Cooper River at Charleston Harbor (IN MLLW)
South Carolina — Water Level & Flood Stage
Located in Charleston County, South Carolina on the Cooper River. Live water level data from USGS, updated every 15 minutes.
Current Water Level
Gage Height
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Streamflow
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Last Reading
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This is an NWS forecast point (LID: CHTS1). Live data may be limited. View on NWS AHPS →
Flood Stages
Major Flood
8 ft
Moderate Flood
7.5 ft
Minor Flood
7 ft
Action Stage
6.5 ft
Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.
What Floods at Each Level
12.52 ft
Record tide level reached in association with Hurricane Hugo which made landfall at Sullivans Island, SC as a Category 4 hurricane at midnight September 22nd, 1989.
10.23 ft
Peak tide level reached in association with an unnamed hurricane that made landfall near Hilton Head Island, SC as a Category 2 hurricane on August 11th, 1940.
9.92 ft
Peak tide level reached in association with Tropical Storm Irma on September 11th, 2017.
9.86 ft
Peak tide level reached in association with a strong area of low pressure on December 17th, 2023. Ranks as the highest non-tropical tide level on record.
9.29 ft
Peak tide level reached in association with Hurricane Matthew which made landfall near McClellanville, SC as a Category 1 hurricane on October 8th, 2016.
9.23 ft
Peak tide level reached in association with Tropical Storm Idalia on August 30th, 2023.
8.64 ft
Peak tide level reached in association with Hurricane David which made landfall near Sapelo Island, GA as a Category 1 hurricane on September 4th, 1979.
8.15 ft
Peak tide level reached in association with an unnamed hurricane that made landfall near Ossabaw Island, GA as a Category 2 hurricane on October 15th, 1947.
8.14 ft
Peak tide level reached in association with Hurricane Gracie which made landfall near Edisto Island, SC as a Category 4 hurricane on September 29th, 1959.
8 ft
At 8.0 ft MLLW, major coastal flooding occurs. Widespread flooding occurs in Downtown Charleston with numerous roads flooded and impassable and some impact to structures. Impacts become more extensive all along the southeast South Carolina coast including erosion at area beaches, with limited or no access to docks, piers, and some islands.
7.5 ft
At 7.5 ft MLLW, moderate coastal flooding occurs. In Downtown Charleston, additional impacted roads include HW-17 at HW-61, Market Street, East Bay, Rutledge, and areas around MUSC. Other impacted areas include Long Point Road near Palmetto Islands County Park, locations around the Naval Complex, 12th and 15th Streets on Isle of Palms, and the road leading to Bohicket Marina on Seabrook Island. In Beaufort County, flooding will impact Hunting Island and the Sea Island Parkway near Chowan Creek Bridge.
7 ft
At 7.0 ft MLLW, minor coastal flooding typically begins. Minor flooding on roadways around Downtown Charleston occurs, possibly including Lockwood Drive, Wentworth and Barre, Fishburne and Hagood, and Morrison Drive. As the tide height approaches 7.5 ft MLLW, roads can become impassable and closed. Other impacts outside of Downtown Charleston include minor flooding of low-lying locations near area beaches including Isle of Palms, Sullivan's Island, Folly Beach, Kiawah Island, and Edisto Island.
Impact statements from the National Weather Service, describing what typically happens at each water level.
Low-Water Impacts
-1.5 ft
At -1.5 ft MLLW, very low water levels will occur along the southeast South Carolina coast. This could cause navigation issues along the coast including tidal creeks, inlets, and in marsh areas. Also, areas that are normally under water could be exposed.
What happens as water levels drop, per the National Weather Service.
7-Day Water Level Chart
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Historic Crests
| Date | Stage | Flow |
|---|---|---|
| Sep 21, 1989 | 12.52 ft | — |
| Sep 21, 1989 | 12.52 ft | — |
| Aug 10, 1940 | 10.23 ft | — |
| Aug 10, 1940 | 10.23 ft | — |
| Sep 10, 2017 | 9.92 ft | — |
About This Gauge
NWS LID
CHTS1
River
Cooper River
County
Charleston, SC
Coordinates
32.7750°N, 79.9240°W
Get Flood Alerts for Cooper River
StormCast monitors this gauge and sends a push notification to your phone when the water level crosses into a new flood category — even at 3 AM.
Frequently Asked Questions
What is the current water level of Cooper River at Charleston Harbor (IN MLLW)?
The Cooper River at Charleston Harbor (IN MLLW) gauge is maintained by USGS and reports water levels every 15 minutes. Visit this page to see the latest reading updated live, or download StormCast to get push alerts when levels rise.
What is flood stage for Cooper River at Charleston Harbor (IN MLLW)?
The NWS-defined flood stage for Cooper River at Charleston Harbor (IN MLLW) is 7 feet. Action stage begins at 6.5 feet. Moderate flooding starts at 7.5 feet, and major flooding at 8 feet.
How do I get alerts when Cooper River rises?
Download StormCast free on Google Play, go to River Gauges, and add Cooper River at Charleston Harbor (IN MLLW) to your watchlist. StormCast will send a push notification to your phone whenever the water level crosses into a new NWS flood category — even when your screen is off.
Where is the Cooper River at Charleston Harbor (IN MLLW) gauge located?
The gauge is located in Charleston County, South Carolina at coordinates 32.7750°N, 79.9240°W. Data is provided by the U.S. Geological Survey and the National Weather Service.
On This River
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Source & Notes
Data provided by: Observations courtesy of NOAA National Ocean Service
- <span style="color: #ff0000;">During a Tropical Storm or Hurricane Watch or Warning, inundation mapping provided by the <span style="background-color: #ffff00;"><a style="color: #ff0000; background-color: #ffff00;" href="https://www.nhc.noaa.gov">National Hurricane Center</a></span> (go to the web site and select the storm of interest) reflects a reasonable worst case scenario. The forecast above is the total water forecast that is most likely to occur.</span>