Analytical Methods and Approaches for Water Resources Project Planning is part of a larger study that was conducted in response to a request from the U.S. Congress in the Water Resources Development Act of 2000 for the National Academy of Sciences to review the U.S. Army Corps of Engineer's peer review methods and analytical approaches. This report reviews the Corps' analytical procedures and planning methods, largely in the context of the federal Economic and Environmental Principles and Guidelines for Water and Related Land Resources Implementation Studies, also known as the Principles and Guidelines or "P and G" (P&G), as well as the Corps' Planning Guidance Notebook (PGN).