Slopes of new city roads not helping water drain into Vaigai: Master plan

Madurai: The monsoon is yet to arrive, but pre-monsoon showers have laid bare Madurai’s continuing waterlogging woes. Though inadequate storm water drains and maintenance have been mainly blamed for this situation, lack of proper gradient for newly laid city roads towards Vaigai river has been cited as another factor which has worsened flooding. The city’s master plan released recently by the Directorate of Town and Country Planning flags this issue. The city’s stormwater drainage system is divided into northern and southern zones as the Vaigai runs through the centre of the city. The flow from the northern zone including contributions from the outer periphery catchments is directed to the river. In the southern zone, the river is at a higher elevation and slopes towards the southern periphery of the corporation area. Major retention water bodies like Sellur Kanmai and Vandiyur Kanmai in the northern zone manage the flow into the Vaigai. The east and north zones primarily discharge into the Vaigai while the southern part contributes to Avaniyapuram lake, Samanatham Peria Kanmai and smaller tanks.

According to the draft master plan, independent development of corporation roads without proper integration with drainage slopes towards the Vaigai disrupts water flow and exacerbates drainage. Blocked drain inlets further add to system disruptions and increased flood risks. Encroachments by commercial establishments affect the drainage sections. M Rajan of Vaigai Nathi Makkal Iyakkam says the problem has persisted for about 15 years after roads were developed near riverbanks. “New roads near the bank of the river such as Sourashtrapuram, Sellur and Arapalayam have caused water logging due to improper slopes. Although these areas are less affected because stormwater drains were laid a few years ago, they still experience flooding for 3-4 hours after rainfall,” says he.Illa Mugil, water conservation expert from DHAN Foundation, said concrete lining of 13 channels under JNNURM scheme and subsequent reduction in their width have severely affected the city's natural drainage system. Approximately 800 kilometre of stormwater drains and concrete lining of channels for around 50 kilometre were executed at Rs 275 crore under JNNURM by Madurai corporation. “The concrete lining causes silt to be deposited, which remains due to garbage dumped by residents and plant growth in these temporarily stored silt deposits,” he said.Water experts have called for a comprehensive study of Madurai's drainage system to determine the real slope pattern of the city. P S Navaraj, a member of Madurai Water Forum, said, “The corporation should collaborate with experts to study the roads and drainage patterns.”A senior corporation official said that a Detailed Project Report (DPR) for providing integrated storm water drains (ISWD) in Madurai city is under preparation. It involves comprehensive review and integration of existing, ongoing or proposed stormwater drainage projects. Detailed topographical and levelling surveys followed by hydraulic analysis using standard computer modelling software for water bodies and waterways are part of it. The feasibility study also includes design of micro drains (collector and feeder) as many channels in the city are not interconnected.