Alleviation of Deadly Hazards of RIP Currents Using Near Shore

Rip currents occur every day on many beaches and not only after a storm or at high tide. Deaths from rip currents are a major hazard on global beaches; it is a major cause of surf drowning. In the United States, the rip currents kill nearly 200 to 500 people every year. In Costa Rica Analysis of data from the Judicial Investigation Organization of Costa Rica indicates that drowning is the leading cause of violent death in the country, with 1,391 drownings between 2001 and 2012.

Approximately 590 of those drownings occurred in a marine environment and are listed as being the result of rip currents. In Egypt, according to official data from the Central Agency for Public Mobilization and Statistics (CAPMAS) issued in 2017 drowning accidents and immersion in water unintentionally is about 7% from total different accidents in Egypt, around 1054 male and 220 female with total 1274 people are drowned via drowning accidents. Study of the nearshore is important in areas, where the coastline is influenced by erosion and accretion. These erosion and accretion need some protection structures like groins and break waters, which cause more circulations and rip currents.

Many studies had been carried out to solve problem of rip current, but the problem still exist. This present study assesses the possibility of using new technique as a possible solution for the problems of drowning; also, it presents a vision for decision maker, using a new tool to alleviate the deadly hazards of circulation phenomena and rip currents. For this reason, finding a suitable tool to mark rip currents for warning the swimmers, from the possible hazards due to swimming in the path of rip currents. Furthermore, the objective of this research is determining the hazard area around marine structures of shore protection like groins and breakwaters as well as, the calculation of the characteristics of rip current like its influence distance and its minimum and maximum velocities. The proposed tool is floating self-lighting units, which can generate and save energy for lighting from energy of waves and different currents. The units can be positioned and arranged in the path of rip current, in particular the neck and head area of rip current.

Achieving the goals of this research, field measurements had been carried out, also detailed observations of the effects of longshore varying bathymetry on nearshore circulation. For this purpose numerical models (MIKE 21- SW) and (MIKE 21- FM) were applied on Rosetta promontory ( eastern groin ) , and Baltim coast to determine the current direction and velocity, and also to investigate the circulation flow in the mentioned areas to avoid the dangerous effects of drowning for the swimmers.

In addition, experimental work was performed at the physical model lab of Abu Quir research station, Alex. Egypt. The objective of the experiments is studying the stability of proposed floating units using different wave heights, water depth, and different diameters of circular units. It is concluded after the analysis of data that, the current’s velocities beside the breakwaters are almost large values, where the speed of the rip currents can be 0.5 m/sec up to 1.50 m/sec and extend to 30 m up to 150 m towards the sea (in Egypt). It is recommended that for decision makers, the proposed floating device can be a tool for the reduction of rip current hazard.

For swimmers, be watchful at all times, especially when swimming at unguarded beaches. Stay at least 100 m away from breakwaters, groins, piers and jetties, because permanent rip currents often exist alongside these structures. It is required to characterize the rip hazard at the most popular beaches on the coastal zone in Egypt.

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