Abdul Wahab Khan
Panaji: The proposed diversion of the Mhadei river by Karnataka has been identified as a major environmental risk for Goa, with the State of the Environment Report 2025 warning that the project could destabilise the Mandovi basin, threaten water security and disrupt fragile ecosystems across the state.
The report said Karnataka’s proposal to divert Mhadei waters to the Malaprabha basin to address water scarcity could reduce downstream flows into Goa. It said such diversion could lead to a decline in water flow in the Mandovi basin and reduce the transport of silt that helps maintain soil fertility in floodplain areas.
More than 43 per cent of Goa’s population depends on the Mhadei–Mandovi river system as a primary source of freshwater. The report said reduced flows could worsen water shortages during dry months and accelerate salinity intrusion. It warned of the risk of saline intrusion extending further inland, contaminating aquifers and agricultural fields.
The ecological impact could be substantial, the report said. The Mhadei Wildlife Sanctuary, located around 300 metres from the proposed diversion site, is a recognised ‘Important Bird and Biodiversity Area’. The report said reduced water availability could have cascading effects on ecosystem services and wildlife habitats.
Downstream impacts may include changes in the Mandovi estuary, where increased salinity could affect mangroves, tidal forests, mudflats and fisheries. The report said these ecosystems play a role in protecting the coastline from erosion and storms.
The report also highlighted the role of the Mhadei in transporting nutrients from the Western Ghats to the Arabian Sea. It said disrupted flows could affect marine biodiversity, fish stocks and coastal livelihoods.
Cultural and heritage sites associated with the river may also be affected. The report said altered hydrology could impact areas such as Bhagwan Mahavir Sanctuary, Dudhsagar and Surla waterfalls, temples linked to the Mhadei and sacred groves.
Agriculture, including khazan lands and Puransheti farming systems, could face increased stress. The report said changes in flow patterns could heighten flood risks during monsoons and intensify drought conditions in dry periods.
The report added that reduced freshwater systems could increase Goa’s vulnerability to climate-related events such as flooding and coastal erosion. It said the Mhadei issue extended beyond water sharing and required careful consideration of ecological impacts.
