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ENVIS Technical Report 131,   October 2017
KORAMANGALA FLOODS: CAUSES
      
Mismanagement of Landscape: Abuse of Bellandur-Agara wetlands, Narrowing and Concretising RajaKaluve and
encroachment of storm water drains, Dumping of solid waste & building debris, Apathy of Civic Agencies
T.V. Ramachandra        Vinay S        Bharath H. Aithal
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Section 1
Section 2
Section 3
Section 4
Section 5
Section 6
Section 7
Section 8
Section 9
HIGHLIGHTS

Flooding in Koramangala locality is mainly due to

  1. The abuse of wetlands with the Construction activities in the valley zone (SEZ by Karnataka Industrial Areas Development Board (KIADB)) of Agara-Bellandur Lake. Wetland was earlier aiding in retaining the rain water, ground water recharge and bioremediation
  2.  dumping of construction and demolition wastes in the wetland region, (iv) alteration of topography in the region and
  3. removal of storm water drains (connecting Agara- Bellandur lakes),
  4. narrowing and concretising rajakaluves (connecting Bellandur lake from Agara as well as S T Bed sides)

During the field work on 1 May 2017 along with CEO, KLCDA it was observed

  1. Rajakaluve (storm water drain) connecting Bellandur Lake from city market side is narrowed to 28.5 m against the original width of 60 m (Figure 1) and also violating recent NGT guidelines (of maintaining storm water drains physical integrity as well as maintaining the buffer). This is mainly to help the encroachers of storm water drains while bypassing NGT’s guidelines of storm water drain buffer regions
  2. Concretisation of storm water – this would affect the hydrological functional ability of storm water drains – ground water recharge, remediation and flood mitigation
  3. Concretization and narrowing the drains has only enhanced the flooding in the city, observed recently (15th August 2017, 24th August 2017).
  4. implications of concretization: Impaired Ecosystem Functions - bioremediation and groundwater recharge (but maximization of benefits to consultants with frequent floods)
  5. BBMP while wasting the public money has made Bangalore landscape vulnerable with frequent floods.


Figure 1: Rajakaluve A: from Agara Lake to Bellandur Lake

Reduced Channel size (senseless narrowing drains violating NGT guidelines to
maintain integrity of storm water drain with buffer) – drain itself is reduced by 50% (Cadastral map – 45 m, current width as per Google Earth: 20m)

Flooding is a consequence of mismanagement of wetlands,  narrowing Rajakaluves (storm water drain) and the removal of first and second order drains. Irrational decision of SEZ in wetlands has enhanced the flooding episodes in the region and citizens are now vulnerable to recurring flooding hazards (with increased precipitation and associated factors). CITIZEN ARE PAYING (WITH THE DAMAGES TO PROPERTIES AND LOSS OF LIFE) FOR IRRATIONAL DECISIONS OF DECISION MAKERS.

RECOMMENDATION:

  1. RECOVER WETLANDS (BELLANDUR-AGARA) AND RESTORE INTEGRITY ON PRIORITY -Shift  the proposed SEZ (in the ecologically fragile Bellandur-Agara wetlands) to other location in Karnataka immediately,
  2. Reestablish interconnectivity among lakes by removing all blockades (encroachments, solid waste dumping)
  3. Restore removed drains - Maintain the integrity of drains (as per cadastral maps) and reestablish connectivity through drains
  4. Protect Valley zones and Buffer regions of wetlands: protect valley zones considering ecological function and these regions are ‘NO DEVELOPMENT ZONES’ as per CDP 2005, 2015
  5. Restore wetlands (between Agara and Bellandur lakes) and set up STP (Sewage Treatment Plant) with constructed wetlands (similar to Jakkur Lake) in this region.
  6. Stop narrowing and concretising natural drains
  7. Remove the compound wall altering the hydrologic regime – leading to escalation of flooding impact
  8. Penalise decision makers for violation of norms – acquiring wetlands (valley zone) for industrial activities, narrowing and concretising natural drains, allowing constructions in lake (wetlands) bed and in drains, deliberating violating NGT guidelines of buffer zone  for lakes and Rajakaluves (narrowing drains to help encroachers).
  9. Single Agency to manage lakes (preferably KLCDA as per 5 June 2015 Gazette Notification and Wetlands Rule 2016, GoI) – currently fragmented governance with too many para-state agencies (inefficient, incompetent and deliberately mismanaged)