The Interstate River Water Disputes Act, 1956 (IRWD Act) is an Act of the Parliament of India enacted under Article 262 of Constitution of India on the eve of reorganization of states on linguistic basis to resolve the water disputes that would arise in the use, control and distribution of an interstate river or river valley. Article 262 of the Indian Constitution provides a role for the Union government in adjudicating conflicts surrounding interstate rivers that arise among the State governments. This Act (IRWD Act) has been amended subsequently, with the most recent amendment in 2002. This Act has evolved from the laws which were extant during the British Raj.
River waters use / harnessing is included in states jurisdiction (entry 17 of state list, Schedule 7 of Indian Constitution). However, the union government with parliament approval can make laws on regulation and development of interstate rivers and river valleys to the extent such water resources are directly under its control when expedient in the public interest (entry 56 of union list, Schedule 7 of Indian Constitution). Damodar Valley Corporation, NHPC, River Boards Act 1956, etc under the control of the union government, are referable to Entry 56 of the union list. Regulation means imposing restrictions or upper ceiling for certain types of water uses to prevent over exploitation of water or protect the ecology and productivity of an interstate river basin. Development means harnessing the water resources. Regulation and development (not administration and ownership) shall be in the interest of public. When union government wants to take over an interstate river project under its control by law (as provided in the constitution) from states per entry 56 of the Union List, it has to take the approval of the riparian states' legislature assemblies before passing such bill in the Parliament per Article 252 of the constitution. The phrase 'by law' means all the applicable Articles of the Constitution shall be fulfilled/adhered. Otherwise, the rights of the Union per entries 53, 54 and 56 of the Union List are similar to a right given to the Union per the concurrent list. When public interest is served, President may also establish an interstate council as per Article 263 to inquire and recommend the dispute that has arisen between the states of India.
IRWD Act (section 2c2) validates the previous agreements (if any) among the basin states to harness the water of an interstate river/ river valley. This act is confined to states of India and not applicable to union territories. Only concerned state governments are entitled to participate in the tribunal adjudication and non-government entities are not permitted.
Transboundary Rivers Water Sharing Treaties Any river water sharing treaty made with other countries, has to be ratified by the Parliament per Article 253 after deciding the share of the Indian riparian states per Article 262 to make the treaty constitutionally valid or enforceable by the judiciary as India follows dualist theory for the implementation of international treaties/laws. The Indian government has signed Indus Waters Treaty with Pakistan, Ganga water sharing treaty with Bangladesh, etc. without the approval by the Parliament. In April 2025, India suspended unilaterally the Indus Waters Treaty while some disputes resolution proceedings of the Court of Arbitration (CoA) or Neutral Expert were ongoing. Implementation of any award rendered by an international tribunal/CoA against India can be challenged in the Indian Courts on the grounds that the treaty is not valid under the constitution of India since it was not formally ratified by the Parliament per Article 253 of the constitution. In the absence of required approval by the Parliament per Article 253 of the Indian Constitution, which is of fundamental importance, despite discussions on the subject in the Parliament, the ratified treaty is invalid per Article 46 (1) of VCLT.
Water disputes IRWD Act is applicable only to interstate rivers/river valleys. Water disputes per section 2c of this Act means any dispute including interpretation and implementation of any agreement with respect to use, distribution or control of waters of an interstate river. An action of one state should affect the interests of one or more other states. Then only a water dispute is deemed to have arisen under IRWD Act (section 3). It can be divided into two independent parts for clarity purpose in understanding the techno-legal application of the IRWD Act.
Actions of a downstream state affecting the interest of an upstream state A downstream state's action can affect the upstream state's interest only in one case. i.e. when a downstream state is building a dam/barrage near its state boundary and submerging the territory of an upstream state on permanent/temporary basis. Other than this action, no other action of a downstream state could affect the upstream state's interest which they have been using for economic, ecological and spiritual/ religious aspects. The meaning of the word ‘interest’ in this context is concern/importance/significance/relevance / consequence of losing the prevailing water use or purpose.
Actions of an upstream state affecting the interest of a downstream state Whereas all the actions of an upstream state to use or control or distribute the water of an interstate river can affect the downstream states in one way or other. The following are some examples but not complete:
Consuming river water for any beneficial use such as irrigation, drinking water, industrial, recreation, recharging of groundwater, groundwater use, enhanced evaporation losses, enhancing rainwater use efficiency, obstructing non-flood flows of the river, transferring water to outside the river basin, etc. (i.e. any man-made /aided action of converting water into water vapor & losing to the atmosphere by evapotranspiration / evaporation processes and also transferring river water outside the river basin). This is generally done by constructing water storage reservoirs and subsequently using water for the above purposes. Quality of water can also be diminished/altered/ controlled in the action of using water. It would take place by accumulating the dissolved salts in the remaining water after its use. The dissolved salts content of water increases due to its consumption and also the addition of more salts by anthropogenic activity. Also causing water more silt laden/turbid is a man-made water quality alteration that can be caused by mining and deforestation activities. Bringing water from other river basins for upstream states' use also affects water quality in downstream states.
Generally, river water is transferred to water deficit areas for use after creating the infrastructure for its storage (water reservoirs) and distribution network (canals, pipelines, groundwater charging, etc.). All these acts fall under the river water distribution and control category under IRWD Act. All the above actions of an upstream state are legal causes of water dispute to the downstream states since their existing interests are affected as given below:
Decrease in water availability:- When an upstream state contemplates water use, it would block the lean season river flows initially by constructing low-cost barrages and tries to store the peak flood waters ultimately by constructing massive water storage reservoirs. In this process, the river flow regime is altered drastically converting it to ephemeral/dry in most of the time except during floods. It also alters the ecology of the river located in downstream states affecting its riverine vegetation and aquatic flora & fauna. Already the delta area of rivers is eroding/shrinking when adequate river water is not reaching the sea. This process of river water harnessing affects the downstream state's interests as they are deprived of constantly available river water which they had been using for their interests. Alternatively, the downstream state needs to store more flood water in reservoirs to cater to the existing water use. Deterioration in water quality:- If the water use is 75% of the total available water in the river, the concentration of the dissolved salts in the river water increases by four folds. Alteration in river water quality / alkalinity / salinity effects growth of traditionally cultivated crops as they are not best suitable with the enhanced soil alkalinity and or soil salinity. They either give a lesser yield or consume more saline water for the same yield. Also the aquatic flora & fauna would face survival threat / diminished growth with the enhanced water salinity and or alkalinity. If the river is blocked to reach the Sea (i.e. basin closure) in most of the years, the ecology/fisheries of the surrounding Sea/river mouth area is also affected. Also there is a threat of Sea water ingress into estuaries/delta of the river contaminating groundwater.
The use or control or distribution of river water in an upstream state is invariably denial of prevailing use/purpose in the downstream state as it is altering the natural flow regime of river water with respect to quantity, quality and time of availability in downstream states. Also dam failures in upstream states can create flash floods or further dam failures in downstream states causing unprecedented property damage and loss of human lives. IRWD Act (section 3) clearly stipulates that mere anticipation of a riparian state actions which can affect other riparian state interests is enough to raise interstate water dispute.
The activities of an upstream state without affecting downstream states' interests are peak flood control measures by impounding the flood waters only (not base flows) in 100% or more capacity storage reservoirs for use without affecting water quality appreciably and the run-off hydropower generation taken up in its territory.
Procedure This Act can be divided into two parts: up to section 5.1 is first part and from the Section 5.2 is later part. The purpose of first part (pre adjudication process by the tribunal) is for identifying, with the involvement of Supreme Court (SC) if needed, the valid water disputes which can be adjudicated by the tribunal. Whenever a water dispute is not in the scope of this Act, such water related disputes between the States is in the jurisdiction of SC per Article 131 of the constitution. Incase a water dispute raised by a State is contested by other riparian States, SC will decide whether such dispute is a valid water dispute falling in the scope of this Act.