Seawalls and Signage: How Beach Access Management Affects Rip Current Safety

Abstract

Rip currents are concentrated flows of water flowing out to sea faster than the surrounding waves. These currents form as a result of alongshore variations in wave set-up driven by variable nearshore morphology or hard structures that interrupt the longshore current. Recent research from the United States, Costa Rica, Australia, and the United Kingdom suggests that the beach going public is mostly unaware of how to identify, avoid, and escape rip currents. As a result, hundreds of rip current related deaths occur worldwide each year, making rip currents a global health hazard. While an increasing number of programs are created in coastal countries, many aimed at increasing public awareness and education, signage, or improving lifeguard programs, there is increasing evidence that existing warning systems and signage are ineffective because beach users are unable to translate the warning into a real-world feature. Further evidence suggests that beach access management can inadvertently steer unsuspecting beach users towards rip-prone areas, increasing the chances of a drowning occurring on that beach. For example, alongshore variations in the offshore bathymetry at Pensacola Beach, Florida responsible for semi-permanent rip-prone sections of the beach are also responsible for the development of relatively small dunes in the backshore. Beach access points were preferentially built in the areas with smaller dunes, thereby focusing beach-users towards the most rip-prone sections of the beach. In another example from Jaco Beach, Costa Rica, public beach access points are adjacent to stream outlets that are responsible for creating a nearshore terrace and rip morphology, and are focusing beach users’ access and activity towards rip-prone sections of the beach. In contrast, the evenly spaced beach access ramps from the seawall down to the sand of Australia’s famous Bondi Beach in Sydney do not focus beach-users and activity towards rip-prone sections of the beach. However, the placement of a popular bus stop and hostels invite the most vulnerable and unaware beach users swimmers towards the southern end of the beach with a large semi-permanent rip current called the “Backpacker’s Express.” Through these examples, we conclude that when developers do not consider beach and nearshore geomorphology in their designs for beach access management, they may lead unsuspecting and unaware beach users towards the rip hazard and increase the potential for drownings.