After a junior-high school student drowned a few days ago at Shalun Beach in New Taipei City’s Tamsui District (淡水), New Taipei City Deputy Mayor Hsu Chih-chien (許志堅) decided to set up designated swim zones to stop people from going into the water in dangerous areas and to prevent anyone else from drowning. However, this would not appear to be the best way to deal with the matter and it cannot be expected that people would avoid the ocean altogether.
Swimming at the beach is potentially dangerous. The sea is a complicated place and there are no truly safe beaches. For example, when there is a typhoon that has not yet made landfall, the sky is normally bright and sunny.
Ocean water flows in three typical movements: ocean currents; waves; and morning and evening tides.
Waves do not occur without wind, but before a typhoon hits, swells formed in areas of the deep sea are subject to wind pressures, which means water near beaches is full of strong undercurrents. Swells change in size rapidly and are therefore very easily overlooked. Scuba divers in rocky areas can be hit by sudden swells, which push them against rocks that can knock them out. They are at great risk of suffocating if they are not found within minutes of the accident.
This reminds me of an incident that happened about 20 years ago. A student from National Taiwan University’s Department of Zoology had just returned to Taipei after a practicum in Penghu. Her mother told her that there was a typhoon out at sea and advised her not to go to the beach. However, she went with a group of classmates to the beach at Bitoujiao (鼻頭角) and they all went swimming. Around noon, the others realized she was missing and she was later found to have died of drowning. One cannot imagine the pain her parents must have felt. This is a reminder to everyone that people should not go swimming on their own near rocky areas at the beach and should not swim in the ocean when a typhoon is approaching.
Another thing we must be aware of is rip currents. Beaches are not entirely flat and trenches form in outlets as a result of water washing up into river currents. When tides are retreating, ocean water gathers in these trenches, causing strong tidal current zones which head offshore. If you get caught in such a rip current, do not to swim directly to shore, because you will only exhaust yourself. In addition, a rip current retreats faster than you can swim, so you will move further and further away from the shore and end up exhausted and might drown.
If you get caught in a rip current, remember to swim parallel to the shore to escape the rip current and then swim back to shore along either side of the rip current once it has lost its force as a result of the retreating tide.
It is the government’s responsibility to put up signs to warn the public about areas with rip currents, but very few marine scientists remind politicians about this responsibility. When I was a doctoral student at the University of Tokyo’s Ocean Research Institute from 1977 to 1980, I had an Indian classmate who was sent by the Indian government to the university to research rip currents because each year many tourists die at beaches in India as a result of these natural forces.
Beaches are beautiful, but dangerous, and the government cannot stop people from going near the ocean. The best way to prevent accidents is by teaching the public about the ocean.