Fort Lauderdale is nicknamed the "Venice of America" due to its roughly 165 miles (266 km) of canals. During the king tides, the local Miami area tide gauge at Virginia Key shows levels running at times 1 foot (0.30 m) or more over datum.įort Lauderdale has installed over one hundred tidal valves since 2013 to combat flooding. NOAA tide gauge data for most stations shows current water level graphs relative to a fixed vertical datum, as well as mean sea level trends for some stations. While the tide range is very small in Miami, averaging about 2 ft (0.61 m), with the greatest range being less than 2 m (6.6 ft), the area is very acute to minute differences down to single inches due to the vast area at low elevation. The 20 king tide event levels reached about 4 feet (1.2 m) MLLW, 3 feet (0.9 m) above mean sea level, or about 2 ft (0.61 m) NAVD88, and nearly the same above MHHW. In the Miami metropolitan area, where the vast majority of the land is below 10 ft (3.0 m), even a one-foot increase over the average high tide can cause widespread flooding.
TIDE GRAPH WATCH INSTALL
The issue is more bipartisan in South Florida, particularly in places like Miami Beach, where a several hundred million dollar project is underway to install more than 50 pumps and physically raise roads to combat the flooding, mainly along the west side of South Beach, formerly a mangrove wetland where the average elevation is less than one meter (3.3 feet). This amid Florida, specifically South Florida and the Miami metropolitan area being one of the most at risk areas in the world for the potential effects of sea level rise, and where the frequency and severity of tidal flooding events increased in the 21st century. In Florida, controversy arose when state-level government mandated that the term "nuisance flooding" and other terms be used in place of terms such as sea level rise, climate change and global warming, prompting allegations of climate change denial, specifically against Governor Rick Scott. Saltwater in drain on a bayfront street (Brickell Bay Drive) in Miami just up to street level while not a direct flood, this inhibits normal passive, gravity-based drainage. As glaciers retreat, there is less firn (water-retaining snow) so that more meltwater runs directly into the watershed over deeper, impervious glacial ice. Ī warming climate causes physical changes to the types of ice on a glacier. Abnormally hot temperatures not only swell rivers and creeks directly through accelerated snowmelt, but can burst ice dams and cause water from glacial lakes to swell waterways less predictably. Further, regions with glaciers also experience sunny day flooding as climate change alters the dynamics of glacier meltwater. Sunny day flooding is often associated with coastal regions, where sea level rise attributed to global warming can send water into the streets on days with elevated high tides. In Miami Beach, where resilience work is underway, the pump systems replace insufficient gravity-based systems.
However, while this may prevent a majority of the tidal intrusion, it also inhibits drainage during exceptionally high tides that shut the valves. One passive solution to intrusion through drainage systems are one way back-flow valves in drainage ways. Thus, even normal rainfall or storm surge events can cause greatly amplified flooding effects. Tidal flooding is capable of greatly inhibiting natural gravity-based drainage systems in low-lying areas when it reaches levels that are below visible inundation of the surface, but which are high enough to incapacitate the lower drainage or sewer system. Geographies faced with these issues can utilize coastal management practices to mitigate the effects in some areas, but increasingly these kinds of floods may develop into coastal flooding that requires managed retreat or other more extensive climate change adaptation practices are needed for vulnerable areas.
This kind of flooding is becoming more common in cities and other human-occupied coastal areas as sea level rise associated with climate change and other human-related environmental impacts such as coastal erosion and land subsidence increase the vulnerability of infrastructure. These kinds of floods tend not to be a high risk to property or human safety, but further stress coastal infrastructure in low lying areas. The highest tides of the year may be known as the king tide, with the month varying by location.
TIDE GRAPH WATCH FULL
Tidal flooding, also known as sunny day flooding or nuisance flooding, is the temporary inundation of low-lying areas, especially streets, during exceptionally high tide events, such as at full and new moons. Octotidal flooding on a sunny day, during the "king tides" in Brickell, Miami that peaked at 4 ft MLLW.
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