East Kolkata Wetlands

What is the issue?

The state government is planning a “proper utilisation” of the land currently lying along the east Kolkata wetlands.

What is Ramsar Site?

• The east Kolkata wetlands is the biggest ecological asset of the city and a Ramsar Site.
• A Ramsar Site is a wetland (shallow waters) which is designated to be of international importance under the Convention on Wetlands, an intergovernmental environmental treaty established nearly 50 years ago (1971) by UNESCO.
• It came into force in 1975 and takes its name from Ramsar, the Iranian city where the convention was adopted.

What is the significance of East Kolkata Wetland?

• The east Kolkata wetlands are a fascinating natural resource to which tremendous value has been added by traditional knowledge.
• The wetlands have been historically created by a natural shift of the Bidyadhari, a tributary of the Ganga.
• The land on which Kolkata is built slopes to the east.
• So the British created canals to take out the city’s waste water into in the wetlands.

What happens to this waste water?

• The traditional knowledge is used to treat this waste water.
• For the past century, the waste water has been first fed into settling ponds.
• There the biodegradation of organic components takes place.
• Then the nutrient-rich sewage is transferred into a fish pond to improve the organic quality of the water.
• Fish is grown in this pond and the used water is transferred to fields to irrigate crop.

How else is the wetland helpful?

• In the 12,500 hectares of wetlands, water bodies account for almost 50%, agricultural land - 39%, garbage landfills - 5% and urban and rural settlements over 10%.
• The wetlands grow 10,500 tonnes of fish per year and 150 tonnes of vegetables per day, providing livelihood for over 50,000 people.
• The solid waste brought to the landfills is composted in pits and used for growing paddy and vegetables.
• The natural process saves Rs 500 crore annually in sewage treatment costs.

What is the current problem?

• The government has assured to maintain the balance between ecology and development.
• But the reality is that the wetlands are slowly and steadily disappearing.
• Satellite imagery indicates that in Bhagabanpur, a part of the wetlands, water bodies have shrunk from 77% to 14% of the area since 2002.
• This is corroborated by census data which say that during the 2001-11 decade, there was a fourfold rise in the number of houses and population density in the area.
• The nature of the liquid waste coming to the wetlands from the city is changing.
• The presence of non-biodegradable chemicals is increasing as income and lifestyle in the city change.
• With the increase in lead and mercury used for the manufacture of batteries, paint and glass, city will have to forget about relishing the fish and vegetables that come out of the wetlands.
• Therefore the timely warning to be taken seriously to reduce the chemicals in the sewage and to save the wetlands.

Source: Business Standard