Thol lake located 40 kms from Ahmedabad, which is a legally protected wetland, will soon be fed with discharge from a Sewage Treatment Plant (STP), planned upstream as per a decision taken by the state forest department.

The decision comes five months after the lake was designated by Ramsar Convention as a wetland of international importance.

Gujarat Urban Development Company Limited (GUDC), a state government undertaking for executing urban infrastructure projects, had floated tenders for this STP having capacity to treat 33.10 million litres per day (MLD). Five firms have submitted tenders as of March 9 when the tender was closed for the project, and the project is estimated to cost Rs 46.64 crore.

The forest department gave the green light to the project on the condition that discharge of treated wastewater from the STP shall not disturb routine birdlife in Thol and that periodic water quality testing reports shall be submitted to the forest department.

For now, the proposed STP will treat 15 MLD of wastewater generated by Kalol and around two MLD generated by thousands of residents of Kalol-Ola-Borisana and Kalol-Saij-Borisana areas of AUDA but capacity utilisation will go up as population increase in future.

The STP, which will be funded by the central government under the Atal Mission for Rejuvenation and Urban Transformation (AMRUT), will discharge treated wastewater into Saij-HAJIPUR water channel running through Moti Bhoyan and Karoli villages and eventually draining into Thol lake via the Eastern Drain.

A man-made water canal, the Eastern Drain is one of the 21 drains dug more than a century ago to channel and store runoff in Mehsana district.

At least four government agencies—the GUDC, forest department, irrigation department and the Gujarat Pollution Control Board, will have to work together now to ensure the water quality in Thol lake remains conducive to its ecology and wildlife.

Among the richest wetlands of the state, Thol lake was constructed in 1912 as an irrigation tank with catchment area of 155 sqare kms. Besides the Eastern Drain, it is also fed by two minor drains — Saij-Hajipur kans and Irana-Indrap-Vamaj kans. But the lake has since turned into an important wildlife habitat, especially for waterbirds, including dozens of species of international migratory birds as it falls on the Central Asian Flyway.

The Ramsar Secretariat, while designating it as a wetland of international importance last April, had noted that Thol sanctuary which is part of Nal Sarovar Wildlife Division, supports more than 320 species of birds, which is half the total number of species found in the state and more than 110 species of waterfowls, which is 43 per cent of waterfowl species found in India.

Forest officers complain that sewage water that flows into Thol lake sometimes, has been a menace recently.

“We take it up with irrigation department immediately and ask them to check the flow. But as we don’t have jurisdiction over the catchment area of the lake, it all depends on the cooperation of the irrigation department,” says a forest officer.

Shyamal Tikadar, Principal Chief conservator of Forests (wildlife) and the Chief Wildlife Warden of Gujarat, cleared the STP project last September stipulating that the project will have to comply with the Environment (Protection) Amendment Rules, 2017 issued by the Union Ministry of Environment, Forest and Climate Change (MoEFCC) and directions issued by the National Green Tribunal (NGT) by its order of April 30, 2019 .

The PCCF laid down that while discharging water from the STP, care should be taken that “routine life of birds in Thol sanctuary is not disturbed and that reports of periodic quality testing of treated wastewater should be submitted to the deputy conservator of forests of Nal Sarovar Bird Sanctuary at Sanand”.

Tikadar says that the forest department can only lay conditions on such projects.

“It is for the Gujarat Pollution Control Board (GPCB) to set parameters for treatment of wastewater and to decide as to what type of water will be safe to be discharged which eventually may end up in an important wetland. We don’t have that technical expertise,” he told The Sunday Express.

Twenty kilometres upstream the Thol lake, Balaji Kantoji Thakor, a farmer in Kalol is busy tending to his crops oblivious of the stench emanating from a pond bordering his 18 bigha farm.

Dark-grey wastewater, streaming from Kalol town every day flows into this oxidation pond through small channels, creating froth on the pond surface.

“With more development in this area, larger volumes of wastewater is being discharged in the pond and water enters our fields during heavy rains. But it is not a significant loss given the fact that the pond supplies water free of cost to irrigate our crops round the year. So, we have never complained,” says 33-year-old Thakor, adding farmers of the area have remained dependent on the pond for the past many years as drawing water from borewells is a costly affair.

Now with the STP, the situation will change for the better for the likes of Thakor.

Kalol municipality does not have any facility to treat domestic sewage and therefore around 15 MLD of untreated wastewater flows into the pond near PSM Hospital and from there, through agricultural field, ends up in water channels which lead to Thol lake, 20 kilometres downstream.

Environmentalists and wildlife enthusiasts, however, are concerned at the prospect of sewage water reaching Thol.

“Releasing waste water into a wetland without treatment or even with insufficient treatment can prove hazardous for the wetland. If the wastewater is in the form of untreated domestic sewage, it may lead to accelerated eutrophication (nutrient enrichment) owing to the excessive concentration of nutrients like phosphates and nitrates. It may further lead to algal blooming which may further cause aesthetic deterioration, dissolved oxygen depletion and fish kill,” says Ketan Tatu, an Ahmedabad-based wetland researcher. He adds that it is not a wise step given that Thol was listed as a Ramsar site less than a year ago.

Incidentally, the Gujarat High Court is suo motu hearing a case of pollution in the Sabarmati river by STPs and Effluent Treatment Plants (ETPs) not meeting specified norms. The HC-constituted joint task force (JTF) has found how STPs of Ahmedabad Municipal Corporation were discharging untreated wastewater directly in the Sabarmati river. Rohit Patel, manager of projects division and incharge of the Kalol STP project, however, says that the STP is necessary.

“The oxidation pond, more or less, leaves the domestic wastewater untreated,” he says, adding the sewage generation in this area is projected to go up to 33 MLD in coming years and that something needs to be done about this.

B Suchindra, Chief Conservator of Forests of Gandhinagar wildlife circle, says the STP will help check the flow of untreated sewage into Thol.

“There might be leakages, leading to sewage water entering Thol these days. However, so far, there has been no noticeable change in Thol wetland. We have not seen any mass mortality among fish or birds,” says Suchindra, adding, “With regards to Kalol STP, they had made a proper proposal as to how they will treat the wastewater and what will be the chemical composition of treated wastewater that they will discharge from the STP.”

When asked if the STP will lead to centralisation of sewage collection and hence more discharge in one channel, the CCF said, “There will be change in the flow but the irrigation department will take care of it.”

Nitin Vora, chief officer of Kalol municipality, meanwhile, assures that the treated water will not damage Thol and that the civic body has plans to sell treated wastewater. “The GIDC Kalol estate has water needs as do farmers. There are rates fixed by the irrigation department and we plan to monetise our treated wastewater,” says Vora.

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