Ponce de Leon Inlet, FL: An integrated hydrodynamic and morphologic assessment of design alternatives using the U.S. Army Corps of Engineers' Coastal Modeling System.

摘要

Ponce de Leon Inlet, FL is one of 154 federally-maintained inlets by the U.S. Army Corps of Engineers (USACE). Shoaling and channel migration have caused persistently hazardous navigation conditions since stabilization of the inlet in 1972 by a dual-jetty weir system, and eventual closure of the weir in 1984. In 1993, the Coastal and Hydraulics Laboratory (CHL) of the U.S. Army Engineer Research and Development Center (ERDC) initiated the Coastal Inlets Research Program (CIRP) to study the complex morphological and hydrodynamic changes of coastal inlets, which occur on a variety of temporal and spatial scales, and to develop technology specific for addressing operation and maintenance concerns. Ponce de Leon Inlet was chosen for the initial field investigation using long-term comprehensive monitoring from 1995 to 1997 (Howell, 1996; King et al., 1999) to generate a baseline analysis of physical conditions and to establish an available archive of data.;The present study utilized the Coastal Modeling System (CMS) developed by the USACE to produce high-resolution 2D, depth-integrated, fully coupled hydrodynamic, wave, sediment transport, and morphology change simulations of proposed alterations in the configuration of Ponce de Leon's dual-jettied inlet system. The primary objective is an assessment of predicted geophysical changes within the inlet system to determine the appropriate redesign that improves navigation and reduces structural stress on the north jetty and shoaling of the south spit.;After performing a 3-month calibration and 7-month validation of the model setup, 15 alternate designs were developed based on an extension of the south jetty and included reopening the weir, an artificial hard bottom in the deep water channel, realignment of the navigation channel, and south jetty spurs both emerged and submerged. Comparison of net morphologic changes, normalized volume changes within 15 sub-domains, and of hydrodynamic changes during both spring and neap tides allowed the best 6 options to be modeled for long-term changes, to include fall and winter storm events. Taken in total with the three areas of concern in mind, the South Jetty Extension with Submergent Spur, Hard Bottom, and Channel was considered the optimal candidate modeled in this study.