Loktak Lake

Loktak Lake, situated near Moirang in the Bishnupur district of Manipur, is the largest freshwater lake in northeastern India, with a water-spread area that fluctuates between roughly 250 and 500 square kilometres across seasons. The lake is fed principally by the Manipur River and its tributaries and historically functioned as a natural flood-balancing reservoir for the Imphal valley. Its legal and conservation significance rests on its designation as a Wetland of International Importance under the Ramsar Convention on Wetlands of 1971; India listed Loktak as Ramsar Site No. 463 on 23 March 1990, recognising it as a representative example of a natural freshwater lake supporting distinctive biodiversity and the livelihoods of fishing communities. The lake is governed domestically through the Manipur Loktak Lake (Protection) Act, 2006, which established a statutory authority for its management and conservation.

The most distinctive ecological feature of Loktak is the phumdi — heterogeneous masses of floating vegetation, soil, and organic matter at various stages of decomposition that drift across the lake surface. These floating biomass islands range from thin mats to thick, walkable platforms several feet deep, and they are the structural foundation of the lake's unique ecosystem. The largest contiguous phumdi forms Keibul Lamjao National Park, the world's only floating national park, gazetted in 1977 over an area of approximately 40 square kilometres. The phumdi support grasses on which herbivores graze and provide the substrate for traditional fishing practices, including the construction of circular enclosures known as athaphum used by local fishers to corral fish.

Keibul Lamjao is the last natural habitat of the sangai (Rucervus eldii eldii), the Manipur brow-antlered deer, often called the dancing deer for its careful gait across the springy phumdi. The sangai is the state animal of Manipur and is classified as Endangered on the IUCN Red List; its population, which fell to near extinction in the mid-twentieth century, has been rebuilt under protected management to several hundred individuals. The deer's survival is biologically tied to phumdi thickness: when floating mats thin below roughly one metre, the animals cannot bear their own weight, linking the species' fate directly to the lake's hydrology and nutrient balance.

The hydrology of Loktak was transformed by the commissioning of the Loktak Hydroelectric Project in 1983, operated by the National Hydroelectric Power Corporation (NHPC), with an installed capacity of 105 megawatts at the Leimatak power station. The associated Ithai Barrage, built downstream at the confluence of the Manipur and Khuga rivers, maintains an artificially elevated and stabilised water level to ensure year-round generation. This barrage eliminated the lake's natural seasonal drawdown, which historically dried and compacted the phumdi against the lakebed during the dry season, allowing the floating mats to draw nutrients from the substrate. Permanent inundation has caused phumdi to thin and degrade, threatening the very ecosystem the lake's Ramsar status protects.

Loktak should be distinguished from adjacent conservation concepts. Unlike a wildlife sanctuary, Keibul Lamjao holds the higher protection status of a national park under the Wildlife (Protection) Act, 1972, prohibiting most human exploitation within its boundaries. Loktak's Ramsar listing differs from a UNESCO World Heritage or biosphere reserve designation: Ramsar is a wetland-specific intergovernmental treaty obligation focused on wise use, not a UNESCO instrument. The lake's most consequential international flag, however, is its placement on the Montreux Record — the Ramsar register of listed wetlands where ecological character has changed, is changing, or is likely to change as a result of human interference. Loktak was added to the Montreux Record on 16 June 1993, principally due to deforestation in the catchment, siltation, and the hydrological disruption from the Ithai Barrage.

Controversy surrounds the trade-off between power generation, conservation, and the rights of the lake's resident fishing communities. The Loktak Development Authority's clearance and demolition of floating huts and phumdi-dwellings in November 2011, conducted under provisions of the 2006 Act, displaced fishing families and drew sustained criticism from civil-society groups who argued the operation criminalised traditional livelihoods while leaving the upstream hydropower regime untouched. Debates persist over whether decommissioning or seasonally operating the Ithai Barrage could restore natural drawdown without sacrificing electricity supply to a power-deficit state. Catchment degradation, nutrient loading from agriculture, and proliferation of invasive aquatic weeds and unmanaged phumdi continue to be flagged in successive monitoring assessments.

For the working practitioner — particularly the civil-services aspirant preparing General Studies Paper III on environment and the journalist or desk officer tracking northeastern ecology — Loktak is a compact case study in the tension between development infrastructure and treaty-bound conservation. It illustrates how a single engineering intervention can trigger an international flagging mechanism (the Montreux Record), how domestic wetland legislation interacts with community land and water rights, and how a flagship endangered species can become an index of ecosystem health. Loktak recurs in examination questions on Ramsar sites, floating ecosystems, and human–wildlife conflict, and it remains a live policy file in Manipur where water-level management, livelihood protection, and biodiversity restoration are still being reconciled.