Challenge: The Waldorf Astoria Resort is built on a narrow strip of land at the base of a steep cliff on the southern tip of Cabo San Lucas, where active and threatening hurricane seasons create a transient and unpredictable sandy beach. The challenge was to protect the resort’s infrastructure from storm events as well as to build and stabilize a wide beach berm for guests and recreational activities that was consistent throughout the seasons.
Solution: For adequate protection from storms, the resort required a seawall designed to withstand erosion and wave runup while releasing water from rainfall. To develop the seawall design parameters (water surface elevation [WSE] and wave climate), INTERA constructed and calibrated ADCIRC and SWAN models that were used to hindcast the WSE and wave climate associated with a previous hurricane and design storm. Using the model simulation results, the initial beach profile at the site, and the beach sediment properties, we developed and applied a cross-shore beach erosion model to provide the design profiles for the seawall. INTERA collaborated with an architectural firm to provide a cost effective and functional yet aesthetically pleasing design. The final design incorporates an infrastructure-grade marine composite sheet pile wall with uniaxial geogrid support, an extensive drainage system, and a concrete façade that includes a cap with a recurve designed to reduce overtopping from wave run-up during storm events. While the seawall proved extremely effective in protecting the resort itself, INTERA was again retained after the active hurricane seasons of 2014 and 2015 to develop a solution for protecting the resort’s beach. We completed a feasibility evaluation that determined the installation of a T-head groin field would be an effective means of widening the beach berm. Design conditions including waves, water levels, and sediment transport were developed and used to establish the conceptual T-head groin field configuration. Simulation results from a SWAN+ADCIRC model were then used to assess wave runup levels, post-storm cross shore erosion, and downdrift effects and identify the optimal T-head locations and configuration design. INTERA also provided permitting assistance, developed plans and specifications, evaluated construction bids, and oversaw the construction of the T-head groin field.
Results: The seawall has withstood multiple storm events without damage, including the uncharacteristically active (21 named storms) 2014 eastern Pacific hurricane season. After less than two years, the T-head groin field has helped create a sizeable beach that is now maintained year-round, thereby providing the beachfront experience that draws guests to Cabo San Lucas.