GUWAHATI, Oct 20 - An expert committee constituted by the State government to study the flooding problem of the Lokapriya Gopinath Bordoloi International (LGBI) Airport here, has recommended urgent steps to make a detailed basin and sub-basin level hydrological study of the Kalbhog and Kalmoni rivers with possible future land use and land cover change (LULC) scenario and with due consideration to climate change.
The committee, headed by Prof Arup Sarma of IIT Guwahati, maintains that this study will provide maximum possible discharge at different critical locations for design of adequate channel section for safe drainage of the surface water of the area.
It needs mention that the LGBI Airport and its adjoining areas, located on the southern side of the Brahmaputra, face frequent flooding during monsoon. The area receives stormwater from the upper catchments of Kalmoni and Kalbhog river basins, which because of drainage congestion, and also because of high water level of the Brahmaputra, cannot drain out the water to their ultimate outlet, the Brahmaputra.
Kalmoni river, which is to carry water to the Deepor Beel, is no longer carrying much water because of partial blockage of its main channel by various man-made structures. A major chunk of the water from this point rather moves through an existing irrigation channel towards the Kalbhog river, through agricultural and habitat area located on the southern part of the airport.
It was found by the expert committee that at the point where the Kalmoni has been diverted to meet the Kalbhog, the volume of Kalbhog water swells up with additional load from the Kalmoni.
Again, it is found at the NH crossing of the Kalbhog, near the Patanjali complex, that the downstream of the Kalbhog from this point is partially blocked by vegetation and several constructional activities are narrowing down its original channel.
The Padma Lake, located on the western side of the airport, has to play an important role in the drainage system of the airport area by receiving and retaining the stormwater from the airport side and releasing the same on to the Kalbhog river. But, over time, it has found its capacity getting reduced. This is because of the growth of human habitations on its periphery.
The existing Kalbhog sluice gate does not have adequate capacity to match the present rate of flow it receives. However, the Water Resources Department (WRD) has reported that the work order has already been issued for a new five-shutter sluice gate at this point.
According to the expert committee, the Greater Guwahati Drainage Phase-VI Channel of the WRD connecting Dakhala area, near Kukurmara, to Dora Beel, revealed that this drain was planned and constructed to drain out the water from Palasbari-Dakhala area. This drain could have been used advantageously to divert water from the Kalbhog river to Dora Beel by constructing a connecting channel from Kalbhog to the inlet of this point, which could have also helped in solving the problem of flood in greater Guwahati. But the constructional activities in this area have put a question mark on the scope of having such a connection now.
A significant change in land use has occurred in the airport and its adjacent areas because of construction of roads, houses, residential colonies and industrial and commercial units. Reduction in infiltration has increased the surface water volume and thus the channels which were adequate earlier, have been rendered inadequate.
While, because of land use change and reduction of depression storage the surface volume is increasing, the drainage capacities are also getting reduced because of encroachments in different forms. There is also the absence of a holistic planning for the drainage system in the area.
The committee also recommends removal of all blockages to the flow of the Padma Lake, Kalmoni and Kalbhog rivers. It further says the Guwahati Master Plan for 2025 ought to be reviewed to ensure adequacy of drainage provision. If required, for scientific development of this area the government may consider implementation of the Land Pulling Policy.