Wetlands are most important freshwater resource on Earth. They help in maintaining the ecological balance of the region. Wetlands, natural and manmade, freshwater or brackish, provide numerous ecological services. They provide habitat to aquatic flora and fauna, as well as numerous species of birds, including migratory species. Wetlands are under threat from drainage and conversion for agriculture and human settlements, besides pollution. They are the most threatened and fragile ecosystems that respond very quickly even to a little change in the composition of abiotic and biotic factors. This study was done to understand the ecosystem prevailing the Chikkabettahalli Lake which is located in Adityanagar, Vidyaranyapura, Bengaluru, Karnataka. The physico-Chemical and Biological composition of the lake was studied using standard protocols.  Nutrient availability in Chikkabettahalli lake water is high which is evident from the results of physico- chemical analysis, the presence of fully covered varied macrophyte species and pollution tolerant algal species. Hence, the light penetration is obstructed and dissolved oxygen (DO) level is depleted in the lake. Reduction in the lake area was observed due to dumping of building debris and solid waste and also encroachment.
The loss of ecologically sensitive wetlands in Bangalore is due to the uncoordinated pattern of urban growth. This is due to a lack of good governance and decentralized administration evident from a lack of coordination among many para-state agencies, which has led to unsustainable use of the land and other resources. Failure to deal with water as a finite resource is leading to the unnecessary destruction of lakes and marshes that provide us with water. This failure in turn is threatening all options for the survival and security of plants, animals, humans, etc. There is an urgent need for conservation and sustainable management of wetlands, which requires;

Keywords: wetlands, encroachment, pollution, nutrients enrichment