How Latest 2-D and CFD Modeling Capabilities Can Support Dam Rehabilitations

Lake Lenape Dam is a High Hazard Potential Dam located in New Jersey. The existing spillway can’t safely pass the spillway design flood (SDF), and at high flows the spillway gets submerged due to high tailwater elevations. To safely pass the SDF and reduce upstream flooding, a labyrinth spillway was proposed to replace the existing linear spillway. A 2-D model was developed to evaluate the flood impacts of the proposed labyrinth spillway. Empirical formulas for labyrinth weir flow were used to validate the 2-D model results. Due to the complex hydraulic conditions that occur with the submergence of the proposed labyrinth spillway at high flows, the conventional empirical formulas for labyrinth weir flow become uncertain. Therefore, a Computational Fluid Dynamics (CFD) model of the proposed labyrinth spillway was developed. The final 2-D model results have a good agreement with the empirical formulas and CFD results. The 2-D model was used for upstream and downstream flood mapping, while the CFD model was used to more closely evaluate the labyrinth spillway. This project highlights how integrated 2-D and CFD models can support dam rehabilitation projects.