ENVIS Technical Report: 114,  July 2016
   T.V. Ramachandra*       Vinay S      Durga Madhab Mahapatra      Sincy Varghese      Bharath H. Aithal  
Energy and Wetlands Research Group, Centre for Ecological Sciences, Indian Institute of Science, Bangalore – 560012, India.
*Corresponding author: cestvr@ces.iisc.ernet.in
Conclusion and Recommendations


Pristine wetlands ecosystem in Bangalore has been experiencing threat due to unplanned, senseless rapid urbanization. The study brings out that there is sufficient water available in the region, but fails to understand the inability or ineffectiveness of the local administrators to sustainably manage the water resources in the region. Sufficient water is available to meet everyone’s requirement;  (i) 14.80 TMC , if water harvesting is undertaken through surface water bodies; this requires rejuvenation of lakes and reestablishment of interconnectivity; harvesting of rainwater (at decentralized levels),   (ii) 16.04 TMC - treatment and reuse of sewage.

Lakes (wetlands) aided in recharging groundwater resources, moderating micro climate, supported local livelihood (fish, fodder, etc.), irrigation and domestic water demand apart from recreation facilities. Washing, household activities, vegetable cultivation and fishing are the regular activities in the lake for livelihood. Multi-storied buildings have come up on some lake beds intervening the natural catchment flow leading to sharp decline and deteriorating quality of water bodies. Unauthorised construction in valley zones, lakebeds and storm water drains highlight the weak and fragmented governance. This is correlated with the increase in unauthorized constructions violating town planning norms (city development plan) which has affected severely open spaces and in particular water bodies. Problems encountered by Bangaloreans due to mismanagement of water bodies in Bangalore are:

  • Decline in groundwater table: Water table has declined to 300 m from 28 m and 400 to 500 m in intensely urbanised area such as Whitefield, etc. over a period of 20 years with the decline in wetlands and green spaces.
  • Recurring episodes of fish mortality: Large-scale fish mortality in recent months further highlights the level of contamination and irresponsible management of water bodies. Sustained inflow of untreated sewage has increased the organic content beyond the threshold of remediation capability of respective water bodies. Increasing temperature (of 34 to 35 °C) with the onset of summer, enhanced the biological activities (evident from higher BOD and Ammonia) that lowered dissolved oxygen levels leading to fish death due to asphyxiation.
  • Floods: Conversion of wetlands to residential and commercial layouts has compounded the problem by removing the interconnectivities in an undulating terrain. Encroachment of natural drains, alteration of topography involving the construction of high-rise buildings, removal of vegetative cover, reclamation of wetlands are the prime reasons for frequent flooding even during normal rainfall post 2000.
  • Heat island: Surface and atmospheric temperatures are increased by anthropogenic heat discharge due to energy consumption, increased land surface coverage by artificial materials having high heat capacities and conductivities, and the associated decreases in vegetation and water pervious surfaces, which reduce surface temperature through evapotranspiration. An increase of ~2 to 2.5 ºC during the last decade highlights implication of explosive urban growth on local climate, necessitating appropriate strategies for the sustainable management of natural resources.
  • Ecosystem goods and services: Valuation of tangible benefits (fish, fodder, drinking water, etc.) reveal that wetlands provides goods worth Rs. 10500 per hectare per day (compared to Rs 20 in polluted lake), and sustains the local livelihood. This also emphasises the need for rejuvenation and sustainable management of water bodies.

The restoration and conservation strategies has to be implemented for maintaining the ecological health of aquatic ecosystems, aquatic biodiversity in the region, inter-connectivity among lakes, preserve its physical integrity (shorelines, banks and bottom configurations) and water quality to support healthy riparian, aquatic and wetland ecosystems. The regular monitoring of water bodies and public awareness will help in developing appropriate conservation and management strategies.

The success of rejuvenation depends on:
  • Good governance (currently too many para-state agencies and lack of co-ordination). Single agency with the statutory and financial autonomy to be the custodian of natural resources [ownership, regular maintenance and action against polluters (encroachers as well as those contaminate through untreated sewage and effluents, dumping of solid wastes)]. Effective judicial system for speedy disposal of conflicts related to encroachment.
  • Digitation of land records (especially common lands – lakes, open spaces, parks, etc.) and availability of this geo-referenced data with query based information system to public;
  • Removal of encroachment of lakes / wetlands, lake beds and storm water drains (connecting feeders)  after the survey based on reliable cadastral maps; Ensure proper fencing of lakes and to make land grabbing cognizable non-bail offence;
  • Restriction of the entry of untreated sewage and industrial effluents into lakes; Decentralised treatment of sewage (preferably at ward levels). Letting only treated sewage into the lake (as in Jakkur lake); Ensure that sewage generated in a locality /ward is treated locally;
  • Removal of nutrient rich sediments – to enhance the storage capacity, improve groundwater recharge, to minimise further contamination of treated water, etc.; De-silting of lakes has to be done on priority (at least once in three years) to enhance the storage capacity as well as to remove nutrient (N and higher amounts of P) enriched sediments. De-silting of lakes helps in recharging ground water and further treatment (as soil acts  as filter).
  • Ban on use of phosphates in the manufacture of detergents; will minimise frothing and eutropication of waterbodies;
  • Regular removal of macrophytes (Eichhornia sp., Alternanthera sp. etc.) in the lakes;
  • Implementation of ‘polluter pays’ principle as per water act 1974;
  • Planting native species of macrophytes in the buffer zone (riparian vegetation)  as well as in select open spaces of lake catchment area;
  • Stop solid wastes and construction debris dumping into lakes / in the lake bed; Ban on filling a portion of lake with building debris.
  • Restrictions on the diversion of lake for any other purposes;
  • Complete ban on construction activities in the valley zones.
  • Decentralised management of lakes through local lake committees involving all stakeholders

Current Status


  • Poor water quality
  • Regular harvesting of macrophytes – helps in curtailing nutrients accumulation
  • Improve aeration – (a) installing fountains, removing all blockages, (b) widening and increasing number of channels / outlets
  • Stop dumping of municipal solid waste
  • Evict all waste processing units (in the vicinity of lakes and lake bed)
  • Stop dumping of construction and demolition (C & D) wastes in Rajakaluve, Valley zones and Lake beds
  •  Strengthen legal cell (at BBMP, BDA, Forest Department, KLCDA) to address all illegalities  and evolve fast track mechanism to speedy disposal and eviction of encroachers and for penalising polluters
  • Ensure that all apartments let only treated water to the lake. Implement mechanisms such as separate electric meters (net metering) and updating of details at respective resident association websites (including a copy at BWSSB web site)
  • Providing water quality details (each apartment discharge) – inflow to the lake at respective resident association websites (including a copy at BWSSB web site)
  • Functional ETP’s to ensure zero untreated effluent discharges by industries. KSPCB to ensure zero untreated effluent discharges.
  • Evolving surprise environment audit mechanisms to ensure zero untreated effluent discharges to storm water drains (and lakes). Vetting of inspection report by the respective resident lake association.
  • Installation of surveillance cameras at the outlet of BWSSB STP (inlet of the lakes) and availability of electricity consumption details and surveillance camera streaming details to the public (through cloud sourcing or any other efficient and optimal mechanisms)
  • Formation of local residents association for each lake involving of all stakeholders to aid in regular monitoring and management.
  • Evolve mechanisms to make respective elected members (councilors, MLA and MP) and local ward engineers and bureaucrats accountable for lake and open area status in their respective jurisdiction.
  • Physical integrity of lakes and storm water drains
  • Surveying and mapping of water body (including flood plains) and buffer zones (30 m as per BDA; 75 m as per NGT)
  • Surveying and mapping valley zones (eco-sensitive zone as per RMP 2015, and green belt as per CDP 2005). Remove all encroachments without any consideration.
  • Recover the area identified for setting up STP (40 acres as per RMP 2015) in the region between Agaram and Ballandur lakes
  • Remove all encroachments (lake bed, Raja kaluves, storm water drains) to prevent calamities related to floods
  • Identify the common lands, kharab lands, streams, drains, tracks and paths (as per cadastral / revenue maps) in K and C Valley and on priority between the Agara, Bellandur and Varthur Lakes. This land would be useful to setup waste water treatment plants (STP’s) and constructed wetlands.
  • Identify the areas required for setting up decentralised treatment plants (and if required mechanisms to acquire these lands for public utility)
  • Alteration in topography and unplanned concretisation

Refrain from granting any consent for establishment of large scale projects in the immediate vicinity of lakes with immediate effect (Bangalore is undergoing unplanned, un-realistic urbanisation)

  • Fragmented, un-co-ordinated lake Governance
  • Strengthen KLDCA – single agency / custodian to address all issues related to lakes (including maintenance, monitoring, management and removal of all illegalities) and interconnected drains. This helps in minimising fragmented governance.
  • KLDCA shall be managed only by an administrator knowledgeable of lake issues.
  • Scientifically competent committee with active academic institution tie-up for regular monitoring and to address the lake issues.


Short and Long Term Measures

Current Status



  • Untreated Sewage
  • No more untreated sewage diversions in the city.
  • Decentralised treatment of sewage (city sewage as well as local sewage in the vicinity of the lake). Model similar to Jakkur Lake – STP with constructed wetlands and algal ponds.
  • Removal of nutrients;
  • Helps in reuse of water;
  • Removal of contaminants;
  • Regulates nutrient enrichment;
  • Recharge of groundwater without any contaminants
  • Untreated Industrial Effluents

Enforcement of ‘Polluter pays principle’. Ensure zero discharge through efficient effluent treatment plants.

  • Heavy metal will not get into food chain. Currently vegetables grown with the lake water has higher heavy metals
  • Less kidney failures and instances of cancer in the city
  • Nutrient enriched sediments

De-silting of lake (wet dredging / excavation).

  • Efficient mechanism of rainwater harvesting. Water yield in the catchment is 5.3 TMC and storage capacity of lakes is about 7.5TMC.
  • Increase the storage capacity
  • Enhances the groundwater recharging potential
  • Encroachment of lakebeds, valley zone and rajakaluves

Evict all encroachments.

  • Common lands  would be available for setting up STP, wetlands
  • Removal of encroachments of Rajakaluves and drains would re-establish interconnectivity among lakes so that water would move from one lake to another, enabling treatment of water (through aeration)
  • Regular maintenance of macrophytes

Macrophytes harvesting at regular interval

  • Helps in further treatment of water as macrophytes uptake nutrients and regular harvesting would prevent accumulations
  • Supports livelihood of local people
  • Scope for generating energy (biogas)
  • Frothing and fire

Ban phosphorous use in detergents or regulate detergent with phosphorous in market

  • Reduces eutrophication of lakes(nutrient enrichment
  • Minimises the instance of frothing
  • Minimises health issues  (skin, respiratory, etc.) related to contaminated air;
  • Reduces accident instances
  • To cater the local water demands
    • Rejuvenate all lakes and reestablish interconnectivities;
    • Create more lakes supported by natural vegetation cover in its catchment
  • Re-Create more spaces with both riparian (in the buffer zone of a lake) and natural vegetation (in lake’s catchment – at least 33% green cover),which acts as barrier against flash flooding and allows controlled release of water during post monsoons.




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