JOIN USIISc professor's blueprint favours Jakkur model for Bellandur, Varthur lakes
A blueprint for rejuvenation of Bellandur and Varthur lakes has called for treatment of sewage through integrated constructed wetlands on the lines of the Jakkur lake model. This model has combined secondary treatment plant with constructed wetlands and algae ponds to remove nutrients from the lake.
Prepared by Dr T V Ramachandra and team from the Indian Institute of Science (IISc) Centre for Ecological Studies, the blueprint also seeks recovery of the area identified for Sewage Treatment Plant (STP) in the region between Agaram and Bellandur lakes. The Revised Master Plan (RMP-2015) had shown this area as 40 acres.
On the suggested Jakkur model, the blueprint said: “Complete removal of nutrients and chemical contaminants happens when treated sewage (secondary treated) passes through constructed wetlands and algae pond, undergoes bio-physical and chemical processes. The water in the lake is almost potable with minimal nutrients and microbial counts.”
This model, it said, has been functional successfully for the last five years after interventions to rejuvenate the lake. “This system is one of the self-sustainable ways of lake management while benefitting all stakeholders - washing, fishing, irrigation and local communities.” Other key recommendations are adoption of state-of-the-art technology such as wet dredging to remove deposited sediments, removal of all encroachments without any considerations or political interventions (lake bed, stormwater drains, buffer zone) and banning use of phosphates in the manufacture of detergents. This, the blueprint says, will minimise frothing and eutrophication of water bodies.
Geo-referenced data
The blueprint also talks about the need to digitise land records, particularly those linked to lakes and making available this geo-referenced data with query-based information system to the public. It also wants planting of native species of macrophytes in the buffer zone (riparian vegetation) as well as in select open spaces of lake catchment area.
High built-up areas around lake
On Varthur lake, the blueprint noted that in the 75 m buffer zone, built-up areas have increased from 5% (2002) to 30% (2016) with the decline of vegetation (agriculture, horticulture).
On the valley between Bellandur and Varthur lakes, the blueprint had this to say: “The land fillings have breached both rajakaluve and lakes. Rajakaluves have reduced in width from as high as 35 m to less than 8 m, apart from the loss of natural stream network connecting the lakes and rajakaluves.”