CHENNAI: An independent study by the Uvakai Research Foundation has raised serious concerns over the proposed Parandur greenfield airport, warning that the Rs 29,144 crore project could significantly worsen flooding in Chennai by disrupting critical upstream water systems.
The report, which presents a detailed hydrological and legal review of the Pre-Feasibility Report prepared by the Tamil Nadu Industrial Development Corporation, cautions that the project, in its present form, may violate established principles of water governance and constitutional safeguards.
The study directly contests the claim that the project site does not contain natural wetlands. According to Uvakai’s findings, nearly 576.74 hectares, or about 26.5% of the total project area, comprise active water bodies, including lakes, irrigation tanks, drainage channels and groundwater recharge zones. These features currently act as vital flood buffers for the Chennai metropolitan region, the report notes.
One of the key criticisms relates to the misclassification of river basins in official project documents. While the Pre-Feasibility Report places the airport site within the Lower Palar river basin, the study shows that around 66% of the area actually falls within the Cooum river basin. The remaining portions are hydrologically linked to the Adyar river system through channels such as the Kamban Kalvai, which ultimately feeds into Chembarambakkam Lake, one of Chennai’s major water reservoirs.
The report estimates that the Parandur landscape currently stores about 9.32 million cubic metres, or 0.33 TMC, of water, absorbing rainfall and moderating flood flows. Nearly 80% of these water bodies are either missing or inadequately documented in the official report, it adds.
Uvakai warns that the removal or constriction of these upstream water bodies could push an additional 10,000 to 12,000 cusecs of runoff into Chennai’s river systems during peak rainfall events, potentially overwhelming already stressed urban waterways.
The study highlights the limited carrying capacity of the city’s rivers. The Adyar river, designed to carry about 72,000 cusecs, recorded flows of nearly 1.26 lakh cusecs during the 2015 floods. The Cooum river, with a capacity of around 35,000 cusecs, saw flows exceeding one lakh cusecs during the same period. Any further upstream discharge could intensify flooding across low-lying areas of the city, the report cautions.
It also recalls observations made by the Comptroller and Auditor General in 2017, which linked Chennai’s recurring floods to the loss of upstream storage, encroachment of water bodies and the absence of basin-level planning.
Beyond hydrological concerns, the foundation flags several legal and procedural issues. A Government Order for the acquisition of about 5,746 acres was issued in October 2023, even before hydrological findings were made public. The proposed closure or diversion of 33 water bodies, the report argues, could conflict with Articles 21, 48A and 51A(g) of the Constitution, which relate to the right to life and environmental protection.
The study also cites the 2005 L. Krishnan versus State of Tamil Nadu judgment, which prohibits the alienation of lakes and water bodies for development. In addition, it notes that Parandur is located about 42 km away, by aerial distance, from the existing Chennai International Airport, potentially violating the 150 km norm prescribed for greenfield airports.
Describing the issue as one of long-term urban safety, the Uvakai Research Foundation has urged the State and Union governments to impose an immediate pause on further clearances, land acquisition and land use changes linked to the project. It has also called for independent, basin-scale flood modelling and the public release of the findings of a State-appointed expert committee, whose report has reportedly remained undisclosed since February 2023.