ABSTRACT
The tempestuous Brahmaputra gave rise to innumerable wetlands during its senescent course; one such instance is the Deepor Beel—a wetland of international significance as recognized by the Ramsar Convention in 2002. It acts as a local carbon sink because phytoplanktons growing therein are great carbon sequesters. It may well be labeled as the lungs of Guwahati city. The Beel recharges groundwater tables and “acts like a sponge to control floods.” A part of it has been designated as a bird sanctuary, courtesy of the myriad avifauna that finds their abode in the landscape. A large chunk of the wetland has been infested by water hyacinth, an invasive species, leading to disappearance of native floral species. The hit and miss development spree that the Guwahati city has embarked on has caused a shear stress on the wetland causing the system’s endemic processes to distort. Transport arteries are the major trails of human encroachment in the region. Untreated sewage from the city is discharged into the Beel through the Bahini and Bharalu rivers. The contaminated ground water from the peripheral landfill site of Guwahati Municipal Corporation (GMC) infiltrates into the Beel. The forests in the southern precincts have been subjected to logging and this has aggravated erosion and consequent siltation in the region. Studies on the physicochemical properties of water reveal that the water is contaminated, explaining the high turbidity. Water Quality Index (WQI) in most parts of Deepor Beel is quite high, rendering it unfit for drinking. Sizeable concentrations of heavy and trace metals have been found in the wetland in recent research endeavors. The increase of fishing practices along with the frequent disturbance of lake water by boats causes extensive churning of organic matter, leading to sprawl of aquatic flora and reduction in fish population. The wetland ecosystem is actually shrinking and the aquatic vegetation is increasing rapidly. The wetland ranges from mesotrophic to eutrophic in different times of the year. The increasing eutrophication of the lake has led to levels of dissolved oxygen plummeting as low as to be able to create a hypoxic condition for aquatic fauna. It is causing gradual conversion of the wetland to grassland. Pesticides used in the adjacent agricultural fields find their way into the lake ecosystem by means of runoff, causing biomagnification. The absorption capacity of the Beel during flood events has now decreased leading to artificial water-logging in the city. Self-purifying capacity of the wetland is also compromised because of pollution. The dumping site needs to be relocated to an alternative area away from the wetland. Ecotourism can be used as leverage to conserve the wetland through wise planning for sustainable management of the ecology along with revenue gains and improved well-being of local communities through “responsible tourism” in a natural landscape. This paper is an attempt at reviewing few of the noted research works done on the ecology of Deepor Beel, its vulnerability to urban encroachments, and solutions posited for the same.
