DELRAY BEACH, FL (BocaNewsNow.com) (Source: Delray Beach Police) — Delray Beach residents may notice that water levels are slightly higher than usual along the Intracoastal Waterway and the finger canals. The high levels are due to King Tides, naturally occurring high tides that happen yearly. Residents may see water in roadways that comes up through storm drains, as well as water levels that are higher than some sea walls and docks Tuesday to Thursday, which may result in flooded yards or streets.
The impact to the city from King Tides should end by Nov. 2. Back flow preventers have been installed on some of the stormwater outfalls, and the city has inspected catch basins and tidal valves in the areas of concern and put up barricades in areas known to flood to reduce the potential for neighbors driving off flooded streets.
Frequently Asked Questions
What are King Tides?
King Tides generally occur in the fall when the alignment of the sun, moon and earth generate higher than normal tides. Local weather conditions causing onshore winds, rising sea levels and inclement weather including extreme precipitation can combine to exacerbate flooding risks, especially in low-lying coastal areas.
I have lived here for many years and never had a problem before. Why are we experiencing these kinds of issues with King Tides now?
Delray Beach has been settled for more than 100 years with many neighborhoods being built 50, 60 or 70 years ago. In the past century, sea level has risen by nearly 10 inches. The result is tides that are nearly a foot higher than when some of these properties were built. Sea level is continuing to rise, meaning this problem will persist into the future.
What is the city doing to address this?
Prior to the king tide “season,” city staff gather to discuss the potential impacts of the tides on emergency preparedness; maritime navigation; the construction of bridges, docks, and seawalls; the operation of wastewater and storm water collection systems. The city has installed some tidal valves in affected neighborhoods, which have helped to reduce the impacts of the high tides in those locations. The city is also implementing a Stormwater Master Plan to improve the drainage.
Why didn’t my coastal street flood last fall but it is flooded today?
Tide predictions can differ from the actual sea level rise or fall. Predicted tidal heights are those expected during average weather conditions. When weather conditions differ from what is considered average, water levels can be significantly altered. Generally, prolonged onshore winds (wind towards the land from the east) or a low barometric pressure can produce higher sea levels than predicted, while offshore winds (wind away from the land) and high barometric pressure can result in lower sea levels than predicted.
I live in a coastal neighborhood, and my street is flooded at high tide. How long will the flooding last?
In southeast Florida, tides peak to a high and low water level twice a day, or roughly every 12 hours and 20 minutes. Tidal flooding in low lying areas will be greatest a few hours before and after the peak of the high tide.
Why do the streets flood during these tides?
There are two types of flooding that occur during high tides: tidal flooding and storm flooding. These high tides cause ocean and canal waters to rise, overtopping seawalls and travelling up the storm pipes through the catch basins and into the streets throughout the city and South Florida. This is tidal (saltwater) flooding of those areas. Rainfall that coincides with the predicted high tide cannot only exacerbate tidal flooding in the coastal areas, but also can cause stormwater (freshwater) flooding further inland. As the high tide moves into the stormwater pipes and up into the catch basins, it takes up capacity in the stormwater management system and prevents stormwater from being discharged. This results in freshwater flooding for those neighborhoods upstream of the discharge point, as the stormwater cannot drain off the land until the tide recedes.