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Hydrograph River at a Glance Download
St. Marks River at St. Marks (in MHHW) Tide Height (ft)Forecast: -2.4 ft 1:00AM Jul 16, 2019Forecast: -1.6 ft 2:00AM Jul 16, 2019Forecast: -0.97 ft 3:00AM Jul 16, 2019Forecast: -0.73 ft 4:00AM Jul 16, 2019Forecast: -0.9 ft 5:00AM Jul 16, 2019Forecast: -1.24 ft 6:00AM Jul 16, 2019Forecast: -1.63 ft 7:00AM Jul 16, 2019Forecast: -2.05 ft 8:00AM Jul 16, 2019Forecast: -2.01 ft 9:00AM Jul 16, 2019Forecast: -1.94 ft 10:00AM Jul 16, 2019Forecast: -1.6 ft 11:00AM Jul 16, 2019Forecast: -1.18 ft 12:00PM Jul 16, 2019Forecast: -0.71 ft 1:00PM Jul 16, 2019Forecast: -0.38 ft 2:00PM Jul 16, 2019Forecast: -0.12 ft 3:00PM Jul 16, 2019Forecast: -0.27 ft 4:00PM Jul 16, 2019Forecast: -0.7 ft 5:00PM Jul 16, 2019Forecast: -1.37 ft 6:00PM Jul 16, 2019Forecast: -2.16 ft 7:00PM Jul 16, 2019Forecast: -2.96 ft 8:00PM Jul 16, 2019Forecast: -3.6 ft 9:00PM Jul 16, 2019Forecast: -3.98 ft 10:00PM Jul 16, 2019Forecast: -4.1 ft 11:00PM Jul 16, 2019Forecast: -3.67 ft 12:00AM Jul 17, 2019Forecast: -2.99 ft 1:00AM Jul 17, 2019Forecast: -2.1 ft 2:00AM Jul 17, 2019Forecast: -1.27 ft 3:00AM Jul 17, 2019Forecast: -0.79 ft 4:00AM Jul 17, 2019Forecast: -0.71 ft 5:00AM Jul 17, 2019Forecast: -0.89 ft 6:00AM Jul 17, 2019Forecast: -1.31 ft 7:00AM Jul 17, 2019Forecast: -1.73 ft 8:00AM Jul 17, 2019Forecast: -2.03 ft 9:00AM Jul 17, 2019Forecast: -2.13 ft 10:00AM Jul 17, 2019Forecast: -1.95 ft 11:00AM Jul 17, 2019Forecast: -1.5 ft 12:00PM Jul 17, 2019Forecast: -0.89 ft 1:00PM Jul 17, 2019Forecast: -0.32 ft 2:00PM Jul 17, 2019Forecast: 0.14 ft 3:00PM Jul 17, 2019Highest Forecast: 0.17 ft 4:00PM Jul 17, 2019Forecast: -0.01 ft 5:00PM Jul 17, 2019Forecast: -0.55 ft 6:00PM Jul 17, 2019Forecast: -1.28 ft 7:00PM Jul 17, 2019Forecast: -2.09 ft 8:00PM Jul 17, 2019Forecast: -2.92 ft 9:00PM Jul 17, 2019Forecast: -3.46 ft 10:00PM Jul 17, 2019Forecast: -3.88 ft 11:00PM Jul 17, 2019Forecast: -3.8 ft 12:00AM Jul 18, 2019Forecast: -3.3 ft 1:00AM Jul 18, 2019Forecast: -2.44 ft 2:00AM Jul 18, 2019Forecast: -1.58 ft 3:00AM Jul 18, 2019Forecast: -0.99 ft 4:00AM Jul 18, 2019Forecast: -0.7 ft 5:00AM Jul 18, 2019Forecast: -0.87 ft 6:00AM Jul 18, 2019Forecast: -1.25 ft 7:00AM Jul 18, 2019Forecast: -1.73 ft 8:00AM Jul 18, 2019Forecast: -2.24 ft 9:00AM Jul 18, 2019Forecast: -2.59 ft 10:00AM Jul 18, 2019Forecast: -2.6 ft 11:00AM Jul 18, 2019Forecast: -2.29 ft 12:00PM Jul 18, 2019Forecast: -1.73 ft 1:00PM Jul 18, 2019Forecast: -1.09 ft 2:00PM Jul 18, 2019Forecast: -0.46 ft 3:00PM Jul 18, 2019Forecast: -0.13 ft 4:00PM Jul 18, 2019Forecast: -0.14 ft 5:00PM Jul 18, 2019Forecast: -0.54 ft 6:00PM Jul 18, 2019Forecast: -1.28 ft 7:00PM Jul 18, 2019Northwest Florida Water Management DistrictMRKF1 Graph Created (12:21AM Jul 16, 2019)Forecast (issued 3:00PM Jul 15)Flood Stage is 2 ft
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Tabular Data (UTC)
Tabular Data (EDT)
XML Data
RSS Files
Datum: Not Available
NOTE: Water levels are referenced to the Mean Higher High Water (MHHW) Datum. This datum can be used to approximate sea water inundation of normally dry ground near the coast. For specific impacts, please refer to the statements on this page.

NOTE: Gauge reading affected by tides.

NOTE: Forecasts for the St. Marks River at St. Marks (in MHHW) are issued routinely year-round.

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Upstream Gauge - near Newport on Old Magnolia Rd Upstream Gauge
Flood Categories (in feet)
Major Flood Stage: 5.1
Moderate Flood Stage: 3.4
Flood Stage: 2
Action Stage: 1.2
Low Stage (in feet): -5.3

Historic Crests
(1) 8.01 ft on 10/10/2018
(2) 5.08 ft on 09/02/2016
(3) 2.89 ft on 05/28/2018
(4) 2.73 ft on 10/08/2017
(5) 2.72 ft on 06/06/2016
Show More Historic Crests

(P): Preliminary values subject to further review.

Recent Crests
(1) 8.01 ft on 10/10/2018
(2) 2.89 ft on 05/28/2018
(3) 2.73 ft on 10/08/2017
(4) 1.56 ft on 01/22/2017
(5) 5.08 ft on 09/02/2016
Show More Recent Crests

(P): Preliminary values subject to further review.

Low Water Records
Currently none available.

For more information on your flood risk go to

Zoom Level:14
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Gauge LocationGauge Map Marker
Latitude/Longitude Disclaimer: The gauge location shown in the above map is the approximate location based on the latitude/longitude coordinates provided to the NWS by the gauge owner.
Flood Impacts & Photos Collapse
If you notice any errors in the below information, please contact our Webmaster
12.1 Flooding of historic proportions. Most of the town of St. Marks floods up to the second story. Water may extend as far inland as Commerce Blvd east of Woodville Highway. Access to areas south of Bloxham Cutoff and east of the Wakulla River will be impossible.
9.1 Catastrophic flooding south of US-98 between the Wakulla and St Marks Rivers. Riverside portions of St. Marks will be under 7 feet of water with most of the town flooded up to 5 feet of water. Portions of the town of St Marks will be under water up to 7 feet deep. US-98 will flood in numerous spots between the Wakulla and St Marks Rivers restricting access by motor vehicle.
7.1 Access to Purdom Power Plant becomes restricted above this level. Portions of the plant are prone to flooding at this level. On the west bank of the St Marks River above the town of St Marks, homes not elevated will flood at this level as far as 2 miles north of US-98.
5.1 Flood waters inundate much of the town of St Marks south of Sylvania Avenue and Whaley Street. Water depth will be up to 3 feet along portions of Riverside Drive in town.
4.1 Flooding expands across City Park Avenue, affecting residences west of Fire Escape Road. Homes in this area not elevated are prone to flooding. Upstream on the St Marks River, homes on the west bank of the river at St Marks Rivers Edge Road and off Old Plank Road experience flooding in their backyard. Homes and structures in these areas not elevated are subject to flooding above this level.
3.4 Flooding worsens in the town of St Marks. Flood waters extend more than one quarter mile north of town on Port Leon Drive. Flooding begins to surround residences west of City Park Avenue along the Wakulla River. Structures not elevated are prone to flooding.
2.9 Riverside drive floods up to 1 ft deep in spots, affecting businesses near the intersection of Port Leon Drive.
2.4 Old Fort Road is completely flooded. Flooding expands across portions of the San Marcos De Apalachee State Park.
1.9 Water will flood Old Fort Road beyond the boat ramp for a few hundred yards and be several inches deep.
1.4 Water will begin to flood the lower portion of Old Fort Road near the boat ramp.
(1) Downstream view below gauge
(2) Confluence of St Marks River (left) and Wakulla River (right)
(3) Gauge platform south of boat ramp
(4) Upstream view from gauge toward town of St Marks
About This Location Collapse

Latitude: 30.150556° N, Longitude: 84.210556° W, Horizontal Datum: NAD83/WGS84

River Stage
Reference Frame
Gauge Height Flood Stage Uses
NWS stage 0 ft 2 ft Interpreting hydrographs and NWS watch, warnings, and forecasts, and inundation maps
Vertical Datum Elevation
(gauge height = 0)
(gauge height = flood stage)
Elevation information source
NAVD88 1.83 3.83 Survey grade GPS equipment, FEMA flood plain maps, newer USGS topographic maps
NGVD 29 Not Available Not Available Older USGS topographic maps, NGVD29 benchmarks
MSL Not Available Not Available Older USGS topographic maps, MSL benchmarks
Other 0.00 2 Mean Higher High Water - used to approximate inundation
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The National Weather Service prepares its forecasts and other services in collaboration with agencies like the US Geological Survey, US Bureau of Reclamation, US Army Corps of Engineers, Natural Resource Conservation Service, National Park Service, ALERT Users Group, Bureau of Indian Affairs, and many state and local emergency managers across the country. For details, please click here.
NWS Information
National Weather Service
Tallahassee Weather Forecast Office
Love Building FL State University
Tallahassee, FL 32306-4509
(850) 942-8833
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Page last modified: 1-Mar-2019 12:35 AM
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