Adambakkam Lake and the (Beautiful) Blue Devil

By Lucy Gibson

In the city of Chennai, Tamil Nadu, lies a water body by the name of Adambakkam Lake, a lake which gives its name to the nearby locality of Adambakkam. However, due to a neglect which extends for nearly a decade, this once pristine lake which was a lifeline to thousands of agriculturalists, now resembles a swamp. Moreover, the much discussed revival plans, considering the fixing of the lake boundary to prevent further encroachments, and the laying of walk pathways to encourage recreational activities remain on paper.

The woes of Adambakkam stem largely from three sources: encroachment, sewage, and rubbish. As a victim of encroachment, both residential and commercial, Adambakkam Lake which only around 25 years extended over approximately 86 acres, has now shrunk to just 6 acres. Additionally sewage from the nearby St Thomas Mount is now let into the lake. Finally, Adambakkam Lake is choked by the dumping of rubbish in its waters at a pace at which nearby environmental organisations, such as the E.F.I. struggle to control.  

Water hyacinth and rubbish on and in Adambakkam Lake. Source: New Indian Express.

Together these three sources of trouble amount to an additional problem – water hyacinth.

Untreated sewage from stormwater drains and houses adjacent to Adambakkam Lake contaminate the water, leading to the formation of a thick cover of water hyacinth and invasive weeds on the lake surface. This only adds to the problems facing Adambakkam Lake.

Water hyacinth, with its beautiful flowers and shapes of leaves, is in fact, often referred to as the “(beautiful) blue devil”. This is because it is actually an incredibly harmful invasive weed which drains oxygen from the water body.

Eichhornia crassipes (water hyacinth). Source: Wikipedia.

When left uncontrolled, water hyacinth will cover lakes and ponds entirely. This dramatically affects water flows, as well as blocks sunlight from reaching native aquatic plants which often die. The decay processes deplete dissolved oxygen in the water; as a result of this, fish stocks become significantly depleted and the water body becomes a prime habitat for mosquitos.

Water hyacinth often invades bodies of water that have already been affected by human activities.

But Adambakkam Lake is significant for another reason: it represents one of Chennai’s remaining water bodies.

Since the beginning of the 20th century Chennai has witnessed a steady decline and deterioration in water bodies and open spaces; it is estimated that more than half of the wetlands have been converted for other uses. Chennai had about 150 small and big water bodies in and around the city, but today the number has been reduced to 27. Adambakkam Lake remains an important water body, but in its current state, offers little.

Due to its plain terrain, Chennai lacks a natural gradient for free run-off. This necessitates an effective storm water draining system. The sewage system in Chennai was originally designed for a population of 0.65 million – it is now much below the required capacity. In 2020, there were 10,971,108 people living in the city of Chennai, making Chennai by all accounts a megacity (a city with a population of more than 10 million residents).

In theory, Adambakkam Lake ought to offer a much needed place for flood water to drain into during the monsoon. However, due to the water hyacinth occupying the areas in and around the lake many people fear that there is now little space for flood water to drain and Adambakkam Lake can offer little protection.

The situation does not seem to be improving.

In 2020, the Water Resources Department planned to restore the original storage capacity of Adambakkam Lake, as well as strengthen the bund and improve the lake with recreational facilities – at a cost of ₹3.5 crore. However, progress has stalled. Historically, previous plans back in 2014 for example, have also been postponed; in 2014 this was due to a lack of funds.

Residents now are calling for the waterbody to be restored and desilted before the monsoon season to prevent flooding in the surrounding localities. There is a threat of flooding in areas such as Adambakkam, Thillai Ganga Nagar and Nanganallur during the northeast monsoon.

The longer projects are delayed, the further the encroachments. Desilting, however, would lead to an increase in groundwater level.

There is an urgent need to desilt, deepen and fence Adambakkam Lake.

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