Scientists' Explanation for Exploration 3B

Florida’s Future Sea Level

Image Source:
and Video Source
(right): SFWMD

South Florida is ground zero for sea level rise. As you learned in this investigation, sea level rise is a problem we must consider in the future, but it is also one that is impacting the residents of South Florida right now! One of the most urgent issues is saltwater intrusion. This occurs because of the porous limestone that underlies Florida. As sea levels rise, saltwater moves through the porous limestone into the many wells along our coast, which are our source of drinking water. Many of our coastal wells have already needed to be moved inland. At the same time, the rising seawater pushes freshwater upward, causing more flooding events inland

Spring Tides
Spring Tides Image Source: NOAA

Currently, we are seeing these flooding events only during major rain events or during extreme high tides. Higher tides occur when the sun, moon, and Earth are aligned so that the gravitational attraction of both the sun and moon on Earth is greatest. These spring tides occur during the new and full moon phases each lunar month. 

In the fall or autumn, the moon is slightly closer to Earth and the spring tides are even higher. These extremely high tides, sometimes referred to as King Tides, will become more prevalent in the future. Once or twice a year, the tides can be so high in some areas of South Florida that many streets become flooded during the high tides. During the King Tide of October 2014, high tides reached 4 feet or greater at the Lake Worth Pier tide gauge for 7 consecutive days.  

King Tide
King Tide. Image Source: UCS
Delray Beach King Tide
King Tide event in Delray Beach, Florida on October 8,
2014. Image Source: Alana Edwards

As sea levels continue to rise, these events will increase. You learned in the previous exploration that a 0.5 meter of sea level rise can cause approximately 573 flooding events per year. This means that approximately three quarters of the year will experience extreme high tide events twice a day. For much of that time, the water will be so high that it will not retreat for several days causing constant flooding over this period. Consider how this will affect your life. What will you have to do differently?

South Florida is not the only area of the U. S. that will face these flooding events. A major portion of the east coast of the U. S. as at risk. The figure shows 52 locations that were analyzed on the East and Gulf Coasts. Currently there are not many locations that flood on a regular basis. However, by 2045, the frequency of coastal tidal events are expected to increase by 10 times as often. 

Tidal Flooding Frequency
The Growing Frequency and Spread of Tidal Flooding. Image Source: USC