Reclamation Information Sharing Environment (RISE)

We developed a novel three-tiered approach to quantify and spatially represent zones of sediment erosion, bedrock erosion, and subsequent sediment deposition associated with a range of flow events on an unlined spillway at New Melones Dam, located approximately 45 miles northeast of Modesto, California. Our three-tiered approach includes the application of: (1) the Sedimentation and River Hydraulics two-dimensional (SRH-2D) sediment transport model to inform sediment removal and deposition; (2) a two-dimensional (2D) probabilistic erosion model using the Annandale Erodibility Index Method (Annandale, 1995) to inform the potential for bedrock erosion across the full spatial extent of the spillway; and (3) the Hurst one-dimensional (1D) Erosion model (H1DE), a 1D bedrock incision model (Hurst et al., 2021), to inform the timing and magnitude of vertical incision into bedrock and the potential for knickpoint (headcut) propagation.