Session 8: 

Assessment of Environmental Status of an Urban Water Body: A First Step in Restoration Ecology Kanhere Z.D.1 and Gunale V.R. 2 
1Department of Environmental Sciences, University of Pune, Pune - 411 007, India
2Department of Botany, University of Pune, Pune - 411 007, India
 

Pune is known as a city of culture, education and at present it is the 7th ranking industrial metropolis in India. During last 2 decades, there has been tremendous increase in overall development leading to increase in population. The freshwater ecosystems in urban areas play an important role and are also affected by developmental activities. Pashan Lake is a freshwater lake in Pune city. It is a century old man made lake and was used as drinking water source for certain part of the city. In the process of development, a number of housing complexes is built up in its catchment area due to inclusion of many peripheral areas in the municipal administration. As a result, there is increase in siltation as also the domestic waste from the housing complexes. A number of other human activities like washing, cattle bathing etc. add to increasing load of nutrients.

As a result, there is gradual degradation of lake water quality. This is evident from series of work, undertaken since 1976. There is massive growth of aquatic weed, Ipomea aquatica and Ipomea carnea and Azolla to name few, which indicates eutrophication. The West side of the lake, which is near the highway (NH4) has started converting into marshy land. All these changes are indicative of ageing of lake.

There has been gradual decline in Dissolved Oxygen and increase in CO2, nutrients and change in biotic communities such as algae and macrophytes. The use of saprobial indices shows mesotrophic to eutrophic conditions of the lake. Increased infestation of  macrophytes indicates increasing siltation. In view of such changes the authorities have stopped the use of lake water for drinking. At the same time measures are underway to restore the lake.

The present study has contributed in understanding the gradual changes both in term of biotic and abiotic component of lake ecosystem, which has lead to restoration measures. The paper aims to discuss the status of the lake and use of restoration methods based on natural process as evident from the assessment studies.