A level-set finite-element method is employed to investigate the free surface flow of two conceptual fish passage designs. While one design has a right-angled entrance from the reservoir to the fish passage chute, the other has a curved-shaped entrance. The numerical results are validated with hydraulic experiments through comparison of the free surface location and the pressure distribution in the spillway. It is observed that the right-angled design yields a curved free surface and pressure distribution in the vicinity of the entrance due to large strains, whereas the curved-shaped design yields a smooth flow transition with small strains. The subatmospheirc pressure distributions near the spillway ogee crest for both designs exhibit similar flow patterns. It is concluded that the curved-shaped design is more favorable for fish passage because of the feature of a smooth flow transition with small strains.