[Assam] Rainwater harvesting in hilly areas holds key(The Assam Tribune, Saturday, August 02, 2008)

[Buljit Buragohain]

Rainwater harvesting in hilly areas holds key

By Ajit Patowary
 GUWAHATI, Aug 1 – Two IIT-Guwahati (IITG) study projects on Guwahati flash floods, between 2002 and 2006, found that effective rainwater harvesting in the hilly areas of the city would be able to reduce around 80 per cent of the storm water run-off.

The scientists conducting the studies suggested that for the topography and environment of the low-lying areas of the city changghar type structures were the most suitable ones. The practice of earth filling in those areas was also responsible for the menace of flash floods the city had become notorious for.

And for the hilly areas of the city, they found the ridge-facing houses as the most suitable structures for abodes, said Prof Arup Sarma, who led the studies.

The scientists involved in the 2005-06 study also suggested, besides the above, two storage points in the Meghalaya hills, restoration of the water holding capacity of the city wetlands, installation of automatic rain gauges with online information facilities at places like Narengi, Hatigarh Chariali, Zoo, Silpukhuri, Rupnagar-Birubari, Srumataria etc.

They also suggested sluice gates with pumping facilities at 20 different locations where storm water routes were there.

Besides, they called for measures to bring an end to the practice of haphazard disposal of garbage, blockage of water channels by pipes, wires and supporting structures of the bridges etc.

Moreover, the compounds of the city localities should also have permeability to provide infiltration of rainwater. The use of surface water instead of ground water should be encouraged as well to avoid additional load of water on the channels as well as sinking of the ground water table and thereby self-poisoning, observed the IITG scientists. 

According to Prof Sarma, the first study project was carried out between 2002-04 with him as the Principal Investigator. The other members of the team were—Dr V Chandramouli and Dr B Singh— who were Co-investigators of the project. The Union Human Resource Development Ministry sponsored it.

The second project was undertaken by the IITG as its own academic project with Prof Sarma as the Project Guide and his students as the team members. 

The first study project found that the denuded city hills used to lead to a rise in the sediment yield in their adjacent plains by ten times. Moreover, such hills lead to a 20 per cent rise in the water yield, that is, storm water run-off, in their adjacent plain areas.

A complete vegetation cover reduces the sediment yield by around five times and water yield by around 20 per cent, found the IITG scientists. They came to the conclusion that land-use development and housing development planning in hilly areas would reduce both sediment and water yield.
 
 
(The Assam Tribune,Saturday, August 02, 2008) 

 


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