Abstract
The Central Valley of California is one of the most flood prone areas on earth. The flood protection system within the central valley comprised of levees, floodwalls, bypasses and relief structures to provide protection downstream of the flood control reservoirs. The levees around urban areas provide protection to its designed level and may be subject to failures due to hydraulic and geotechnical conditions during a significant storm event. For better preparedness and responses to events of flood emergencies, Flood Emergency Mangers have to be able to predict potential dangers. The ability to forecast real time inundation depths and time, and accurate inundation boundaries as well as flood wave velocity are essential for Flood Emergency Managers to make critical response decisions to reduce property damage and life safety. In particular, reasonable prediction of time of flood depth and extents with respect to critical infrastructure within the urban areas help identify suitable evacuation routes to order timely evacuation in the face of a catastrophic levee failure. This also helps locate high ground to facilitate rescue operation during a flood emergency. Higher order overland flow models can be used to forecast dynamic propagation of flood wave within the floodplain due to levee failure along the main stream of the river system. One of the challenges of such real-time dynamic urban flood modeling using depth averaged 2D Navier-Stokes solver or simplified quasi-2D hydraulic models lies in modeling flows in and around complex features such as buildings, bridges and structural features to account their effects on flood distribution and dynamics. Incorporating detailed geometric or parametric features in the model can result in higher run time as well as instability, which can be one of the limitations of high-resolution models for real time predictions and may slow down the emergency decision making process compromising the public safety. The objective of the study was to investigate challenges and potentials of the application of a quasi-two dimensional hydraulic model (FLO-2D) to forecast real time dynamic inundation characteristic in an urban floodplain due to levee breach. Primarily the study focused on analyzing optimum model configuration that can be utilized to minimize model instability and run-time for real time applications to simulate the dynamics and distribution of flood volumes due to levee breach scenario within the study area. The Greenhaven-Pocket neighborhood of Sacramento, California was chosen for the study.