Great Lakes Water Levels

Great Lakes water levels are continuously monitored by U.S. and Canadian federal agencies in the region through a binational partnership. NOAA-GLERL relies on this water level data to conduct research on components of the regional water budget and to improve predictive models. Water level monitoring stations are operated by NOAA's Center for Operational Oceanographic Products and Services (CO-OPS) and the Department of Fisheries and Oceans' Canadian Hydrographic Service. The U.S. Army Corps of Engineers (Detroit, Chicago, Buffalo) and Environment Canada play crucial roles in research, coordination of data and operational seasonal water level forecasts for the basin.

For more information on particular aspects of Great Lakes Water Levels, use the tabs above:

  • Monitoring Network: learn how Great Lakes water levels are measured
  • Observations: examine current and historical water level conditions
  • Forecasts: seasonal and multi-decadal projections of Great Lakes water levels


Displayed here left to right: Top row - Water level monitoring station (Mackinaw City, MI), Water level forecast image from the NOAA-GLERL AHPS model, Satellite image of the Great Lakes, Bottom row - National Park Service photo, Over-lake evaporation is estimated from flux measurements made at this lighthouse in northern Lake Michigan, Low water levels cause access problems (Michigan Sea Grant, 2013), High water levels cause erosion and threaten property (1985, Lake Michigan)

Contact:

Drew Gronewold, Hydrologist
NOAA/GLERL
4840 S. State Rd.
Ann Arbor, MI 48108-9719

734-741-2444
Tim Hunter, Computer Specialist
NOAA/GLERL
4840 S. State Rd.
Ann Arbor, MI 48108-9719

734-741-2344
Anne Clites, Physical Scientist
NOAA/GLERL
4840 S. State Rd.
Ann Arbor, MI 48108-9719

734-741-2282
Joeseph Smith, General Programmer/Analyst
CILER
4840 S. State Rd.
Ann Arbor, MI 48108-9719

734-741-2252
Additional Federal Agency Contacts for Great Lakes Water Levels

Great Lakes Water Levels Monitoring Network

Great Lakes water levels data constitute one of the longest high quality hydrometeorological data sets in North America with United States' reference gauge records beginning in 1860. Monitoring Great Lakes water levels is an important part of NOAA's mission to understand and predict changes in climate, weather, oceans, and coasts.

Individual Station Data

The map above shows the locations for the 53 NOAA/NOS Center for Operational Oceanographic Products and Services (CO-OPS) water level stations on the Great Lakes and connecting channels (blue squares). These stations record a 3 minute average water level every 6 minutes. The data are also archived in hourly, daily, and monthly averages. To view their data, click on the NOAA/NOS/CO-OPS icon below.

The Canadian Hydrographic Service, part of the Department of Fisheries and Oceans, monitors Great Lakes water levels on the Canadian shoreline at 33 monitoring stations (red squares above). To view their data, click on the DFO/CHS emblem below.



Lake-wide average water levels (1918 - Present)

Lake-wide average levels are used in forecasting models and for monitoring the Great Lakes water budget. The Coordinating Committee on Great Lakes Basic Hydraulic and Hydrologic Data (from here on referred to as the Coordinating Committee), an international advisory group of government agencies, determines which water level stations are used to derive the lake-wide averages. These are shown on the map above. These data are available starting in 1918 because before that time, there were too few gauges to calculate a reasonable lake-wide average.

Lake Superior Lake Michigan-Huron Lake St. Clair Lake Erie Lake Ontario
Duluth, MN Ludington, Mackinaw City, Harbor Beach, MI St. Clair Shores, MI Toledo, Cleveland, Fairport, OH Rochester, Oswego, NY
Marquette C.G., Pt Iroquois, MI Milwaukee, WIBelle River, ON Port Stanley, Port Colborne, ON Port Weller, Toronto, Cobourg, Kingston, ON
Michipicoten, Thunder Bay, ON Thessalon, Tobermory, ON

Network of gauges used to determine lake-wide averages.

Master gauge stations (1860-Present)

Each lake has one water level station that is designated as the master gauge, based on length of record and minimal relative vertical crustal movement. Current master gauge stations are shown on the map above and underlined on the lake-wide average table above.

Great Lakes Water Level Observations

Superior Michigan-Huron St. Clair Erie Ontario

NOAA water level observations are available at specific locations, as described on the Monitoring Network page or as a lake-wide average. These lake-wide averages are based on a select set of U.S. and Canadian station data as determined by the Coordinating Committee. The observation data shown below is from each lake's master gauge.

This map shows the locations of the master gauges for each lake. The charts below show measurements made at the stations. From left to right, the master gauge locations are: Marquette C.G. (Coast Guard), MI (Superior), Harbor Beach, MI (Michigan-Huron), St. Clair Shores, MI (St. Clair), Fairport, OH (Erie), Oswego, NY (Ontario).

Current Levels

The links below reveal plots of daily lake levels (blue) compared with last year's levels (black) and their annual averages (reds). The monthly averages are shown as a step plot through the daily averages. Plotted in the background are the coordinated (official) averages (green), record highs (cyan), and record lows (brown) per month as documented here in meters and here in feet. Daily levels are from each lake's master gauge, produced by NOAA/NOS/CO-OPS.

Superior (at Marquette C.G., MI - 9099018)


Michigan-Huron (at Harbor Beach, MI - 9075014)


St. Clair (at St. Clair Shores, MI - 9034052)


Erie (at Fairport, OH - 9063053)


Ontario (at Oswego, NY - 9052030)


Other Current Level Plots

The following are GIF image versions of the above plots, the daily levels compared with last year's levels:


Additionally, we have GIF image plots of daily levels compared with the per-month max, min, and mean levels:

Water Level Fluctuation on Different Time Scales


The annual rise and fall cycle of water levels visible via the Great Lakes Water Level Dashboard

The water levels of the Great Lakes fluctuate at different time scales to different forces. Very short-term water level changes, viewable in the interactive charts above, are caused by wind and storms. These short-term (hours to days) effects can be dramatic, and can cause the lake levels from one side of the lake to the other to vary by several meters for a short time. Each of the Great Lakes has an annual rise and fall cycle driven by the timing of precipitation, snow melt, and evaporation. In general, the lakes are at their lowest levels in the winter and highest levels in summer or fall. The range in annual rise is from 11 to 20 inches.

Hydrographs

A hydrograph provides a way of seeing seasonal and decadal changes in the flow or discharge of a waterway. The hydrographs for the Great Lakes period of record (starting in 1860 or 1900) illustrate different water regimes over time.

The plots and data files below show the annual average water levels (based on lake-wide averages) for every year as well as the long-term mean level in meters, IGLD85. Click images to enlarge, and click the data link to download the respective plot's numerical data in CSV format.

Information on the CSV data

Each .csv file ('comma-separated-values') contains 1 header line followed by two columns: year, annual average water level (m, IGLD85). Water levels from 1860 through 1917 are from the master gauge. Values for Lake Superior and Lake Erie are adjusted to the outlet using the equation shown to more closely represent a lake-wide average level. Water levels from 1918 to present are lake-wide average levels based on a network of U.S. and Canadian gauges shown here.

Superior

Data
Michigan-Huron

Data
St. Clair

Data
Erie

Data
Ontario

Data

Great Lakes Water Level Forecasts

Official Coordinated Forecasts


From the U.S. Army Corps of Engineers and Environment Canada

There is one official seasonal water level forecast for the Great Lakes, issued jointly by the U.S. Army Corps of Engineers - Detroit District and Environment Canada's Great Lakes-St. Lawrence Regulation Office during the first week of each month. These agencies have operational authority through the International Joint Commission to oversee operation of the control structures on the St. Marys River (Lake Superior outlet; Corps-Detroit) and the St. Lawrence River (Lake Ontario outlet; Corps-Buffalo). Each agency utilizes a number of tools to produce their own 6-month forecast for Great Lakes lake-wide average water levels. They collaborate to issue one joint forecast each month, which is distributed widely. The seasonal forecast is also available on each agency's website:



GLERL AHPS Seasonal Forecast


From the GLERL-AHPS

NOAA GLERL operates a research-oriented forecast model called The Advanced Hydrologic Prediction System. AHPS combines near real-time data with a suite of mathematical models developed at GLERL to simulate the current state of basin hydrology. It runs every day at our lab to predict lake-wide average water levels as well as hydrologic variables for the Great Lakes and Georgian Bay from 1 to 9 months in the future. AHPS is one of the tools used by the Corps of Engineers and Environment Canada each month in their forecast analysis. See NOAA-GLERL's Great Lakes Monthly Hydrologic Data.

Contact:

Drew Gronewold
NOAA/GLERL
4840 S. State Rd.
Ann Arbor, MI 48108-9719

734-741-2444
Tim Hunter
NOAA/GLERL
4840 S. State Rd.
Ann Arbor, MI 48108-9719

734-741-2344


Multi-Decadal Forecasts from Recent Climate Studies


From the GLERL-GLHCD


Long-term projections for future Great Lakes water levels are highly uncertain. Many studies have been published in the past several decades that use global climate models to assess the impact that future climates will have on Great Lakes water levels. Although a thorough understanding of each study will require reading the source material, the Great Lakes Hydro-Climate Dashboard allows us to put these different projections side by side for visual comparison. Open the Legend and Menu through the yellow button, select the research tab, and then the Multi-Decadal Level Forecasts tab to see these forecasts. Recent studies indicate there is little evidence that future water level variability will greatly exceed the historical range.

Contact:

Brent Lofgren
NOAA/GLERL
4840 S. State Rd.
Ann Arbor, MI 48108-9719

734-741-2383


Short-term Water Levels and Meteorology


From the GLERL-GLCFS

If your needs for water level information are more local and real time, a better application is the Great Lakes Coastal Forecast System (GLCFS). This well-documented query tool gives access to both nowcasts and forecasts (up to 5 days) for water levels, wave heights, wind speed, currents, air and water temperature, and ice.


From, respectively, HECWFS and USL.

GLCFS products for specific areas include the Huron to Erie Connecting Waterways Forecasting System (HECWFS) and the Upper St. Lawrence (USL) River forecasting system.

Contact:

Eric Anderson
NOAA/GLERL
4840 S. State Rd.
Ann Arbor, MI 48108-9719

734-741-2293
Greg Lang
NOAA/GLERL
4840 S. State Rd.
Ann Arbor, MI 48108-9719

734-741-2250