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King Tides and Sea Level Rise
Enough Pie's Awakening: King Tide
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Charleston is at a crossroads. Flooded streets and rising waters affect us more and more. By 2045, Charleston will experience sunny day tidal flooding 180 days out of the year — averaging every other day. The decisions and actions we take NOW as residents of the Lowcountry are critical to our future.



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Enough Pie has assembled a team of artists, scientists, organizations and thought leaders including the City of Charleston to shine a light on rising waters through public art, parades, lectures, and events from April 29-May 26 across the Upper Peninsula. All are welcome.  Their programming is free. This is an opportunity to be inspired, learn and make a difference.  Want to know what you can do, click here.

KING TIDES - What are they?

Sunny day floods that occurs during the highest of high tides. They are independent of floods caused from the ocean by storm surges or floods caused by rainfall, but King Tides can make flooding from storms and rain more severe. King Tides are predicted and expected over the course of the year.

The term "King Tide" is a non-scientific term used to describe the highest seasonal tides that occur each year. For example, in Charleston, the average high tide range is about 5.5 ft., whereas during a King Tide event the high tide range may reach 7 ft. or higher. These tides occur naturally and are typically caused when a spring tide (when the sun, moon, and earth align during a new and full moon, increasing tide ranges) takes place when the moon is closest to Earth during the 28-day elliptical orbit (know as perigee).

Resources:
SCDHEC King Tides Initiative
SCDHEC Tide Tables
EPA King Tides & Climate Change


KING TIDES - What's happening?
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Sunny day flooding increased from approximately 2 days per year in 1970 to 11 days per year in 2014 and is projected to increase to 180 days per year in 2045 (see Figure 1). King Tides give us a glimpse into the future of what our tides will be like as the sea level rises over the coming years.

Resources:
King Tides Project: Snap the Shore, See the Future
Union of Concerned Scientist - Encroaching Tides


SEA LEVEL RISE - What's happening?
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Charleston has experienced 1 foot of rising seas over the past century based on trends from 1921 to 2013 (see Figure 2). Mean Sea Level always varies between months, but the recent trend in Charleston is a rise of about 1/8 of an inch each year. One hundred years ago, the mean monthly sea level in Charleston was about 1 foot lower than it is today. This rise has contributed to the frequency and
severity of King Tide flooding.

Resources: 
City of Charleston Sea Level Rise Viewer
NOAA Tides & Currents - Sea Level Trends


SEA LEVEL RISE - What's next?
The curves in Figure 3 represent changes in sea-level height by the 2100 relative to mean sea-level. The lowest curve represents the increase (approximately 2') in sea level if the production rate of heat trapping gases in the atmosphere (caused by fossil fuel burning, methane production, deforestation, etc) does not continue to increase over time. The middle curve represents the increase (approximately 4') in sea level if continued production of heat trapping gases results in some glacial ice melt. The highest curve represents the increase (approximately 7') in sea level if the rate of heat trapping gas production increases and glacial ice melts more quickly.

Resources:
NOAA Sea Level Rise Viewer
City of Charleston Sea Level Rise Viewer

IMPACTS - What are they?
– Frequent tidal flooding
– Increased flooding during rains
– Increased storm surge during tropical storms
– Economic loses (damage to residential and business properties, time, access to businesses)
– Environmental concerns (marsh loss, saltwater intrusion)
– Risk to historic & cultural resources

What's next? What can we do?
Mitigate: Protect, Adapt, & Retreat
Mitigate: Be stewards of energy resources and reduce coal & oil-based energy consumption.
Protect: Keep the water away from valuable assets (people, places, & things). Examples include large engineering projects to pump water, build levees and walls to keep water out, & beach renourishing projects.
Adapt: Plan to live with water rather than fight it. Purchase flood insurance to protect properties and businesses, store water in the landscape, design green spaces for flood control, use living shorelines to maintain beach and marsh habitat, prevent building within floodplains, elevate structures (buildings,
homes, and roads), maintain storm drainage systems and keep them clean, & develop and implement more robust stormwater regulations.
Retreat: Relocate valuable resources to high ground.

AWAKENING V: KING TIDE DATA STEERING COMMITTEE:

Dan Burger - Director, Coastal Services Division - OCRM & Chair Charleston Resilience Network
Jared Bramblett, PE - Civil Engineer, Davis & Floyd
Mary Culver, PhD - NOAA Office of Coastal Management
Bobbie Lyon, PhD - Adjunct Professor, College of Charleston Grice Marine Lab & Co-Founder, Cultivate - Community Art & Science
Jessica Hardesty Norris, PhD - Conservation Ecologist, Biohabitats & President Audubon Society
Joshua Robinson, PE - Robinson Design Engineers
Carolee Williams - Project Manager, City of Charleston Department of Planning, Preservation, & Sustainability