Performance Indices for Operational Considerations of Coastal Hydraulic Structures

Abstract Multipurpose hydraulic structure operations in coastal regions and inland are severely impacted during high stages (water levels) combined with or without local precipitation extremes. Operational and discharge capabilities of the coastal structures are sometimes adversely affected by high upstream stage and downstream sea levels influencing the tailwater conditions. There have been many improvements in assessing canal structures concerning structural safety or hydraulic efficiency; however, operators have limited tools for decision-making and assessment during severe events. In this study, extreme (headwater and tailwater) stages and precipitation datasets were evaluated in a dependency analysis (DA), and furthermore, several indices were proposed and developed to assess the operative capabilities of the structures. The proposed indices assess the vulnerability, resilience, catchment response, and level of service (LOS) of the coastal structures at extreme stages linked to precipitation events. The developed indices can help evaluate the extreme stage levels based on any threshold stage level of interest, such as canal bank elevations, bypass elevation, or top-of-high operating levels. The methodology was applied to nine coastal hydraulic structures in Southern Florida, USA. Results point to advantages of DA and indices-based assessments that can lead to improved operations of coastal and inland hydraulic structures under extreme hydrometeorological conditions.