The floating Paradise of Manipur
Loktak Lake is the largest freshwater lake
in North -East India is famous for the phumdis floating over it. Keibul Lamjao the only floating national park in the world floats over it.It is located near Moirang in Manipur state, India.
The etymology of Loktak is Lok = "stream" and tak = "the end". The Keibul Lamjao National Park, which is the last natural refuge of the endangered sangai or Manipur brow-antlered deer (Cervus eldi eldi), one of three subspecies of Eld's deer, covering an area of 40 km2 (15 sq mi), is situated in the southeastern shores of this lake and is the largest of all the phumdis in the lake.
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 fisherman who live in the surrounding areas and on phumdis, also known as “phumshongs”. Human activity has 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. It was also listed under the Montreux Record on 16 June 1993, "a record of Ramsar sites where changes in ecological character have occurred, are occurring or are likely to occur".
Topography and geography
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. Drainage pattern, typical of hilly terrain, is sub-dendritic, sub-parallel and sub-radial, which is dictated by the structure and lithology of the area. Imphal, Iril and Thoubal River valleys also exhibit a meandering river course.
At the Ithai barrage outlet of the Lake, the direct catchment area draining into the lake is 980 km2 (380 sq mi) out of which 430 km2 (170 sq mi) is under paddy cultivation, 150 km2 (58 sq mi) under habitation and 400 km2 (150 sq mi) under forest cover.The area of the lake is 236.21 km2 (91.20 sq mi), 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 70.3 km2 (27.1 sq mi) 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.[10]
The Northern Zone, extending from eastern side of Nambol River near Ngaikhong Khunou to Phabakchao including Maibam Phumlak, has five main streams/rivers namely the Manipur river, Nambul, Nambol, Thongjaorok and Ningthoukhong flowing into the lake. The zone is separated from the central zone by large phumdis (varying thickness of 0.4 to 4.5 m or 1.3 to 14.8 ft) that stretches from the northwest to the southeast. During January to March, phumdis in this area are usually burnt for construction of fish cum paddy farms; many large fish farms with raised levees have been built.
Phumdis in the Lake – circular ones, called athapums, are artificially created for fishing.
The Central Zone, extending from Awang Laisoi pat (western side of Nambol River near Ngaikhong Khunou) to Laphu pat (between Khordak channel and Imphal River) encloses prominent islands of Thanga, Karang and Ithing. It is the main open water zone of the lake, which was relatively free from phumdis in the past, but over the years 'athaphums' (artificially created phumdis for fishing) constructed by villagers for fishing have proliferated choking the entire lake. The State Fisheries Department has established a fisheries centre within this zone at Takmu pat for fisheries development
The Southern Zone encompasses the Keibul Lamjao National Park, Ungamel and Kumbi pats at the southern part of the lake and the zone is linked with Khuga River by the Ungamel channel. The Imphal River is also linked with this zone by the Khordak channel. The western catchment drained by the Kangshoibi River flows into this zone. Proliferation of phumdis has been observed near the mouth of Ungamel channel, Kumbi pat, Nongmaikhong and Khordak area.
Geology
Cretaceous limestone, the Disang with Serpentinites (Lower to Middle Eocene–Upper Cretaceous), the Surmas and the Tipams (Miocene) are the dominant rock formations in the catchment of the Manipur basin. Higher reaches of hills have the Disang and Tipam groups of rocks while Surma group occurs in the lower reaches. Grey sandstone–grit–conglomerate–limestone sequences intruded by serpentinites containing minor amounts of enstalite, chromite, amphiboles and magnetite constitute the Disang formation. Argillaceous and arneceous sequence represents the Surma and Tipam groups, respectively.
Climate
With an average annual rainfall of 1,183 mm (46.57 in) tropical monsoon climate prevails in the valley. Temperatures range from 0 to 35 °C (32 to 95 °F). February and March are the driest months.
