Yamuna river floodplains remain under severe threat amidst proposed policy dilutions: SANDRP

In an article published by the South Asia Network on Dams, Rivers and People (SANDRP) titled "Yamuna Manthan Aug 2026: Floodplains remain under threat", a series of recent scientific studies and regulatory developments highlight a critical reality: relying solely on sewage treatment and pollution control will not revive the Yamuna River. 

The SANDRP article emphasizes that "their findings make it clear that cleaning sewage alone will not revive the river" and that "protecting natural flows, restoring floodplain connectivity and conserving wetlands are equally important for reducing flood risk, recharging groundwater and sustaining the river's ecology." 

Despite these ecological imperatives, SANDRP warns that "undoubtedly, the Yamuna floodplain has already suffered extensive encroachment, fragmentation and ecological damage due to weak governance," with recent administrative moves threatening to further dilute existing safeguards.

​A major point of contention highlighted in the article is the Delhi Development Authority’s (DDA) proposal under the draft Master Plan for Delhi-2047 to divide the ecologically sensitive 9,934-hectare Zone O floodplain into two distinct sub-zones: Zone O-1, covering 6,295 hectares along the riverbed as a high-protection area corresponding to a 1-in-25-year flood return period, and Zone O-2, covering the outer sections to allow regulated recreational activities, green spaces, and a 52-km cycle track. 

SANDRP strongly criticizes this move, noting that "the proposal, reportedly sent to the Ministry of Housing and Urban Affairs (MoHUA) as part of the Delhi Master Plan 2047, is intended to facilitate the regularization of unauthorized colonies in the Yamuna floodplain." The article urges that "MoHUA should not approve this proposal as it would legitimize encroachments in one of Delhi's most ecologically sensitive areas," adding that "it would further dilute the already weakened Zone O provisions and set a dangerous precedent for floodplain governance across the country." 

Bhim Singh Rawat of SANDRP observed that the DDA, which was made the custodian of the Yamuna floodplain, was instead working towards weakening the laws meant to protect it, stating, "On the one hand, DDA has been stalling scientific demarcation of floodplain in ongoing NGT cases for several years and now it is changing the very definition. The one-in-100-year flood should be the baseline, not 25-year flooding period. The last two flooding episodes have shown that even with smaller water discharges, the carrying capacity of the river in Delhi has been severely compromised."

​Compounding this regulatory ambiguity, SANDRP notes that the Union Ministry of Jal Shakti notified the River Ganga Authorities Second Amendment Order 2026 on August 7, 2026. This updated framework divides floodplains into an active floodplain corresponding to a 1-in-5-year flood, a regulatory zone between 1-in-5-year and 1-in-25-year floods, and a warning zone between 1-in-25-year and 1-in-100-year floods. Crucially, the notification drops previous explicit references to a "construction-free zone," stating instead that riverbanks and floodplains shall be maintained to reduce pollution sources and preserve groundwater recharge functions. 

SANDRP points out that "while the amendment classifies floodplains into different categories, it does not clearly define the development restrictions applicable to the newly created regulatory and warning zones," creating fresh ambiguity rather than strengthening protections.

​These policy shifts occur alongside alarming scientific findings detailed in the article regarding the long-term hydrogeomorphic decline of the river. A study by researchers from Delhi University and IISER Bhopal, titled "Two Centuries of Hydrogeomorphic Changes: Width–Discharge Dynamics of the Urbanised Yamuna River in Delhi", analyzed satellite imagery, historical archives, and a 1799 baseline map to reveal that upstream barrage diversions and urban expansion have caused massive losses. 

SANDRP cites the report's finding that "the river's ecological features have thinned alongside it. Sandy mid-channel islands that once covered nearly 20 sq km in 1985 have shrunk to just 4 sq km by 2020, signalling the loss of habitats that helped maintain the river's ecological balance."

​Further landscape analysis by Neenu and Mitthan Lal Kansal published in Environmental and Sustainability Indicators demonstrates how land-use changes in the Upper Yamuna Basin are pushing the ecosystem toward a critical tipping point. 

The SANDRP article highlights that water bodies in the basin shrank from 1.36 percent of total area in 2004 to just 0.62 percent in 2024, warning that "the Upper Yamuna Basin is now approaching a tipping point where urban growth, hydrological stress, ecological decline and climatic vulnerability are reinforcing one another."

​Beyond flood mitigation, SANDRP explains that "Delhi's alluvial floodplains, formed over thousands of years by the shifting Yamuna, create a freshwater aquifer that naturally filters and improves river water before it enters the city's water supply," but cautions that encroachment threatens to destroy this vital ecosystem service. Addressing these challenges requires MoHUA to reject the proposed bifurcation of Zone O and prioritize scientific floodplain mapping and physical demarcation. 

As the SANDRP article concludes, India still lacks a dedicated national law to define and protect river floodplains, and as Shiv Singh Rawat writes in the article's concluding editorial perspective, "the Yamuna's revival demands long-term, science-based river basin management, transparent governance, and sustained political commitment, rather than piecemeal clean-up projects focused only on pollution control. Restoring floodplains may be the single most important investment."