Southern California is bracing for a combination of the highest tides of the year and large waves Jan. 11-12.
What are King Tides?
While the term King Tide isn’t a scientific term, it is used to describe very high tides, caused when there is alignment of the gravitational pull between sun, moon and Earth. When King Tides occur during floods or storms, water levels can rise higher and have the potential to cause great damage to the coastline and coastal property.
King Tides: These types of tides occur naturally and regularly, and are predictable and expected, although they are not an everyday occurrence.
According to the California Coastal Commission, California will be greatly impacted by sea level rise. For example, San Francisco is projected to see a rise between 1.1 and 2.7 feet by 2050. By 2100, it could experience between 3.4 and 6.9 feet of sea level rise with a potential for more than 10 feet of rise if there is extreme melting of the West Antarctic ice sheet.
King Tides themselves are not related to climate change, but they allow us to experience what higher sea level will be like. King Tides are the highest high tides of the year — 1 to 2 feet higher than average high tides, which is a good approximation of how high we expect everyday tides to be over the next few decades due to human-caused sea level rise. When you observe the King Tides, imagine seeing these tides (and the associated flooded streets, beaches and wetlands) every day. Understanding what a King Tide looks like today will help us plan for future sea level rise.
Send your photos
The California Coastal Commission wants you to send them your photos.
To learn more go to here.
Be careful, some Southern California beaches are expected to have waves in the 4-7 foot range Thursday.
You can find the tide forecast for 30 days ahead anywhere in the U.S. here.
Nourishing the beaches
The graphics below are from the U.S. Army Corps of Engineers. Coastal engineers expect that large storms will induce sediment transport from the nourished beach and move sand offshore. When this happens, waves begin to break farther from the shoreline, thus weakening their force before they reach the shoreline. In this way, beach nourishment projects help protect dunes and property from further erosion, decrease flooding, and limit how far ashore storm surge will go.
A wide, flat beach berm with a sufficient volume of sand keeps the erosive power of the waves from reaching and destroying the dunes and structures and can reduce damages significantly from waves, inundation and erosion. Without beach nourishment, the starting point for damage would be farther onshore; a nourished beach, with sufficient sand volume and healthy dunes, absorbs the storm’s energy, even during slow-moving storms, and helps prevent damages to structures and infrastructure.
You can read a lot more about the U.S. Army Corps of Engineers beach nourishment projects in a PDF here.
Major scale
San Clemente is expected to get 250,000 cubic yards of sand dredged from Oceanside to place between T Street and Linda Lane in a $15 million project. Another $23 million project is depositing 1.85 million cubic yards of sand at Sunset Beach which will fortify the beaches for some 12 miles toward Newport Beach. The latter project continues through February.
How big is 250,000 cubic yards of sand?
An acre is 4,840 square yards. If you cover it 1-yard deep, that’s 4,840 cubic yards.
The San Clemente project is about 51 acres of sand 1-yard deep
The Sunset Beach project is about 382 acres of sand 1-yard deep.
The average dump truck usually carries about 10 to 14 cubic yards.
Sources: The U.S. Army Corps of Engineers, The Journal of Coastal Research, The California Coastal Commission, Scripps Institute of Oceanography, California Beaches, The Inertia, Tideforecast.com
