PANAJI
Nearly 64 per cent of Goa's notified wetlands, including the internationally recognised Nanda Lake Ramsar site in Curchorem, are facing serious ecological threats right from encroachment, pollution, intensive agriculture to unsustainable harvesting of resources, according to the wetland assessment by the Union Ministry for Environment, Forest and Climate Change.
Of the State's 25 notified wetlands, 16 have been identified as being under varying degrees of pressure from human activities and environmental degradation, resulting into encroachment, pollution, siltation, aquaculture, mining, alteration, etc. Almost all these wetlands are suffering from multiple ecological threats.
The findings are particularly alarming for Nanda Lake, a 42-hectare wetland that was designated a Ramsar Site in August 2022 for its ecological significance. The Lake is facing manifold threats, including siltation, intensive agriculture, aquaculture, encroachment, pollution, overgrazing and unsustainable harvesting of wetland resources.
Other major wetlands under stress include Carambolim Lake (58 ha), threatened by encroachment, unregulated tourism pressure, siltation and mining-related activities; Batim Lake (26.55 ha), affected by hydrological alterations, siltation, pollution and resource extraction; and Bondvol Lake (8 ha), facing encroachment, mining, overgrazing and changes to natural water regimes.
Apart from Batim, alteration of natural hydrological regimes has been reported in Bondvol, Sulabhat, Tarvalem and Xeldem lakes, which are also under threat due to encroachment along with Carambolim, Cottambi and Dhasi lakes.
The report notes that alteration of natural hydrological regimes is emerging as a major concern. “Alteration of natural hydrological regimes often leads to reduced water availability, altered hydro-period, loss of connectivity with biodiversity habitats, impeded nutrient exchange and other processes which significantly enhance their degradation,” it said.
Siltation has emerged as another widespread threat affecting most of Goa's wetlands, including Chimbel, Coneix, Cottambi, Dhasi, Durga, Pali, Pilerne, Sarzora, Sulabhat, Tarvalem and Xeldem lakes. The Ministry says excessive sediment deposition reduces water-holding capacity, affects ecosystem functions and accelerates eutrophication through nutrient-rich runoff from agricultural lands.
Pollution from untreated waste, agricultural chemicals and urban runoff has further degraded wetlands like Batim, Bondvol, Carambolim, Chimbel, Coneix, Cottambi, Dhasi, Durga, Pali, Pilerne, Sarzora, Sulabhat, Tarvalem and Xeldem while mining of salt, sand and laterite and unsustainable extraction of wetland resources continue to place additional pressure on these ecosystems. The wetlands are also under threat due to the spread of invasive alien species.
