Wetlands are not wastelands

On Tuesday November 15, 29 flamingos arrived in Pallikaranai, which sends out mixed signals. They have arrived early, which implies that water levels have gone down. Meanwhile, PWD officials are cleaning water channels, striving to create flow-through for rain water, arriving from the southern side of Pallikaranai, through Buckingham Canal to Mutttukadu and thereon to the sea.

Shoring up of bunds along water bodies are happening all across the city, with official supervision, and there is extra diligence this year, after the experiences  from the havoc during last year’s monsoon. Desilting and cleaning of water bodies, and allowing for free flow is important even during non-monsoon days, for a very simple reason. Unless water bodies retain water, through slow percolation, the water table in all areas would continue to fall. The city’s water needs are met from the water table in many of the outlaying areas. 

The arrival of flamingos and the water level are inter-dependent. Last year, the ‘mouth’ of Muttukadu was broken open by government officials. The breach was huge, and the swollen waters found the outlet. However, in the process, the marshland of Pallikaranai lost water much too fast. Unprecedented rains occurred on November 30, and by December 4, Pallikaranai marshland was dry, since the bunds were breached indiscriminately by human intervention. Marshlands are important reservoirs of our ecosystem. The salt water and rain water result in estuaries which not only improve the water table but also allow birds to thrive. 

There are three important channels through which rain water reaches the sea. The Cooum (near Napier bridge), the Adyar estuary and Muttukadu. Due to last year’s unprecedented rainfall and the extensive water logging in south Chennai, the focus has remained largely on Pallikaranai. However, all water bodies are important. A year-long study on water bodies, done a couple of years ago, was carried out extensively, in order to investigate the ecological significance of the water bodies. The study showed there was a great diversity of flora and fauna, across the lakes. 

The study also attempted to compare the past and present status of the water bodies. It is believed there were 150 of them a few decades ago. The Nature Trust has personally inspected 31 water bodies in south Chennai. Our study indicates that Meenambakkam, Ullagaram and Hasthinapuram lakes have ceased to exist. There is also evidence of extensive encroachment along almost all the water bodies. The exception could be around the southern side of Pallikaranai (Agaramthen, Ottiayambakkam Periya Eri, Ottiayambakkam Chinna Eri, Perumbakkam and Sittalapakkam. 

In our report, we highlighted the fact that developments around the lake area have led to destruction of inlet and outlet to the lakes. Connectivity to Pallikaranai marsh exists only for fa ew lakes like Agaramthen, Ottiayambakkam Periya eri, Perumbakkam and Sittalapakkam. 

Over the years, the water bodies have also increasingly felt the impact of pollution. Our water analysis of  Pallikaranai marshlands showed that the level of turbidity, total dissolved solids (TDS), EC, phosphate, free ammonia, sodium, Biochemical Oxygen Demand (BOD) & Chemical Oxygen Demand (COD) are  in excess of the the permissible limit in many of the sample locations. Other parameters such as pH, calcium, magnesium, iron, manganese, nitrite, nitrates, chlorides, fluorides, sulphates and chromium are well within the prescribed limits. 

Though these levels are now within the permissible limit, discharge of partially treated or untreated sewage water, dumping of solid waste and burning of garbage by humans leads to polluting of all the lakes and water bodies will be contaminated. Hence there is an immediate need to restore, conserve and preserve these lakes to maintain and improve the ecological balance. 

However, wetlands are often misused as wasteland by many. Recently there were reports of indiscriminate dumping of garbage in Thenneri Lake in Kancheepuram district. This is rarely an isolated case. Often, garbage is dumped in lakes and tanks. As soon as a wetland dries, people either dump waste there, or encroachments take place or huge apartment complexes come up along the water bodies. In the latter case, the onus of maintaining the water body and ensuring that the domestic waste is not let into the lake or pond or tank, should be vested with the developers or residents. Action should be taken to control the encroachments, dumping of garbage and letting out of sewage into the lakes.  Desilting of lakes wherever necessary should be done in a phased manner, to retain the water capacity and ground water recharge. Maintaining the inlet and outlet canal in the water bodies would help during the flooding season. 

The fundamental requirement is to spread the awareness that wetlands  are not  wastelands, where one can do as one pleases.