Floodings increased in Mumbai , Why ? An integrated approach to Permanent Solution
We wish to share with all some basic technical issues related to solving
the yearly flooding problems of Mumbai during the monsoons.
1. The standard excuse by BMC – SWD engineers for floods is that ” you are
in a low lying area “. Every one knows that Mumbai has been
created by reclamation of the Arabian sea , so Mumbai being low
lying in the context 26/7 deluge has always been vulnerable to flood events. It is in this context that Watson UK was appointed by GOM to study in 1991 and recommend solutions to Floodings.
2. The land of Mumbai in most places is at sea level or even
below sea level . It means that the daily high tides and
particularly the Highest High Tides ( HHT ) will force large mass of water
into the land unless there is a method of stopping the water from
entering the residential areas and draining back the water into the
sea.
3. On behalf of the Guzdar Scheme Residents Trust we have had the
opportunity to interact with the Chitale Commission ( to study causes and recommend solutions to the 26/7 floodings ) in 2005 , and understand from their report that there are several positions ( over 180 ) in the city of Mumbai which are flood prone , eg. Guzdar area in Santacruz(W); this information is not new but known to BMC for over a decade ; so what long term and permanent solutions have the BMC/ GOM implemented ! None whatsoever otherwise the 26/7 deluge could have certainly been avoided.
4. All over the world , the method of preventing high tide waters from entering the residential areas along the coast is :
a) to retain swampy/marshy lands which act as sponge areas and absorb the surplus waters.
b) Make available open lands for recreation and parks which in extreme situations can hold the surplus water or act for seepage into the soil.
c) to design and erect flood or sluice gates which are closed during high tides – stops sea water from entering the land – and during the low tides kept open –
allows the sea water to flow back into the sea.
5. Study the eg of Holland which lies 7 ms below sea level ,
with design of dykes the country has prevented flooding from most
of the hurricanes and storms.
6. The sea ward side of the flood gates is the outfall of the
sea and no constructions should ever have come up . But what is
the reality ? In collusion with land sharks , bureaucrats and
politicians , the natural mangroves are massacred and the sea filled
up with generous donations of debris by the sharks all along the
West Coast of Mumbai despite the MOE & F regulations. How can the
GOM allow such flagrant violations of the CRZ laws.
7. A report from Chitale Commn. ( appointed by the CM post 26/7 )
on the study of Mumbai floods , reminds BMC that flood gates had
to be put up in over 180 positions and only 7 or 8 are existing.
One must ascertain the location of these to be installed flood gates and what
each gate will cost – design and cost of each flood gate will be different depending upon the high tide levels and the local topography.
8. We are aware that Watson , the UK based Hydraulics Co.
generated the Brimstovat report in 1992 / 3 and recommended solutions
to stopping the floods in the entire city of Mumbai with costs ,
eg. the Green Street / P & T Nallah in the GSRT, Santacruz (W) area.
The BMC slept over it for over 10 years – why ? – the standard
excuse given by all in the BMC including the MC is that it could not be implemented because of Funds. The recent expression by BMC- SWD engineers is that the Brimstovat report is outdated , an outright false statement.
9. Funds availability , we all know is not at all the problem as even annual budgets are not fully utilized . The issue is how systematically without concern , the Govt. is throwing away precious Funds allocated for Long Term and permanent solutions into the drains by compromising with only short term solutions , ignoring the long term and sustainable solutions . By strict monitoring during every stage of implementation vis a vis International Standards as well as expenses , crores of Rs. can be ploughed back for ensuring Projects that conform to World class Quality .
An independant Experts Committee with residents participation must
investigate what follow up actions were taken in the BMC on the
Brimsovat report and why the recommendations were not implemented.
Names of those responsible for negligence must be made public.
10. A study made during the British days – we are not aware if the
study has been updated at all since then – states that based on the HHT levels recorded of 27.05 m , a Datum line was fixed on the Town Hall steps – mark
available even today – the minimum plinth levels of buildings was
fixed at 28 m ie all bldgs ground floor levels had to be above
28 ms so that in the worst case the flood waters would not enter
the houses. It should be noted that based on the rising of sea levels
( an universal phenomena ) , a height of 28 m appx, was fixed , 1 m higher than
the HHTL , so as to avoid floods inside the ground floors for at
least a century. In the light of the fact that the glaciers are
melting at a higher rate , the study of future prediction of HHT levels vis a vis Mumbai has to be carried out by an Internationally recognized experts body.
11. Most bldg. plinth levels in the city of Mumbai are as per the
standards of 28 m laid down in the pre independence days.
12. It is a wrong impression created by the Govt. that because
the rains in Santacruz were far higher than Colaba the flooding
took place . Rains of intensity of 944 mm as on 26/7/05 would have
taken place in the last century , no one can say ‘ it did not’
as we did not have the recording mechanism except in Santacruz
which can detect only within a 5 km radius.
13. Most of the developments in the suburbs took place post
independence and the GOM/BMC did not bother to restudy the HHT
lines and fix the min plinth levels for the different localities
in the suburbs nor follow the rules laid down for the island
city.
We have studied that many plinth levels in the suburbs are well
below 28 m and no flood gates have been installed ; also the natural creeks/sea, flood basins and natural wet lands have been encroached upon or filled up ;
so what is surprising that floods take place regularly in the suburbs of Mumbai ?
14. In the Guzdar Bandh area the 4 flood gates were pulled down 6
years back – a political decision – and till today they have not
been reinstalled ; the floods have intensified over these years and
yet the GOM has not implemented a permanent solution despite the
Hon. High Court Directions starting from 2001. Why are Tax paying citizens being victimized year after year ?
15. Also persistent raising of roads over the past 4 decades has resulted in the levels of roads with respect to the mean sea level being raised several feet higher than the plinth levels of buildings ; in fact the road levels are universally designed to be below the plinth levels in coastal areas so as to avoid flooding inside the houses.
As very rightly expressed it is questionable if spending this 1200
crores will at all guarantee and bring permanent relief from floods
to all the citizens of Mumbai.
We learn that there is a move in the Govt. to engage Watson again to
take up the study and come out with solutions for the whole of Mumbai .
Our recommendation is that a team of BMC engineers , Watson and
knowlegeable citizens must be made jointly accountable for both
Quality and Timeliness of Implementation and be allowed to take
decisions on monitoring for Quality work of Contractors and
shortening the approval procedures to shorten the cycle time ; if
need be Govt. should bring in a special legislation to handle the entire
Flooding project
We believe the right solution to prevent repetitive flooding of Mumbai or for that matter prevent a catastrophe from a Tsunami is beyond the comprehension of the BMC engineers and needs study by world class Geophysical and Civil engineers.
The real solution lies in having the best world brains and come out with an Universal Technical and permanent solution that will guarantee Mumbai to be a flood free mega city.
The cost of this massive project should in no way be a deterrent as Private or
World Bank Funds will come in as long as there is a highly professional/experts approach that strictly adheres to International specification during implementation, be by Govt. or Private enterprise.
The task of making Mumbai flood free has to be one of the two top priorities along with affordable housing for slum dwellers, for the Govt. of Maharashtra to change Mumbai into a World Class Mega city.
Prepared by the Technical Team of Guzdar Scheme Residents Trust
Dr. N.Desai , ex Director National Institute of Oceanography & Practicing Consultant
Mr. J.N.Soni, ex Sr. Scientist BARC & Practising Enterpreuneur
Mr. S.D.Patrawala , Civil Eng & Practicing Consultant
Mr.P.K.Mukherjee – B.Sc. G & G , I I T , Kgp. & .;Practicing Mngt Consultant
9th Nov 2006
from-
Email- proschaya@vsnl.com