Detailed Project Description

A sand transfer plant or sand bypassing system operates at Lake Worth Inlet, Florida. The inlet is located between the communities of Riviera Beach (to the north) and West Palm Beach (to the South). Both communities are located in the Palm Beach County area. The inlet is approximately 800-ft (244 m) wide, and a 400-ft (122 m) wide and 35 ft (11 m) deep navigation channel is maintained annually by dredging. North and south jetties maintain channel alignment. On the open coast, a fillet forms on the north side of the north jetty due to the net alongshore transport of sediment to the south. A sand bypassing plant presently mines the subaerial region of the up-drift fillet and discharges the material within 100-ft (15 m) down-drift of the south jetty. The bypassing plant was constructed by the Town of Palm Beach and is presently operated by Palm Beach County.

US Army Corps of Engineers (USACE), in cooperation with Palm Beach County, the Town of West Palm Beach, and the Port of Palm Beach are investigating several scenarios for increasing the volume of sediment bypassed to down drift beaches and to reduce maintenance dredging at the Lake Worth Inlet navigation channel. To facilitate bypassing of sediment at the inlet, alternatives include extending single or multiple discharge lines further down-drift and increasing the volume of material dredged from the up-drift fillet.

An important element of the assessment of alternatives is to develop an understanding of the localized coastal system including long- and short-term erosion rates and hydrodynamics. To gain an understanding of these processes, USAE District, Jacksonville has conducted GENESIS numerical model shoreline change simulations. Preliminary model results reveal that a nodal point in sediment transport may exist south of the inlet within 3000-ft (914 m) of the south jetty, with directions of net littoral transport to the north and south diverging from the point.

In support the numerical investigation, a video-based remote sensing metric system (an Argus Beach Monitoring Station) is installed and maintained to monitor the evolution of submerged and emergent morphology on open-coast beaches adjacent to the inlet. The installation provides cost-effective monitoring of shoreline change at beaches adjacent to the inlet with high spatial and temporal resolution. The installation is designed to monitor the shoreline orientation of the fillet on the north side of the inlet and to monitor shoreline orientation on the south side of the inlet to include the region of the identified sediment transport nodal point.