Bottom racks are critical for diverting flow for small hydropower projects. This study investigates the hydraulic behavior of a mesh-panel bottom rack, comprising longitudinal and transverse bars, under clear-water conditions using a numerical model developed with the Flow-3D finite volume code. The research focuses on the discharge dividing streamline (DDS) and derives an empirical regression equation for its position based on model results. The numerical model is calibrated and validated against experimental data from Bina, yielding average relative errors of 3.4% for diverted discharge (Qd) and 1.9% for remaining discharge (Qr). The pressure distribution and vertical flow velocity analyses reveal that negative pressure around the transverse bars enhances diverted discharge. The vertical velocity distribution shows that outflow begins after approximately 30% of the rack length. The deep velocity distribution extracted from the Flow-3D model matches experimental data well, achieving a coefficient of determination (R² = 0.98) and a relative error (Er = 0.32%). This study proposes a regression relation to estimate the normalized DDS position, facilitating easy determination of diverted discharge in river diversion projects by measuring the approaching flow depth.