A project documenting
Sea Level Rise & Flooding in the Lowcountry

01 OVERVIEW ︎︎︎
02 LATEST ︎︎︎   
03 ARCHIVE ︎︎︎

Mean High Water (MHW) is a project documenting the impacts of sea level rise 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 45% of all coastal floods observed in Charleston Harbor from 1953 through 2020 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%.

This project was started by photographer and engineer Jared Bramblett in 2020. It is intended to be an evolving and collaborative documentation of the impacts of rising seas and how communities are adapting to them. If you are interested in participating and submitting to the project, please reach out. All content on this site is copyrighted. If you are interested in using any content, please submit a request.

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Jared Bramblett

All thoughts and opinions presented on this site are solely those of the author and are not necessarily those of any other organizations.

Charleston Harbor, Cooper River Entrance1

Coastal Floods (>7-ft MLLW)2
89 (2019)
68 (2020)
58 (2015)
55 (2016)
46 (2017)

Major Coastal Floods (>8-ft MLLW)2
7 (2020)
6 (2015)
4 (2019)
3 (2018)
2 (2009)

Peak Tide Crests (MLLW)3
09/22/1989 - 12.52-ft (Hugo)
08/11/1940 - 10.23-ft (Unnamed)
09/11/2017 - 9.92-ft (Irma)
10/08/2016 - 9.29 (Matthew)
01/01/1987 - 8.81-ft 

22 of the 36 (61%) major flood tides on record have occurred since 2015.3

Statistics current as of 1/31/2021


1Tidal 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.

2NOAA Coastal Flood Event Database
This is a database maintained by the NOAA Coastal Services Center 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.

3Advanced Hydrologic Prediction Center, Charleston, SC
Forecasts for water levels at the tidal bench mark based on meteorological predictions are presented here.

A Quiet, Record Setting January

4 FEBRUARY 2021 - Jared Bramblett

January 2021 seemed like a quiet month for coastal (tidal) flooding. There were five (5) tides that exceeded the 7-ft MLLW coastal flood threshold, with the highest only reaching 7.05-ft. The impacts from these events were relatively minor, and mitigation measures implemented over the past few years prevented impacts in low-lying areas of Eastside and Harleston Village. There were still some inundation along Hagood Avenue in Westside and possibly along US Highway 61 near the Ashley River Bridges.

January has historically been a quiet month for tidal flooding. Reviewing the NOAA Coastal Flood Event Database, the five (5) flood tides of January 2021 were actually record setting. Prior, the most flood tides observed in the harbor were four (4) in 1983, 1999, and 2016. The graph below shows the number of tidal flood events during the month of January since 1922. So while the impacts of coastal flooding in January 2021 were minor, the frequency of the flooding is increasing. There were no coastal floods recorded in January until 1980, and since then there have been 47. The last January where we didn’t record tidal flooding was eight (8) years ago in 2013.

© 2021