Cuttack, July 25: The reappearance of silt loads in the main and branch drains in several places across the city have left the civic administration worried.

The recurrence of silt has reduced the carrying capacity of the drains.

The annual de-silting operation is taken up ahead of the monsoon to prevent waterlogging and inundation of houses. The municipal corporation spends nearly Rs 2 crore on it every year.

The civic body had claimed that the exercise, which covered the entire drainage system of the city, was completed by the first week of July. However, heavy rain on the night of July 16 had led to acute waterlogging and inundation of several areas with sewage flowing on the streets, trapping more than two lakh people in their homes.

The situation was attributed to 112mm rainfall in less than 90 minutes as compared to the 12mm rainfall per hour that the city drains have the capacity to manage.

Sources in the corporation's engineering division conceded that a spell of heavy rain now could spell more disaster as the carrying capacity of the main and branch drains had gone down by nearly 50 per cent in several stretches because of silt deposition.

Besides, the silt that was left after the water receded from the waterlogged areas was also adding to the problem with the public dumping more solid waste on them.

"We have launched a fresh exercise today to clear all the blockages in the form of sediments and solid waste to make the drains rain-ready in the next 24 hours," municipal commissioner Bikash Mohapatra told The Telegraph today.

According to corporation engineers, the drains in the city do not have the required gradient and this results in silt being deposited faster than the amount the flowing water can wash away.

Completion of the Japan International Cooperation (Jica)-assisted mega sewerage and drainage project is expected to fix the perennial problem of waterlogging in the city.

When completed, the city will, for the first time, get a separate drainage and sewage system, resulting in decrease in load on the drainage system, an engineer said.

As part of the project, the 22km-long open main drain and connecting drains will be refurbished by way of concrete flooring, heightened sidewall and cover.

Work on this project is no continuing on different stretches measuring up to a total length of 7km.

"The blockages due to silt load and solid wastes in the main drains have been formed in the stretches where the Jica project's concrete flooring work is in progress," the corporation's chairman of standing committee for sanitation Ranjan Kumar Biswal said.

"The engineering division has identified major blockage points in the main drains and branch drains in Tulsipur, Sutahat, Patapol, Meria Bazar, Bajrakbati, Malgodown and Matrubhawan. The blockage clearance operation has been undertaken today accordingly," Biswal said.

Professorpada resident Biranchi Narayan Mishra said: "Silt loads were excavated from the main drain and branch drains Bajrakbati till here a month ago. But it is evident that silt has formed again."

The city's entire drainage system is around 1729km long with 22km of main drains, 159km of branch drains and nearly 548km of tertiary drains.