Abstract: This report summarizes the numerical modeling and probabilistic analysis performed by the US Army Engineer Research and Development Center Coastal and Hydraulics Laboratory (CHL) as part of the Upper Barataria Basin (UBB) Coastal Storm Risk Management (CSRM) Study. The intent of this work, performed for the US Army Corps of Engineers (USACE) and St. Paul District, was to evaluate project alternatives to assess flooding risks induced by coastal storms in coastal Louisiana. This study applied the USACE’s Coastal Storm Modeling System for storm surge and wave modeling and Coastal Hazards System–Probabilistic Framework (CHS-PF) to quantify water level and wave hazards, leveraging existing synthetic tropical cyclones (TCs) from the Coastal Hazards System¬–Louisiana (CHS-LA) study for levee recertification. Using a reduced storm suite (RSS) of synthetic TCs from CHS-LA, hydrodynamic model simulations were performed on an updated grid, including five proposed levee systems, to produce storm responses at more than 184,000 mesh node locations and over 21000 special save point locations within the UBB project area. Through the application of the CHS-PF, the joint probability analysis of TC atmospheric-forcing parameters and their associated storm responses were assessed for the estimation of still water level (SWL), significant wave height (Hm0), and wave peak period (Tp) annual exceedance frequencies ranging from 10 to 1 × 10−4 yr−1 to evaluate the impact of the UBB with- and without-project conditions.