GUWAHATI: This monsoon, the city has received at least three rounds of heavy downpour - the kind that would have otherwise inundated the flood-prone areas of the city for at least 5-6 hours. And yet, the city has not registered a flash flood of high magnitude reminiscent of earlier years.
The Guwahati Metropolitan Development Authority (GMDA), one of the main civic bodies executing various projects to curb water logging, credits this development to the two-pronged approach taken this year – commissioning the Noonmati Drainage system and the de-siltation drives undertaken by GMDA, Guwahati Municipal Corporation (GMC) and Public Works Department (PWD). The Noonmati Drainage System connects the water flow from Sunsali Hill, Jyoti Nagar, Noonmati, Sector I onto Narengi before emptying out into the Brahmaputra River at Bonda.
“The localities of Nabin Nagar and Anil Nagar act as a natural basin in the city where water from the Jyotinagar and Sunsali Hills flows in via Noonmati, Bamunimaidan and Zoo Road inundating those areas too. The Bharalu River, thus, gets overloaded and causes floods. We have diverted that water through the new drain which will be channelled directly into the Brahmaputra through Bonda Jan area,” Debajit Das, chief engineer of GMDA told G Plus.
“The pump capacity right now is enough to draw out the water coming down from the hills as is evident from the lack of flash floods this year. As the load increases in the coming days, we will increase the pump capacity as and when required,” Das added.
This comes as a breather for the city dwellers, especially those living in Zoo Road, Nabin Nagar, Anil Nagar areas, as even until the last monsoon, these areas were found inundated by flood water for 12-24 hours.
“It is the beginning of July and we have almost reached the end of the monsoon. But there were no major flash flood woes in the city. It happened in a few select areas but the water receded within half an hour which is quite impressive as compared to the past few years,” Dwipen Deka, a resident of Junali area, said.
Last year, Deka’s residence was inundated for almost 12 hours by water overflowing from the Bharalu River damaging his furniture and books in the ground floor.
Regarding the de-siltation drives, Das said, “The de-siltation works are jointly conducted by GMDA, GMC and PWD in different parts of the city. While the GMDA has dredged the major water bodies such as Seelsako, Pamohi and Barkhola, the GMC and PWD had dug out the major drains in the city.”
Rs 115 crore drainage project by NHAI to solve all flash flood troubles: GMDA
The Rs 115 crore worth drainage project to divert storm water flowing from Meghalaya to the Basistha River that is awaiting sanction from the National Highway Authority of India (NHAI) is expected to solve all the flash flood problems of the city.
Most of the city's flood water was channelled naturally through the Bharalu and the Bahini Rivers. With a rise in the city’s load on those rivers due to lack of a sewerage system, the rivers, during monsoons, used to get overloaded. To mitigate this, GMDA was using water pumps. Although the system gave momentary relief, heavy showers often brought misery to the residents.
While the Bharalu River was burdened by water coming from the hills in the city, there often used to be flooding in the Khanapara and Basistha areas of the city due to storm water coming down from Meghalaya. There was no channel to take that water through a particular route.
“The plan was to make an alternative channel through which the water coming down from the hills in Meghalaya will be channelized into the Basishta River. GMDA had conducted a survey and assessed the amount of rainwater that comes down from the hills of Meghalaya during peak rain. A channel is being constructed within the Assam border to collect the rainwater and channelize it to the Basistha River," Dhiren Baruah, former chairman of GMDA had said when he was in office until a few months ago.
The National Highway Authority of India (NHAI) was asked to complete the project under the supervision of GMDA.
The detailed project report was sanctioned by chief minister Sarbananda Sonowal last year.
"The first phase of project cost of Rs 115 crores has already been commissioned,” Baruah had added.
Debojit Das, chief engineer of GMDA, said that the authority is awaiting sanction from the NHAI’s end.
“Once the NHAI sanctions the project, work will start on war footing. All the assessments have already been done. Once this project is completed, there won’t be any flooding along the GS Road,” Das said.
He added, “Currently, the bulk of the city’s storm water pressure falls on the Bharalu and Basistha Rivers. We can also use the water bodies around and the other channels.”
While this project is awaiting sanction, the GMDA is also trying to clear the Deepor Beel so that it does not get overloaded by the water pressure on it and the aesthetics of the Ramsar site water body can be kept intact.