Loktak Lake & Floating Islands: Manipur Travel Guide

Loktak Lake sits in the southern part of Imphal Valley in Manipur at approximately 768 meters above sea level, covering an area that fluctuates between 266 and 500 square kilometers depending on seasonal water levels. The lake is the largest freshwater body in Northeast India and serves as the primary water source for hydropower generation, irrigation, and drinking water for Imphal and surrounding districts. The Manipur River flows through the lake, which receives water from multiple tributaries including the Nambul River, Nambol River, Ungamel River, and several smaller streams draining the surrounding hills. The lake's surface is marked by circular masses of vegetation, soil, and organic matter called phumdis, which float on the water and rise and fall with changes in water level. These phumdis range in thickness from several centimeters to over two meters and are composed primarily of decomposed plant material, living root systems, and soil held together by the rhizomes of wetland plants.

The formation of phumdis occurs through natural processes where vegetation grows on the lake bed during periods of low water, and when water levels rise the buoyant root mats detach and float to the surface. The largest phumdi measures approximately 40 square kilometers and supports Keibul Lamjao National Park, the only floating national park in the world and the last natural habitat of the Sangai, or Manipur brow-antlered deer. The Sangai population numbered fewer than 20 individuals in the 1950s but has recovered to approximately 260 animals as of recent wildlife census data, though the species remains classified as Endangered by the International Union for Conservation of Nature. These deer have adapted to the floating substrate, walking on the phumdis with splayed hooves that distribute their weight across the vegetation mat. The park covers 40 square kilometers of the southeastern portion of Loktak Lake and was designated a national park in 1977 after serving as a wildlife sanctuary since 1966.

The lake supports approximately 233 species of aquatic plants, 100 species of birds, and 425 species of animals including 54 mammal species and 45 fish species. Migratory waterfowl arrive during winter months, including the northern pintail, common teal, and spot-billed pelican. The endemic fish species include Pengba (Osteobrama belangeri), which holds cultural significance in Manipuri cuisine and religious practices. Local communities have traditionally fished the lake using methods adapted to the phumdi environment, constructing temporary fishing huts on the floating masses and using conical bamboo traps called phabum. The fisheries support approximately 55 fishing villages around the lake perimeter, with an estimated 100,000 people depending directly on the lake for their livelihoods.

The construction of the Ithai Barrage at the southern outlet of the lake in 1983 fundamentally altered the lake's ecology by maintaining artificially high water levels year-round to support the Loktak Hydroelectric Project. Before the barrage construction, seasonal water level fluctuations averaged three meters annually, allowing phumdis to ground during the dry season and enabling the decomposition of organic matter and the regeneration of vegetation. The fixed water level maintained by the barrage prevents this natural cycle, causing phumdis to remain permanently floating and leading to the accumulation of decomposing organic matter that increases water acidity and reduces dissolved oxygen levels. The lake's pH has shifted toward acidic conditions, and dissolved oxygen concentrations in some areas have dropped below levels necessary to support fish spawning. The area covered by phumdis has increased from approximately 165 square kilometers in 1967 to over 400 square kilometers in recent assessments, with much of this increase consisting of dead and decomposing vegetation rather than the living root mats that characterized traditional phumdis.

The hydroelectric project generates 105 megawatts of power using water released from the barrage, supplying electricity to Imphal and surrounding areas. The project operates as a run-of-river scheme, meaning water flows through turbines rather than being stored in a large reservoir, but the barrage structure itself functions as a control point that maintains lake levels approximately 1.5 meters above the historical average. This elevation has inundated agricultural land around the lake perimeter and submerged structures in lakeside villages. Legal challenges to the barrage operations have proceeded through Indian courts since the 1980s, with affected communities arguing that the structure violates their traditional rights and damages the lake ecosystem. The Supreme Court of India and the National Green Tribunal have issued multiple orders directing restoration efforts, but implementation remains contested due to conflicts between hydropower production requirements and ecological restoration goals.

The traditional lifestyle of the Loktak fishing communities involves living on phumdis in structures called phumshangs, which are small huts built on wooden platforms anchored to the floating vegetation. These dwellings allow year-round access to fishing grounds and serve as temporary residences during intensive fishing seasons. The communities practice a form of aquaculture called athaphum cultivation, where they clear sections of phumdi to create open water enclosures for raising fish. The fish are fed with aquatic vegetation and kitchen scraps, and the enclosures are harvested after several months of growth. This practice has expanded significantly since the barrage construction made it possible to maintain stable water levels conducive to aquaculture, but it also contributes to phumdi proliferation and water quality degradation as excess feed and fish waste accumulate.

The Sangai's diet consists primarily of plants found on and around the phumdis, including various grasses, reeds, and aquatic vegetation. The deer feed during early morning and late evening hours, spending midday resting on the denser sections of phumdi that support their weight. Males develop antlers with brow tines that curve forward in a distinctive pattern that gives the species its common name. The breeding season occurs from October to February, with females giving birth to single fawns after a gestation period of approximately seven months. Predation pressure within Keibul Lamjao National Park remains low, but habitat degradation from changing phumdi composition poses the primary threat to population recovery. The park's management plan includes anti-poaching patrols, habitat monitoring, and efforts to control phumdi proliferation in core Sangai habitat areas.

The lake plays a central role in Manipuri cultural and religious life, particularly during the annual Moirang Lai Haraoba festival, which celebrates pre-Hindu indigenous deities and includes rituals performed on the lake. The festival occurs during April and May and involves processions of traditional dancers and musicians who travel by boat to specific locations on the lake considered sacred. The Loktak Development Authority, established by the Government of Manipur in 1987, holds responsibility for coordinating conservation and development activities around the lake. The authority's mandate includes controlling phumdi growth, managing water quality, regulating fishing practices, and implementing community-based conservation programs. Phumdi removal operations began in the 2000s using mechanical harvesters and manual cutting, but the rate of removal has not kept pace with new phumdi formation, particularly in areas where nutrient loading from agricultural runoff and sewage discharge accelerates plant growth.

Water quality monitoring conducted by research institutions including the Indian Institute of Technology Guwahati and Manipur University has documented declining dissolved oxygen levels, increasing biochemical oxygen demand, and elevated concentrations of nitrogen and phosphorus compounds indicative of eutrophication. The lake receives untreated sewage from Imphal city through the Nambul River, which enters the lake on the western side. Industrial discharge from small-scale manufacturing units and agricultural runoff containing fertilizers and pesticides further contribute to nutrient loading. The Government of Manipur has initiated sewage treatment infrastructure projects for Imphal, but most domestic wastewater continues to flow directly into tributaries feeding the lake.

The communities around Loktak have organized collective action groups to advocate for lake restoration and to participate in management decisions. The Loktak Lake Peoples' Movement and the All Loktak Lake Areas Fishermen's Union represent fishing communities in negotiations with government authorities and hydropower operators. These organizations have documented changes in fish populations, water quality, and fishing yields through participatory monitoring programs. Traditional fish species that require flowing water for spawning, including several cyprinid species, have declined substantially, while species tolerant of low oxygen conditions have increased. The introduction of exotic species including common carp and tilapia for aquaculture has altered the lake's fish community structure, with introduced species now comprising a significant proportion of total fish biomass.

Tourism infrastructure around Loktak Lake includes the Sendra Island tourism complex on the northeastern shore, accessible by road from Imphal approximately 48 kilometers away. The complex offers boat services to Keibul Lamjao National Park and viewpoints overlooking the phumdi-covered lake surface. The Manipur Tourism Department operates guided tours during winter months when migratory birds arrive and weather conditions favor wildlife viewing. Visitor numbers remain modest compared to other Northeast India destinations, partly due to restrictions on movement within some areas of Manipur that require permits for non-residents. The Sangai is the state animal of Manipur and appears on government symbols and cultural emblems, making Loktak Lake and Keibul Lamjao a point of regional identity.

Scientific research on Loktak's ecology has intensified since the 1990s, with studies examining phumdi dynamics, fish population genetics, bird migration patterns, and the impacts of water level regulation on wetland vegetation. Remote sensing analysis using satellite imagery has tracked changes in phumdi coverage and water extent over multiple decades. Core samples taken from phumdi mats reveal layers of organic accumulation that provide a chronological record of vegetation composition and environmental conditions. Pollen analysis from these cores indicates shifts in plant communities corresponding to changes in water level management. The lake's importance for biodiversity led to its designation as a Wetland of International Importance under the Ramsar Convention in 1990, and it was included in the Montreux Record in 1993 due to ecological degradation, though it was later removed from the Montreux Record in 2013 following reports of management improvements.

The future of Loktak Lake depends on balancing hydropower production requirements, ecological restoration goals, and the livelihoods of dependent communities. Proposed management interventions include modifying barrage operations to allow seasonal water level fluctuations that approximate natural conditions, expanding sewage treatment capacity for Imphal, implementing nutrient reduction programs in the watershed, and creating alternative livelihood opportunities for fishing communities affected by reduced fish yields. The political and economic complexity of these interventions means that implementation timelines remain uncertain, while the lake's ecological trajectory continues toward conditions increasingly different from its historical state.