Mumbai urban drainage

Question 1

human factors

Answer 1

140 year old drainage system
cant cope with monsoon season
depletion of mangroces making room for e.g., prawn fishing
urbanisaiton means increase concrete (impermeable surfaces) - more surface run off
reclaiming of swamp land - building on top without properly draining
can no longer absorb water

Question 2

natural factors

Answer 2

monsoon season
Mumbai’s location (on peninsula)
global warming increasing sea level
flat topography - easily flooded
increase in extreme weather events (climate change)

Question 3

2005 Mumbai flood

Answer 3

over 1000 deaths
cost of damage $1.7 billion
Mithi river only body of water for rain to drain into
once 100s of metres wide - now only 40
change of natural course (international airport reclaimed land on the Mithi)
heavy focus on infrastructure and urban growth - Mumbai’s natural drainage paths have been concreted and built over
Total of 5300 acres of wetlands hold seawater outside of city to prevent flooding (alleviate risk)
2017 - opened for developed

Question 4

strategies suggested

Answer 4

building climate desilience
investing in natural and built infrastructure - e.g., mangroves, salt marshes, green roofs and urban wetlands
permeable paving (SUDS)
BMC strategy
improving governance and regulation - improve environmental governance