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

Abstract : Shoaling and channel migration at Ponce de Leon Inlet, FL, 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. This study utilized the Coastal Modeling System (CMS) 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. Fifteen 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 hydrodynamic changes during both spring and neap tides allowed the best 6 options to be modeled for long-term changes. The South Jetty Extension with Submergent Spur, Hard Bottom, and Channel was considered the optimal candidate modeled in this study.