Planning Tool Methods and Results

Since the publication of the 2007 Coastal Master Plan, the Louisiana Coastal Protection and Restoration Authority (CPRA) has procured over $20 billion to support planning, engineering and design, and construction of hundreds of restoration and protection projects. Scientific understanding of coastal processes, how the coast will evolve in the future, and the effects of coastal investments continue to be incomplete. As such, the CPRA Planning Tool was developed to help formulate the 2012 Coastal Master Plan and was revised for the 2017 Coastal Master Plan. As part of the 2023 Coastal Master Plan, the Planning Tool was again updated to use more detailed modeling data, including a structure-based asset inventory, and to respond to new CPRA planning priorities. This report builds upon the preliminary methodology guide in Groves et al. (2021) Planning Tool Overview, to describe methods actually used to generate the results of the 2023 Planning Tool analysis. Major improvements described in this document include, but are not limited to: (1) annual estimation of project benefits, (2) development of two implementation periods (IPs) with an intermediate modeling step that considers initial restoration projects in the future landscape for the second period, (3) evaluation of a new land sustainability constraint, (4) consideration of sediment borrow costs, (5) optimization of a robust set of project alternatives to ensure good performance across considered scenarios, and (6) inclusion of an equity-based decision driver.