GUWAHATI, Dec 7 – To solve the flash flood problem of the city once and for all, the State Government should demarcate the areas earmarked in the Guwahati Master Plan as reserved areas by erecting boundary pillars at a distance of 15 metres to 30 metres around the areas.
Filling up of the low-lying areas within these boundary pillars should be prohibited and the Government should also acquire the plots of low-lying land belonging to the private owners, said Dr Binoy Kumar Das, one of the architects of the 1971 Master Plan for Water Supply, Sewerage and Drainage of Guwahati Metropolitan District.
He suggested that these areas should be dug and the soil thus collected should be used in erecting rampart-like structures around these areas and these highlands should be used for plantation. The dug-out areas should be provided with waterways. Water sports facilities may be developed in these areas.
The subterranean areas within the city, which are still free from human occupation, should be identified with the help of the GPS and acquired urgently in order to prevent their filling up and to facilitate their development as reservoirs.
The Government should make it mandatory for the Guwahatians to preserve individually the rainwater generated within their respective campuses and to use the excess rainwater to recharge the groundwater table. There should be provision for developing one-third of the free holdings of land as reservoirs.
These two measures would be able to reduce at least 30 per cent of the storm water pressure on the city drainage system. The Guwahati Metropolitan Development Authority (GMDA) and the Guwahati Municipal Corporation (GMC) should prohibit earth filling and construction activities within 15 metres of the city’s natural drainage channels – the Bharalu, the Mora Bharalu and the Bahini – with urgent steps. The Bharalu-Mora Bharalu conjunction should be widened in proportion to the width of the Bharalu.
The builders or the estate developers, who are developing large plots, should be made to develop one-third of the area being developed by them as stormwater reservoirs. The soil thus dug out should be used in filling up the rest of the plots. Such measures are adopted in Vietnam, where the reservoirs thus created are used for water sports, garden irrigation, etc., purposes.
The city drains should be provided with leaning cross-section cast-iron grills at regular intervals to capture the floating objects so that such objects could be removed easily.
Moreover, the storm water drains should not be provided with concrete bottoms and the side walls of these drains should have holes at regular intervals. Shape of these drains should be trapezoidal. Such provisions would make an amount of storm water percolate down and would thus help reducing the size of the storm water inside the drains.
Some reservoirs should be created at the crucial points of the foothill areas of the city to catch the stormwater rushing down from the hills. In creating such reservoirs, concrete walls should be built to arrest the flow of stormwater with provisions for releasing the stored water at a restricted pace.