Thursday, August 9, 2012

Loktak Lake, Manipur

Loktak Lake is the largest fresh water lake in Northeast India. It is located in the state of Manipur. Loktak Lake is known as the only floating lake in the world due to the floating phoomdis on it. It has an area of 300sq km and has been recognised as Ramsar site in 1990. The lake is referred to as the “lifeline of Manipur” because the lake is highly productive and many lives depend on the lake for endurance. The lake is also an Important Bird Area as it’s a potential breeding site for waterfowl and is a staging site for migratory birds. There are varied types of habitat supported by lake due to which the lake is blessed with rich diversity flora and fauna. 

Etymology of Loktak: Lok = "stream" and tak = "the end". The place where streams end.

The thick band of phoomdis towards north of Loktak Lake maintains the water quality and also acts as sink for important nutrients like N, P, K and for carbon sequestration. The floating wetland is the most productive ecosystems as it provides source of living to people. The lake is also potential breeding site of many birds, fishes, amphibians and Sangai. The phoomdis are vital habitats for Sangai whose hooves are adapted to move over phoomdis. The lake also regulates the local climate of the state, apart from this it recharges ground water, retains storm water, dilutes the pollutants for maintaining the water quality.

The Loktak Lake is highly productive aquatic ecosystem known for its biodiversity and habitat diversity. There are varied types of habitat supported by lake as phoomdis which is heterogeneous mass of soil, vegetation and organic matter, rooted floating plants which is today threatened by proliferation ofphoomdis, open water habitat which is also threatened by phoomdis, shallow water areas, peripheral dyke fish-farming areas and these varied habitats provide services to local people. 

The lake is economically important for being the largest source of many commercially important species of fishes and edible aquatic plants which include Trapa natans bispinosaEuryale feroxZizania latifolia,Alpinia allughasNymphea albaN.stellata while the plants like Phragmites karka, Erianthus are used for roofing and Leersia hexandraSacciolepis myosuroides are used as fodder. The plants species constituting phoomdis are used as fodder, food, and fuel, hut construction, fencing and medicinal purpose especially the veterinary medicines, handicrafts. The lake is an important economic resource through the provision of irrigation for 24,000ha farming fields, hydropower, drinking water to city dwellers and fisheries. The fishing in lake is accomplished through the age-old method of aggregation and capture by man-made floating islands called Phoom or Phoomdis. The fishermen community is called Ngameese who live in floating huts called phumsang constructed on phoomdis. The phoomdis support large congregation of migratory, pelagic and resident fishes which use these floating islands as potential breeding grounds. The lake has recreational significance as it is a famous tourist spot due to its serene beauty.

The lake is now endangered with a number of threats:

1. Siltation: due to excessive deforestation in adjoining hills and shifting cultivation (jhum) along the catchment area
2. Eutrophication: the lake is eutrophic due to increased loading of P,N into lake caused due to dumping of domestic waste, inflow of organochlorine pesticide from paddy fields
3. Pollution:  untreated industrial waste which has resulted into increased growth of macrophytes, phytoplanktons and thereby escalating water pollution.
4. Loktak Hydroelectric Power Plant:  The impacts of Loktak Hydel Project includes inundation of agricultural fields of catchment area, decline in diversity of avifauna and pisces, thinning of phoomdiswhich threatens the potential habitat of Sangai deer, and siltation due to outflow of silt- laden water.
5.  Encroachment for agricultural activities and fish farms.

*Phoomdis: Heterogeneous mass of vegetation, soil, and organic matters at various stages of decomposition.


Information provided by NECEER, Imphal