties introduced in lake were grass carp, silver carp and the old varieties of the local fishes like Channa punctata (ngamu), Anabas testudineus (ukabi), Anguilla (ngaril), pangba, tharak, and ngashap stated to be under serious decline.

;Fauna

thumb|right|Hoolock gibbon seen in the precincts of the Lake in the Keibul Lamjo National Park

Fauna recorded in the precincts of the Lake in the Keibul Lamjo National Park are the Indian python, sambar, barking deer, the endangered sangai species of Eld's deer, wild bear, Muntiacus muntjak, rhesus monkey, hoolock gibbon, stump-tailed macaque, Indian civet Viverra zibetha, marbled cat and Temminck's golden cat.

The degradation of the catchment area has occurred. Deforestation and shifting cultivation in the catchment areas have accelerated the process of soil erosion resulting in the lake’s shrinkage due to siltation. The annual silt flow into the lake is estimated to be 336,350 tonnes.

The nutrients from catchment area and domestic sewage from Imphal city carried by Nambul River are discharged into the lake affecting its water quality, thus encouraging the growth of water hyacinth and phumdis. All these activities have direct bearing on ecological stability of the lake. Interference in navigation and overall aesthetic value of the Lake are other reported adverse effects.

The thickness of phumdis has decreased in the Keibul Lamjao National Park thereby threatening the survival of sangai deer and interference in the migration of fishes from the Chindwin–Irrawaddy River system of Myanmar resulting in changes in the species composition.

Loktak Development Authority

To address all the issues raised on the health of the lake, as detailed above, Government of Manipur has set up the Loktak Development Authority (LDA) under "The Manipur Loktak Lake (Protection) Act, 2006 (Manipur Act 3 of 2006)" with the objective "to provide for administration, control, protection, improvement, conservation and development of the natural environment of the Loktak Lake and for matters connected with as incidental thereto."

Based on all the analysis, the future approach suggested involves mitigation measures as elaborated are: i) The Nambol River carries sewage of nutrients of Imphal town into the lake which results in prolific growth of phumdis and deteriorates water quality. This is an urban problem and there is urgent need to treat and control this aspect, even if it is expensive;

ii) Reduce soil erosion and sedimentation of the lake by enlarging the scope of micro-watersheds in the catchment area treatment plan;

iii) Construct a channel through the Keibul Lamjao National Park to enable phumdis to settle at the bed of the lake;

iv) Resolve the encroachment problem, by demarcating the lake boundary, which would result in a targeted and concerted action plan;

v) Implement action plans that are economically viable and technically feasible resulting in livelihood enhancement such as evolving an attractive resettlement plan for the phumdi dwellers backed by remunerative livelihood program; and

vi) Examine introduction of fishing net instead of Athapum (Athapam means phumdis in circular shape floating in the lake, planted or cultured artificially for catching fish) practiced presently to be dismantled. In November 2016, Environment ministry has taken keen interest in preserving loktak lake and has formed a panel of five members for this purpose.

thumb|Fishing on Loktak Lake

References

External links

The world's only floating national park – BBC Travel