Bihar and Jharkhand end a 25-year deadlock with a 5.75:2 MAF Sone water-sharing agreement, finally unlocking the Indrapuri Reservoir project
Tourism Department, Government of Bihar
For 25 years, a fixed quantity of river water sat at the centre of an unresolved argument between two Indian states that were once one. The Sone (Son) river, which flows out of the Amarkantak plateau and joins the Ganga near Patna, has long been the backbone of irrigation across South Bihar's drought-prone plateau districts. When Jharkhand split off from Bihar in 2000, it inherited a large share of the river's catchment but no clear entitlement to its water — a gap that stalled a major reservoir project for a generation and turned a routine administrative question into a slow-burning inter-state standoff. In August 2026, that standoff formally ended. This explainer walks through where the dispute came from, why it took a quarter-century to settle, and what the final agreement actually says.
At its core, it was a fight over a fixed number: 7.75 million acre-feet (MAF) of water a year from the Sone (Son) river. Both Bihar and Jharkhand agreed the number itself wasn't in question — what they couldn't agree on for a quarter-century was how to split it between them, per ETV Bharat and the Outlook explainer on the issue.
It traces back to the Bansagar Agreement of 1973, signed by undivided Bihar, Uttar Pradesh, and Madhya Pradesh to govern sharing of Sone waters and the cost of the Bansagar dam in MP. Under that agreement, undivided Bihar's entitlement out of the river's total 14.25 MAF was fixed at 7.75 MAF, as as per ANI.
Because "undivided Bihar" stopped existing. When Jharkhand was carved out of Bihar in November 2000, it inherited a large share of the Sone's catchment area — but the 1973 agreement had never anticipated a second successor state and said nothing about how the 7.75 MAF should be divided between them. Jharkhand argued that since much of the catchment lay within its borders, it deserved a defined share; Bihar, meanwhile, continued to lean on the 1973 pact to claim the full entitlement, as Business Standard reported. Neither position was formally wrong — the 1973 agreement simply hadn't accounted for a split state, which is what kept the argument alive for so long.
The most tangible casualty was the Indrapuri Reservoir Project (originally conceived in the 1980s as the "Kadwan Reservoir Scheme"), planned on the Sone between Kadwan in Jharkhand's Garhwa district and Matiwan in Bihar's Rohtas district. Its detailed project report sat with the Central Water Commission from 1987 to 2004 over a submergence-area survey dispute with Uttar Pradesh, and even after that was resolved, Jharkhand withheld consent for the reservoir in the absence of an agreed water-sharing formula, per ETV Bharat's reporting. Without Jharkhand's sign-off, a project meant to stabilise irrigation across eight Bihar districts through the Sone canal system stayed on paper for decades.
The breakthrough came at the 27th meeting of the Eastern Zonal Council, held in Ranchi on July 10, 2025, and chaired directly by Union Home Minister Amit Shah. The Eastern Zonal Council is a constitutional forum (functioning under Article 263 of the Constitution) meant to help states thrash out exactly this kind of inter-state friction, and it brought Bihar's Deputy Chief Minister Samrat Chaudhary and Water Resources Minister Vijay Kumar Chaudhary face to face with Jharkhand's representatives under central mediation, as reported by ETV Bharat and Patna Press. At that meeting, both sides agreed to a formula: of the 7.75 MAF, Bihar would get 5.75 MAF and Jharkhand 2 MAF.
No — it went through a formal ratification chain over the following year. The Central Water Commission drafted the MoU based on the July 2025 consensus and circulated it to both states; the Bihar Cabinet approved the draft in January 2026, clearing the way for the Indrapuri project on its side. Both states then gave their formal consent to the draft, as noted by the Free Press Journal. The dispute was formally and finally sealed on August 31, 2026, when Bihar and Jharkhand signed the MoU in New Delhi.
The MoU was signed in the presence of Union Home Minister Amit Shah, Union Jal Shakti Minister C.R. Patil, Bihar Chief Minister Samrat Choudhary, Jharkhand Chief Minister Hemant Soren, Bihar Deputy CM Vijay Kumar Choudhary, and Union Home Secretary Govind Mohan, according to The Logical Indian. Shah called it a "permanent" resolution and framed it as the fourth inter-state water-sharing agreement reached in 2026, describing it as an example of "Team Bharat" cooperative federalism, per Business Standard. Bihar's Chief Minister, for his part, described it as the start of "a new chapter of cooperation, trust, and shared development" between the two states, as ANI reported.
Out of the 7.75 MAF originally allocated to undivided Bihar under the Bansagar Agreement:
Bihar: 5.75 MAF
Jharkhand: 2.00 MAF
This is the same 5.75:2 formula reached in Ranchi in July 2025 — the year that followed was essentially about converting political consensus into a signed, binding instrument.
In Bihar, the agreement is expected to unlock construction of the long-stalled Indrapuri Reservoir, strengthening irrigation via the Sone canal system across eight districts: Bhojpur, Buxar, Rohtas, Kaimur, Aurangabad, Patna, Gaya, and Arwal, per APAC News Network and The Statesman. In Jharkhand, districts like Palamu and Garhwa stand to gain improved irrigation and drinking-water access. More significantly, the deal gives Jharkhand something it never formally had in 25 years: a legally recognised entitlement to a defined quantity of Sone water, ending the ambiguity that had underpinned its objection to the reservoir in the first place, per Outlook.
MAF stands for million acre-feet — one acre-foot is the volume of water needed to cover one acre to a depth of one foot, roughly 1,233 cubic metres. The Sone's total assessed availability at the point of diversion was pegged at 14.25 MAF under the Bansagar-era calculations; undivided Bihar's 7.75 MAF share was over half of that. For scale, the river's catchment area at the existing barrage runs to roughly 69,000 sq. km, spanning parts of Madhya Pradesh, Uttar Pradesh, Chhattisgarh, Jharkhand, and Bihar before the water reaches the diversion point.
Yes, and this is a common point of confusion. The existing Indrapuri Barrage (also called the Sone Barrage), commissioned in 1968 in Rohtas district, is a 1,407-metre diversion structure — reportedly the fourth-longest barrage in the world — built by Hindustan Construction Company to replace an 1874-era anicut at Dehri. It diverts water into the historic Sone Canal System (the Low Level and High Level canal networks) but has no significant storage capacity of its own — it simply raises the river level enough to feed canals.
What the water-sharing dispute was actually holding up is a separate, upstream storage reservoir — originally conceived in the 1980s as the "Kadwan Reservoir Scheme" and later renamed the Indrapuri Reservoir Scheme, to be built between Kadwan (Jharkhand) and Matiwan (Bihar). Unlike the existing barrage, this would impound water for release through the dry season rather than merely diverting the river's natural flow, per ETV Bharat.
The reservoir's detailed project report (DPR) had a troubled path through the Central Water Commission well before Jharkhand's consent became the sticking point. It sat pending from 1987 to 2004 over a submergence-area survey dispute with Uttar Pradesh — since part of the proposed reservoir's backwater would submerge UP territory — and a fresh survey by the Survey of India wasn't conducted until 2005–07, per ETV Bharat's account. Even after a consultant-prepared DPR reached the CWC and Bihar formally asked for its approval in July 2021, the Commission held off because a prior water-sharing agreement between Bihar and Jharkhand was a precondition for sign-off — which is exactly the piece that took until 2025–26 to fall into place.
Yes — the Sone's flow at Indrapuri is not just a function of rainfall in its own catchment but of two major upstream dams built decades apart: the Rihand Dam in Uttar Pradesh (1962) and the Bansagar Dam in Madhya Pradesh, both of which regulate flow before the river reaches Bihar and Jharkhand. This is part of why the 1973 Bansagar Agreement bundled water-sharing together with cost-sharing for the Bansagar dam itself — the three states co-financed the structure that now determines how much water is even available to divide.
Worth reading that word carefully. There is no Supreme Court decree or tribunal award behind this settlement — unlike disputes such as Punjab-Haryana's Sutlej-Yamuna Link, which went through years of adjudication, the Sone dispute was closed through a political MoU negotiated under the Eastern Zonal Council and signed by two state governments and the Centre. That makes it faster to conclude but also means its durability depends on continued political goodwill rather than binding legal force. It's also worth noting the original 1973 Bansagar Agreement never anticipated a bifurcated Bihar in the first place — so this MoU isn't so much a "resolution" of that old treaty as a new allocation formula improvised decades later to fill a gap the original agreement never addressed.
Because interstate river disputes in India routinely outlast the technical mechanisms designed to resolve them — years of lower-level talks between Bihar and Jharkhand's water departments had failed to produce a formula. What changed the outcome, per Outlook's reporting, was direct high-level political intervention: The Home Minister personally chairing the Eastern Zonal Council meeting in July 2025 gave both states a reason and a forum to close the gap quickly, rather than let it drift for another decade.
With the water-sharing question settled, the next milestone is construction of the Indrapuri Reservoir itself, between Kadwan (Jharkhand) and Matiwan (Bihar). Officials from both states are now expected to work out implementation details — design, funding, and timelines — for a project whose detailed report has technically existed since the 1980s but could never move past the water-sharing impasse, as Patna Press notes.