River interlinking promises water security but may create 'ecological highways' for invasive species. Critically examine the ecological trade-offs of the National Perspective Plan.

The National Perspective Plan (NPP, 1980) proposes moving water from "surplus" to "deficit" basins through 30 links under its Himalayan and Peninsular components [2]. It promises water security, but an ATREE study warns that the canals could become "ecological highways" for invasive alien species (IAS) [1]. Current project appraisal largely ignores this trade-off.

Gains: water security

• Drought-proofing: Ken–Betwa, the first link to be implemented, targets 10.62 lakh ha of irrigation and drinking water for about 62 lakh people in drought-prone Bundelkhand [3].
• Cleaner energy: the full plan would transfer about 174 BCM of water and generate about 34,000 MW of hydropower [1].
• Mitigation: an Integrated Landscape Management Plan for Greater Panna aims to offset the habitat lost [4].

Costs: ecological risks

• Invasion corridors: the Lower Ganga hosts 13–15 IAS and could become a major source of invasives for the Mahanadi [1].
• Biotic homogenisation: isolated basins hold range-restricted endemic species. Linking them can "flatten" this unique biota and spread aquatic pathogens [1].
• Irreversibility: a canal can be closed, but an invasive fish that breeds in a new river cannot be removed.
• Habitat loss: the Daudhan reservoir will submerge about 9,000 ha, including 4,141 ha of Panna Tiger Reserve core [4]. Dams also block fish migration and sediment flows [1].
• Hydrological fallacy: "surplus" and "deficit" are static averages that hide seasonal variability [1].
• Equity: farmers in receiving basins gain, while fishers in invaded basins, often in another State, bear the cost.

Assessment The risk is uneven. Ken–Betwa joins two Yamuna tributaries, so its invasion risk is lower. Links between separate basins, such as Ganga to Mahanadi, carry the highest risk [1]. Yet project-wise EIAs check submergence at the dam site, not species moving across the network.

The NPP's promise of water security is real, but its ecological costs are uneven and partly irreversible. NWDA should add basin-level invasive-risk screening to every project report [1]. Clearances should assess cumulative, network-wide impact, and links should be sequenced by risk, with links inside one river system first. Such safeguards would balance the right to water (Article 21) with Article 48A's environmental duty, in line with SDGs 6 and 15.