Issues of Wetlands in Manipur
Major issues of the wetlands in Manipur are
- discharge of urban wastes through urban drains;
- increase of eutrophication (nutrients);
- silt accumulation;
- rapid increase and expansion of Phumdi distribution;
- high counts of E- coli & Faecal contamination;
- illegal encroachment;
- deforestation in catchment
- loss of wetland biodiversity;
- changes of wise use practices;
Management Action Plan :
Environmental Management Planning (EMP) is to ensure and effectively check from any further environmental degradation. It may be emphasized into two approaches as
1. Management based on standards, in which the polluters could choose a suitable technique for pollution control, based on their evaluation for technical feasibility and economic viability; and
2. Management based on best practicable means.
Moreover, strategic plan is to be adopted for its wise use and sustainable development as wetlands, through their ecological and hydrological functions, provide invaluable services, products and benefits to human populations. EMP should be made to ensure & promote proper functions and values of a wetland / lake for generations to come with conservation of biological diversity .
Manipur, though once reported to have about 155 marsh, peat, water reservoir, lake and wetlands, etc. making it a unique ecosystem that fulfills improvement functions in the overall water cycle of the basins, and providing habitats for wildlife, due to little attention given during past few decades in terms of their conservation and management, the number of these wetlands have become very few. However, they are becoming important day by day in view of the possible consequences of the climate change adaptation programmes and globalization in economic development. Conservation of these unique spaces are in needs of special effort by the whole society with both technical & financial supports/inputs.
In a case study of Loktak catchment, land wise use information had been laid down by using multi-temporal satellite data for a period of 12 years i.e. 1990 to 2002 (source : LRIS, Nov 2003, SAC, ISRO, Ahmedabad). In the report it was reflected to have the constant increase in built up land, dense forest & water bodies / aqua pond within the Loktak Lake catchment (Fig. 1.i, iv & v) along with salient decrease of wetland coverage (Fig 1.iii). The increase of water body distribution is stated to be mainly due to multipurpose hydro electric power projects in the lake. The tremendous increase in built up land is noted to have been alarmingly remarkable.
On the other hand, the critical issue for proliferation of phumdis (floating biomass) and weeds into the wetlands of the state has also been increasing to the tune of 2000 - 2500 ha per year, of which about 40%is represented only by dry phumdis. High concentration of nutrients (NPK) in the wetland leads to rapid proliferation of these phumdis in a fast manner. Contribution of excess quantity of nutrient load into the lake water from the urban wastes & agricultural residue runoff through its inlets including major streams may also be accountable upto a large extent.
Direct discharge of urban waste from Imphal city into the Loktak lake through Nambul River has become one of the cause for polluting the Lake. Nambul river having a total catchment area of 277.9 sq. km and total length of 54.70 km (including 8 km of Kangchup hill catchment) discharging at an average quantum of 380 (pre monsoon) to 740 (post monsoon) cumecs to the Loktak Lake. The river passes about 18.36 km in urban area of Imphal city and out of which a total length of about 4.75 km has been identified as polluted zone, touching 15 Municipal Wards. From these municipal wards, an estimated amount of 50.32 MT per day of urban solid waste and 15.97 MLD (approx.) of combine sewers as waste water are being received by the Nambul river directly and may or part of it ultimately taken to the Loktak Lake thereby deteriorating the Lake quality seriously
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In the quality analysis monitoring of the Nambul river at different monitoring station, BOD level has been found to have increased at a rate of 1.2 mg/l per year (1980s) and 1.8 mg/l per year since 1990s onwards. The average BOD load from 1990 to 2005 has been reported as 9.25 mg/l, 20.83 mg/l and 10.47 mg/l at the U/S, mid stream & D/S of the river, respectively. Besides BOD, about 25,000 TC/100 ml in the inlets of Nambul river within the core zone has been observed. Taking into account of the above estimated BOD load, nutrients, pathogens, expected heavy metals, etc. into the Loktak Lake from urban area through Nambul River, a strategic action plan for constant monitoring and covering all the physico-chemical parameters checking of the river water quality before it reaches the Loktak lake is the need of the hour. Due consideration for an integrated treatment approach like WSP (waste stabilization pond), techniques (tapping, treating & flow back after treatment), or any similar ones for the polluted outfalls, along with different programmes like solid waste management, catchment area treatment, river front development, low cost sanitation, environment education, may be given in order to improve / restore the Loktak Lake quality.