Nagpur’s main water source has lost storage capacity to silt, studies find

Sediment accumulation has reduced the live storage capacity of Totladoh dam, a key source of drinking water for Nagpur, according to two assessments documenting storage losses over several decades.

The findings have implications for the city’s long-term water security because Totladoh supplies around 520 million litres per day (MLD) of Nagpur’s total treated-water requirement of approximately 740 MLD. The remaining 220 MLD comes from the Kanhan river.

A Maharashtra Engineering Research Institute assessment recorded a loss of 74.07 million cubic metres of live storage between 1986 and 2010. A separate satellite-based study by researchers at Visvesvaraya National Institute of Technology, Nagpur, estimated that the reservoir had lost 17.63 per cent of its original live storage capacity by 2020, reported The Times of India.

The assessments use different reference capacities and should not be treated as directly comparable. An updated official survey is needed to reconcile the estimates and establish the extent of storage loss since the 2010 survey.

According to Water Resources Department data, Totladoh held 480.2 million cubic metres of water on October 11, 2026. This represented 47.22 per cent of its currently listed designed live storage capacity.

On the corresponding date in 2025, the reservoir held 99.76 per cent of that capacity.

The MERI assessment recorded a decline in live storage capacity from 1,091 million cubic metres when the dam was impounded in 1986 to 1,016.93 million cubic metres in the 2010 survey.

The VNIT study, published in 2022, used Landsat 8 satellite imagery to assess sedimentation between 1982 and 2020. It estimated the reservoir’s live storage capacity at 889.88 million cubic metres in 2020, against a reference capacity of 1,080.32 million cubic metres.

The reservoir is estimated to accumulate around 2.66 million cubic metres of sediment annually, equivalent to approximately 0.25 per cent of its original live storage capacity.

Sedimentation reduces the amount of water a reservoir can retain and its ability to capture monsoon inflows for use during periods of lower rainfall. The long-term decline in storage capacity therefore presents an additional challenge for a city that relies heavily on the reservoir.

The findings highlight the importance of updated reservoir-capacity assessments and long-term water-resource planning as Nagpur’s demand continues to place pressure on its supply system.