Inter-Basin Water Transfer: Hydrologic Water Balance and Link Canal Hydraulics
Inter-basin water transfer diverts surface runoff from donor basins with surplus water to recipient basins experiencing deficit. Evaluating basin yield viability requires establishing a long-term hydrologic water balance equation: $P - E - R - \Delta S = 0$ Where $P$ is precipitation, $E$ is evapotranspiration, $R$ is surface/subsurface runoff, and $\Delta S$ is storage change. Surpluses are determined based on $75\%$ dependable annual yield $(Y_{75}),$ calculated from flow duration curves. Link canal hydraulic design incorporates head loss equations for long-distance open channels and lift stations: $$h_f = \frac{f \cdot L \cdot v^2}{2 \cdot g \cdot D}$$ Where $f$ is Darcy friction factor, $L$ is link conduit length, $v$ is flow velocity, and $D$ is equivalent hydraulic diameter. Managing spatial water availability mismatch across India—where the Ganga-Brahmaputra basins hold significant surface runoff while southern peninsular rivers face acute seasonal deficits—drives the Na...