Why in news?
Project developer NHPC Limited has sought permission to divert about 3,278 hectares of forest for the proposed Kamala hydroelectric project in Arunachal Pradesh. The Indian Express reported on 22 October 2026 that the forest proposal was listed for appraisal on 23 October. The 1,720-megawatt project would store water on the Kamala River to generate electricity and help moderate floods. Its forest footprint extends across Kamle, Kra Daadi and Kurung Kumey districts, with about 23.4 lakh trees identified for proposed felling. This brings the project's energy and flood-management aims into direct consideration alongside forest habitats and affected communities. The Cabinet had approved investment in April; the new application concerns a different permission. A scheduled appraisal does not itself establish that forest clearance has been granted or that those trees have been felled.
A tributary project within the Brahmaputra network
The Kamala, also written Kamla in project documents, is a right-bank tributary of the Subansiri. The Subansiri in turn feeds the Brahmaputra. Right and left banks are identified while looking downstream, not by a fixed east–west rule. The proposed dam lies near Tamen in Kamle district, in the hilly Lower Himalayan region. It is not the separate Subansiri Lower dam. The drainage connection explains why this tributary project is discussed in relation to flood management farther downstream. Its immediate land and habitat changes, however, occur in the Kamala valley.
The project components and reservoir do not have an identical administrative footprint. NHPC's September 2025 draft assessment places the main works in Kamle and the major reservoir area in Kamle and Kra Daadi. A smaller land requirement associated with flood moderation extends into Kurung Kumey. The locator identifies the proposed dam point, while the separate schematic explains the river connection. Neither depicts the future reservoir's boundary. Keeping these distinctions clear avoids treating the entire forest proposal as a single construction site or placing the project on the wrong river.
How stored river water becomes electricity
The scheme proposes a 216-metre concrete gravity dam, measured from its deepest foundation, and an underground powerhouse. A gravity dam resists water pressure through its substantial weight. In a hydroelectric plant, water passes through a waterway towards turbines, which drive electricity generators. The available flow and the vertical difference in water level, called the head, help determine the power obtainable. Water is the moving energy source, rather than a fuel burnt inside the plant. Electricity can then enter the wider grid through the associated electrical infrastructure.
Storage changes when some water can be used, but does not create an unlimited supply. Holding water allows an operator to time releases within the reservoir's limits instead of relying only on that moment's incoming flow. This can help meet periods of high electricity demand. The electricity actually available still depends on water conditions, operating requirements and equipment availability. A proposed storage facility therefore has both a generating design and a water-management problem to solve; installed capacity alone cannot describe its year-round output.
Capacity, annual energy and flood storage measure different things
The Cabinet's 8 April announcement specifies eight 210-megawatt units and one 40-megawatt unit, adding to 1,720 megawatts. It projects annual generation of about 6,870 million units. In electricity billing, one unit means one kilowatt-hour, so this is 6.87 billion kilowatt-hours a year. Megawatts measure the rate of generation; annual units measure the accumulated electricity. Operating at the full stated capacity every hour of a non-leap year would produce about 15.07 billion kilowatt-hours. That arithmetic comparison explains why capacity and expected annual energy are not interchangeable promises.
The environmental appraisal describes a dedicated flood-storage cushion above the normal full-reservoir level. Its purpose is to retain part of an incoming flood and manage its release. This can reduce the peak instead of passing all water downstream immediately. It is flood moderation, not flood elimination. Available space, incoming flows and release decisions matter. Nor does a tributary reservoir control rainfall and every other tributary across the Brahmaputra valley. Flood benefits must be judged through actual operating rules and performance, not inferred solely from the dam's height.
Investment approval is not the same as environmental permission
The Cabinet Committee on Economic Affairs approved an investment of ₹26,069.50 crore, with an estimated completion period of 96 months. The stated implementation arrangement is a joint venture between NHPC and the Arunachal Pradesh government. These are investment and development decisions. They do not remove the need for the relevant environmental and forest permissions. An estimated duration does not establish that the clock began on the news date. Nor does it assure electricity on a fixed calendar deadline.
The river-valley Expert Appraisal Committee considered Kamala in January 2026 and recommended environmental clearance subject to conditions. Its record specifically requires in-principle forest clearance before environmental clearance is granted. This is different from the October forest-diversion appraisal. The Environment Ministry's PARIVESH clearance portal also distinguishes in-principle approval from final forest approval following compliance with conditions. The sequence matters because a recommendation, permission, compliance requirement and completed work are separate stages. A favourable step in one process cannot be used as proof that all the others are finished.
What the forest and community footprint requires
The appraisal record identifies 3,278.0904 hectares of forest in the proposal, or about 32.78 square kilometres. The tree count is a proposed removal estimate, not a record of completed cutting. A forest is also more than the number of standing trees. Habitat connections, river access and adjoining land use affect how its loss is experienced. The January committee sought ecosystem restoration and mitigation planning in consultation with forest authorities, experts and local people. A financial allocation or written plan still needs implementation and monitoring.
The Indian Express cites a social assessment identifying 5,440 affected families across 126 villages. Being affected does not necessarily mean that every family must move. Land acquisition, lost access or livelihood changes can have different consequences from physical relocation. The report also notes that the inspected site lies outside designated protected areas, but that habitat and wildlife movement would still be affected. A location outside a national park is therefore not equivalent to a location without ecological importance. Compensation and rehabilitation need to address the actual form of each household's loss.
River protection continues below the dam. The appraisal calls for monitoring environmental-flow releases: water retained in the downstream channel for its ecological functions. Construction also requires attention to excavated material, slope stability and water pollution. These are connected issues in a steep valley, where poorly contained material can reach streams. Monitoring is needed to establish whether mitigation works, rather than treating its inclusion in a document as the outcome. The same principle applies to promised roads, services and local employment: commitments should be assessed against delivery.
Benefits need a credible route from commitment to delivery
The April announcement envisages a 12% free-power share for the State and an additional 1% earmarked for local-area development. These are distinct from direct cash compensation to an affected family. NHPC's civil tender separately describes diversion tunnels, dam works, approach roads, bridges and temporary water barriers called cofferdams. A tender sets out work sought from contractors; it does not prove that the works have been awarded or completed. The practical question is how electricity, flood-management functions, environmental obligations and community benefits will be delivered together. Responsibilities for each must remain clear through construction and operation.
Conclusion
Kamala combines a substantial proposed electricity resource with a large forest and community footprint. Its location on a Subansiri tributary connects local changes in the valley with wider water-management aims. The October forest application is therefore not a minor formality following investment approval. The substantive test is whether permissions, operating arrangements, mitigation and rehabilitation can make the promised benefits credible while addressing the losses they entail. Neither a planned megawatt figure nor a tree count alone answers that question.