Mean High Water


A project documenting the impacts of sea level rise & flooding across the South Carolina Lowcountry.
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TABLE OF CONTENTS
01. New Project Coming Soon...
02. A Primer on Flooding in Charleston
03. Elevations on MLLW Datum
04. Photographic Archive of Flooding
05.  Flooding Resources





USEFUL LINKS
National Water Level Prediction Service
NOAA Observed Water Levels
NWS Coastal Flood Event Database
Charleston TideEYE Dashboard





Hurricane Idalia
August 30, 2023
Peak Elevation: 9.23-ft MLLW (6.09-ft NAVD88)
Peak Time: 00:18 GMT (08:18PM EST)

  • The surge during Hurricane Idalia’s passing of Charleston was the 5th highest on record in the Harbor, and it came within an inch of Hurricane Matthew’s surge in 2016.
  • The surge was driven by the timing and direction of Idalia’s path and it’s occurrence during a ‘king tide’ driven by August’s 2nd full moon. 
  • As of the end of August, we have seen 4 ‘major’ tidal floods in the harbor this year. With four month remaining, 2023 is already tide for 3rd in occurrences of major tidal floods in a year (tied with 2021 & 2019). 2020 holds the record for most major tidal floods (7). 

Morrison Drive
Union Pier
Society St. at Washington St.
Washington St.
Washington St.
Faber St.
North Market St.
High Battery
High Battery
High Battery
High Battery
High Battery
Water St.
Water St.
Water St.
Water St. at Church St.
Water St. at Church St.
Water St.
Water St. at Church St.
Church St.
S. Battery St.
S. Battery St.
S. Battery St.
Legare St.
Rutledge Ave.
Beaufain St.
Legare St.
Legare St.
S. Battery St.
S. Battery St.
Legare St.
Beaufain St.

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