Change in building code for rain harvesting

Dhaka,  Fri,  22 September 2017
Published : 09 Aug 2017, 20:43:21

Change in building code for rain harvesting

The Rajdhani Unnayan Kartripakha's (RAJUK's) move to change the city building code can give a mistaken impression at the first look. But once the objective of this move becomes clear, the city development agency is likely to receive generous applause. It wants rain harvesting on rooftop of all buildings in the city to be mandatory. In that case, a change in the building code is a prerequisite. In case of older buildings, the task will indeed be more challenging than in the case of relatively newer buildings. Under the project, the RAJUK wants to incorporate both rain water harvesting and ground water recharging. The purpose of rain water harvesting is clear enough. It will be reserved for everyday use. By doing so, it will also reduce the pressure on the underground water, the table of which has fallen drastically. The purpose of ground water replenishment is likely to have a mixed result, though. Why? For recharging, there is need for open space. Unfortunately, in this city concrete or asphalted roads and streets have covered most of the city's surface area. 

Notwithstanding the various constraints the initiative is likely to encounter, its merit cannot be undermined. The proposed building code is not only meant for buildings to be constructed, but also envisages to cover the existing 300,000 of them. Of these structures, 275,000 are residential and 40,000 are commercial establishments. If all these residential houses and commercial buildings have provision for rain water collection on rooftop and then retention in underground reservoir, the total amount of water stored will be of enormous quantity. In a wet monsoon like this year's, the collection of water can dispense with the regular pumping of water by the Water and Sewerage Authority (WASA). 

Here is an initiative that also calls for coordination between and among different agencies serving city dwellers. The city corporations and a few other bodies have unused lands at their disposal. If the water that accumulates on streets and roads could be channelised to the unused open spaces, the water could easily recharge the underground ultimately. Earlier it happened on account of the backyard water bodies such as ponds, canals and low-lying swamps within the city vicinity.  Most such water bodies now filled up, water cannot stay there and seep into the soil below. Reviving those water bodies is an impossible proposition. Now their alternatives have to be found out. 

Rain water harvesting is definitely one such alternative. But it will involve a massive programme. Architectural designs of roofs have to be appropriate for making this to happen. For the 300,000 buildings it will be a kind of retrofitting. Expert engineers will have to be engaged in accomplishing the job. Some of the old and dilapidated buildings will certainly prove unfit for such retrofitting. In that case, if there is extra space available, that space can be used for the purpose. The project will be a success during wet monsoons but not equally so during a monsoon like that of the previous year. The citizens of the capital must brace them for such a lean prospect as well at times.

Editor : A.H.M Moazzem Hossain
Published by the Editor for International Publications Limited from Tropicana Tower (4th floor), 45, Topkhana Road, GPO Box : 2526 Dhaka- 1000 and printed by him from City Publishing House Ltd., 1 RK Mission Road, Dhaka-1000.
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