What lies beneath our city
Last month, this newspaper reported that a water body was discovered at around seven metres under the 86-year-old heritage building of KEM hospital. When workers were drilling the ground, water spouted out. On drilling further, architects found water flowing underneath the building. The discovery created a minor stir.india Updated: Jul 15, 2012 01:06 IST
Last month, this newspaper reported that a water body was discovered at around seven metres under the 86-year-old heritage building of KEM hospital. When workers were drilling the ground, water spouted out. On drilling further, architects found water flowing underneath the building. The discovery created a minor stir.
Built in 1926, KEM Hospital is a Heritage Building, a protected structure. This is praiseworthy. But the land on which it was built is about 60 million years old and merits a much stronger claim to our protection. Do we even know what that land looks like?
Mumbai, we are repeatedly told, is the agglomeration of an archipelago. Some of its islands are still identifiable as discrete entities. Having spent the past four years trying to understand a small hill on the largest of these islands, I know all too well the difficulties of trying to understand landforms in a repeatedly razed-and-overbuilt landscape. Human memory is brief and selective. Our city nourishes a thriving industry in potted histories — all these are anecdotal and largely unverifiable. So where does one look for clues?
I was lucky to be able to tour these islands with observers who jotted down their observations when geology was still a new and exciting science. Their notes and occasional maps showed me what lies beneath. Therefore I’m unfazed by this upwelling under KEM Hospital.
A century before 1926, the land in this area was still unbuilt. Let us scrutinise the co-ordinates during that period. To the west was the central basaltic tract of volcanic rock. To the east were ‘The Flats’— central marshy land that extended between the rocks of Worli in the west, Mahim in the north and Malabar Hill in the south. In the frenetic phase of empire-building that followed the First War of Independence, a great deal of the island was exposed — and examined. We’ve forgotten that. We’ve forgotten also that every time a pipe was laid down or a ditch dug there was a geologist taking notes. These notes tell us that 36 feet beneath the central rocky tract of the island there was a freshwater stratum. Once upon a time, this region was a coastal lagoon. The entire urban spread of central Mumbai sits atop this lagoon. Our surprise about the water body below KEM is a measure of both our naivety and ignorance.
Mumbai will not behave very differently from other coastal cities built on lagoons. Venice is a disaster already. With sea levels rising globally, we can expect the same of other locations with similar geomorphologies. The fact that water has been found seven metres beneath KEM Hospital suggests that the rising sea level has already opened up ancient water channels that nourished this prehistoric lagoon. It is not unreasonable to predict that in the future Mumbai will become a city of concrete unmoored over a filling lagoon.
It is imperative for the city to plan its development in accordance with the natural geomorphology of its islands. As sea levels rise, erased landforms will reveal themselves. Lost rivers will reappear, as they did in the flood of July 26, 2005. The land will reassert itself and impose its supremacy over our human invasion. What will we do about that?
Kalpana Swaminathan and Ishrat Syed are surgeons who write together as Kalpish Ratna. Their new book Once Upon A Hill is in bookstores now.