Understanding environmental flow
Restoring River Health through Environmental Flow: Environmental Flow (E-flow) refers to the quantity, timing, and quality of water required in a river system to sustain ecosystems and the human livelihoods that rely on them. It is not just about water levels but maintaining natural flow patterns that support aquatic life, floodplains, and estuaries.
The concept has gained importance as Indian rivers, especially the Ganga and its tributaries, face ecological strain due to human activities. These include dam constructions, urban pollution, and riverbed encroachments, all of which disrupt natural water cycles.
Union government initiatives
The Union Jal Shakti Minister recently chaired a high-level meeting to assess E-flow implementation in the Ganga Basin. This initiative aims to enforce minimum environmental flow norms to prevent ecological collapse.
The meeting emphasized the importance of coordination between state pollution control boards, irrigation departments, and the Central Water Commission (CWC) to ensure uninterrupted base flows in key river stretches, especially during lean seasons.
Why e-flow matters
The disruption of environmental flows leads to loss of biodiversity, drying up of wetlands, degradation of aquatic habitats, and the collapse of fish populations. It also affects the natural cleaning capacity of rivers, making them more susceptible to pollution accumulation.
E-flow ensures the self-purifying ability of rivers, supports agricultural cycles in riparian zones, and maintains soil moisture in adjoining areas. This is essential for maintaining the ecological integrity of the entire riverine system.
Static GK fact: India has more than 20 major river basins, with the Ganga-Brahmaputra system being the largest.
Monitoring and compliance
The National Mission for Clean Ganga (NMCG), under the Namami Gange Programme, plays a pivotal role in monitoring E-flow compliance. Technologies like remote sensing, telemetry systems, and hydrological modelling are used to ensure that minimum flow standards are maintained.
In 2018, the CWC issued E-flow norms for different segments of the Ganga, prescribing minimum water flow (expressed in cumecs) to be maintained throughout the year.
Static GK Tip: The Ganga is India’s longest river, flowing over 2,500 km and supporting nearly 40% of the country’s population.
Future directions
The government plans to replicate E-flow strategies in other river basins like Yamuna, Krishna, and Godavari. There is also a push towards integrating E-flow requirements into hydropower and irrigation project approvals.
Experts advocate for community participation and scientific river basin planning to sustain long-term gains from E-flow policies.
Static Usthadian Current Affairs Table
Restoring River Health through Environmental Flow:
| Topic | Detail |
| E-flow definition | Quantity, timing, and quality of water to sustain ecosystems |
| Ministry in charge | Union Jal Shakti Ministry |
| Major river discussed | Ganga River |
| Key monitoring agency | Central Water Commission (CWC) |
| Supporting mission | National Mission for Clean Ganga (NMCG) |
| Year E-flow norms introduced | 2018 |
| Key program name | Namami Gange |
| Major ecological benefit | Maintains biodiversity and natural river functions |
| Technology used | Remote sensing, telemetry, hydrological modelling |
| Future river targets | Yamuna, Krishna, Godavari |
