A study conducted by the Centre for Lake Conservation, Environmental Management and Policy Research Institute (EMPRI), Bangalore, has revealed that out of 81 existing water bodies in Bangalore, nine were highly polluted, 22 moderately polluted and 50 were the least polluted.
Researchers P Jeya Prakash, P P Dash, D J Mythriand and V Sreenivas, who presented a paper titled “Assessment and conservation strategies for water bodies of Bangalore,’ at a workshop held in Mysore Zoo recently, said the study was carried out in three zones; already developed, yet to be developed and green belt area.
All the identified water bodies were coded and a health card for each was prepared. Result shows that out of 117 identified water bodies, 36 have disappeared because of several anthropogenic activities. Seasonal GPS tracking of water bodies revealed 50 per cent reduction in water spread area during summer. Land Use/Land Cover change analysis (40 years data) showed an increase in built-up area, decrease in tree cover, open ground and agriculture areas.
Out of 33 water bodies tested, 25 were found to exceed the standards for pH, 19 for turbidity, 16 for free CO2 and potassium, 12 for dissolved oxygen, eight for total dissolved solids, biological oxygen demand, total hardness and sodium. Heavy metal analysis showed five heavy metals exceeded the standard limits in several water bodies.
Documentation of biodiversity in and around these water bodies and analysis through Shannon diversity index showed that the diversity of aquatic plants, fungi, benthos, frog and reptile was low (0-1); diversity of trees, bacteria, fish, mammals was moderate (1-2); diversity of shrubs and herbs, phytoplankton, zooplankton, insects, butterflies, birds was good (2-3).
The paper said the stakeholders view was also received to derive the strategies under the six sub-heads for lake conservation, restoration and management. The present work is expected to help the government authorities, local people, NGOs and decision makers in the protection of water bodies.
It said Bangalore once termed the ‘City of Lakes’ is becoming a ‘city of concrete jungle,’ due to tremendous growth of IT industries, increase in population and urbanisation. Not only lakes, but also the whole ecosystem of Bangalore is deteriorating. Small water bodies which are the feeders for major water bodies have become vulnerable on account of encroachment, discharge of sewage and dumping of garbage.
Identification, mapping, and documentation of lake records are the primary steps to prevent them from further degradation. The paper also formulated strategies to protect and manage them in a more scientific way.
However, environmental activist A N Yellappa Reddy has a different say on Bangalore lakes. “I certainly do not go by the report. Though I do not know the parameteres under which these output are arrived at, I believe that 80 per cent of the lakes in Bangalore are deteriorating. The weeds have been increasing, industrial discharge are uncontrolled and the solid waste dumping continues in most lakes in Banglore.”