Shore Protective Revetment Crowned with Pedestrian Walkway at Strand Beach, California

Abstract

To provide adequate protection against storm wave attack, minimize terrace slope erosion, enhance public safety, and maintain lateral beach access, the 2,100-foot aged riprap revetment was repaired under the site’s development plan at Strand Beach, California. Furthermore, to promote public use of the project beach area and enhance the aesthetic scenic view, an 8-foot wide pedestrian walkway with a 3-foot high retaining wall was built atop the revetment. The integrated walkway/retaining wall structure provides additional protection against storm wave impingement. A 3-year post-construction beach monitoring program was implemented to document any potential revetment construction impact on coastal processes at Strand Beach after the revetment repair. It was found that the coastal processes impact on Strand Beach as a result of the revetment repair is inconsequential. BACKGROUND A planned oceanfront development site located at Strand Beach, Dana Point, California, shown in Figure 1, was historically protected by an aged riprap revetment against storm wave attack. Years of service had left the under-engineered riprap revetment with dislodged stones and incapable of its shore protective function. Figure 2 illustrates the pre-project revetment condition at Strand Beach. The engineering task primarily involved repair of the aged, under-designed riprap revetment with larger stones to provide shore protection against increasing occurrence of severe storm wave attack resulting potentially from meteorological change owing to the global warming effect. The repair, however, would need to satisfy requirements related to land use, aesthetic, biological, ecological, recreational and water quality issues. PERMIT PROCESS A coastal engineering assessment for the proposed development plan was prepared to characterize local and regional coastal processes (Noble Consultants Inc, 2001 & 2002). Comparison of various shore protective alternatives was performed to identify potential project impacts related to wave characteristics in the surf zone as well as