THIRUVANANTHAPURAM: The iconic Vembanad lake -- the lifeline of the state's backwater tourism -- is operating far beyond its ecological limits.

The lake's recreational carrying capacity has exceeded by almost 200%, with 926 houseboats currently operating against a permissible limit of 461. A recent study, commissioned by the State Wetland Authority Kerala (SWAK), has recommended immediate moratorium on new registrations and strict permit-based controls to protect the Ramsar-listed wetland.

SWAK launched the study following a High Court order based on a petition filed by some houseboat owners and the fishing community against the State Maritime Board granting permission for more vessels to operate.

The study, Recreational Carrying Capacity of Vembanad Lake for Sustainable Wetland Tourism, was done with technical assistance from the Centre for Water Research Development Management.

Maritime Board urged to implement permit system

An official with SWAK told the TNIE that the report will be submitted before the HC soon. "Vembanad Lake is under severe ecological stress from overcrowded tourism and untreated waste discharge. Without regulation, the system will become unsustainable -- both environmentally and economically," the official said, adding that further action on the study will be undertaken based on the HC order.

Water quality tests from houseboat discharges revealed dangerously high pollution levels, including extreme biochemical oxygen demand (BOD up to 1,600 mg/L) and bacterial contamination. Many boats were found to be overloaded, with over 80% violating safety norms, the study says.

The report urges the Kerala Maritime Board to implement a permit and tracking system, ban unregistered vessels, and transition of the fleet to solar or battery propulsion within five years. It also calls for zoning the lake into core, buffer, and regulated areas, improved waste management at terminals, and continuous water quality monitoring.