Impact of urbanization on the quality of water in a natural reservoir: a case study with the Deepor Beel in Guwahati city, India

The Deepor Bed l is a natural, freshwater wetland in the south-west corner of Guwahati, India. The Bed l harbours a large number of migratory aquatic birds, especially in winter, and is a Ramsar site since 2002. The wetland provides livelihood to the people of the surrounding villages through collection and sale of fish, nymphaea nuts and flower, ornamental fish, orchids, medicinal plants, etc. The water quality of the Beel is threatened by excessive fishing, hunting of water birds, pollution from pesticides and fertilizers and infestation by water hyacinth. The present work reports on the water quality of the wetland by continuous monitoring from February to July, covering the dry, temperate period and the wet, hot and humid period. Sampling was carried out at 10 sites for physical and aggregate properties, metallic and nonmetallic constituents, organic contaminants and microbiological parameters.