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.
All content presented on this site is copyrighted. To inquire about content usage, please submit a request.
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
A Primer on Flooding in Charleston
NWS Coastal Flood Event Database
This is a database maintained by the National Weather Service Charleston that tracks coastal flooding in Charleston and Savannah. It is referenced often throughout this site, particularly when discussing the number of coastal floods that have occurred in Charleston Harbor.
Tidal Benchmark Station - Charleston, Cooper River Entrance, SC - Station ID: 8665530
This is the homepage for the Charleston Tidal Benchmark, which serves as the main tide gauge referenced for tide levels in the Charleston region. The tidal datums (e.g. MLLW, MHW, MHHW) for Charleston are presented here. Lunar tide levels predictions can be found here, and the database of historic tide levels can be accessed here.
Advanced Hydrologic Prediction Service, Charleston, SC
Forecasts for water levels at the tidal bench mark based on meteorological predictions are presented here.
The Preservation Society of Charleston - The Halsey Map
City of Charleston Flooding & Sea Level Rise Strategy
City of Charleston Flooding Tools
Local Tide Trends Dashboard
Charleston Resilience Network