And why working with nature is always best…

inundated wetlands

Before we talk about the East Kolkata Wetlands, let’s establish what wetlands are and why we should care about them.

While the regulatory definition of a wetland is complicated, the average person recognizes wetlands as marshes, swamps, bogs, fens, bayous, and the like, basically, swamp-like places that are wet and mucky and hold standing water.  Wetlands are important for a variety of reasons:  they control flooding, acting as a safe harbor for flood waters to recede slowly rather than rushing off downstream via stormwater drain conduits; they filter out toxins — such as heavy metals, oily contaminants and excess fertilizers and pesticides — that would otherwise reach the rivers, streams and groundwater by capturing them in their soils; and they provide a home to a variety of flora and fauna that thrive in watery places, among other things.  Coastal wetlands act as a barrier between the mainland and the ocean, giving that vast body of water the space to expand and contract as storms and winds dictate, providing a much needed buffer in times of severe weather. 

While we appreciate the value of wetlands here in the states, in at least one part of India, their lives and livelihoods depend upon it.  The City of Calcutta has a population of five million people with an additional two million “floaters” — those without a permanent home — and no wastewater treatment system, but what it does have is a gem of a natural treatment system in the form of the East Kolkata Wetlands (EKW).  The EKW are considered the City’s biggest asset. In 2002, these amazing wetlands were recognized as a Ramsar Site for the benefits they provided to society. 

In comparison, imagine the City of Philadelphia with its population of 1.5 million without sewage treatment as it was at the end of the 19th century. Everything ended up in the streets and, ultimately, the Delaware and the Schuylkill Rivers.  Even with a population somewhere shy of 55,000, that was an incredible amount of sewage for Philly’s rivers to manage.  Beginning in 1901, the City of Philadelphia began building sand filtration plants; by 1914 in response to an outbreak of typhoid, chlorine treatment had been added, resulting in a  dramatic decrease of water-borne diseases. 

By contrast, Calcutta doesn’t use chlorine, but works directly with nature to bring about the same result. To quote Dr. Arun Deb, a founder and Board member of the Global Water Alliance in his recent editorial entitled, “Engineering History and Heritage,” by ICE Publishing: 

“The EKW is an example of wonderful large wetlands, demonstrating that a city can have a large symbiotic ecosystem that provides sewage treatment, aquaculture and agricultural lands for the city, generating livelihood for thousands of people.”

To read Dr. Deb’s full editorial, click here.

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