MEAN HIGH WATER


Flooding & Sea Level Rise in the SC Lowcountry





ABOUT
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 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%.

MHW was started in 2020 by photographer and engineer Jared Bramblett. It is intended to be an evolving and collaborative documentation of the impacts of flooding. 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.


CONTACT
Jared Bramblett
jaredbramblett@gmail.com

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


01    INDEX︎︎︎
02    CHARLESTON UNDER WATER ︎︎︎
03    LATEST/NEXT ︎︎︎
04    NEWSLETTER ︎︎︎
05    RESOURCES︎︎︎





RECORDS & STATISTICS
Charleston Harbor, Cooper River Entrance1

Coastal Floods (>7-ft MLLW)2
1.
2.
3.
4.
5.
89 (2019)
68 (2020)
58 (2015)
55 (2016)
46 (2017, 2021)

Major Coastal Floods (>8-ft MLLW)2
1.
2.
3.
4.
5.
7 (2020)
6 (2015)
4 (2021)
4 (2019)
3 (2018)

Peak Tide Crests (MLLW)3
1.
2.
3.
4.
5.
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 

26 of the 40 (65%) major flood tides on record have occurred since 2015.3

Statistics current as of 07/01/2022


REFERENCES

1Tidal Benchmark Station - Charleston, Cooper River Entrance, SC - Station ID: 8665530

2NWS Coastal Flood Event Database

3Advanced Hydrologic Prediction Service, Charleston, SC 

A Quiet, Record Setting January

February 4, 2021
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.




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