Reply: Design and construction of a 3 km (2 mi) long shoreline protection system for the City of Luna Pier

In 1982, N.K. Becker & Associates Ltd. designed a precast concrete flood protection and beach restoration system for the 3 km (2 mi) long Lake Erie shoreline of the City of Luna Pier, Michigan. The construction of these works, which included beach sills, shorewalls, and a marina basin, was completed in 1984.The shorewall system is unique in that it was designed of interconnected, open-ended, earth-filled, thin-walled precast concrete cylinders, placed on-end and in-line to form a continuous wall. This seawall design was selected by the City of Luna Pier over alternative systems because it was estimated to cost 50% less than conventional steel sheet piling or cast-in-place concrete systems.During the final design, hydraulic model tests were carried out at both the University of Michigan and the University of Windsor to study the uprush, scour, longshore transport, and wave pressure characteristics of the proposed system. The methods used to design this economical and functional flood protection system are presented along with an analysis of its performance to date. Key words: beach, beach sill, flushing, hydraulic model testing, ice, longshore drift, overtopping, precast cellular concrete wall system, scour, shorewall, uprush, water levels, waves, wave deflector.