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Web Portal Changes: The Advanced Hydrologic Prediction Service (AHPS) hosted at will be replaced by the National Water Prediction Service (NWPS), with a target of Spring 2024. Existing AHPS content and features will be preserved and expanded within NWPS. The NWS is now accepting feedback on NWPS. Please visit for more information.

Experimental National Water Center Products: Flood Inundation Mapping services are now available for 10% of the U.S. population. Please visit for more information. The National Hydrologic Discussion, Area Hydrologic Discussion, Flood Hazard Outlook, and real-time geospatial services depicting River Forecast Center and National Water Model forecasts, continue to be accessible via the URL above, as described in the StoryMap here.

DID YOU KNOW... Please try our new TEST hydrograph page link at: - Just replace “abcde” with your local hydrograph five character ID found in the lower left corner of the hydrograph.  In late March of 2024, the base URL path will become  Feedback can be provided HERE

Hydrograph River at a Glance Download
Tugalo River at YONAH DAM Pool (ft)Observed: 743.05 ft at 7:00AM Nov 27, 2023Observed: 743.17 ft at 7:00AM Nov 28, 2023Highest Observation: 743.54 ft at 7:00AM Nov 29, 2023Observed: 743.37 ft at 7:00AM Nov 30, 2023Observed: 743.03 ft at 7:00AM Dec 01, 2023Observed: 743.39 ft at 7:00AM Dec 02, 2023Observed: 743.16 ft at 7:00AM Dec 03, 2023Observed: 743.14 ft at 7:00AM Dec 04, 2023Observed: 743.31 ft at 7:00AM Dec 05, 2023YNHG1(plotting HPIRZ) Graph Created (3:36AM Dec 6, 2023)ObservedLatest observed value: 743.31 ft at 7:00 AM EST 5-Dec-2023. Flood Stage is 748 ft
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Tabular Data (UTC)
Tabular Data (EST)
XML Data
RSS Files
Datum: Not Available
NOTE: Forecasts are not available for the Tugalo River at YONAH DAM. Only observed stages are available for this point.
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Upstream Gauge - at TUGALO DAM Upstream Gauge Downstream Gauge Downstream Gauge - at Hartwell Dam
Flood Categories (in feet)
Major Flood Stage: 758
Moderate Flood Stage: 754
Flood Stage: 748
Action Stage: 744.2
Low Stage (in feet): 0

Historic Crests
(1) 748.70 ft on 01/01/1900
(2) 746.47 ft on 05/30/2018
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(P): Preliminary values subject to further review.

Recent Crests
(1) 746.47 ft on 05/30/2018
(2) 744.84 ft on 12/30/2015
Show More Recent Crests

(P): Preliminary values subject to further review.

Low Water Records
Currently none available.
Zoom Level:16
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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.
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If you notice any errors in the below information, please contact our Webmaster
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Latitude: 34.679722° N, Longitude: 83.330000° W, Horizontal Datum: NAD83/WGS84

River Stage
Reference Frame
Gauge Height Flood Stage Uses
NWS stage 0 ft 748 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 Not Available Not Available Survey grade GPS equipment, FEMA flood plain maps, newer USGS topographic maps
NGVD 29 654.20 Not Available Older USGS topographic maps, NGVD29 benchmarks
MSL Not Available Not Available Older USGS topographic maps, MSL benchmarks
Other Not Available Not Available  
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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
Greenville-Spartanburg Weather Forecast Office
1549 GSP Drive
Greer, SC 29651
(864) 848-3859
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Page last modified: 2-Nov-2020 7:30 PM
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