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Journalism of Courage
Mumbai the financial capital of India solely depends upon its transport system. One day8217;s cessation of traffic registers a loss of Rs 50 crore directly and Rs 200 crore indirectly. During the monsoon period from June to September at least two to three times the train traffic is suspended along with 90 per cent road traffic getting out of gear.
To cope up with this phenomenon let us understand the reasons, steps being taken and the short and long term solution to reduce the disruption to traffic particularly railway traffic.
They are a constant source of flooding even during non-monsoon months. A knee deep water was existing under Milan subway on January 15, 1993. During high tide of 3.85 m, the Grant Road to Matunga on Western Railway and Byculla to Vikhroli along Central Railway main line, some portions of Wadala-Kurla section gets wet at cess level which is around 60 cm below average rail level. This happens even during non monsoon period. Thus tide level is the main constraint for maintaining free flow of road or rail traffic during rains.
On an average Mumbai records rainfall between 80quot; to 120quot; 2000 mm to 3000 mm. The present day drainage system was good enough for an intensity of 25 mm rain per hour, which has further been reduced to around 18-20 mm per hour intensity since the open area, which used to later lot of water to subsoil no longer exist. Characteristics of catchment area are also very dominant factor for draining out water.
The run-off has increased due to development of areas. It has changed normal drainage courses and the storm water which used to be gradient based now needs pumping along with the relocation, redesigning and provision of new drainage system, which can withstand the normal rainfall for next 50 years.
Under these circumstances the flood of certain critical areas like Grant Road to Mahim, Masjid to Vikhroli and Sewri to Kurla on railway tracks will take place at least thrice in a year.
Existing hydraulic deficiencies with the system which compared with flooding of the area, indicate severe blocks in the drainage channel, reduction in area of drainage channel due to other utilities and due to siltation. The heaviest water level above pair level was recorded on October 16 non monsoon month 1951, waterlevel 48242;-8quot; above Mahalaxmi platform level.
During a critical study of rainfall conducted between June 8 and 10, 1995 the rail traffic was closed down for 48 hrs between Dadar and Grant Road on WR and Masjid and Sion on CR. The result clearly indicated that during low tide, the water level was more than 300 mm above rail level and it is during this period when water started rising, the railways try to remove the rakes to safer places so that post-flooding services are not effected.
Some suggestions to improve the situation:
i Desilting operations on both railways and the BMC should start by March 15 every year;
ii All railway culverts are laid as silt traps, same should be modified on the BMC area also by proving silt traps by deepening or by side blooming with trap doors at every 500 mtrs of the drain system;
iii Encroachments along the drain should be cleared for at least 5 m from the side and where encroachment is on the top of the drain, the manholes on which huts have come up, should be cleared and enclosed as prohibited area;
iv To ease the run-off during high tide level the storage area my be increased by providing concrete structures under areas like Mahalaxmi Race Course and Shivaji Park; v Drainage in suburbs should be provided which can withstand next 100 to 150 years. The suburbs have developed at faster pace, than the city and most areas are having open drainage system. This may pose problems after 10 to 15 years.
Wherever gates have been provided like at Love Grove and Cleave Land Bunder, they should be closed well in advance of high tide during rains and opened immediately after the tide has started receding. This aspect is normally not coordinated by railways and the BMC resulting in delay for draining out trapped water in shortest possible time.
Topographically Mumbai is flood prone. We have to live with floods. Our efforts should be concentrated on operations which will cause less damage, less loss of time and decreasing the frequency of recurring floods. City needs different approach than the suburbs and we must wake up today to forestall the city conditions in suburbs tomorrow.
G L Masand is former executive engineer of Western Railways
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