An updated USACE approach to the evaluation of coastal total water levels for present and future flood risk analysis

Abstract

Abstract. 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. Water level range, magnitude of extremes, and frequency will all contribute to the stability, operation, and performance of a given project. 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. Being aware of the different cross shore zones of total water level calculation and impacts informs exposure and impact assessments. 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. An adaptive management approach provides a process for dealing with future uncertainties and involves developing plans that envisage a range of futures, incorporates ongoing monitoring, and permits transitions from one approach to another. Identifying thresholds beyond which stability or performance are adversely impacted is an important way to understand current and future vulnerability with respect to water levels, especially within the flood risk mission area. The USACE total water level Engineering Technical Letter (ETL) in development will guide how to evaluate total water levels for USACE coastal missions.

A Novel Framework for Parametric Analysis of Coastal Transition Zone Modeling

“…Development, operation, and management of infrastructure located in coastal areas require accurate estimations of water level ranges, magnitude, and frequencies in the areas between the coast and the upland where tides no longer influence water level variation, that is, the coastal transition zone (CTZ) (Moritz et al 2016; Couasnon et al 2020). For this purpose, an initiative is underway to enhance the National Water Model (NWM) (NOAA 2016) by including water level predictions in CTZs (Bakhtyar et al 2020).…”

Urban Flooding Risk Assessment Based on Numerical Simulation of Sub-catchment Area: A Case Study From Chengdu, China

“…Presently, urban flood management has changed from engineering defense measures to risk management (Johnson et al 2007). Urban flood risk assessment aims to analyze current or future flood risk information, identify high-risk areas, and provide decision support for flood mitigation measures (Moritz et al 2016). Traditionally, three primary approaches are used to assess flood risk (Yin et al 2015), historical disaster mathematical statistics method (HDMS) (Nott 2006), multi-criteria analysis (MCA) (Guo et al 2014), and scenario simulation analysis (SSA) (Zhu et al 2016).…”