Mean High Water (MHW) is a project documenting the impacts of sea level rise & flooding in and beyond the South Carolina Lowcountry. The title is in reference to the MHW tidal datum defined and maintained by the NOAA Center for Operational Oceanographic Products and Service.
The tides of Charleston Harbor and the Atlantic Ocean are increasingly encroaching into the natural and built environment of Charleston and the Lowcountry. The rate of increase in the number of coastal flood events is alarming. Approximately 53.3% of all coastal floods observed in Charleston Harbor from 1921 through 2022 have occurred since 2010. An average of 18.8 coastal floods occurred per year in the 1990s. In the 2010s, the annual average was 42.4 coastal floods2, an increase of over 200%.
MHW was started in 2020 by photographer and engineer Jared Bramblett. This is intended to be an evolving and collaborative documentation of the impacts of flooding. If you are interested in participating, please reach out.
All thoughts and opinions presented on this site are solely those of the author and are not necessarily those of any other organization.
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Charleston Harbor, Cooper River Entrance1
Coastal Floods (>7-ft MLLW)2
Major Coastal Floods (>8-ft MLLW)2
Peak Tide Crests (ft, MLLW)3 Statistics current as of 08/31/2023
Sea Level Rise Trend (1901-2022)1
Sea level trend of 1.13-ft per 100 years (1901-2022)
1 Tidal Benchmark Station - Charleston, Cooper River Entrance, SC - Station ID: 8665530
2 NWS Coastal Flood Event Database
3 Advanced Hydrologic Predictions Service, Charleston, SC
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).
Peak Time: 01:24 GMT (09:24PM EST)