Ocean Lifeguard Prevention and Rescue Activities in Newport Beach: Analyses using Activity Data Collected in Real-Time with a Computer Aided Dispatch System

Abstract

Ocean lifeguards have protected bathers from drowning in developed countries for decades, and efforts to establish ocean lifesaving bodies in low- and middle-income countries are increasing. Given the importance and prevalence of the profession around the world, surprisingly few studies have investigated the nature of ocean lifeguard activity, and little is known about ocean lifeguard interventions in the drowning process. This thesis has two major components: (1) to characterize the nature of primary and secondary lifeguard drowning prevention interventions, specifically describing variation in time and location of lifeguard activity; and (2) to investigate the relationship between wave height and changing water levels with the occurrence of ocean rescue in the study location. Data for this research were collected in 2015 and 2016 by lifeguards in Newport Beach, California, using a Computer Aided Dispatch (CAD) system. Lifeguard activity data was recorded in real-time, which provided intensely detailed records that were linked to external data collection systems. We described temporal trends, conducted scan statistic GIS analysis, and described the variant staffing elements of lifeguard primary and secondary prevention. Mixed effects negative binomial regression was used to examine the association between wave height and changing water levels with rescue frequency in the study location. Lifeguard rescues did not happen homogeneously in time and space, and were statistically associated with wave height and water level changes. Importantly, varying effects of environmental variables were observed, indicating other factors undocumented in these data have a role in causing rescues. This research represents a first attempt at analyzing ocean lifeguard activity data collected in real-time with a Computer Aided Dispatch system.