Natural Law is the most important


This interview has been translated from Marathi.

28th February, 2021

Written by Sasha Shinde

Artwork by Arshan Kazi

By the banks of Lake Kavesar, nestled and hidden from view in the confines of Thane’s posh Hiranandani Estate, is my scheduled interview with Dr. Pramod Salaskar, an eminent limnologist who has been working on Powai Lake for more than twenty years. He weighs in on the current situation of the lakes in Thane, how development of lakes often reduces its life, and why it is important to have educational centres near lakes.

How did you get involved in this particular area of study?

My doctorate was on Powai Lake, and I am the first doctorate from Mumbai University who chose this subject. No one had gotten their doctorate on this subject, limnology, before. It is a subject that not many know of. It is not even a part of any course at Mumbai University. I was sponsored by music director, Naushad Ali himself, without whose support it would be impossible for me to have completed my doctorate.

Limnology means the study of standing water bodies. There are many types of limnology- like that for lakes. But before that, we need to understand what a lake is. A lake is not just the surface of water, and the area it occupies; it includes the basin (catchment area) too. The lake basin with the water surface together constitutes the lake. So, for any conservation of lakes, it is very important to improve the lake catchment area. It is essential that there be a lake catchment area of at least 500-1000 metres, but due to urbanisation, in places like Mumbai, Pune, and Thane, this area isn’t present around any lake.

Is this what is known as Integrated Basin Management?

ILBM, or Integrated Lake Basin Management- like I said before, when you say lake, you can’t just improve the water surface; the catchment area should be reserved and improved. The fish, birds, and other animals, should be allowed to survive in the weeds and plants next to the lake. These birds then feed on the unwanted organisms in the lakes reducing their population.  For this, planting of native species in the lake basin area is necessary, as opposed to ornamental plants. The plants that are needed for natural treatment systems should be planted like Cannae or here, at Kavesar Lake, they have planted Typha species (cattails), which is good but should just be on one side. Or there could be Vetiver or any other species which are pretty but also serve the purpose of filtration.

You’ve worked on Kavesar Lake. What was the situation like before and after you started?

I started working at Kavesar Lake a while ago, on 17th December, and that time, the whole lake was covered in weeds. The immediate point of concern was removing the weeds. The weeds are necessary at the borders of the water, while the middle surface area should be free from weeds. This makes it so sunlight can penetrate a certain level below the water surface for photosynthesis, facilitating oxygen formation. Oxygen depletion leads to aging of the lake, and the number of organisms within the lake declines. 

Firstly, the weeds have to be removed manually. Chemical cleaning gives immediate results, but the weeds just die and get deposited at the bottom of the lake. Within a month or two, they start decomposing, using the oxygen to do so, creating an anoxic zone. The chemical too stays within the water, damaging water quality. Herbivorous fish would have been an alternative except for the fact that the waste material released by them serve as a favourable environment for weeds to grow creating an unending cycle. So, regular manual removal of weeds is essential- the removed weeds can then be used as fertilizer. 

Secondly, people staying close by often transfer fish from their home aquariums into the lake, and this isn’t specific just to this lake. Once they enter the water however, they do not let the native species of the lake survive, eating the juvenile native species before they can repopulate. The aquarium fish, like the giant gourami (Osphronemus goramy) or African catfish, may also increase in population because they have no natural predator; neither snakes nor birds will touch them. It is very difficult to remove African catfish from the lakes, even with nets, and the government even brought forth a ban on releasing them into any water body in 2010. It damages the ecosystem and biodiversity existing in the lake. 

As such, we don’t have to work much on the improvement of the lakes, nature takes care of itself. 

What is the role of governments in maintaining our lakes?

There are buildings and towers constructed next to the catchment areas. While constructing a building, ecological clearance is necessary from the government. It is important for the government to make sure that the topology is not getting affected while giving these permissions, but unfortunately that is not the case. Maintaining the catchment area is not a concern at all. Sometimes constructions start right next to the waterbody, creating a profit for big builders- as lakefront property. Among citizens also, there is a serious lack of awareness. Even the eatery stalls such as the ones that sell pani-puri, next to the lakes should be removed, because the waste of the same is then dumped into the water body. It creates a multitude of issues, killing organisms within the lake.

There are many laws related to maintenance of lakes and their biodiversity, but they lack proper implementation.The most important of them however, is the law of nature. According to this, if you remove an organism from a space, another organism will take its place. If you remove the catchment area from the lake, you will be able to see its adverse effects almost immediately. 

Having said that, festivals should be held near the lakes. Similar to the festival that is held to increase awareness about flamingos, this would invite the public, especially younger children to take an awareness in lakes.

Speaking of awareness programmes, how important are they and do they actually make a difference?

They do make a difference. But it is also imperative for them to happen by the lake side. Explaining the importance of lakes over presentations inside the confines of a classroom is not as effective as taking children out there to see for themselves. 

This is where Sarovar Samvarthini comes into the picture. Scientists should be giving out information and conducting programmes to reach even the youngest children. Sarovar is a lake and Samvardhini is a conservation society. So together, it means having a Lake Conservation society. This concept was first introduced by Dr. Madhavrao Chitale. He said wherever there’s a lake, there should be a body that monitors water quality, maintains a record, and publishes papers and records to forward to the respective governing/civil body. This would be useful during conservation efforts in the future.The language used in this communication should be such that it is understood by laypeople- including the lake communities, fishermen, and other stakeholders- and the use of regional language is imperative. Although it is scientific work, complex, research-minded language should be avoided, and simple language must be used.

I conduct research on Powai Lake, assessing water quality among other things, often taking young students and children with me, and have been doing so for a very long time now. But I still think I do not know even 1% of what the lake is, despite being a scientist, and a doctorate. If you go sit by the fisherwomen who work near the lake, they would have the knowledge of every single drop, having spent most of their life there. They might not be able to express what they know eloquently, but they say that 10-15 years ago they would drink water straight out of the lake and now they can’t. The amount of catch has also gone down, and now when they bring out fish from water it smells like kerosene; their hands itch when they come out of the water. These things can’t be observed by going once or twice to the lake. This is why education centres are needed near lakes, to allow people to see for themselves and learn how our lakes need our help. The observation skills that the fisherwomen have are something that we can learn from.