Drains clogged with dung, wires
UNCLOGGING THE CAPITAL Delhi govt report recommends separate sewerage and storm water drainage systems to prevent waterlogging
Why do even light showers leave Delhi’s roads flooded? Why do labourers die while cleaning drains? Why do drains remain constantly choked despite dredging?
A Delhi government report says that the network of storm water drains in the city carries almost everything from cow dung to untreated industrial waste, garbage to construction waste and even power cables.
The report, prepared by a committee of chief engineers of PWD and civic bodies, has recommended separate sewerage and storm water drainage systems to prevent waterlogging and outbreak of epidemics.
The report has been prepared after chief minister Arvind Kejriwal said that manual scavenging of drains should be done away with and suggested that possibility of mechanised cleaning of drains should be explored.
Sarvagya Kumar Srivastava (engineer-in-chief PWD), VK Jain (chief engineer, irrigation and flood control), PC Meena (engineer-in-chief, East DMC), Umesh Sachdeva (engineer-in-chief, South DMC) and Vijay Prakash (engineer-in-chief, North DMC) were part of the committee that submitted the report last week.
As per the report, Delhi has a drain network of 3,468km managed by nine agencies. In 2016, the agencies removed 11,89,000 metric tonnes of silt from the drain.
“Ideally, storm water drains should carry only the rainwater, but there are a large numbers of colonies that do not have a sewerage system and the sewerage discharge from these colonies flows into storm water drains. As a result, the drains carry the discharge round the year and are filled with not only sewage but also solid waste in some cases,” the report said.
According to the report, the main cause of flooding is blockage of natural water flow.
“Over the years, hundreds of colonies have sprung up in across Delhi. Majority of the colonies are situated on the ‘Original Flood Plains’ of Yamuna. In addition, natural water bodies have been encroached upon. These factors have resulted in blockage and in some cases disappearance of natural water courses. Rainwater, when it does not get entry into natural water bodies or water courses, finds its way to flow into surrounding roads or habited areas and thus causing flooding in the area,” the report said.
The report also blamed mushrooming of illegal colonies for the problem. “These colonies have come up in an unplanned manner and have no provisions for basic civic amenities including sewerage and drainage,” it read.
The study found that in the absence of a proper sewerage systems, large drains cater to the mixed flow of the sewage and storm water. The drains, designed for storm water, carry additional load of sewage and even solid waste generated by nearby households and commercial areas. This results in flooding even with a minor downpour.
“Another cause responsible for flooding is the dumping of solid waste, garbage, cow dung and construction and demolition waste,” the report said.
The report also flagged poor sweeping mechanisms in Delhi as road waste/ garbage is dumped in storm water drains.
“Cow dung is disposed of into storm water drains from dairies spread across the city. This results in blockage of drains that are not designed to cater to this. These drains have to be cleaned regularly to keep them flowing,” the report said.
The panel has recommended an investment of ₹3,100 crore in latest technology for mechanised cleaning of drains. For long term solutions, the committee has recommended building a sewerage system and adequate number of treatment plants.
Delhi water minister Rajendra Gautam said about 50% of the city, most of which has unauthorised colonies and some villages, is yet to come under the sewage network. “We are working on it. There are issues regarding regularisation of unauthorised colonies but we are still trying to make sure that all residents are part of the water and sewer network,” Gautam said.
According to Delhi Jal Board officials, more than 7,000km of sewage lines will be added to the existing network by 2031 and it will incur a cost of ₹20,000 crore.
A Public Works Department official said the agency is working on solutions.
“Delhi needs a large-scale