The Ministry of Road Transport and Highways (MoRTH) and the Bihar government signed an agreement in New Delhi on 3 November 2026 for scientific desilting of rivers and water bodies in Bihar. The desilted material will be used to build National Highways in the state under the Nadi Sanjivani initiative. The plan links flood control, river restoration and road building in a single model.
What Is Silt, Siltation and Desilting?
Silt is fine mineral material carried by flowing water and deposited on riverbeds, banks and farmland. Siltation is the slow build up of this material inside rivers, lakes, dams and reservoirs. Desilting is the planned removal of such deposits to restore depth, storage and free flow of water.
Silt particles sit between sand and clay in size. Sand grains are coarse and gritty. Clay particles are extremely fine and sticky. Silt feels smooth and powdery when dry and holds water better than sand but drains better than clay. This middle character decides where silt can be used.
| Material | Particle Size | Key Property | Common Use |
|---|---|---|---|
| Sand | 0.075 mm to 4.75 mm | Coarse, high drainage | Concrete and road base |
| Silt | 0.002 mm to 0.075 mm | Smooth, moderate water retention | Embankments, subgrade and farmland top layer when tested safe |
| Clay | Less than 0.002 mm | Very fine, sticky, swells and shrinks | Bricks and lining, but risky for roads without treatment |
Siltation reduces the ability of a river to carry monsoon water. The bed rises, drains choke and water spills over banks. In dams and barrages, silt cuts live storage and clogs intakes. Desilting reverses part of this loss by deepening and widening the channel in approved stretches.
Desilting is different from dredging in scale and purpose. Desilting usually means shallow, selective removal of fresh deposits from rivers, lakes, drains and water bodies to improve flow and storage. Dredging is a broader term that includes deep excavation in ports, harbours, shipping channels and large reservoirs, often with heavy machines and continuous maintenance cycles.
What the MoRTH Bihar MoU Under Nadi Sanjivani Promises
The Ministry of Road Transport and Highways (MoRTH) is the central ministry in charge of National Highway development, road transport policy and motor vehicle laws. The National Highways Authority of India (NHAI), set up under the NHAI Act, 1988 and operational since February 1995, builds and maintains the highways entrusted to it. The Bihar government is the partner state in this agreement.
The MoU was signed in New Delhi in the presence of Union Road Transport and Highways Minister Nitin Gadkari and Bihar Chief Minister Samrat Choudhary. Its full title is Nadi Sanjivani, Nadi Punarjeevan, Sadak Navnirman, which signals river revival joined with new road building. The pact covers scientific desilting of identified rivers and water bodies and free supply of suitable silt for highway work.
The numbers define the scale. The NHAI will use 243 lakh cubic metres of suitable silt in 16 ongoing National Highway projects. Another 835 lakh cubic metres is proposed for 27 future projects, subject to testing and approvals. The silt will be supplied without royalty or cost of material to lower project costs.
The wider highway footprint in Bihar explains why the demand is large. At present 39 NHAI projects covering about 1,561 km and worth about ₹58,340 crore are under construction. Another 11 projects covering about 1,982 km and worth about ₹1,85,200 crore are proposed. Ready availability of fill material near project sites can cut delays caused by soil shortage, transport over long distances and royalty disputes.
Why Bihar Needs Desilting: Floods, Shrinking Rivers and Buried Farms
Bihar is among the most flood prone states in India. Around 76 percent of the population in north Bihar faces recurring flood risk. Major rivers such as the Ganga, Kosi, Gandak, Bagmati, Burhi Gandak, Son, Ghaghra, Falgu and Mahananda carry heavy water and sediment loads through the plains.
Seven of these rivers enter Bihar from Nepal after dropping sharply from Himalayan slopes. The sudden fall in slope forces the water to drop its sand and silt load on the plains of Bihar. The Kosi, often called the sorrow of Bihar, alone carries about 120 million cubic metres of silt each year, with nearly 94 percent arriving during the monsoon.
Embankments built to contain floods have narrowed the channels. Sediment that once spread across floodplains now stays inside the walls and raises the bed by several centimetres each year. Studies of the Kosi between Chhatra and Birpur estimate hundreds of millions of cubic metres of deposits after embankment construction. A raised bed holds less water, puts more pressure on embankments and increases breaches, backflow and waterlogging.
The state government has reported silt thickness of 10 metres or more in some stretches. Flood sand spread over fields buries crops and reduces soil fertility. To address this, Bihar has framed the Bihar Water Sources Restoration and Silt Management Policy, 2026. The policy creates a legal route to clear water bodies and to remove flood deposited sand and silt from farmland to give relief to farmers.
How Excavated Silt Will Be Used in National Highway Projects
Highway construction needs huge volumes of earth for embankments, subgrade layers and raising road levels above flood lines. Contractors usually buy ordinary soil, fly ash, plastic waste or construction debris based on availability and design approval. Scarcity of soil near sites raises costs and slows work.
Under Nadi Sanjivani, the NHAI will lift suitable silt from approved river stretches and ponds and test it before use. Only material that passes MoRTH specifications for road and bridge works and relevant Indian Roads Congress (IRC) codes will go into road layers. The Indian Roads Congress, set up in 1934 and registered in 1937, is the apex body that frames road design standards in India.
Early project lists include dredging in the Ganga, Gandak, Kosi, Son, Ghaghra, Falgu, Dhamhi, Ghoghari and Bhutahi rivers. The receiving road works include stretches such as Manikpur to Sahebganj, Bakarpur to Manikpur, Munger to Mirzachauki, Bhagalpur Bypass to Rasulpur, Umagaon to Saharsa, Kishanganj to Bahadurganj and Bhagalpur to Kharhara. The Varanasi to Ranchi to Kolkata corridor and the Sahebganj to Areraj to Bettiah stretch are also on the list.
The logic is simple. Silt taken from a choked channel increases the water carrying and retention capacity of that channel. The same silt, when compacted in a road embankment, replaces fresh topsoil dug from farms. This protects productive land, cuts purchase and transport costs and keeps both river and road works moving together.
How Scientific Desilting Will Be Carried Out With Safeguards
Desilting under the MoU will follow detailed technical checks, not open digging. Each water body will be surveyed before approval. Extraction will be allowed only at notified sites and within fixed depth and volume limits.
The Road Construction Department (RCD) of Bihar will act as the nodal department. A state level coordination committee will examine NHAI proposals, speed up approvals, track progress and settle field issues. The mechanism will work within the Bihar Water Sources Restoration and Silt Management Policy, 2026 and all environmental and mining rules.
| Safeguard | What It Means in Practice |
|---|---|
| Approved locations only | No digging outside surveyed stretches near bridges, embankments or sensitive banks |
| Prescribed limits | Fixed depth and quantity caps to protect river flow and ecology |
| Material testing | Lab checks under MoRTH and IRC norms before silt enters road work |
| Joint measurement | NHAI and state teams record extracted, transported and used quantities together |
| Digital tracking | Online records and periodic reconciliation to ensure transparency |
River rejuvenation, the wider goal cited in the pact, means bringing a degraded river back to health through cleaner flow, stable banks and restored storage. Here it includes better drainage, revival of ponds and reservoirs, reduced pressure on embankments and reuse of the removed material instead of dumping it. Sand, silt and fine sediments that meet quality norms can go to embankments. Unsuitable or polluted material will be kept out of road use.
What the Buldhana Pattern Teaches About Linking Roads and Water
The Bihar model draws directly from Maharashtra’s Buldhana Pattern. In Buldhana district, soil from ponds, tanks, drains and riverbeds was used for National Highway embankments. In return, contractors deepened and widened those water bodies at no material cost to the state.
The results were large. About 225 lakh cubic metres of soil was used in road work. Storage capacity rose by about 22,500 thousand cubic metres without payment for earth. Wells were recharged, water supply schemes gained supply and farmers received irrigation benefit. The Union road transport ministry issued directions in 2017 asking states to allow road agencies to lift earth from identified water bodies without charging for the material, while contractors would bear digging and transport costs.
NITI Aayog later appreciated the approach and began work on national guidance for joining road building with water conservation. For Bihar, the lesson is that desilting solves two shortages at once. Rivers regain space for flood water. Roads gain nearby fill without cutting fertile topsoil or distant hillocks. If the Bihar rollout succeeds, the ministry plans to extend the same method to other flood and silt affected states.
Bihar’s highway base has already grown sharply. The National Highway network in the state rose from 4,615 km in 2014 to about 6,500 km at present. Around 29 new bridges over major rivers have been taken up since 2014. Vision 2047 plans about 1,800 km of expressways in Bihar so that a high speed corridor lies within 50 km reach anywhere in the state.
Key Takeaways
- MoRTH and Bihar signed the Nadi Sanjivani MoU on 3 November 2026 in New Delhi for scientific desilting and silt use in highways.
- 243 lakh cubic metres of silt will be used in 16 ongoing highway projects and 835 lakh cubic metres is proposed for 27 future projects.
- Bihar notified the Bihar Water Sources Restoration and Silt Management Policy, 2026 with the Road Construction Department as nodal agency.
- The model follows the Buldhana Pattern, which used 225 lakh cubic metres of excavated soil for roads in Maharashtra.
- The NHAI, operational since February 1995 under the NHAI Act, 1988, will test silt under MoRTH and IRC norms before road use.
