Rejuvenation of lakes


Bellandur lake in Bengaluru has been in the news in recent months for the surge of foam and froth from the polluted lake, and the rise of smoke and flames from the area surrounding it.


  • Due to heavy rainfall in the city, the stinking froth and foam rose as high as 10 to 12 feet from Bellandar and spread onto the streets, endangering traffic and entering shops and homes across the road, causing huge inconvenience.
  • In May 2015, the Bellandur lake was on fire, creating enormous fear and anxiety in the minds of the people living in the area.
  • The Central Pollution Control Board (CPCB) submitted a report to the Union Ministry of Environment, Forests and Climate Change, highlighting the sustained inflow of untreated sewage and industrial effluents as the principal forces behind the phenomena of froth and fire.
  • Subsequently, an expert committee set up by the state government submitted its report on rejuvenation of the lake in October 2016.

Why the condition of lakes is very unhealthy?

  • Out of 480 million litres per day (MLD) of wastewater discharged to the lake, only 308 MLD is treated.
  • According to the CPCB, 75 per cent of the measured pollution in our rivers from point sources is from municipal sewage and 25 per cent is from industrial effluents.
  • Wastewater or sewage (estimated as 80 per cent of the water consumed in the city) is typically under-estimated.
  • Untreated wastewater or sewage finds its way to local water bodies; it feeds the growth of water-weeds, which blankets surface water.
  • The huge roots of water hyacinth absorb impurities and can lock up pollutants in the water.
  • Surfactants are clearly a cause of foam formation.

Why there is need for rejuvenation of lakes?

  • Rejuvenation of lakes will help in rain water harvest and extend water security during non-rainy seasons.
  • It provides alternate opportunities like fishing and provides grazing area for livestock.
  • The beds of lakes and tanks over the period of time deposits soil rich in nutrient and humus due to the decomposition of organic matters, fishes and other water organisms. Such soils, having high water retention capacity, if used as top soil helps farmers also by reducing cost of fertilizers.
  • Lakes and tanks recharge ground water aquifers. This helps in tube well irrigation.
  • Social cohesion – Lakes exist as Common Property Resources.

Benefit to farmers:

  • Top soil of the dried lakes, ponds and tanks are rich in organic content (humus). Thus, dredged soil can be supplied to farmers which will give immense benefits like requirement of less or no nutrient inputs, high yields and good quality production
  • This soil can also be used to cover less fertility soils like red laterite soil for making them fertile and drought proof as this soil has good water retention capacity
  • Rejuvenation of lakes leads to groundwater replenishment with more percolation of water, and also increases water holding capacity – increases availability of water.

What are the impacts of polluted lakes ?

  • The microbes feeding on the rotting organic matter consume all the oxygen in the water, disturbing the ecology for the survival of fish life.
  • When such organic matter naturally breaks down, it releases fatty acids that float to the surface.
  • These act as natural surfactants, which allow minute bubbles to form which often persist for a long time. This is how foam is formed and turns into froth.
  • Phosphorus in detergents entered into wastewater which hugely promotes the growth of water plants.
  • Phosphorus is useful for agriculture, but it is directly responsible for choking our surface waters with aquatic vegetation

What are the solutions?

  • The National Green Tribunal turned its attention to the problems of the Bellandur lake in February, expressed extreme dissatisfaction on the unhealthy condition of the lake in its successive hearings.
  • The tribunal has issued a number of directions highlighting the solutions :
  1. The need for removal of silt from the lake
  2. Treatment of municipal sewage which is going into the water body
  3. Closure of polluting industries
  4. Ban on dumping of municipal solid waste around the lake
  5. Penalty on apartment buildings in the area which are sending untreated sewage to the lake and an environmental fine of Rs 5 lakh on anyone found dumping waste in and around the lake.
  • Recently, the NGT has asked all departments of the government to work together to prepare an Action Plan by September 7 for cleaning up the lake.
  • Adoption of rainwater harvesting and water saving
  • There should be strict ban on converting lake and other water reservoirs into construction ,road et
  • Government support for revival of all those lake and tanks which has been degraded in terms of 3F (fund ,function functionary)
  • Interlinking of perennial river to reservoirs by doing this we can recharge ground water along with irrigation
  • Use of satellite level of ground water
  • solar power plant can be set up on canal that will prevent water evaporation and land
  • There should be awareness in society regarding importance of ground water and convince term by EIBC( Education ,Information ,Behavior ,and communication
  • CSR , Panchyati raj ,MGNREGA, Block can give big boost up in terms of finance and man power

What India should learn from International examples?

  • In the late 1950s and the 1960s in the United States, lakes, rivers, and sewage treatment plants experienced foam formation, caused by synthetic laundry detergents that were highly resistant to chemical breakdown.
  • Now, by law, the lathering agent of all detergents on the market must be biodegradable. They therefore quickly lose their ability to cause foaming and are unable to produce long-lasting foam.
  • India also need to adopt the similar regulations that is, the surfactants in detergents must be biodegradable
  • The problem was first identified when Lake Erie, on the US-Canada border, turned green and its aquatic life began dying for want of oxygen, as dying plants sank to the bottom and rotted, consuming dissolved oxygen from the water. This is called eutrophication.
  • Both countries rapidly responded with an international treaty in 1970 which, has since 1973, limited the phosphorus content in their detergents to a maximum of 2.2 per cent.

What is the meaning of Eutrophication?

  • Eutrophication is an enrichment of water by nutrient salts that causes structural changes to the ecosystem such as: increased production of algae and aquatic plants, depletion of fish species, general deterioration of water quality and other effects that reduce and preclude use
  • Eutrophication is a form of water pollution, caused by excessive loading of dissolved and particulate organic matter and inorganic nutrients.
  • According to the survey of the state of the World’s lakes, a project promoted by the Internal Lake Environment Committee, Eutrophication affects 54% of Asian lakes, 53% of those in Europe, 48% of those in North America, 41% of those in South America and 28% of those in Africa.
  • The cultural eutrophication process consists of a continuous increase in the contribution of nutrients, mainly nitrogen and phosphorus (organic load) until it exceeds the capacity of the water body (i.e. the capacity of a lake, river or sea to purify itself) , triggering structural changes in the waters.

What are the problems in India?

  • India has no mandatory rules limiting phosphorus content in detergents and laundry bars.
  • Even the demand for detergents has grown at the rate of 10-11 per cent per annum between 2005 and 2010, and is likely to have been faster in the subsequent years because of rapid urbanisation.
  • The phosphorus content in the detergents in India is much higher than 2.2 per cent.
  • It is extremely important that a lower limit closer to the global norm is placed on phosphorus content and its labelling becomes mandatory for all detergents in the Indian market so that caring citizens can make eco-friendly purchasing choices.
  • Aquatic vegetation not yet covered by the rules under the Environment Protection Act 1986.
  • Waste management is critical — solid waste (garbage), liquid waste (sewage), and acquatic waste.
  • Additional challenges are posed by encroachment, which diminishes catchments for freshwater.
  • Urban planning in India must ensure that wetlands which are natural recharge zones are typically not disturbed.
  • Natural drains which provide a safe exit to storm-water including flood-water and also recharge ground water, should be protected from encroachment.

What are the measures adopted by government?

  • Dredging of dried lake beds and tank beds in the drought affected areas
  • Implementation of Wetland Conservation measures as per Ramsar Convention
  • Digging deep trenches surrounding the lakes to avoid waste dumping, especially in urban areas
  • Exclusive missions of various state governments like Mission Kakatiya of Telangana for rejuvenating lakes, ponds and tanks.
  • Rejuvenation works taken up under MGNREGA, PMKSY etc
  • New Municipal and Solid Waste Management Rules mandates segregation, recycling and reuse of waste, and emphasis on waste treatment before discharging.


Rejuvenation of lakes and tanks is an important step in recharging groundwater and fighting drought, especially in India.  Therefore, it is high time that the government should initiate strong steps to protect and rejuvenate all lakes and other existing water bodies.

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