Constructing storage dams alters natural hydrological regimes, disrupting downstream river ecosystems. Environmental Flows (E-Flows) quantify the quantity, timing, and quality of freshwater flows required to sustain riverine ecosystems. Hydrological alteration is evaluated using the Indicators of Hydrologic Alteration (IHA) framework across five flow parameters: Magnitude of monthly flow conditions. Magnitude and duration of annual extreme flows (high and low pulses). Timing of annual extreme conditions. Frequency and duration of high/low pulses. Rate and frequency of water condition changes (rise and fall rates). Hydraulic rating methods evaluate minimum required discharge using the wetted perimeter (P) versus discharge (Q) curve break-point: $\frac{dP}{dQ} \to \text{maximum}.$ To restore ecological health along regulated rivers like the Ganga and Yamuna, national environmental frameworks mandate minimum seasonal E-Flow releases from storage structures and barrages. Indian wa...