An Approach to Evaluating Coastal Total Water Levels over Varied Temporal and Spatial Scales for Future Design and Vulnerability Assessment

USACE coastal missions, operations, programs, and projects must be resilient to the full range of forseeable water levels, including extreme water levels, as well as the changing conditions that those water levels can induce at a project location. Understanding which component of total water level or combination of components controls performance (and at what time scale) is critical to the design and evaluation of a project. Estimating future conditions over the project life recognizes that there will be both stationary and nonstationary contributions to the total water level (TWL) over time, necessitating the consideration of scenarios in project alternative development. The USACE total water level Engineering Technical Letter (ETL) will provide a guide to evaluate total water levels for USACE coastal missions. While this paper focuses on coastal water levels, the component approach to water levels could be applied to other non-coastal locations.