Inside Madhya Pradesh’s 17-year quest to build India’s longest irrigation tunnel

After 17 years of construction marked by delays, accidents and technical challenges, the 11.95-km Sleemanabad Tunnel in Madhya Pradesh’s Katni district is in its final phase, with only 92 metres of excavation remaining.

Legend says the rivers Narmada and Sonbhadra, born in the Maikal hills, were destined to flow in opposite directions and never meet. The tunnel will allow Narmada waters to enter the Son basin for the first time through a man-made passage beneath the Vindhyas.

Built by the Narmada Valley Development Authority (NVDA), the tunnel is the backbone of the Bargi Diversion Project, carrying water from the Rani Avanti Bai Sagar (Bargi) dam near Jabalpur to drought-prone regions of Vindhya.

More than 300 engineers and labourers are working in shifts to meet the deadline. The project witnessed multiple setbacks, including cave-ins, flooding, toxic gases, groundwater seepage and machinery failures. Three workers lost their lives during the construction period.

An American-made Robbins Tunnel Boring Machine repeatedly broke down due to difficult geological conditions comprising marble, limestone, dolomite, slate and underground cavities. Engineers later deployed a German HK tunnelling machine and began excavation from both ends in 2016.

Originally estimated at Rs 799 crore, the project's cost rose to nearly Rs 1,600 crore because of prolonged delays, technical complications and extensive dewatering operations required to manage groundwater seepage.

Once operational, the Bargi Diversion Project will irrigate nearly 2.45 lakh hectares across around 1,450 villages in Katni, Satna, Maihar, Rewa and Panna districts, while also supplying drinking and industrial water to Jabalpur and Katni.