The construction of Santa Maria and La Pinta islands are nearing completion just offshore of Panama City, Panama which will result in waterfront developable land close to the city core. The islands are situated south of Punta Pacifica in front of Panama City. Wave activity in the Bay of Panama is dominated by swell waves generated by far-off storm events in the Southern Hemisphere. Typical wave periods range from 14 to 21 seconds. The area also suffers from extended durations of 20 seconds swell waves. A multidisciplinary design team led by coastal engineers was tasked with designing a recreational mega-yacht harbor, to be situated between the islands. The harbor design had to achieve satisfactory tranquility in the berths, provide safe navigation though the entrance for vessels up to 61 meters (200 feet) in length, maintain water quality circulation, minimize siltation, and offer aesthetic and recreational amenities.
Unlike shorter period wind waves, swells refract and diffract much more severely, propagate much deeper into embayments due to their longer wavelengths, reflect more strongly, and are more difficult to absorb. Furthermore, in shallow waters these swells become highly grouped and exhibit complex non-linear characteristics. Designing a harbor entrance to minimize the propagation of this swell action to the berths is therefore much more challenging and requires innovative engineering to overcome the problem. This presentation provides an overview of the state-of-the-art modeling techniques, physical model testing, and unique engineering approaches applied to create a successful harbor entrance design in a complex swell-wave climate.
The design evolved by modeling various combinations of breakwater lengths and configurations and by incorporating an absorptive beach into the construction of the island containment breakwater. A rigorous numerical analysis was performed using a Non Linear Wave Transformation Model based on the Boussinesq equations to realistically simulate the swell wave behavior and diffraction patterns. Animations of the wave action were created to explore wave behavior patterns not readily apparent in the simple reporting of wave heights. Physical modeling explored various wave absorbing rubble beach profiles to further mitigate swell wave energy at the base of the harbor entrance and dissipate reflective resonance within the channel. The subsequent basin design and test results demonstrate a clear and successful indication of the performance to be expected from the constructed harbor design.